Project acronym: WATERBIOTECH

Grant Agreement number: 265972

Project title: Biotechnology for Africa’s sustainable water supply Funding Scheme: KBBE.2010.3.5-02

Deliverable D2.5

Technical and non-technical requirements to overcome the present difficulties faced by the concerned regions

Due date of deliverable: August 31st, 2012

Start date of project: 01.08.2011 Duration: 30 months

Project coordinator: TTZ Bremerhaven, Germany

i

Preliminary Remarks

This report presents the technical and non-technical requirements to be considered in

installing wastewater treatment plants in 7 African countries. They are meant to overcome or

avoid the present difficulties faced in operating and maintaining existing treatment plants in

Algeria, Burkina Faso, Egypt, Ghana, Morocco, Senegal and Tunisia. Technical (e.g. water

treatment and recycling practices know-how, logistics, installation, operation and

maintenance) and non-technical (e.g. institutions, legal framework, financial issues, markets

for recycled water, and environmental and health effects) requirements were defined by BOKU

(Universitaet fuer Bodenkultur Wien, Austria) and CITET (Centre International des

Technologies de l'Environnement de Tunis, Tunisia), respectively, with support of IWMI

(International Water Management Institute, Ghana) as task leader.

Information not specifically referenced in this Report is based on the Information in

Deliverable 2.4 “Evaluation of the existing water biotechnologies and water management

strategies in the targeted countries” (Report) which was previously prepared.

ii

Content

1 Introduction .......................................................................................................................... 1

1.1 Background and motivation .......................................................................................... 1

1.2 Objectives ...................................................................................................................... 1

2 Methodology ......................................................................................................................... 1

2.1 Overview on the concerned regions ............................................................................. 2

2.2 Data acquisition ............................................................................................................. 2

3 Findings from the data survey ............................................................................................... 2

3.1 Data acquisition ............................................................................................................. 2

3.2 Plant size ....................................................................................................................... 3

3.3 Regulations .................................................................................................................... 3

3.4 Overall status in the concerned regions ....................................................................... 3

3.5 Difficulties and challenges faced ................................................................................... 4

3.5.1 Generation ............................................................................................................ 5

3.5.2 Collection ............................................................................................................... 5

3.5.3 Treatment .............................................................................................................. 6

3.5.4 Discharge ............................................................................................................... 6

3.5.5 Reuse ..................................................................................................................... 6

3.5.6 General .................................................................................................................. 7

3.6 Technology related results ............................................................................................ 8

3.6.1 Activated sludge systems ...................................................................................... 9

3.6.2 Pond systems ......................................................................................................... 9

3.6.3 Other systems ..................................................................................................... 10

4 Technical requirements ....................................................................................................... 10

4.1 General remarks and overview ................................................................................... 10

iii

4.2 Technical requirements in detail ................................................................................. 13

4.2.1 Quality of the effluent ......................................................................................... 13

4.2.2 Number of inhabitants ........................................................................................ 15

4.2.3 Aerial footprint (space requirements) ................................................................ 16

4.2.4 Origin and concentration of pollution in wastewater (load characteristics) and treatment versatility ........................................................................................................... 16

4.2.5 Climatology (temperature impacts) .................................................................... 18

4.2.6 Production and quality of generated sludge (excess sludge production) ........... 18

4.2.7 Production of by-products (Resource oriented sanitation) ................................ 19

4.2.8 Complexity of operation and maintenance (O&M) ............................................ 20

4.2.9 Power demand .................................................................................................... 21

5 Non-technical requirements ............................................................................................... 22

5.1 General remarks and overview ................................................................................... 22

5.2 Non-Technical requirements in detail ......................................................................... 23

5.2.1 Legal aspects ....................................................................................................... 23

5.2.2 Management aspects .......................................................................................... 23

5.2.3 Economic aspects ................................................................................................ 24

5.2.4 Social aspects ...................................................................................................... 24

5.2.5 Environmental aspects ........................................................................................ 25

6 Summary and conclusions ................................................................................................... 25

7 References ........................................................................................................................... 27

8 Annexes ............................................................................................................................... 29

8.1 Definition of criteria according to Garfi et al. ............................................................. 30

8.2 Non-technical requirements according to Garfi and Garcia, 2010. ............................ 43

iv

List of Tables

Table 1: Overview on effluent requirements for the main wastewater treatment parameters in

comparison to the EU UWWDT 91/271 EEC. Selected parameters for comparison; secondary

treatment or treatment requirements for receiving water bodies. ............................................. 3

Table 2: Overview on the coverage of water infrastructure in the case study countries. ............ 8

Table 3: Overview on the most common wastewater treatment systems (in operation)

reported from the countries. ........................................................................................................ 8

Table 4: Summary on technical criteria and the related requirements derived from data

analysis. ....................................................................................................................................... 11

Table 5: Overview on treatment performance of standard wastewater treatment technologies.

..................................................................................................................................................... 14

Table 6: Recommended implementation range for different purification technologies. .......... 15

Table 7: Wastewater technology needed according to the level of wastewater contamination

..................................................................................................................................................... 17

Table 8: Classification of technologies according to their capacity of adaptation on daily

fluctuations of wastewater. ........................................................................................................ 17

Table 9: Comparison of excess sludge withdrawal of treatment technologies. ......................... 18

Table 10: Classification of technologies according to the level of stabilization of the generated

sludge .......................................................................................................................................... 19

Table 11: Comparison of technologies according to their complexity in the operation and

maintenance................................................................................................................................ 20

Table 12: Summary on non-technical criteria and the related requirements derived from data

analysis. ....................................................................................................................................... 22

v

List of Figures

Figure 1: Simplified flow scheme of wastewater systems for the summary of survey results. .... 4

Figure 2: The resource oriented sanitation concept (Langergraber and Müllegger, 2005). ....... 19

vi

Acronyms

AS Activated sludge BOD5 5-day biochemical oxygen demand CFU Colony forming unit COD Chemical oxygen demand DW Drinking water EC Escherichia Coli FC Fecal coliforms HACCP Hazard analysis and critical control points HFCW Horizontal flow constructed wetland LA Lagoons / pond systems MBR Membrane bio reactor O&M Operation and maintenance PE Population Equivalent RBC Rotating biological contactor SBR Sequencing batch reactor SS Suspended solids ST Septic tank TC Total coliforms VFCW Vertical flow constructed wetland WP Work package WW Waste water

vii

Executive summary

Biological treatment of wastewater is a proven remediation methodology which has

undergone many improvements over more than five decades. The data survey within

WATERBIOTECH, which concerned 7 countries in total, that is Algeria, Burkina Faso, Egypt,

Ghana, Morocco, Senegal and Tunisia, showed that many of such treatment systems have

been known and used for decades but are not satisfying the current (and future) demands of

the different countries and also cope with high failure rate in some cases. The results showed

that the conditions of Northern and Sub-Saharan Africa imply further technical and non-

technical requirements than under conventional conditions like in Europe. On the other hand,

while the Northern African case study countries showed that water reuse is more and more

important, for Sub-Saharan countries, public health issues come as the first priority.

Eventually, both aspects of public health and reuse (which also finally impacts public health)

have impact on the requirements to be met in order to safely provide an appropriate effluent

quality.

The reasons for failure of technologies or whole systems are manifold. The survey showed that

numerous non-technical aspects, mainly related to management, economic and social factors

influence the operation and maintenance of wastewater treatment plants. Indeed, experience

has confirmed that to achieve successful O&M, a good mix of technology, economic, social,

institutional factors, to keep the efforts as low as possible under the conditions and objectives

given, is required. On the other hand, operation experience of municipal plants showed that

increasing impact from industrial discharge has adverse impact on treatment performance.

Therefore, by implementing treatments that have a lower sensitivity on wastewater quality, it

might be possible to address this issue. Better would be however pretreatment at the

industrial source. Also, in the African context, the power demand of treatment plants has two

aspects: providing low energy processes and energy production. Each side is a matter of

objectives and framework conditions strongly related to O&M. For smaller systems at

decentralized level, low energy is to be favored whereas for large systems, energy production

may be the way to go. Tackling both options at the same time is possible, but seldom.

None of existing technologies can cover all the requirements suggested; they all have strengths

and weaknesses. Efficient or innovative alternative to tackle the issues more effectively have

to support an infrastructure development towards full coverage of wastewater produced and

appropriate treatment which means to carefully consider the challenges of system

implementation (financial, technical, social and operational) as well as risks for use and

discharge. The immense costs of full coverage can only be covered by a step by step approach.

E.g. operational secondary treatment is of higher value than non-operational tertiary

treatment. Small systems should be less regulated than large systems where qualified staff and

resources are available for the operation of a more complex technology. Innovative

alternatives following the HACCP approach (WHO, 2006) may offer options supporting this

strategy, e.g. allowing modular layout with easy upgrade possibility, also where treatment is

not yet perfect.

1

1 Introduction

1.1 Background and motivation

As basis for the knowledge transfer of appropriate innovative biotechnological water

treatment for the different African regions, the knowledge on existing practices is essential.

Further, analyses of experiences with those technologies and systems shall help to identify the

main challenges, problems and drivers for the current situation. In connection with regional

segmentation, WATERBIOTECH wishes to develop suggestions about how to overcome the

difficulties using innovation and best practice. The challenge of this procedure is the

consideration of the different boundary conditions present at large communities, urban, peri-

urban and rural areas with scattered settlements. Further, water and sanitation systems are

subject to transition, especially in the fast growing urban centers of emerging economies and

developing countries. In most countries, not all wastewater is collected (e.g. through sewer

systems) and not all collected wastewater is treated. This situation gives room for further

diversification on existing systems.

Despite the term ‘biotechnology’ is widely referred to high end application of bioprocesses to

pharmacology or medical science, here it refers to all processes for water and wastewater

treatment that use bacteria or other organisms to achieve an improvement of water quality.

Within the following, the technology related aspects have to be seen as a component of water

management from water abstraction until the discharge to receiving environments. Single

technologies may ease the way to overcome difficulties but the whole systems have to be

considered in order to develop sustainable solutions; technological components such as

collection and treatment but also organizational aspects. Beside the definition of technical

requirements, the consideration of non-technical requirements is the basis for sustainable

infrastructure development.

1.2 Objectives

The objective of the definition of technical and non-technical requirements is to provide a

framework to evaluate existing technologies, practices and systems and to identify appropriate

alternatives and improvements. Within WATERBIOTECH, this framework will be applied at two

different stages: 1) for the evaluation of existing practices reported from the partner countries

(Work Package, WP2) and 2) for the identification of innovative solutions to complement,

replace or update existing systems (WP3).

2 Methodology

The development of technical requirements is based on case study experiences under the

conditions reported from Africa. The regional segmentation (D1.1) provides the basis for a

general applicability of the findings. The reported data have been analysed for best practices

but also for challenges and difficulties that lead to unsatisfactory situation.

2

2.1 Overview on the concerned regions

Summary and detailed background information on the case study countries is given in D1.1

‘Regions segmentation and characteristics description’.

2.2 Data acquisition

The survey of the existing water supply and sanitation infrastructure was structured in three

levels to cover all stakeholders involved:

1st Step Questionnaire: Regulators and authorities

Data related to water supply and sanitation, experiences with biotechnologies. This

questionnaire was addressed to ministries and major national agencies, regulatory bodies

(environmental protection agencies, etc.), research institutions, service providers (such as

relevant NGOs, private companies and consultants) and donor organizations within the water

and sanitation sector.

2nd Step Questionnaire: Management and operators

Data related to the functionality of water supply units and wastewater management. This

questionnaire was addressed to water and wastewater treatment plant managers and other

specialists working on the ground.

3rd Step Questionnaire: End-Users

Data on the use of (treated) wastewater. This questionnaire was addressed to treated or

untreated water/wastewater users associations, NGOs and leaders of communities.

3 Findings from the data survey

3.1 Data acquisition

Information coverage and data quality strongly vary over the survey and the

comprehensiveness of the case study findings are depending on the knowledge and willingness

to report information at the different contact points for the questionnaires. Information on

water treatment for drinking water (DW) production is very limited in general;

biotechnological methods for potable water supply (e.g. bio-filtration) are only mentioned at

some points but are not reported as implemented. Slow sand filtration as only biotech system

reported for DW treatment (Ghana). Hence the majority of the data focus on sanitation and

wastewater treatment. Within the reported information different terms and abbreviations are

used for comparable systems. In some cased answers of the questionnaire show that the

function of some system is not fully understood.

3

3.2 Plant size

The information reported in the 1st and 2nd step questionnaires cover a wide range of

wastewater treatment plant size. The results range from small sized plants for single estates

(e.g. Hotels) up to centralized systems covering mayor parts of urban centers.

3.3 Regulations

The regulations on treatment standards and effluent requirements differ over the case study

countries. Strict emission thresholds can be found in some of the countries. Some of them are

even stricter than the emission regulations of the European Union (UWWTD, 1991). In Table 1,

the emission standards on the main wastewater parameters are compared to the Urban

Wastewater Treatment Directive of the European Union.

Table 1: Overview on effluent requirements for the main wastewater treatment parameters in

comparison to the EU UWWDT 91/271 EEC. Selected parameters for comparison; secondary

treatment or treatment requirements for receiving water bodies.

Country COD mg/l BOD mg/l TN mg/l TP mg/l Hygiene CFU/100ml

EU 1 125 25 - - -

EU 2 125 25 15 3 or 10 4 2 3 or 1 4 -

Algeria 90 30 51.5 0.05 FC 2000

Burkina Faso 150 50 - - FC 1000

Egypt 80 40 - - EC 100

Ghana 250 50 - - TC 400

Senegal 100 40 30 10 FC 2000

Tunisia 90 30 30 0.1 FC 2000

Morocco 250 120 - - - 1

For non-sensitive areas and all plant sizes. 2 For sensitive areas and plant size >10,000 PE.

3 For plant size < 100,000 Population Equivalent (PE).

4 For plant size >100,000 PE.

Minimal reduction rates of 91/271 EEC not shown.

It has to be noticed that the limitations of nutrients for effluents to be reused can be contra

productive where agricultural reuse is part of the plan. Also, thresholds for hygienic parameter

for treated domestic effluents that are not reused and not discharged to sensitive receiving

areas (e.g. with nearby DW resources) only imply further treatment costs but do not support

environmental conservation.

3.4 Overall status in the concerned regions

As general outcome, the main difficulties reported in Deliverable 2.4 are in line with the widely

known situation in many African countries:

Insufficient treatment capacity of the existing systems (hydraulic and/or organic overload)

Insufficient coverage by wastewater (collection and) treatment

Mal function of existing systems, especially where run by the public sector

Operation problems due to power shortage

4

Insufficient treatment results compared to design

High costs for investments, maintenance and operation

Limited funds and cost-recovery

Non adequate or non-reinforced legislation, e.g. to regulate informal reuse

Heavy and complicated administrative procedure (for maintenance) in the public sector

Lack of (incentives for) qualified personnel to adjust/modify process when needed

Limited staff number, also in need of training and motivation

Limited political will to address sanitary and environmental issues

Social reject of treated wastewater reuse due to its bad quality (varies regionally)

Lack of control via qualified analytical laboratories

Looking at the information on systems widely implemented the number of different treatment

types mentioned is wide and corresponds to the technologies that are also found in Europe.

The reported technologies are proven since decades:

Technical treatment systems (Biological aerobic and anaerobic)

Natural treatment (Biological aerobic and anaerobic)

Combination of technical and natural systems

When it comes to large scale, i.e. a high share of population coverage the technical diversity is

reduced (3.6). Also the use of some sanitation products, like biogas, compost, struvite, etc. is

limited and not reported at large scale. For water reuse the situation is different: Increasing

agricultural demand and high pressure on fresh water resources impose a need to use treated

wastewater for agriculture. This is the case not only as expected in the North African regions

but also in Sub-Saharan Africa where seasonal water shortage is common.

3.5 Difficulties and challenges faced

In the following, the main system

are analyzed for strengths and weaknesses in

view of related technical and non-technical

requirements. Single results and reports from

countries are not specifically referred to; the

results are summarized as common issues

towards a system based analysis. The

following

Figure 1 shows the system scheme with the technical components that have been investigated and analyzed.

Figure 1: Simplified flow scheme of

5

wastewater systems for the summary of

survey results.

3.5.1 Generation

The wastewater generation underlies a dynamic development in the different case study

countries impacted by economic and demographic developments under the country specific

conditions. Natural resources, settlement structures, population development as well as

growing industry and agriculture impact the water use and hence the production of

wastewater of different quality and quantity. Rural and urban areas show significant

differences as also reported in the literature (Tumwine, 2004; Wilderer, 2004).

According to the type of industry present the discharge to public sewers leads to high loads,

strong load variation (degradable compounds), elevated treatment plant emissions (non-

biodegradable and hardly biodegradable substances) or direct inhibition of biological systems

(toxic substances). These effects are observed at different magnitudes. Reduced water

consumption due to frequent water shortage in comparison to e.g. European countries leads

to lower dilution, hence higher concentrations also from domestic sources and common

blockages.

3.5.2 Collection

The collection system provides urban drainage and the input for the treatment plants. In the

most cases reported, a sewer system provides the core of the wastewater inflow to treatment

plants. Additional septage transport by trucks or other means is also present in some cases.

The hydraulics of collection systems (sewer systems) are often impacted by damages, breaks,

blockage and malfunction of pumping stations. Damages and breaks are reported from

vandalism as well as from aging of networks without proper maintenance and rehabilitation.

Robbery on mechanical equipment has also been reported. Blockages are often a result of

solid waste materials dumped into the sewer systems; common practices where sewer lines

are easily accessible via open drainage channels. Pump operation is impacted by power cuts as

well as by the lack of maintenance or replacement. Reasons for the latter are explained in

3.5.6. Hydraulic malfunction impacts the system as a whole and leads to severe environmental

and health impacts in the worst case.

As mentioned above, the collection system defines the load conditions of the subsequent

treatment. Insufficient capacity of the treatment plant to cope with the delivered load is a

common problem reported. Reasons for that are manifold, but mainly related to: 1) the

increase of wastewater collected, e.g. due to population growth and urban expansion, which

cannot be covered by many (old) treatment plants; 2) the lack of long term treatment capacity

upgrade according to expanding networks due to various (technical and non-technical) reasons

(3.5.6). In case of strong deviation from wastewater collection and treatment capacity, a

substantial part of sewage is released untreated (e.g. Camberene STP, Senegal). Release into

the urban environment is also observed where treatment plants are dysfunctional or

temporarily disconnected, like common in Ghana.

6

Other problems are overload and load variation from industrial discharge to sewer systems

and flooding following heavy rains or consecutive rains. The input of connected facilities is

often not clear in terms of quality (composition, toxic compounds, organics) and quantity (daily

and weekly variations according to production schemes).

3.5.3 Treatment

Following the previous chapter, plants suffering on overload conditions have been reported

frequently. Besides odor generation, discharge limits are not met since the removal rates are

too low to reach the requirements. In some cases the adverse impact of industrial discharges

(e.g. oil) is specifically known to cause operation problems. In some countries, analytical

abilities is limited due to insufficiency of qualified laboratories or high cost of analyses, etc. The

non-compliance to given treatment standards in many cases (for discharge to receiving

environments or for reuse) has various further reasons. One is the strictness of regulations

(see also 3.3) that simply cannot be met by the applied technologies – not even under optimal

conditions (out aged). Many plants are not designed to meet certain (reuse) standards,

upgrade would be necessary. In some cases regulations changed over time but treatment

quality could not be improved to follow demands.

In the same manner as described for sewer networks, insufficient operation and maintenance,

replacement of over aged or broken equipment lead to insufficient removal of pollution.

Complete breakdown of old plants due to lack of maintenance and re-investments are also

reported. Power cuts lead to problems where pumping, aeration and other processes with

energy demand take place. At worst, non-continuous operation of whole or parts of plants was

reported due to power shortage. O&M issues are often connected to financial issues (3.5.6)

that limit the resources that would be necessary to reach optimal system performance.

In a number of cases the plant monitoring (sampling and analyses) is not carried out in a

frequency that allows sound information on the status of the system. As result, plant managers

cannot improve the system performance on a technical basis, even if there would be technical

control means.

3.5.4 Discharge

To summarize, the results for discharge related issues concern the direct impact on public

health and environment. Two aspects of wastewater treatment are the main issues:

insufficient effluent quality and inappropriate excess sludge disposal. Depending on the type of

receiving environment, ocean, surface and groundwater contaminations have been reported

as outcome. Water borne diseases are likely to follow inappropriate disposal of wastewaters,

which is especially of concern in the Sub-Saharan region.

3.5.5 Reuse

Reuse challenges are observed preferably in the case study countries of North Africa but are

also an issue in the Sub-Saharan regions. Comparable to standards for discharges to receiving

water bodies, reuse standards shall compile risk management in a practicable form. Referring

7

to the multiple problems of treatment operation stated above, insufficient treatment for reuse

is often observed and poses risks to health and environment, especially if alternative risk

reduction options are not in place, as advocated e.g. by WHO (2006). As result, severe impacts

were reported within target countries where insufficiently treated wastewater is applied in

agriculture resulting in plant damage and soil deterioration. On the other hand, reuse

standards are seen as inappropriate to guarantee safety and harmlessness of the reuse.

Political and socio-economic factors such as a lack of awareness on both governance and user

side (farmers) generate unfavorable conditions for reuse. E.g. low tariffs on fresh water and

hence treated wastewater for irrigation limit the possibility to sell treated water and to

generate income for the plant operation (Algeria, Tunisia).

The system of water reuse shows an extended complexity where inappropriate use (unsafe

quality) leads to severe risks on the one hand and non-existing reuse wastes an option for

alternative water sources. Anyway, the complexity requires adapted approaches considering

technical, organizational and governance aspects, like promoted by WHO (2006).

3.5.6 General

General issues cross-linking the experiences from different system components as summarized

above, are often important for a number of problems faced in one system.

Finance: Financial problem arises in all cases. It affects the installation as well as the

operation of treatment plants. In Morocco for example, construction of some treatment

plants could not be achieved. On the other hand, limited budgets for wastewater running

operation linked with high energy cost can lead to insufficient maintenance. Low wages

and limited number of staff are also mentioned.

Several challenges are mentioned, in connection with tariffs and cost coverage. They

include insufficient/inappropriate cost recovery, social barriers to reuse, lack of staff

incentives, etc. In general, cost recovery from reuse is too low to cover even the operating

costs of the added irrigation components, leading to dependency on foreign aid and

governmental support. Exceptions can be treatment systems generating energy (Evans et

al., 2012).

Management: Differences can be observed, depending on the nature of the operators

(public, private, domestic or industrial). In the public sector, for wastewater plant

construction, there does not seem to be a clear strategic planning taking into

consideration urbanization and living standard development for the maintenance and

operation of the treatment plants. For example, day to day maintenance of treatment

plants always faced two main problems: heavy administrative procedure for maintenance

and lack of short-term maintenance planning (e.g. in many cases no spare parts available

or easily accessible). Local capacities for overall planning (long term, midterm, project

planning) are also limited.

Personnel: Workers in charge of treatment plants lack the full capacity to maintain them.

The insufficiency of staff number is also mentioned in some cases. Personnel staff is not

motivated/encouraged to maintain treatment plants, especially in the public sector.

8

Income generation (e.g. from reuse): In principle, wastewater reuse provides a means for

income generation. However, in some countries, low quality of treated wastewater or

restrictive legislation does not allow treatment plants to benefit from the reuse. Low

freshwater tariffs were mentioned above.

3.6 Technology related results

Sanitation coverage (with improved toilet systems) does not imply coverage in terms of

wastewater collection (sewer connection rates), and sewer connections also not wastewater

treatment. Table 2 compares the coverage for the case study countries to show the significant

discrepancies that exist on this issue.

Table 2: Overview on the coverage of water infrastructure in the case study countries.

Country Water supply1 (%) Sanitation1 % WW Treatment2 (%)

Algeria 83 95 58

Burkina Faso 76 11 n.a.

Egypt 99 94 80

Ghana 82 13 n.a. (<5%)

Morocco 81 69 12

Senegal 69 51 n.a.

Tunisia 94 85 87 1Improved, according to JMP (2010) for the total population.

2Secondary treatment level.

As most of the treatment plants are activated sludge (AS) systems, pond systems or related

treatment types, the results of the survey will be analyzed for those two main types. Table 3

gives an overview on the most common wastewater treatment technologies in these

countries.

Table 3: Overview on the most common wastewater treatment systems (in operation) reported

from the countries.

Country 1st 2nd 3rd

Algeria Ponds 55% Activated Sludge 45% -

Burkina Faso Ponds only - -

Egypt Activated Sludge 85% Ponds Others

Ghana Ponds 53% Activated Sludge 33% Anaerobic digesters 13%

Senegal Activated Sludge Ponds Others

Morocco Ponds 90% Activated Sludge 5% Others

Tunisia Activated Sludge 82% Ponds 13% Others

Anaerobic digestion for biogas production and electricity generation from excess sludge or co-

digestion is very rarely found although the potential for anaerobic technologies might be high.

A lack of understanding of the requirements in AS plants for biogas production might be a

reason. AS plants with energy generation have been reported from Egypt and Senegal. Many

of the described plants are very old, mostly activated sludge. In the Sub-Saharan countries AS

systems are applied mostly by private entities (industry, hotels) where the North African

9

countries show a wider application at large scale. Combinations of treatment systems

(polishing and tertiary treatment) rarely exist. Due to relatively per capita water consumption,

all plant types have to deal high organics and nutrient concentrations.

As discussed above, the technologies have to be analyzed in a system context. The results

show that many difficulties are of general nature (like lack of staff motivation) and not related

to technology types, where some of the issues are prolonged more for specific technologies

(e.g. energy demand).

3.6.1 Activated sludge systems

Beside Burkina Faso, all countries reported a more or less wide spread use of activated sludge

systems. As biological treatment system which uses suspended sludge as core element,

tertiary treatment can be reached (N and P removal). The basic configuration is the single

stage AS system with sedimentation for the biomass separation. The microbiological basics for

the process design is well understood (Wentzel et al., 1997; Henze et al. 2001). The system

design depends on the treatment objectives, and various guidelines are available (ATV, 2000;

Metcalf and Eddy, 2003; WEF, 2010). Mechanical pre-treatment is mandatory for all

configuration types. For the application in warm climates, the differences in the bio kinetics

have to be considered when applying design guidelines for successful implementation (Walder

et al., 2012, Cao et al., 2008).

According to plant design, multiple stage systems, in combination with anaerobic digestion

and side stream treatment units, are state of the art allowing energy positive operation. In the

following the basic configuration is considered for analyses. Generally summarized,

experiences and opinions reported to be directly related to activated sludge systems are:

Need a lot of energy

Produce a big amount of sewage sludge that has to be transported and disposed

Need high O&M efforts

Are expensive

Need spare parts that have to be imported

Require low footprints

Generate odours

Are prone to power cuts, vandalism and robbery

Sequencing batch reactors and membrane bioreactors are strongly related to AS systems,

different in the hydraulic regime and the retention of biomass. Downgraded AS systems are

aerated tanks or ponds, where no control of sludge age (retention time of the active biomass

in the system) is possible.

3.6.2 Pond systems

Pond systems represent a natural extensive treatment technology that is based on the natural

degradation process present in surface water eco systems. The treatment is based on a

10

combination of sedimentation, aerobic and anaerobic degradation by bacteria and nutrient

uptake by algae in pond. The systems can have a number of separated ponds of different size

and depth in series. Artificial aeration may be also possible, representing the transition to

activated sludge. Generally summarized, experiences and opinions reported to be directly

related to pond systems are:

Have high land demand

Are limited in treatment performance (e.g. nitrification)

Have low O&M demand

Cannot handle industrial discharges

Have low energy demand

Have high water evaporation loss which can be favourable but limits reuse (salinity

increase)

3.6.3 Other systems

A number of other treatment systems were mentioned in the reports, whereas they are only

implemented a single projects or at very decentralized level. Constructed wetlands gain

increased attention as alternative to other extensive methods, especially in rural areas. Studies

on the feasibility of wetland systems for developing countries with reuse aspect have been

conducted (Kivaisi, 2001).

4 Technical requirements

4.1 General remarks and overview

Planning and implementation of water and wastewater infrastructure comprises many aspects,

more than technical requirements only. As summarized above, malfunction of systems is

strongly affected by many non-technical issues. Technical requirements may be suggested to

counter the identified challenges on a technical basis, however organizational and financial

issues (section 5) have to be considered in the background of technologies. Existing

technologies may be more or less suitable for a specific requirement. Hence the

appropriateness of a technology has to be analysed based on technical and non-technical

requirements per case. In the following, the technical requirements are related to the input

and output of a system, the most important technical resources for the system (e.g. land and

energy) and the overall objectives of the treatment (e.g. public health).

Garfi et al. (2011) give the technical criteria to be considered for the evaluation of natural

wastewater treatment technologies for small communities as follows:

Technical criteria:

Quality of effluent (according to the receiving environment)

Number of inhabitants

Available land

Origin and concentration of pollution in wastewater

11

Treatment versatility

Climatology

Production and quality of generated sludge

Complexity of the operation and maintenance

The criteria set above can be used as a basis for the elaboration of the new set of technical

requirements. But, to cover also non-natural treatment systems (e.g. activated sludge) at

larger scale (for urban and peri-urban areas) and re-sue aspects, some additional criteria have

to be considered:

Technical criteria

Quality of effluent according to the reuse requirements

Production of beneficial sanitation by products

Power demand

In the following, the survey results summarized above have been categorized according to this

criteria set. Responding to the specific issues identified, technical requirements are suggested.

Table 4 gives and overview. Note that several requirements may conflict each other.

Therefore, an adapted requirement set has to be defined for a specific project, according to its

conditions and objectives, to support decision making on technologies.

Table 4: Summary of technical criteria and related requirements derived from data analysis.

Criteria /Sub-Criteria Requirements Descriptions

Quality of the effluent (treatment performance)

General Compliant to regulations Treatment capacity has to comply with

regulations and has to ensure that no harm is posed to humans and the receiving environment.

Discharge to environment

Low impact on aquatic systems

Low impact on water resources

Reuse Suitable for reuse

Treatment capacity has to prevent adverse impacts on humans, the receiving environment and agricultural production but keeps beneficial constituents (nutrients) for plant uptake.

Number of inhabitants (plant size)

Load capacity Suitable for catchment development

The system has to be able to cope with the amount of current connection load including a certain future increase.

Management capacity Suitable for local capacities

The management and O&M requirements related to the plant size shall be in line with local capacities.

Aerial footprint (space requirements)

12

Criteria /Sub-Criteria Requirements Descriptions

Space availability Low aerial footprint The applied technology shall ensure the required performance at a minimal aerial footprint.

Origin and concentration of pollution in wastewater (load characteristics) and treatment versatility

Industrial impact Suitable for industrial wastewater

The biological treatment system has to be adaptable to cope with pollution characteristics (composition, toxic content) originating from industrial discharges.

Diurnal variation Insensitive to load variations

Defined variations in loads (hydraulics and concentrations) shall not impact the treatment performance.

Pollution concentration Insensitive to high pollution concentrations

The system performance shall not be adversely impacted by high wastewater concentrations.

Climatology (temperature impacts)

Evaporation Low evaporation rates Where the effluent shall be reused, evaporation shall not significantly impact the effluent discharge volume.

Design Adaptable to warm climates

Temperatures have to be a variable input parameter for System design to ensure optimal lay out for the local climate conditions.

Production and quality of generated sludge (excess sludge production)

Quality Sludge safe to use Sludge treatment shall provide a sufficient quality for further use.

Quantity Low sludge production In case of no sludge use option, the volume of produced excess sludge shall be as low as possible.

Disposal Appropriate disposal scheme

The wastewater treatment system has to include a sufficiently dimensioned sludge treatment and disposal that prevents any adverse impact on the surrounding environment.

Production of sanitation by-products (Resource oriented sanitation)

General Safe use of sanitation by-products

In case of available sanitation by products (compost, struvite, etc.), the system has to provide a sufficient quality for the safe handling and to prevent adverse effects on health and environment from agricultural application, unless post-treatment safety measures are in place (WHO 2006).

13

Criteria /Sub-Criteria Requirements Descriptions

General Limited negative impact of technology on health

The technology must not negatively impact on people and workers’ health. Guidelines and Management standards (such as ISO 14001, or HACCP) have to be followed. Preventive measures such as vaccination have to be put in place and suitable working wears have to be available to workers.

Complexity of operation and maintenance (O&M)

Extensive systems Low maintenance efforts

Under limited local capacities extensive treatment systems with low O&M efforts shall be implied.

Intensive systems Automated and external support

In case of complex systems under limited capacities, automation in combination with contractor’s support shall provide proper operation.

Materials and supplies Use of local materials and supplies

Consideration of locally available supplies shall be as high as possible.

Power demand

General Low energy demand Treatment process and control shall be as independent from power supply as possible.

Control Isolated operation If control systems require permanent power, uninterruptable supply has to be provided for SCDAD system.

Process Energy production

For systems with permanent power demand for processing the wastewater, energy production shall be available to cover as much as possible own demand.

4.2 Technical requirements in detail

The results summarized in Table 4 are detailed below. The descriptions and information given

by Garfi et al. (2011) have been adapted and supplemented according to the conditions of the

WP2.

4.2.1 Quality of the effluent

The aim of wastewater treatment is to safeguard public health and conserve environmental

quality of the receiving environment and achieve a good ecological status of water in

accordance with local regulations (Ortega de Miguel et al. 2011).

14

Table 5 shows the quality parameters of effluent according to the technology considered

(modified from Ortega de Miguel et al. 2011).

Table 5: Overview on treatment performance of standard wastewater treatment technologies.

Treatment efficiency

Techno-logy

Treatment Level SS (%) BOD5 (%) COD (%)

NH4 (%) NT (%) PT (%)

ST

primary 50-60

20-30 20-30 - - -

LA

secondary 40-80 75-85 70-80 30-70 40-80 30-60

VFCW

secondary 90-95

85-90 80-90 >95 20-30 20-30

HFCW

secondary with nitrification

90-95 90-95 80-90 60-70 60-70 20-30

SBR

secondary with nitrification OR secondary with elimination of NT

>90 >90 80-90 90-95 80-85 55-65

AS

secondary with nitrification OR secondary with elimination of NT

>90 >90 80-90 90-95 80-85 55-65

RBC

secondary OR secondary with nitrification

85-95 85-95 80-90 60-80 20-35 10-35

MBR

secondary OR secondary with nitrification OR secondary with elimination of NT

>85-95 85-95 80-90 90-95 70-80 20-30

Acronyms Treatment

ST Septic tank

LA Lagoons / pond systems

VFCW Vertical flow constructed wetland

HFCW Horizontal flow constructed wetland

RBC Rotating biological contactor

MBR Membrane bio reactor

15

SBR Sequencing batch reactor

Table 5 shows the range of treatment performance that can be expected from the

technologies for domestic wastewater under appropriate operation conditions. To select a set

of optional technologies the technical requirements have to be considered:

Compliance to local regulations: see comparison in Table 1.

Low impact on aquatic systems: The conversion of ammonium (NH4) to nitrate (NO3) is a

basic requirement (nitrification) to avoid fish toxicity at higher pH. Further, nitrogen and

phosphorus limitation is important to prevent eutrophication with its impact on oxygen

availability for aquatic organisms (Denitrification, P-Removal).

Low impact on water resource: Hygienic contamination of groundwater resources by

effluent discharge is a major concern. Reduction of e.g. bacterial counts by retention or

disinfection has to be ensured.

Reuse: To ensure sustainable reuse, hygienic parameters (e.g. coliforms) and physical-

chemical parameters (e.g. salinity) are important to prevent risks of water borne diseases,

soil deterioration and adverse impacts on plant growth. Suspended solids impact transport

and distribution devices for irrigation water and shall therefore be as low as possible.

For the reuse benefits an evaluation of the sustainability of the total scheme was suggested by

Zhou Chen et al. (2012).

4.2.2 Number of inhabitants

The number of inhabitants suggests the application of different treatment technologies. Table

3 shows recommended implementation range for different technologies of wastewater

treatment (modified from Ortega de Miguel et al. 2011).

Table 6: Recommended implementation range for different purification technologies.

Technology

Range of population equivalents (PE)

50-200 200-500 500-1,000 1,000-2,000 >2,000

ST

LA

VFCW / HFCW

SBR

AS

RBC

The above summary on the recommended implementation shows the principle applicability of

the systems at different levels of size. This is based on technical design limitations (e.g. influent

16

distribution of constructed wetlands). Considering the results of the survey analyses, plant size

has to fit to further conditions. The following technical requirements have been identified

related to the number of inhabitants defining the plant size:

Suitable for catchment development: A catchment (area where a collection system is/ will

be in place) can be served by different sizes and hence numbers of wastewater treatment

systems (level of centralization). This means that a single central plant can be chosen to

serve a whole catchment or that a number of smaller plants serves sub-catchments. This

has a strong impact on the collection system (sewer) and the technology options for the

plant (Table 6). In all cases the plant size has to cover aspects of catchment development:

estimated future increase of inhabitants as well as changes of settlement structure

(urbanization) that require a system transition (increasing level of centralization).

Suitable for local capacities: As size impacts the options for technology choice, the

technology choice strongly impacts the requirements for management, operation and

maintenance of a plant. Hence, the plant size has to be also seen in relation to the local

capacities (human and financial resources) that are available for plant operation. Capacity

building can be foreseen to increase and adapt human resources. For small-scale or rural

communities, the use of local resources and materials is an asset. The use of locally

available materials helps reducing a community’s dependence on outside sources and

often decreases the cost of the technology itself as well as its maintenance (Hazeltine and

Bull, 2003; Murphy et al. 2009). On the other hand, for many areas in developing

countries, small-scale technologies are often the most socially, economically and

environmentally effective way to address sanitation.

4.2.3 Aerial footprint (space requirements)

Available surface area for the implementation of the treatment plant limits the type and the

number of the technology that are potentially applicable. Further properties related to land

requirements are the efforts for excavation (larger is the volume, more expensive and complex

will be the implantation). Rocky soils favour tank installation above ground. The presence of

shallow aquifers or the proximity of vulnerable areas can also limit the implementation of

systems that need deep excavation. The results of the survey yielded the following technical

requirement:

Low aerial footprint: Topographical limitations (e.g. steep hills, mountainous regions) or

the high value of land for settling or agriculture demand a low aerial footprint of the

treatment plant. The concentration of biomass per volume defines the volume and in the

following also the space requirements for biological treatment systems. Technical systems

have a considerable advantage in this point.

4.2.4 Origin and concentration of pollution in wastewater (load characteristics) and

treatment versatility

The quality of wastewater varies from one locality to another and depends on the local

conditions (population, their habits, business and industries input etc.).

17

Table 7 shows a hint on appropriate technology, according to the level of wastewater

contamination (strengths). To assess the biodegradability of wastewater, characterisation of

biological oxygen demand (BOD), as shown below, is not sufficient. For a first evaluation of the

nature of wastewaters the ratio of easily bio degradable matter (more or less BOD) and non-

easily degradable matter (COD) is useful. Domestic wastewaters normally show a COD: BOD

ratio of two.

Table 7: Wastewater technology needed according to the level of wastewater contamination

TYPE OF WASTEWATER

mgBOD5/l

TECHNOLOGIES

Very appropriate

Appropriate Less appropriate

Heavy contamination 350-500 SBR/MBR HFCW/RBC/AS LA/VFCW

Medium contamination 150-350 ALL TREATMENTS ARE ADEQUATE

Weak contamination <150 LA/HFCW/VFCW AS SBR

The capacity of adaptation to the daily fluctuations of flow and concentration of pollutants

(diurnal variation) is pronounced in small populations because of the concentration of activity

in a few hours throughout the day. Table 8 shows the classification of technologies according

to their capacity of adaptation on daily fluctuations of influent. Table 8 shows the capacity of

adaptation to hydraulic load variations of the considered technologies. All these aspects are

related to the setup of the biological treatment process. The microbiological community only

slowly adapts to changed load conditions. The technical design is therefore crucial on the

ability to buffer load variations and to retain treatment capacity under unfavorable conditions.

Table 8: Classification of technologies according to their capacity of adaptation on daily

fluctuations of wastewater.

Adaptation capacity of different technologies on the daily fluctuations of flow and pollutant load

- +

RBC AS/VFCW SBR/HFCW LA

The following technical requirements have been defined to reflect these issues:

Suitable for industrial discharge: Industrial wastewaters differ from domestic sources

according to the type of industry. Wastewater may be of high load, unfavourable nutrient

composition or may contain toxic compounds that may inhibit biological degradation.

Therefore, the selected system has to allow flexible control of the process. This means that

the biological community is supported by tailored supply of oxygen, retention time,

nutrients and micronutrients. Inhibiting compounds have to be removed prior to the

biological step (e.g. sedimentation/precipitation). Wastewater quality impacts the

18

composition of the microbial community (bacterial species) and also, as a result, sludge

settling properties. Alternative biomass retention to avoid sedimentation may be required

(e.g. filtration). Many industrial wastewaters therefore require a complex combination of

physical, chemical and biological treatment technologies, ideally implemented at their

source to limit the costs of domestic wastewater treatment plants and reduce risks.

Insensitive to load variations: The buffer capacity has to be as high as possible. This can be

reached by inherent large volumes (areas) of the main treatment stage or by additional

buffer capacity added. Fixed bed systems (attached biofilm) are less sensitive to changed

conditions in general.

Insensitive to high pollution concentrations: Low water consumption increases the

concentration of organics and nutrients from domestic sources (low dilution). Attached

and suspended systems act differently on that. High load needs more active biomass

available in the system.

4.2.5 Climatology (temperature impacts)

Temperature is an important climatic factor and especially affects biological processes either in

the treatment of waste water or sludge stabilization. Extensive treatments, like constructed

wetlands, have a greater protection against the cold weather while the lagoons are more

vulnerable to cold climate conditions. For the conditions of the WATERBIOTECH target areas,

two other technical requirements are important:

Low evaporation rates: In case of water reuse as final objective after treatment, the

evaporation rates shall be limited. Low open water surface and covered wastewater

storage are options.

Adaptability to warm climates: As mentioned above the temperature impacts the

conversion rated of the microbial communities. Higher temperatures increase the capacity

of bacteria to utilize the wastewater load. The design of the technology must consider this

fact and include the impact of temperature for tank/surface size and layout.

4.2.6 Production and quality of generated sludge (excess sludge production)

Table 9 shows the classification of technologies according to the amount and the frequency of

the withdrawal of generated sludge, while Table 10: Classification of technologies according to

the state of the generated sludge shows the classification of technologies according to the

level of stabilization of the generated sludge. Stabilization of sludge means that degradable

compounds have been mineralized and that there is no further conversion. Stabilized sludge is

not suitable for biogas production. Note that the experience showed that MBR systems do not

result in a significant reduction of excess sludge production in comparison to AS because the

biomass concentration is limited due to the oxygen transfer needed.

Table 9: Comparison of excess sludge withdrawal of treatment technologies.

Amount and frequency of the withdrawal of generated sludge

- +

19

LA VFCW/HFCW RBC AS/MBR SBR

Table 10: Classification of technologies according to the state of the generated sludge

Technology Sludge stabilization

Yes No

ST X

LA X

RBC X

SBR X

MBR X

AS X

Additionally to the statements above, the following technical requirements have to be

considered:

Sludge safe to use: In case of agricultural use of sewage sludge it has to be provided that

no hygienic risk of adverse impact on agriculture is possible unless alternative safety

measures can be implemented like protective clothing and on-farm treatment. Quality

assurance shall consider the content of heavy metals and other trace pollutants. Many

hydrophobic trace contaminants that might be present in industrial sewage adsorb to

sewage sludge, posing a hazard.

Low sludge production: In case of sludge disposal without use, systems with low sludge

production are favoured. Low loaded systems (natural systems) have higher decay rates

(self-degradation of biomass) and yield lower sludge amounts.

Appropriate disposal scheme: Safe sludge treatment and disposal is an important element

of the treatment system. High costs can be arising for sludge dewatering, thickening,

surplus water treatment and transport.

4.2.7 Production of by-products (Resource oriented sanitation)

Resource oriented sanitation aims at the recovery of wastewater constituents beside the sole water fraction, for beneficial application, e.g. in agriculture. Figure 2 shows the principles of resource oriented sanitation as part of the water supply and sanitation systems. Resources oriented systems are gaining more and more attention in developing as well as in developed countries (Otterpohl, 2004).

Figure 2: The resource oriented sanitation

concept (Langergraber and Müllegger,

2005).

20

For decentralized sanitation structures with the option to use sanitation by-products for

gardening, rural or peri-urban agriculture, this is an option to generate additional benefits and

cover O&M costs. Under the given conditions of small scaled agriculture with need of soil

amelioration, nutrient recovery from human wastes may be applicable under the technical

requirement to ensure

Safe use of sanitation by-products: Hygienic quality and maturity of products has to be

guaranteed by appropriate practices (e.g. composting, struvite production).

Services have to work safely without adverse impacts on the surrounding environment. Also,

the implemented technology must not negatively impact on people and workers’ health.

Guidelines and Management standards (such as ISO 14001 or HACCP, see also WHO 2006)

have to be followed. Preventive measures such as vaccination have to be put in place and

suitable working wears have to be available to workers. One major benefit of treatment plants

is the improvement of sanitation and the decrease in the prevalence of sanitation-related

diseases in the community. Public should be made aware of water, sanitation and hygiene

issues, in connection with the treatment plant. But also where no treatment exist a range of

risk reduction options are available (WHO , 2006; Bos et al., 2012).

4.2.8 Complexity of operation and maintenance (O&M)

Operation and maintenance is the main factor for a stable and effective operation of

wastewater treatment, a properly designed and constructed system presumed. From practical

experience, O&M is more important than the choice between different technologies at

comparable capacity. Table 11 shows the classification of the technologies according to

their complexity.

Table 11: Comparison of technologies according to their complexity in the operation and

maintenance.

Complexity of the operation and maintenance

- +

LA HFCW VFCW RBC, AS SBR MBR

Usually, the operation and maintenance are more complex on intensive technologies than

extensive technologies, by the increased presence of electromechanical equipment while the

extensive often require more extensive workforce. Once again, the technical requirements are

strongly related on the infrastructure layout in terms of level of centralization:

Low maintenance efforts: Low maintenance efforts all always positive, in case of

decentralized systems where limited human and financial resource can be expected this is

21

a crucial factor for the success of treatment implementation. As stated above limited

technical equipment, the use of gravity flow, low monitoring and automated control

devices are needed.

Automated and external support: In case the catchment conditions require more

sophisticated technologies, the use of automated monitoring and control is a way to lower

O&M efforts. A combination of external support (sub-contracted operators) is also

possible for decentralized structures with a number of plants.

Use of local materials and supplies: Finally, to reduce costs and allow fast response in case

of emergency the use local equipment and supplies is important and has to be considered

in project development. Service chains are also important for local business and increase

the sustainability of infrastructures.

4.2.9 Power demand

As last criteria influencing the technical requirements for the sustainable implementation of

wastewater treatment infrastructure under the different African conditions, the demand of

electricity for operations has to be mentioned. There several aspects to be considered.

Electricity may be needed at all system components from wastewater collection and transport

over treatment to discharge of delivery for reuse. The extent depends on the catchment

conditions (e.g. topographies), the selected treatment and reuse objectives (e.g. irrigation

systems). Within treatment the power demand may tackle hydraulics (pumping), processing

(e.g. aeration) and control (monitoring, valves).

Low energy demand: Low energy demand is always a goal for wastewater treatment

(WWT) since significant costs arise from electricity consumption. Natural systems using

gravity flow are the most independent from external energy supplies but also large

centralized technical systems can achieve energy neutral or even energy positive operation

and sell energy to external customers. For technical systems, many new developments aim

on energy optimisation reducing the overall footprint of the plants. Anyway, the conditions

of energy supply in terms of availability (duration, costs) are a baseline for systems

selection. Innovative biological systems (e.g. de-ammonification, bio augmentation) may

be applied to lower the oxygen demand of aerobic suspended systems.

Isolated operation: When permanent and reliable power supply is not provided by public

grit, the system has to be able to operate isolated. If a monitoring and control system is

necessary power cuts have to be bridged by puffers. Limited demand for pumping can be

provided by photovoltaic systems.

Energy production: Anaerobic treatment systems are able to generate biogas from

digestion that might be used for the production of electric and thermal energy. For large

plants with considerable formation of excess sludge, a maximum of conversion of COD to

biogas is favourable. For this, as much COD possible shall be incorporated into the sludge

to guaranty high organics’ content (high load systems). Co-fermentation is a further option

to increase biogas yield for a better energy balance of the system.

Energy management is nowadays a big issue and should be a component of project

development. For existing plants there are guidelines how to develop improvement strategies

22

to decrease the energy demand, costs and to increase efficiency. In developed countries,

energy costs are the second most important cost factor after expenses for personnel (EPA,

2010).

5 Non-technical requirements

5.1 General remarks and overview

In general, when talking about implementation of new technologies, one tends to mainly

focuses on evaluating whether the technology proposed is technically appropriate. Non-

technical requirement for the implementation of water treatment are all aspects which are

complementary to technical aspects and which ensure the sustainability of the functioning of

water treatment plant in urban or rural area (Garfi and Garcia, 2010). The non-technical

requirements are described in table 12.

Table 12: Summary of non-technical criteria and related requirements derived from data

analysis.

Criteria /Sub-Criteria Requirements Descriptions

1. Legal Regulation

Regulations shall be in reasonable connection to technical efforts (costs, complexity, power demand, etc.) that are needed to reach them and to the capacity of the authorities that shall enforce them.

High accountability Institution and staff must become accountable for avoidable failures or mismanagements of treatment plants.

2. Management

High political will At a national level, there must be a clear will to give sanitation an appropriate attention.

High institutional will

Within the institution, there must be a clear will to give sanitation an appropriate attention. This can be translated in a low response time (e.g. when a repair request is made) and by the existence of incentives for performing staff.

3. Economic

Proper budget planning Money O&M must be included in the budget.

Clear funding streams

A guideline has to be elaborated describing procedures to follow and funding sources. Sound concept of tariffs and high collection rates (if applicable) are essential.

Appropriate personnel

Staff working in wastewater plants has to be motivated with good salaries and good social climate. Sufficient number of workers and appropriate expertise

23

Criteria /Sub-Criteria Requirements Descriptions

are also needed.

4. Social

Social acceptance of the technology

Concerned people and end-users of reused water must be comfortable with the technology to put in place.

Social understanding and expectance of the technology

People must know the limitations of the technology and have reasonable expectance towards its efficiency.

5. Environmental Low nuisances

The technology must not be a non-reasonable source of odours and noise.

Good landscape integration

The technology must not be detrimental to the landscape and tourism.

5.2 Non-Technical requirements in detail

5.2.1 Legal aspects

All investigated countries appear to have regulations in place. However, not all regulations of

these countries can be considered reasonable. In many cases, international guidelines are

adopted directly, not taking into consideration local conditions or recognising each country’s

singularities. Instead, expectations, i.e. in connection to technical efforts (costs, complexity,

power demand, etc.) that are needed to meet them and the capacity of the authorities that

shall enforce them, should instead be realistic. For example, small scale units with less capacity

should be covered by less stringent legal requirements. Such a step by step approach would

help moving towards more and more stringent standards.

In addition to updating of legislation for protection of the quality of water resources in the

environmental and public health development of all countries, reinforcement of regulations is

a crucial point. Monitoring requirements (e.g. identification of control parameters and

frequency of measurement) must be defined and adequate to allow proper statistical

interpretation of results. Under the previously mentioned conditions, entities (and their staff)

in charge of the treatment plants must become accountable for serious failures and

mismanagements of the treatment plant. An efficient implementation of standards must go in

parallel with the development, in environmental control agencies, of the institutional

framework necessary for monitoring, controlling, regulating and enforcing the standards. So

far, in many countries the health and environmental agencies, in charge of control and

reinforcement of legislation, are not adequately structured or sufficiently equipped, leading to

a poor control of the various actors of the sanitation sector.

5.2.2 Management aspects

In some African countries, there is a limited political will to give wastewater the appropriate

treatment. Nevertheless, installation, operation and maintenance of treatment plants require

high financial commitments. Without a proper will to operate and maintain the system after its

installation, treatment plants are designed for failure. On the other hand, implementation of

24

new technologies usually face strong barriers as people may desire to be cautious. In Tunisia, it

was reported that despite complains that activated sludge systems are highly energy

demanding, this technology is still selected for new projects although other more appropriate

technologies may fit in some cases.

The same high will must exist within the institution in charge of maintaining the treatment

plant. Low institutional and political will be translated by heavy administrative procedures

which can contribute to increase the response time when a problem is created. Experience has

confirmed that this can contribute to worsening maintenance problem and increase adverse

social and environmental effects. Instead, clear structures and responsibilities, with a budget

assigned to operation and maintenance as well as re-investment, must be in place.

Cross financing of other sectors by water or wastewater tariffs collected must not be allowed.

Staff needs incentive systems for high performance. Employment contracts of the public sector

which are on life-time basis are contra-productive.

5.2.3 Economic aspects

The entity in charge of the treatment plant must regularly (e.g. once a year) plan a proper

budget to cover all expenses that could arise from maintenance and monitoring of treatment

plant. The ways through which this budget will be covered must be clearly identified and fast

when needed. Funding streams may be diverse: through tariffs paid by the population

themselves, subsidies, reuse benefits, etc. Ideally, a plan must also be developed for the long-

term replacement or rehabilitation of the facility.

Cost of implementation of a technology must not be the only factor to be considered for its

selection. Instead, cost of operation and maintenance and other long-term implications must

be factored in the design from the beginning. The costing of the project must take into account

the capacity of beneficiaries to pay for the service provided by the technologies. Sound

concept of tariffs (prices for direct and indirect discharge for domestic and industrial users)

must be designed. Connection of wastewater tariffs to water tariffs can be considered an

option. Tariffs should match the willingness and ability to pay of the users of the technology

and be recovered in a timely manner (Murphy et al. 2009). In general, households should not

have to invest more than 5% of their income for water services (Al-Ghuraiz and Enshassi,

2005).

The implementation of a project must not accentuate differences within the community.

Indeed, implementation of a new treatment plant must not immeasurably improve the income

of some beneficiaries only. Such situation could create social conflicts (Hazeltine and Bull,

2003). Even if employment of local staff is to be preferred, they must receive appropriate

wages to be motivated/dedicated to maintain the treatment plant. Required expertise must be

available and if not, capacity building must be undertaken regularly.

5.2.4 Social aspects

The general social aspects focus on evaluating whether solutions have a positive social impact

on communities. Social acceptance and understanding of technology are keys to successful

25

operation of a technology. It is necessary to actively involve the key stakeholders who may be

affected by the project (neighbouring inhabitants, people connected to treatment plants) at all

steps of the implementation and management. Local participation will contribute to

acceptance of the technology and create an enabling environment for its day-to-day

maintenance. Understanding of the technology may facilitate acceptance of the community

when adverse impacts (e.g. odours) are punctually generated.

On the other hand, social values and cultural changes are likely to influence the type of

technology that is appropriate for a specific country, community, or tribal context. The

technology must consider and respect local customs, which leads to public acceptance of the

technologies and the sustainability and success of projects. It is also important to ensure

access to technology for all members of the local community. Sometimes, rural communities

are constituted by groups of agglomerated households very far to each other. Occasionally,

different groups of people coexist in the same community, such as natives or minority groups.

According to the case, the alternative implemented should involve the whole community to

avoid differences among population.

It can also be beneficial to consider, during the design, components that will be beneficial to

the entire community. Reuse of treated wastewater can address this need.

5.2.5 Environmental aspects

All of the technologies and strategies that are implemented should minimize negative impacts

such as atmospheric emissions, noise, land occupation and effects on the landscape. Indeed,

the new treatment plant must be well integrated in the landscape. This is particularly

important for areas attracting tourists. It must also limit the nuisances to the community and

the environment. Noise is controlled by an indicator that measures the average number of

decibels generated per day. Secondary waste production must be reduced as much as

possible. Atmospheric emissions of odorous compounds, greenhouse gases, etc. are a major

global concern which can influence social acceptance of a technology.

6 Summary and conclusions

Biological wastewater treatment is a proven technology which has undergone many

improvements over more than five decades. Biological organisms removing pollution by

conversion and degradation within growth and respiration is the common element of all types

of those treatment systems. Basically, this is the use of natural life cycles for more or less

technically designed treatment of contaminated waters. Based on the biological core many

different configurations have been developed. Complemented by physical and chemical

techniques, a range of treatment systems is nowadays available. The main types of anaerobic

and aerobic technologies are further dived in attached and suspended systems, combinations

are also frequently implemented.

The data survey within WATERBIOTECH showed that many of the implemented systems are

implemented for decades but many of them are not satisfying even the current demands of

26

the different countries. The survey showed that numerous technical and non-technical aspects

influence the system operation. As to be expected, financial and human capacities have a

major impact, affecting technical performance. Operation and maintenance of system is

crucial, and therefore resulting in the technical requirement to keep the efforts as low as

possible under the conditions and objectives given. Higher treatment efficiency is generally

paid with higher O&M efforts and plant size while insufficient O&M jeopardizes system

performance.

Beside of a number of other technical requirements that are important to counteract the

difficulties present, handling of industrial wastewater and the energy demand are of special

interest. Operation experience of municipal plants showed that increasing impact from

industrial discharge has adverse impact on treatment performance. Here technology may take

a part of the burden by implementing treatments that have a lower sensitivity on wastewater

quality. But in the end this problem has to be tackled by regulation, separating industrial waste

burden from domestic treatment and implementing targeted water treatment for industries.

In the African context, the power demand has two aspects. The first is that in many regions the

public grit is prone to power cuts leading to operation failure at collection, transport

(pumping) and treatment. Secondly, energy costs are a burden for the financial capacities and

lead to operation cuts in the worst case. Technology requirements can tackle these issues at

two lines: providing low energy processes and energy production. Each side is a matter of

objectives and framework conditions and strongly related to O&M. For smaller systems at

decentralized level, low energy is to be favored whereas for large systems, energy production

may be the way to go. Also, tackling both sides at the same plant is possible, but still seldom.

Providing technical requirements only is not sufficient to ensure a successful implementation

and sustainable operation of a wastewater treatment plant. Several non-technical options

have to be considered. They include various management, social, financial environmental and

legal aspects. Technical failures are often a result of poor O&M.

Finally, all existing technologies have strengths and weaknesses. Innovative and efficient

alternative to tackle the issues more effectively are needed to support a step by step

infrastructure development towards full coverage of produced wastewater. Also, regulation

has to carefully consider the challenges of system implementation as well as risks for reuse

and discharge. Small systems should be less regulated than large systems where qualified staff

and resources are available for the operation of a more complex technology. Innovative

alternatives may offer options supporting this strategy, e.g. allowing modular layout with easy

upgrade possibility. Also safety measures can be shared between treatment and non-

treatment options to safeguard public health which allows more flexibility for locally

appropriate reuse (Bos et al., 2012).

27

7 References

Al-Ghuraiz, Y., Enshassi, A. (2005). Ability and willingness to pay for water supply service in the

Gaza Strip. Building and Environment. 40, 1093–1102.

Bos, R. R. Carr and B. Keraita 2012 Assessing and Mitigating Wastewater-Related Health Risks in Low-Income Countries: An Introduction. In: Drechsel, P., C.A. Scott, L. Raschid-Sally, M. Redwood and A. Bahri (eds.) Wastewater irrigation and health: Assessing and mitigation risks in low-income countries. Earthscan-IDRC-IWMI, UK. Cao, Y.S., Wah, Y.L., Ang, C.M., Kandiah, S.R. (2008). Biological Nitrogen Removal Activated

Sludge Process in Warm Climates, Full-scale process investigation, scaled-down laboratory

experimentation and mathematical modeling, IWA Publishing, London.

Chen, Z., Huu Hao Ngo, Wenshan Guo (2012) A critical review on sustainability assessment of recycled water schemes. Science of the Total Environment 426 (2012) 13–31.

Evans, A., Otoo, M., Drechsel, P. (2012). Developing Typologies for Resource Recovery Businesses. Urban Agriculture Magazine Vol 26 (in press).

EPA (2010) Evaluation of Energy Conservation Measures for Wastewater Treatment Facilities.

EPA 832-R-10-005 SEPTEMBER 2010. US Environmental Protection Agency.

European Commission (EC). (1985). Council Directive of 27 June 1985 on the assessment of the

effects of certain public and private projects on the environment (85/337/EEC). European

Commission, Brussels, Belgium.

European Commission (EC). (1999). Guidelines for the Assessment of Indirect and Cumulative

Impacts as well as Impact Interactions. European Commission, Brussels, Belgium.

Garfi, M., and García, J. (2010) Non-technical requirements for implementation of water

treatment technologies. Annex 2.

Garfi, M., García, J., and Neculau, M. (2011) Evaluation criteria for wastewater treatment

technologies assessment. Annex 1.

Hazeltine, B., Bull, C. (2003). Field Guide to Appropriate Technology. Academic Press,

Amsterdam, Netherlands. pp. 874.

Henze, M., Harremoës, P., Jansen, J., Arvin, E. (2002). Wastewater Treatment: Biological and

Chemical Process, 3rd edition, Springer, Berlin Heidelberg, Germany.

Kivaisi, A.K., (2001) The potential for constructed wetlands for wastewater treatment and

reuse in developing countries: a review. Ecological Engineering 16; 545–560.

Langergraber, G., Müllegger, E. (2005): Ecological sanitation - A way to solve global sanitation

problems? Environment International 31(3), 433-444.

Metcalf & Eddy (2003). Wastewater Engineering, Treatment and Reuse, 4th edition, Tata

McGraw-Hill Publishing, USA.

28

Murphy, M. H., McBean, E. A., Farahbakhsh, K. (2009). Appropriate technology – A

comprehensive approach for water and sanitation in the developing world. Technology in

Society 31, 158–167.

Ortega de Miguel, E., Ferrer-Medina, Y., Salas-Rodríguez, J.J., Aragón-Cruz, C. 2011. Manual

para la implantación de sistemas de depuración en pequeñaspoblaciones. Ministerio de Medio

Ambiente y Medio Rural y Marino. p. 455 Madrid, España.

Otterpohl, R., (2004) Options for alternative types of sewerage and treatment systems

directed to improvement of the overall performance. Water Sci Technol. 2002; 45(3):149-58.

Tumwine, J., Thompson, J., Katui-Katua, M., Mujwahuzi, M., Johnstone, N., Porras, I., (2003)

Sanitation and hygiene in urban and rural households in East Africa. Int J Environ Health Res.;

13(2):107-15.

UWWTD (1991) COUNCIL DIRECTIVE of 21May 1991 concerning urban waste water treatment

(91/271/EEC).

Walder, C., Lindtner, S., Proesl, A., Klegraf, F., and Weissenbacher, N., (2012) WWTP design in

warm climates – guideline comparison and parameter adaptation for a full scale activated

sludge plant using mass balancing. Water Science and Technology (accepted).

WEF (2010) MOP 8: Design of Municipal Wastewater Treatment Plants . 5th Edition. WEF

Manual of Practice No. 8. ASCE Manuals and Reports on Engineering Practice No. 76, Water

Environment Federation, Alexandria, VA, U.S.A.

Wentzel, M.C., and Ekama, G.A., (1997) Principles in the Design of Single-Sludge Activated-

Sludge Systems for Biological Removal of Carbon, Nitrogen, and Phosphorus. Water

Environment Research. Vol. 69, No. 7 (1997), pp. 1222-1231.

Wilderer, P.A., (2004) Applying sustainable water management concepts in rural and urban

areas: some thoughts about reasons, means and needs. Water Sci Technol.; 49(7):8-16.

Review.

World Health Organization (WHO). 2006. WHO guidelines for the safe use of wastewater,

excreta and greywater, Vol. II: wastewater use in agriculture. Geneva: World Health

Organization.

World Health Organization (WHO). (2009). The World Health Report 2008 - primary Health

Care (Now More Than Ever). Available at: http://www.who.int/whr/2008/en/index.html

(accessed 11 December 2010).

29

8 Annexes

30

8.1 Definition of criteria according to Garfi et al. 2011

GEMMA - Group of Environmental Engineering and Microbiology

Universitat Politècnica de Catalunya.BarcelonaTech (UPC)

EVALUATION CRITERIA FOR

WASTEWATER TREATMENT

TECHNOLOGIES ASSESSMENT

Ph.D Marianna Garfí, Ph.D Joan García and MSc. Marinela Neculau

1

INTRODUCTION ............................................................................................................................. 2

EVALUATION CRITERIA FOR THE SELECTION OF WASTEWATER TREATMENT BIOTECHNOLOGIES3

TECHNICAL CRITERIA ................................................................................................................. 4

ENVIRONMENTAL CRITERIA ...................................................................................................... 9

SOCIAL CRITERIA ...................................................................................................................... 10

ECONOMIC CRITERIA ............................................................................................................... 12

CONCLUSIONS ......................................................................................................................... 13

2

INTRODUCTION

Multicriteria analysis (MCA) is a flexible and multidisciplinary tool which ranks or

scores a finite number of options on the basis of a set of evaluation criteria (Keeney &

Raiffa 1976; Nijkamp et al. 1990; Saaty 1994; Malczewski 1997; Wilson et al. 2004). In

particular, it is able to solve water and sanitation decision problems which are typically

guided by multiple objectives and which are complex and dynamic in nature (Gough &

Ward 1996; Hajkowicz & Higgins 2008; Hamouda et al. 2009). Due to its flexibility,

MCA has been used to solve water and sanitation problems in industrialized, rural,

developed or developing contexts (Mohanty 1992; Chen et al. 2006; Riesgo & Gomez-

Limon 2006; Gomez-Lopez et al. 2009). Specifically, it is considered an appropriate

assessment method for projects that aim to improve basic needs in developing countries

(Mohanty 1992; Cherni et al. 2007; Garfí et al. 2009; Balana et al. 20I0; Garfí et al.

20II). MCA can consider multiple social, environmental and economic criteria that may

have different units (Hajkowicz & Collins 2007) and could include qualitative and/or

quantitative aspects of the problem in the decisionmaking process (Wilson et al. 2004).

The outcomes are often highly intangible and may include items such as biodiversity,

recreation, scenery and human health. These characteristics of water and sanitation

planning decisions make MCA an attractive approach (Hajkowicz & Higgins 2008).

The selection of criteria to evaluate alternatives is the key decision in MCA as it is

essential to effective assessment. In all these projects general criteria including socio-

economic, environmental and basic technological objectives, must be considered.

Moreover, as there are different kinds of water and sanitation projects (water supply,

water treatment and basic sanitation) which involve using different technologies,

specific criteria are needed too.

The aim of this document is to propose a comprehensive list of performance criteria to

evaluate natural wastewater treatment technologies for small communities.

3

EVALUATION CRITERIA FOR THE SELECTION OF WASTEWATER TREATMENT BIOTECHNOLOGIES

The technical, environmental, social and economic criteria to be considered for the

evaluation of natural wastewater treatment technologies for small communities are:

Technical criteria

Quality of effluent (according to the receiving environment) (T1)

Number of inhabitants (T2)

Available land (T3)

Origin and concentration of pollution in wastewater (T4)

Treatment versatility (T5)

Climatology (T6)

Production and quality of generated sludge (T7)

Complexity of the operation and maintenance (T8)

(Ortega de Miguel et al. 2011)

Environmental criteria

Production of odours (En1)

Noise generation (En2)

Landscape integration (En3)

(Ortega de Miguel et al. 2011)

Social criteria

Local participation and access (S1)

Local culture (S2)

Equality (S3)

Health (S4)

Standard of living (S5)

(Ortega de Miguel et al. 2011)

Economic criteria

Exploitation costs (E1)

Implantation costs (E2)

(Ortega de Miguel et al. 2011)

4

TECHNICAL CRITERIA

The technical aspects mainly focus on evaluating whether the technology proposed in

each alternative is appropriate. The concept of appropriate technologies was introduced

in the 1970s as a technique for development work that addresses the issues of poverty,

social equity, employment, and basic human needs (Schumacher 1973).

The term has been transformed numerous times since its emergence (Ranis 1980; Ntim

1988; Hazeltine & Bull 2003; Kaplinsky 2010). Today, the definition is more loosely

presented, and it has evolved as a concept opposed to a rigid definition that outlines

specific requirements for a technology to be deemed appropriate (Murphy et al. 2009).

Normally, small villages in developing countries are isolated and far from large natural

or technical central sources of fresh water, pipelines and sanitation systems. In these

cases small-scale, de-centralized, low-cost water and sanitation systems are needed

(Faillace 1990; Rheinlander & Grater 2001).

To facilitate the understanding of the points developed, in the Table 1 is the lists with

the abbreviations that relate what type of technology are considered (Ortega de Miguel

et al. 2011).

Table 1. Acronyms used for wastewater treatment technologies

Treatment Acronyms

SEPTIC TANK ST

LAGOONS LA

VERTICAL FLOW CONSTRUCTED WETLAND VFCW

HORIZONTAL FLOW CONSTRUCTED WETLAND HFCW

ROTATING BIOLOGICAL CONTACTOR RBC

MEMBRANE BIO REACTOR MBR

SEQUENCING BATCH REACTOR SBR

Technical criteria includes eight sub-criteria:

Required quality of effluent according to the receiving environment (T1)

The aim of wastewater treatment is to prevent the deterioration of environmental

quality of the receiving environment and achieve a good ecological status of water

masses in accordance with the regulations (Ortega de Miguel et al. 2011). Table 2

shows the quality parameters of effluent according to the technology considered

(Ortega de Miguel et al. 2011). In practice, if the discharge occurs in normal

areas requires a primary or secondary treatment (removal of the organic

material and the containing of suspended solids) (Ortega de Miguel et al. 2011).

5

Table 2. Effluent characteristics according to wastewater treatment technologies

Effluent

characteristics

Technology Treatment Level

SS

(%)

DBO5(%)

DQO(%)

N-NH4

(%)

NT(%)

PT(%)

ST

primary

50-

60

20-30

20-30

-

-

-

LA

secondary

(except

for the SS1)

40-

80

75-85

70-80

30-70

40-80

30-60

VFCW

secondary

90-

95

85-90

80-90

20-25

20-30

20-30

HFCW

secondary with

nitrification

90-

95

90-95

80-90

60-70

60-70

20-30

SBR

secondary with

nitrification OR

secondary with

elimination of

NT

>90

>90

80-90

90-95

80-85

55-65

RBC

secondary OR

secondary with

nitrification2

85-

95

85-95

80-90

60-80

20-35

10-35

MBR

secondary OR

secondary with

nitrification OR

secondary with

elimination of

NT5

85-

95

85-95

80-90

90-95

70-80

20-30

1 - Is not a filtered sample

2- The process achieves one or other level of treatment

Number of inhabitants (T2)

The number of inhabitants suggests the application of different treatment technologies.

Table 3 shows the recommended implementation range for different wastewater

treatment technologies (Ortega de Miguel et al. 2011).

6

Table 3. Recommended implementation range for different purification technologies

Technology Range of population

50-200 200-500 500-1.000 1.000-2.000

ST

LA

VFCW and

HFCW

SBR

RBC

Surface area and characteristics of the available land for

construction of treatment technologies (T3)

Available surface area for the implantation of the treatment plant limits the type and the

number of the technology that are potentially applicable.

The characteristics of the land might include (Ortega de Miguel et al. 2011):

Difficult excavation (larger is the volume, more expensive

and complex will be the implantation).

The presence of shallow aquifers or the proximity of vulnerable areas

(it can make unworkable the use of certain technologies that

require deep excavation).

Origin and concentration of pollution in wastewater (T4)

The quality of wastewater can vary from one locality to another and it depends on the

local conditions (population, their habits, etc.). Table 4 shows the appropriate

technology needed according to the level of wastewater contamination.

Table 4. Wastewater technology needed according to the level of wastewater

contamination

TYPE OF WASTEWAT

ER

mgDBO5

/l

TECHNOLOGIES

Very appropriate Appropriate Less

appropriate

Of heavy contamination 350-500 SBR HFCW/RBC/

MBR

LA/VFCW

Of medium

contamination

150-350 ALL TREATMENTS ARE ADEQUATE

Of weak contamination <150 LA/HFCW/VFC

W

SBR1

1 - May present operational problems if the concentration of DBO5 is less than 100

mg/l

(Ortega de Miguel et al. 2011)

7

Treatment versatility (T5)

The capacity of adaptation to the daily fluctuations of flow and concentration of

pollutants can be very pronounced in small populations because of the concentration

of activity in a few hours throughout the day (Ortega de Miguel et al. 2011). Table 5

shows the classification of technologies according to their capacity of

adaptation on daily fluctuations of influent. Table 6 shows the capacity of

adaptation to hydraulic and organic overloads of the considered technologies.

Table 5 Classification of technologies according to their capacity of

adaptation on daily fluctuations of wastewater

Adaptation capacity of different technologies on the daily fluctuations of flow

and pollutant load

- +

RBC SBR/VFCW HFCW LA

(Ortega de Miguel et al. 2011)

Table 6 Classification of technologies according to their capacity of adaptation

to hydraulic overload and contamination.

Capacity of adaptation to hydraulic overloads

- +

VFCW SBR/RBC/HFCW LA

Capacity of adaptation to organic overloads

- +

VFCW/HFCW RBC LA SBR

(Ortega de Miguel et al. 2011)

Climatology (T6)

Temperature is the most important climatic factor and especially affects biological

processes either in the treatment of waste water or sludge stabilization.

Extensive treatments, like horizontal flow constructed wetlands, have a greater

8

protection against the cold weather while the lagoons are more vulnerable

(Ortega de Miguel et al. 2011).

Production and quality of generated sludge (T7)

Table 7 shows the classification of technologies according to the amount and the

frequency of the withdrawal of generated sludge, while Table 8 shows the classification

of technologies according to the level of stabilization of the generated sludge.

Table 7. Classification of technologies according to the amount and the frequency of

the withdrawal of generated sludge

Amount and frequency of the withdrawal of generated sludge

- +

LA VFCW/HFCW RBC MBR SBR

(Ortega de Miguel et al. 2011)

Table 6. Classification of technologies according to the level of stabilization of

the generated sludge

Technology Sludge stabilization

Yes No

ST X

LA X

RBC X

SBR X

MBR X

(Ortega de Miguel et al. 2011)

Complexity in the exploitation and maintenance (T8)

Table 8 shows the classification of the technologies according to their complexity.

Table 8 Classification of technologies according to their complexity in the

exploitation and maintenance

Complexity of the exploitation and maintenance

- +

LA HFCW VFCW RBC MBR SBR

9

Usually, the operation and maintenance are more complex on intensive technologies

than extensive technologies, by the increased presence

of electromechanical equipment while the extensive often require more extensive

greater workforce (Ortega de Miguel et al. 2011).

ENVIRONMENTAL CRITERIA

During the Earth Summit in Rion de Janeiro, the United Nation declared that the

environmental protection should constitute an integral part of the development process,

to attain sustainable development. In addition, environmental protection should not be

considered in isolation (UN 1992).The decision-making approach must examine every

option in terms of environmental impact, resource requirements, and potential for

resource recovery (Eawag 2005). This section describes the environmental criteria.

They consider the minimization of environmental impacts and natural resources

exploitation. (Garfí et al. 2011)

The United Nations Millennium Declaration (UN 2000) includes: ‘’Ensure

environmental sustainability’’. Thus, all of technologies and strategies that are

implemented should minimize environmental impacts such as atmospheric emissions,

water pollution, waste production, noise, land occupation and effects on the landscape

(Garfí et al. 2011).

Production of odours (En1)

The treatment of wastewater is often considered an unhealthy activity and for this

reason should be far away from the population (usually a minimum distance of two

kilometers).

One of the main environmental impacts related to the treatment stations, and a source of

frequent complaints from the population, is the generation of unpleasant odours.

Table 9 Classification of technologies according to their potential to generate odours

Potential of the generation of bad odors

- +

SBR

MBR1/RBC

1

MBR2/RBC

2/VFCW

HFCW

LA

1 - With primary settlement as primary treatment

2 - With septic tank as primary treatment

10

(Ortega de Miguel et al. 2011)

Noise generation (En2)

The generation of noise at treatment stations usually comes associated with the

operation of electromechanical equipment (pumps, blowers) unless are soundproofed.

Noise is controlled by the indicator that measures the average number of decibels

generated (dB/day) (Ortega de Miguel et al. 2011). Table 10 classifies the considered

technologies according to their generation of noise.

Table 10 Classification of technologies according to their potential to generate noise

Potential for noise generation1

- +

LA/VFCW/HFCW

RBC

SBR/MBR

(Ortega de Miguel et al. 2011)

Landscape integration (En3)

Sometimes, small populations are located in rural and /or areas of high ecological

value or with high quality landscaping. It is necessary to implement solutions which

have a low visual impact. Table 11 classifies the considered technologies according to

their landscape integration.

Table 11 Classification of technologies according to their landscape integration

Landscape integration

- +

RBC/SBR/MBR

LA

VFCW/HFCW

(Ortega de Miguel et al. 2011)

SOCIAL CRITERIA

The social criteria focus on evaluating whether solution have a positive social impact on

communities (Garfí et al. 2011).

11

Local participation and access (S1)

Local community participation considers that it is necessary to actively involve the key

stakeholders who may be affected by the implementation of the technologies. Local

participation can be measured as the percentage of people involved in the implementation

and management of the technolgies. The evaluation of this criterion is quantitative and the

highest score must be assigned to the solution with the highest percentage of local

population involved.

Access to technology for all members of the local community. Sometimes, small

communities are constituted by groups of agglomerated households very far to each other.

Occasionally, different groups of people coexist in the same community, such as natives

or minority groups. According to the case, the alternative implemented should involve the

whole community to avoid differences among population. Access to technology can be

measured qualitatively by the percentage of the population who may be potential

beneficiaries (Garfí et al. 2011).

Respect of local culture (S2)

Social values and cultural changes are likely to influence the type of technology which is

appropriate for a specific country, community, or tribal context (De Forest, 1980). The aim of

respecting local culture is to ensure public acceptance of the technologies and, consequently,

the sustainability and success of it (Garfí et al. 2011). Interviews and meeting with future

users must be carried on to understand the most important factors for social acceptability of

the alternatives (e.g: convenience, cost, working hours, security, etc). The best evaluation is

given to the most appropriate solution from a cultural point of view.

Equality (S3)

Overcoming discrimination, conflict or social inequity means that the projects or

technologies that are implemented should not create a substantial difference in a group’s

social rules. For example, technologies must not violate the rights of women or

indigenous people in the society. However, they should improve the integration of

minority groups, for example (Hazeltine and Bull, 2003; Van Mele et al. 2005).

Health (S4)

Health refers to the possibility of improving the health of beneficiaries and reducing mortality

due to diarrhoeal diseases in children under five years old. WHO stated that diarrhoeal

diseases, which are the second leading cause of death in children under five years, are mainly

due to the lack of safe drinking-water and improved sanitation or wastewater treatment

(WHO, 2009). In this case, technologies can be evaluated according to this criterion in a

qualitatively way. The reduction in disease and/or mortality due to diarrhoeal disease in

children under five years old can be considered. The best solution is the one that is expected

to achieve the higher reduction in diseases and mortality.

Standard of living (S5)

12

Standard of living refers to the possibility of increasing beneficiaries’ income to improve their

living quality. The evaluation in this case should consider rises in income due to the

implementation of the solution. For example the possibility of generating job opportunities for

local people can be considered.

ECONOMIC CRITERIA

The following sections describe the economic criteria, considering the cost of the

solution and the economic impact on beneficiaries.

Note that in this section the costs of operation, maintenance and implementation

considered are from Spain.

Exploitation costs (E1)

In the next Table technologies are classified according to their exploitation costs.

Table 12. Technologies in categorizing depending on exploitation costs (from Spain)

Exploitation costs Technologies

≤ 10 €/inhabitant equivalent per year LA

10-20 €/inhabitant equivalent per year VFCW/ HFCW/ RBC

(€/Inhabitant equivalent per year) estimated for a population of 1000 i-e

i.e.: inhabitant equivalent

(Ortega de Miguel et al. 2011)

Implementation costs (E2)

Table 13 shows the classification of the considered technologies according to their

implementation costs (from Spain). For lack of information SBR and MBR

technologies are excluded

Table 13. Classification of the considered technologies according to their

implementation costs

Implementation costs Technologies

200-300 €/inhabitant equivalent per year LA/ VFCW/ HFCW

>300 €/inhabitant equivalent per year RBC

(€/Inhabitant equivalent per year) estimated for a population of 1000 i-e

i-e: inhabitant equivalent

13

(Ortega de Miguel et al. 2011)

CONCLUSIONS

The most adequate wastewater treatment for small communities should involve not just

aspects of technical optimization, but also environmental, economic and social factors.

The following Table summarizes the classification of the wastewater treatment

technologies for small communities according to the evaluation criteria considered in

this document.

Table 14. Classification of the wastewater treatment technologies for small communities

according to the evaluation criteria

TECHNOLOGIE

S

ST

L

A

VFC

W

HFC

W

RB

C

MB

R

SB

R

Technical

T1 0 0 + + ++ ND ++

T2 0 ++ ++ ++ ++ ND +

T3 0 - + + ++ ++ ++

T4 -- - - - + - ++

T5 N

D

++ 0 + - - 0

T6 0 -- ++ ++ ND ND ND

T7 0 - + + + + ++

T8 N

D

-- - 0 0 + ++

Environment

al

CRITERIA En1 -- 0 - + + ++

En2 ++ ++ ++ 0 -- --

En3 0 ++ ++ -- -- --

Social

S1 0 0 0 0 ++ ++ ++

S2 0 0 0 0 0 0 0

S3 0 0 0 0 0 0 0

S4 -- - + + + + +

S5 -- - 0 0 + + +

Economic

E1 N

D

++ + + + ND ND

E2 N

D

++ + + ++ ND ND

14

Legend

Treatment Acronyms

SEPTIC TANK ST

LAGOONS LA

VERTICAL FLOW CONSTRUCTED WETLAND VFCW

HORIZONTAL FLOW CONSTRUCTED WETLAND HFCW

ROTATING BIOLOGICAL CONTACTOR RBC

MEMBRANE BIO REACTOR MBR

SEQUENCING BATCH REACTOR SBR

Technical criteria

Quality of effluent (according to the receiving environment) (T1)

Number of inhabitants (T2)

Available land (T3)

Origin and concentration of pollution in wastewater (T4)

Treatment versatility (T5)

Climatology (T6)

Production and quality of generated sludge (T7)

Complexity of the operation and maintenance (T8)

Environmental criteria

Production of odours (En1)

Noise generation (En2)

Landscape integration (En3)

Social criteria

Local participation and access (S1)

Local culture (S2)

Equality (S3)

Health (S4)

Standard of living (S5)

Economic criteria

Exploitation costs (E1)

Implantation costs (E2)

Technologies performance

++ Very good

+ Good

0 Normal

- Bad

-- Very bad

ND Not defined

15

References

Al-Kloub, B., A1-Shemmeri, T., Rearman, A. (1997). The role of weights in multi-

criteria decision aid, and the ranking of water projects in Jordan. European Journal of

Operational Research, 99, 278-288.

Balana, B.B., Mathijs, E., Muys, B. (2010). Assessing the sustainability of forest

management: An application of multi-criteria term decision analysis to community forests in

northern Ethiopia. Journal of Environmental Management 91 (6), 1294-1304.

Chen, Y., Kilgour, D. M., Hipel, K. W. (2006). Multiple criteria classification with an

application in water resources planning. Computers & Operations Research 33, 3301–3323.

Cherni, J.A., Dyner, I., Henao, F., Jaramillo, P., Smith, R., and Olalde-Font, R. (2007).

Energy supply for sustainable rural livelihoods. A multi-criteria decision-support system.

Energy Policy, 35 (3), 1493-1504.

Flores, X., Bonmatí, A., Poch, M., Roda, I.R., Jiménez, L., Bañares-Alcántara, R.

(2007). Multicriteria evaluation tools to support the conceptual design of activated

sludge systems. Water Science and Technology 56 (6), 85-94.

Garfí, M., Tondelli, S., Bonoli A. (2009). Multi-criteria decision analysis for waste

management in Saharawi refugee camps. Waste Management, 29, 2729–2739.

Garfí, M., Ferrer-Martí, L., Bonoli, A., Tondelli, S. (2011). Multi criteria analysis for

improving strategic environmental assessment of water programmes. A case study in

semi-arid region of Brazil. Journal of Environmental Management, 92 (3), 665-675.

Gomez-Lopez, M.D., Bayo, J., Garcıa-Cascales, M.S, Angosto, J.M. (2009). Decision support

in disinfection technologies for treated wastewater reuse. Journal of Cleaner Production, 17,

1504–1511.

Gough, J.D., Ward, J.C. (1996). Environmental decision making and lake management.

Journal of Environmental Management 48, 1–15.

Hajkowicz, S., Collins, K. (2007). A Review of Multiple Criteria Analysis for Water

Resource Planning and Management. Water Resources Management 21, 1553–1566.

Hajkowicz, S., Higgins, A. (2008). A comparison of multiple criteria analysis techniques for

water resource management. European Journal of Operational Research 184, 255–265.

Hamouda, M.A., Anderson, W.P., Huck P.M. (2009). Decision support systems in water and

wastewater treatment process selection and design: a review. Water Science and Technology

60 (7), 1757-1770.

J.Comas, J.Alemany, M.Poch, A.Torrens, M.Salgot and J.Bou (2003).Water Science and

Technology Vol 48 N0

11-12, 393-400

Keeney, R. L., Raiffa, H. (1976). Decisions with multiple objectives: preferences and value

tradeoffs. Wiley, New York.

M. Garfi and L. Ferrer-Marti (2011).Decision-making criteria and indicators foe water and

sanitation projects in developing countries.Water science and Technology,83-101

McConville, J., Kain, J.H., Klutsé, A., Kvarnström, E. (2010). Perceptions of local

sustainability in planning sanitation projects in West Africa. Chapter in Social

Perspectives on the Sanitatation Challenge. Vliet, B. Spaargaren, G., Oosterveer, P.

eds). 1st edition. Springer, The Netherlands, 250 pages.

16

Messner, F., Zwirner, O., Karkuschke, M. (2004). Participation in multi-criteria decision

support for the resolution of a water allocation problem in the Spree River basin. Land Use

Policy, 23, 63–75.

Mohanty, R.P. (1992). Project selection by a multiple-criteria decision-making method: an

example from a developing country. International Journal of Project Management, 10 (1),

31-38.

Moura, P., Barraud, S., Baptista, M. (2007). Multicriteria procedure for the design and the

management of infiltration systems. Water Science and Technology, 55 (1), 397-405.

Murphy, M. H., McBean, E. A., Farahbakhsh, K. (2009). Appropriate technology – A

comprehensive approach for water and sanitation in the developing world. Technology in

Society 31, 158–167.

Nijkamp, P., Rietveld, P., and Voogd, H. (1990). Multicriteria evaluation in physical

planning, North Holland, Amsterdam.

Ortega de Miguel, E., Ferrer-Medina, Y., Salas-Rodríguez, J.J., Aragón-Cruz, C. 2011.

Manual para la implantación de sistemas de depuración en pequeñaspoblaciones.

Ministerio de Medio Ambiente y Medio Rural y Marino. p. 455 Madrid, España

Paneque Salgado, P., Corral Quintana, S., Guimarães Pereira, A., Del Moral Ituarte, L.,

Pedregal Mateos, B. (2009). Participative multi-criteria analysis for the evaluation of water

governance alternatives. A case in the Costa del Sol (Málaga). Ecological Economics, 68,

990-1005.

Riesgo, L., Gomez-Limon, J. A. (2006). Multi-criteria policy scenario analysis for public

regulation of irrigated agriculture. Agricultural Systems 91, 1–28.

Saaty, T. L. (1994). Decision making for leaders: The analytic hierarchy process in a complex

world. RWS Publications, Pittsburgh, PA.

Tiwari, D.N., Loof, R., Paudyal, G.N. (1999). Environmental - economic decision-making in

lowland irrigated agriculture using multi-criteria analysis techniques. Agricultural Systems 60,

99-112.

Wilson, D., Whiteman, A., Tormin, A., Environmental Resources Management (ERM).

(2004). Strategic Planning Guide for Municipal Solid Waste Management. Edited by The

International Bank for Reconstruction and Development /The World Bank. Available at:

www.worldbank.org (accessed 5 November 2009).

43

8.2 Non-technical requirements according to Garfi and Garcia, 2010.

GEMMA - Group of Environmental Engineering and Microbiology Universitat Politècnica de

Catalunya.BarcelonaTech (UPC)

Non-technical requirements for implementation of

water treatment technology

A brief review

Ph.D Marianna Garfí, Ph.D Joan García

1

INDEX

NON-TECHNICAL REQUIREMENTS FOR IMPLEMENTATION OF WATER TREATMENT

TECHNOLOGIES ............................................................................................................................. 2

Management aspects .......................................................................................................... 23

Social aspects ...................................................................................................................... 24

Economic aspects ................................................................................................................ 24

Environmental aspects ........................................................................................................ 25

REFERENCES ................................................................................................................................ 25

2

NON-TECHNICAL REQUIREMENTS FOR IMPLEMENTATION OF WATER TREATMENT TECHNOLOGIES

This section describes the general technical, environmental, social and economic requirements to be considered in water projects for small communities.

We took into account the requirements for development projects and the standards for humanitarian projects that are recommended in specific guidelines for international development cooperation or established by international organizations, such as the World Health Organization (WHO), the Steering Committee for Humanitarian Response (SCHR) and the United Nations Development Programme (UNDP). In this paper institutional issues are not considered (OECD, 2006).

Table 1 presents the general requirements for management (GM), social (GS), economic (GE) and environmental (GI) aspects and references of case studies in which these requirements are used. Indicators, guidelines and references are provided for the evaluation of each requirement. Moreover, the type of evaluation is summarized: column (T/L) indicates whether the evaluation of the indicator is quantitative (T) or qualitative (L); and column (X/N) indicates whether the best score in alternatives comparison must be given to the maximum (X) or minimum (N) indicator value. Details of each requirement and indicator are given in next sections. This work was adapted from Garfí and Ferrer-Martí, 2011.

3

Aspects Requirements Sub-requirements Case

Study

Literature Indicators T/L X/N

Management GM1 Technology GM1-

1

Local resources, materials use

and reproducibility

[2], [4] [b] Percentage of local materials and resources used in water

technology

T X

GM1-

1

Small-scale technology [2] [b] Size of the project (i.e. land occupied, energy consumed) L N

GM2 Management [2], [6] [b] Local capacity for management, operation and maintenance L X

Social GS1 Local

participation

and access

GS1-

1

Local community participation [2], [5]

[10], [13]

[b] Percentage of local population involved T X

GS1-

2

Access to technology for all

members of the local community

[2] [c] Percentage of potential beneficiaries T X

GS2 Local culture [2], [6],

[12]

[b] Respect for local culture, appropriateness of the project to the

local cultural of men and woman

L X

GS3 Equality and

migration

GS3-

1

Overcoming discrimination or

conflict

[2], [5],

[15]

[b] Possibility of avoiding conflict among different groups in the

community (i.e. between men and woman)

T X

GS3-

2

Migration due to the lack water

and sanitation services

[2] [e] Percentage of people who can potentially migrate L N

GS4 Health [2] [e] Reduction of children mortality due to diarrhoeal disease L X

GS5

Public

awareness and

standard of

living

GS5-

1

Public awareness on water,

sanitation and hygiene issues

[1], [2],

[9]

[d] Percentage of people trained in water, sanitation and hygiene

issues

L X

GS5-

2

Standard of living [2], [10] - Rate of increase in beneficiaries’ income in comparison with

the minimum wage

T X

Economic GE1 Cost [1], [6] [c] Low cost availability and access, ability to pay T N

GE2 Income and

Employment

GE2-

1

Differences in income [2], [8] [d] Possibility of creating a difference in income that can produce

social conflicts

L N

GE2-

2

Employment of local staff [2], [8],

[10]

[b] Number of locals employed T X

Environmental

GI1 Impact GI1-1 Atmospheric emissions [2], [3],

[6]

[a] Greenhouses gases and other emissions (particulate matter,

sulphur oxides)

T N

GI1-2 Water pollution [3], [6] [a] Quantity of contaminated water generated and related T N

4

contamination (i.e. E. coli and total suspended solids)

GI1-3 Waste production [2], [6] [a] Quantity of solid waste generated T N

GI1-4 Noise [2] [a] Average number of decibels generated T/L N

GI1-5 Landscape impact [8], [10] [a] Changes in landscape due to human exploitation L N

GI2 Natural

resources

GI2-1 Fuel or non-renewable energy

use

[1] [a] Non-renewable energy consumption T N

GI2-2 Water use [13] [a] Water consumption T N

GI2-3 Non-renewable raw material use [2], [6] [a] Raw material consumption T N

GI2-4 Land use and occupation [2], [7] [a] Amount of land used (ha)

1: Al-Kloub et al. 1997; 2: Garfí et al. 2009; 3: Gomez-Lopez et al. 2009; 4: Meierhofer and Wegelin, 2002; 5: Messner et al. 2004; 6: Moura et al. 2007; 7: Ozelkan and

Duckstein, 1996; 8: Paneque et al. 2009; 9: Pérez-Foguet et al., 2003; 10: Riesgo and Gomez-Limon, 2006; 11: Schouten and Moriarty, 2003; 12: Stackhouse, 2000; 13:

Tiwari et al., 1999; 14: Vasiloglou et al. 2009; 15: World Commission on Dams, 2000.

[a] EC, 1985; [b] Hazeltine and Bull, 2003; [c] Murphy et al. 2009; [d] UN, 2000; [e] UNDP, 2008.

Table 1 General requirements for implementation of water treatment technologies in small communities.

1

Management aspects

The general management aspects mainly focus on evaluating whether the technology proposed in each alternative is appropriate. The concept of appropriate technologies was introduced in the 1970s as a technique for development work that addresses the issues of poverty, social equity, employment, and basic human needs (Schumacher, 1973). The term has transformed numerous times since its emergence (Ntim, 1988; Ranis, 1980; Hazeltine and Bull, 2003; Kaplinsky, 2010). Today, the definition is more loosely presented, and it has evolved as a concept opposed to a rigid definition that outlines specific requirements for a technology to be deemed appropriate (Murphy et al., 2009).

In this section we focus the attention on water treatment technologies implementation in small rural communities of developing countries. Normally, small village in rural areas of developing countries are isolated and far from large natural or technical central sources of fresh water, pipelines and sanitation systems. In these cases small-scale, de-central, low-cost water and sanitation systems are needed (Faillace, 1990; Rheinlander and Grater, 2001).

Technology. The technology requirement (GM1) includes two sub-requirements:

Local resources, materials use and reproducibility (GM1-1). The use of locally available materials helps reducing a community’s dependence on outside sources and often decreases the cost of the technology itself (Hazeltine and Bull, 2003). A tool made from local materials by local tradesman is likely to be more affordable and sustainable than a tool imported from the developed world. If a locally made tool breaks, it can be repaired easily, as the materials and expertise used to make it are readily available in the community. However, imported technology that is not made of locally available materials is not as easy to repair, and as a result may become useless to the community (Murphy et al. 2009). The indicator used for this requirement is the percentage of local materials and resources used in water technology. In this case, the indicator can be quantitatively evaluated: the highest score is given to the solution that uses the greatest percentage of local materials and resources.

Small-scale technology (GM1-2). Faillace (1990) and Rheinlander and Grater (2001) argued that small-scale technology is the most socially, economically and environmentally effective way to achieve sustainable development and technology transfer in the specific case of small rural villages of developing countries. It meets the basic needs of beneficiaries, and stimulates and highlights the development of capacity throughout a community. It also increases a community’s knowledge base, indigenous knowledge and capabilities (Murphy et al. 2009). The indicator for this requirement could be the size of projects. This indicator may consider the land occupied and the energy consumed, among other factors. It can be qualitatively evaluated by giving the highest score to the smallest solution according to the context.

Management. Management (GM2) must be appropriate to the local capacities to ensure the affordability of the project. The capacity of people or entities responsible for the management must match the requirement skills for management, operation and maintenance. The indicator in this case measures the degree of local capacities for management, operation and maintenance according to the skills needed. The highest score must be given to the solution which requires the most suitable

2

management according to local capacities. This indicator can be measured qualitatively and a good evaluation is given to solutions that involve appropriate operation and maintenance.

Social aspects

The general social aspects focus on evaluating whether solutions have a positive social impact on communities.

Local participation and access. Local participation and access (GS1) has two sub-requirements:

Local community participation (GS1-1) considers that it is necessary to actively involve the key stakeholders who may be affected by the project in all aspects of the implementation and management. Local participation can be measured as the percentage of people involved in the implementation and management of the project. The evaluation of this indicator is quantitative and the highest score must be assigned to the solution with the highest percentage of local population involved.

Access to technology for all members of the local community (GS1-2). Sometimes, rural communities are constituted by groups of agglomerated households very far to each other. Occasionally, different groups of people coexist in the same community, such as natives or minority groups. According to the case, the alternative implemented should involve the whole community to avoid differences among population. Access to technology can be measured qualitatively by the percentage of the population who may be potential beneficiaries. The highest value must be given to the solution with the highest percentage of potential beneficiaries.

Local culture. Social values and cultural changes are likely to influence the type of technology that is appropriate for a specific country, community, or tribal context (De Forest, 1980). The aim of the local culture (GS2) requirement is to ensure that local customs are respected, which leads to public acceptance of the technologies and the sustainability and success of projects.

In this case, the indicator is the appropriateness of the projects to the local cultural of men and women. Interviews and meeting with future users must be carried on to understand the most important factors for social acceptability of the alternatives (e.g: convenience, cost, working hours, security, etc). The best evaluation is given to the most appropriate solution from a cultural point of view. The indicator can be measured in a qualitative way by considering the specific characteristics of the project.

Equality and migration. Equality and migration (GS3) includes two sub-criteria:

3

Overcoming discrimination, conflict (GS3-1) or social inequity means that the projects or technologies that are implemented should not create a substantial difference in a group’s social rules. For example, technologies must not violate the rights of women or indigenous people in the society. However, they should improve the integration of minority groups, for example (Hazeltine and Bull, 2003; Van Mele et al. 2005). The indicator in this case is the possibility of avoiding conflict among groups in the community, i.e. between men and women. The social context and potential social consequences of the solutions should be analyzed qualitatively. The highest score must be given to the solution that avoids conflicts.

Migration due to lack of water and basic sanitation services (GS3-2). A lack of water resources can force the poor population and especially that of rural areas to leave their communities and migrate to major cities (Garfí et al., 2011). A good project is one that provides access to basic needs and resources and reduces migration. This requirement refers to a sub-goal which is expected to be accomplished in a long term phase of the project. The indicator qualitatively measures the percentage of people who may migrate, considering the tendency in the past and its causes. The highest value can be assigned to the solution that is most effective at preventing migration.

Health. Health (GS4) refers to the possibility of improving the health of beneficiaries and reducing mortality due to diarrhoeal diseases in children under five years old. WHO stated that diarrhoeal diseases, which are the second leading cause of death in children under five years, are mainly due to the lack of safe drinking-water and improved sanitation (WHO, 2009). This requirement refers to a sub-goal which is expected to be accomplished in a long term phase of the project. In this case, the indicator qualitatively evaluates the reduction in disease and/or mortality due to diarrhoeal disease in children under five years old; the best solution is the one that is expected to achieve the higher reduction in diseases and mortality.

Public awareness and standard of living. Public awareness and standard of living involves the following sub-requirements:

Public awareness on water, sanitation and hygiene issues (GS5-1) considers the increase in people’s consciousness in water and hygiene issues. NGOs should carry on meeting and workshops with future users dealing with these themes. The indicator in this case is the percentage of people trained in water, sanitation and hygiene issues in local communities. The highest value is assigned to the solution that contributes to train the greatest percentage of the population.

Standard of living (GS5-2) refers to the possibility of increasing beneficiaries’ income to improve their living quality. The evaluation in this case should consider rises in income due to the implementation of the solution. For example, beneficiaries may be able to take advantage of appropriate technology to create products to sell in the local market or to reduce family expenses (e.g. home water treatment can reduce purchases of bottled water). The indicator measures the rate of increase in beneficiaries’ income compared to the minimum wage. The best evaluation is assigned to the solution that contributes most to increasing beneficiaries’ income quantitatively.

4

Economic aspects

The following sections describe the economic requirement, considering the cost of the solution and the economic impact on beneficiaries.

Cost. The aim of the cost (GE1) requirement is to determine the capacity of beneficiaries to pay for the service provided by the technologies and projects. A common misconception is that an appropriate technology must be inexpensive or represent the ‘‘least-cost’’ solution. This is not always the case. The most important consideration is that the cost should closely match the willingness and ability to pay of the users of the technology (Murphy et al. 2009). This requirement can be measured by analyzing the communities’ ability to pay, which has traditionally been evaluated by considering that households should not be obliged to pay more than 5% of their income for water services (Al-Ghuraiz and Enshassi, 2005). For this indicator, a good evaluation is given when the willingness and ability to pay of the users match the implementation or operation and maintenance costs, according to the case. This requirement is a broad guideline and can be modified according to the condition; for large-scale project it should also consider investment costs on society.

Income and employment. Income and employment (GE2) has the following sub-requirements:

Difference in income (GE2-1) means that, due to implementation of the projects and its strategies, the income of some beneficiaries is immeasurably improved, which creates social conflicts (Hazeltine and Bull, 2003). This occurs, for example, when an international development project is implemented and local staff is engaged with wages that are in line with international rather than local standards. This can create disequilibrium in the local community and cause problems for the family that is affected, particularly when the project and financing end. This requirement refers to a sub-goal which is expected to be accomplished in a long term phase of the project. The indicator in this case evaluates the possibility of creating a difference in income that could produce social conflicts. A high score is given to the solution that reduces this possibility, which can be evaluated qualitatively.

Employment of local staff (GE2-2) considers that the appropriate project should create jobs for local beneficiaries, and thus benefit the local economy. This indicator quantitatively evaluates the number of local workers employed. A higher score is assigned when more local workers are employed.

Environmental aspects

During the Earth Summit in Rio de Janeiro, the United Nations declared that environmental protection should constitute an integral part of the development process, to attain sustainable development. In addition, environmental protection should not be considered in isolation (UN, 1992). Decision-making approach must examine every option in terms of environmental impact, resource requirements, and potential for resource recovery (Eawag, 2005). The following sections

5

describe the environmental requirements. They consider the minimization of environmental impacts and natural resources exploitation.

Impact. The United Nations’ Millennium Declaration (UN, 2000) includes Goal 7: “Ensure environmental sustainability”. Thus, all of the technologies and strategies that are implemented should minimize environmental impacts such as atmospheric emissions, water pollution, waste production, noise, land occupation and effects on the landscape. Requirement GI1 and its sub-requirements (GI1-1 to GI1-7) take into account all possible environmental impacts (EC, 1985; EC, 1999). For all the indicators and requirements listed in this section, the best score is given to the solution that minimizes environmental impact.

Atmospheric emissions (GI1-1) are currently a major global concern. In this case, the indicator is expressed by the greenhouse gases and other emissions (e.g. particular matter and sulphur oxides) generated by the technologies. The evaluation can be both quantitative and qualitative.

Water pollution (GI1-2) considers the nature and the magnitude of water contamination. The indicators for this criterion are the quantity of water polluted (effluent) and the kind of contamination (e.g. the concentration of E. coli, total suspended solids, heavy metals, etc).

Waste production (GI1-3) must be reduced as much as possible. The indicator in this case is the quantity of solid waste that is generated (ton/year), which is evaluated quantitatively.

Noise (GI1-4) is controlled by the indicator that measures the average number of decibels generated (dB/day). This indicator is quantitatively evaluated.

Landscape impact (GI1-5) considers the landscape changes. The indicator is evaluated qualitatively by examining landscape changes that can negatively affect people and nature.

Natural resources. Like GI1, the natural resources (GI2) criterion is linked to Goal 7 of the Millennium Declaration. It is based on the fact that the appropriate project must minimize natural resources’ exploitation. Sub-requirements are described below (EC 1985, EC, 1999). For all the indicators and requirement listed in this section, the best score is given to the solution that best minimizes the consumption of natural resources.

Fuel or non-renewable energy consumption (GI2-1) measures the exploitation of fossil fuels. The indicator for this requirement is non-renewable energy consumption, which can be evaluated quantitatively.

Water consumption (GI2-2) considers water preservation and the reduction of its consumption. The indicator in this case is water consumption in ton/year, which can be calculated quantitatively.

Non-renewable raw materials use (GI2-3). This indicator is the raw material used. It is calculated quantitatively.

Land use and occupation (GI2-4) measure the quantity of land use; it can be calculated quantitatively.

6

REFERENCES

Al-Ghuraiz, Y., Enshassi, A. (2005). Ability and willingness to pay for water supply service in the Gaza Strip. Building and Environment. 40, 1093–1102.

Al-Kloub, B., A1-Shemmeri, T., Rearman, A. (1997). The role of weights in multi-criteria decision aid, and the ranking of water projects in Jordan. European Journal of Operational Research, 99, 278-288.

De Forest PH. (1980). Technology choice in the context of social values – a problem of definition. In: Long FA, Oleson A, editors. Appropriate technology and social values– a critical appraisal. Cambridge, USA: Ballinger Publishing Company. p. 11–25

Eawag: Swiss Federal Institute of Aquatic Science and Technology (2005). Household-Centred Environmental Sanitation. Implementing the Bellagio Principles in Urban Environmental Sanitation. Provisional guideline for decision-makers. Available at: http://www.eawag.ch/organisation/abteilungen/sandec/schwerpunkte/sesp/index (accessed 20 Abril 2010)

European Commission (EC). (1985). Council Directive of 27 June 1985 on the assessment of the effects of certain public and private projects on the environment (85/337/EEC). European Commission, Brussels, Belgium.

European Commission (EC). (1999). Guidelines for the Assessment of Indirect and Cumulative Impacts as well as Impact Interactions. European Commission, Brussels, Belgium.

Faillace, C. (1990). The importance of using simple and indigenous technologies for the exploitation of water resources in rural areas of developing countries. Journal of African Earth Sciences (and the Middle East) 11(1), 217-220.

Garfí, M., Tondelli, S., Bonoli A. (2009). Multi-criteria decision analysis for waste management in Saharawi refugee camps. Waste Management, 29, 2729–2739.

Garfí, M., Ferrer-Martí, L., Bonoli, A., Tondelli, S. (2011). Multi criteria analysis for improving strategic environmental assessment of water programmes. A case study in semi-arid region of Brazil. Journal of Environmental Management, 92(3), 665-675

Gomez-Lopez, M.D., Bayo, J., Garcıa-Cascales, M.S, Angosto, J.M. (2009). Decision support in disinfection technologies for treated wastewater reuse. Journal of Cleaner Production, 17, 1504–1511.

Hazeltine, B., Bull, C. (2003). Field Guide to Appropriate Technology. Academic Press, Amsterdam, Netherlands. pp. 874.

Kaplinsky, R. (2010). Schumacher meets Schumpeter: Appropriate technology below the radar. Research Policy. doi:10.1016/j.respol.2010.10.003.

Meierhofer, R., Wegelin, M. (2002). Solar Water Disinfection. A Guide for the Application of SODIS. Available at: http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_ws/index_EN (accessed 15 May 2010)

Messner, F., Zwirner, O., Karkuschke, M. (2004). Participation in multi-criteria decision support for the resolution of a water allocation problem in the Spree River basin. Land Use Policy, 23, 63–75.

7

Moura, P., Barraud, S., Baptista, M. (2007). Multicriteria procedure for the design and the management of infiltration systems. Water Science and Technology, 55(1), 397-405.

Murphy, M. H., McBean, E. A., Farahbakhsh, K. (2009). Appropriate technology – A comprehensive approach for water and sanitation in the developing world. Technology in Society 31, 158–167.

Ntim B. (1988). In: Buatsi S, editor. Technology transfer – nine case studies. London, UK: IT Publications; p. vii.

Ozelkan, E.C., Duckstein, L. (1996). Analysing Water Resources Alternatives and Handling Criteria by Multi Criterion Decision Techniques. Journal of Environmental Management, 48, 69–96

Paneque Salgado, P., Corral Quintana, S., Guimarães Pereira, A., Del Moral Ituarte, L., Pedregal Mateos, B. (2009). Participative multi-criteria analysis for the evaluation of water governance alternatives. A case in the Costa del Sol (Málaga). Ecological Economics, 68, 990-1005

Pérez-Foguet, A., Carrillo, M., Magrinya, F. (2003). Technology for the development: water and infrastructure. Ingeniería sin Fronteras, Barcelona, Spain. (In Spanish). Available at: https://www.isf.es/menu_publicaciones/pub_libros.php?$sesion_idioma=1&$menu=3&identifica=libros&nombrexml=113 (accessed 15 March 2010)

Rheinlander, J., Grater, F. (2001). Technologies for the desalination of typically 10 m3 of water per day

DESAL10 - a tool for the identification of appropriate de-central solutions. Desalination 139, 393-397.

Riesgo, L., Gomez-Limon, J. A. (2006). Multi-criteria policy scenario analysis for public regulation of irrigated agriculture. Agricultural Systems 91, 1–28

Schouten, T., Moriarty, P. (2003). Community water, community management: From system to service in rural areas. London. ITDG Publishing.

Schumacher, E., F. (1973). Small is Beautiful: Economics as if people mattered. Blond & Briggs. London, UK.

Stackhouse J. (2000). Out of poverty and into something more comfortable. Canada: Vintage Canada.

Tiwari, D.N., Loof, R., Paudyal, G.N. (1999). Environmental - economic decision-making in lowland irrigated agriculture using multi-criteria analysis techniques. Agricultural Systems 60, 99-112

United Nation (UN). (1992). Report of the United Nations Conference on Environment and Development. General Assembly Resolution (A/CONF.151/26 (Vol. I)). UN Earth Summit, Rio de Janeiro, Brazil. Available at: http://www.un.org/documents/ga/conf151/aconf15126-1annex1.htm (accessed 16 December 2008)

United Nation (UN). (2000). United Nation Millennium Declaration. General Assembly Resolution (A/RES/55/2). UN Millennium Summit, New York, U.S.A. Available at: http://www.un.org/millennium/declaration/ares552e.htm (accessed 21 February 2009)

United Nation Development Programme (UNDP). (2008). Human Development Indices: A statistical update 2008. New York U.S.A.

Van Mele P., Salahuddin A., Magor NP. (2005). Innovations in rural extension: case studies from Bangladesh. Cambridge, USA: CABI Publishing.

8

Vasiloglou, V. Lokkas, F. Gravanis, G. (2009). New tool for wastewater treatment units location. Desalination 248:1039–1048.

World Commission on Dams. (2000). Dams and development: a new framework for decision making. The report of the world commission on dams. Earthscan Publications Ltd. London, UK.

World Health Organization (WHO). (2009). The World Health Report 2008 - primary Health Care (Now More Than Ever). Available at: http://www.who.int/whr/2008/en/index.html (accessed 11 December 2010)