Reuse-oriented decentralized wastewater and sewage sludge treatment...

Reuse-oriented decentralized wastewater and sewage sludge treatment for rural settlements in Brazil:

A Cost-benefit Analysis

J. A. Cardona1-2*, O.C. Segovia3, S. Böttger 4, N.A. Medellin 5,6 L. Cavallo7 ; I.E Ribeiro1-8; S. Schlüter 3

1 Training and Demonstration Centre for Decentralized Wastewater Management – BDZ2 Helmholtz Center for Environmental Research UFZ

3 Institute of Technology and Resources Management in the Tropics (ITT)4 Tilia GmbH

5 Facultad de Ingeniería, Centro de Investigación y Estudios de Posgrado, Universidad Autónoma San Luis Potosí6 Instituto Tecnológico de Estudios Superiores. Campus San Luis Potosi

7 Universidade Federal Fluminense UFF8 Escola Politécnica da Universidade Federal da Bahia (UFBA

Content

2

• Problem Approach:

• The role of Decentralized Wastewater Management DWM

• The Challenge of Small Urbanized Rural Settlements SURUS

• CBA Application in Brazil: The project INTECRAL

• Methodology

• Results

• Conclusions

Problem Approach

Currently 2.5 billon people1 lack o of improved sanitation, 70% of them are living in rural and peri-urban areas of less developed nations.

3

Population Growth

Technologies needs

High costs for centralized treatment

plants

1- Joint Monitoring Program World Health Organization UNICEF, JMP 2014

1

4

Initial Situation Decentralized Solution

Semi-central Solution

A

BC

D E

A

BC

D E

Centralized Solution

A

BC

D E

A

BC

ED

DWM may be defined as the collection, treatment, and disposal /reuseof wastewater from indivudual homes, clusters of homes, isolatedcommunities at or near the point of waste generation ( Tschobanoglous, 1995)

The role of Decentralized Wastewater Management DWM

On-site

Decentralized & Cluster

Centralized

5

Some Advantages of DWM

• Adaptation: Resilience infrastructure

• Recycle: Nutrients recovery ( Nitrogen and Phosphorus)

• Wastewater reuse close to generation point

• Integration with agriculture and local economies

• Financial advantages by less collection costs: Centralized approaches require ~

60% -80% only in collection and transportation (2-3)

• Simple operation and less O&M costs (2)

• Community integration

• Attractive for rural and small urbanized rural areas SURUS

6

The Challenge of Small Urbanized Rural Settlements SURUS

• Lack of knowledge about decentralized wastewater

treatment technologies and management concepts.

• Financial reward for using centralized systems (economic of

scale driver in treatment costs, the bigger the better)

• Unfavorable perception of decentralized systems.

• Unfavorability of regulatory system for decentralized

solutions.

• Lack of system thinking applied to wastewater issues.

• Lack of comprehensive Cost-benefit Analysis,

• Regulations and funding oriented around centralized

delivery and collection and point-source discharges

SURUS Area in Nova Friburgo Brazil

Application in Brazil - INTECRAL Project

7

Provide integrated solutions of services and technologies to allow an environmentally sound and economically sustained development of the watersheds in rural Rio de Janeiro within the environment of emerging green markets.

The integrated eco-technology and services solutions address:

• Monitoring for decision support in integrated planning and risk management

• Governance issues of green markets for land use, land & biodiversity conservation, and water conservation

• Technological adaptation in the agricultural, restoration and sanitation sectors.

Methodology for Economic Assessment

8

1. Regional Status Quo Analysis 2. Socio-economic survey of the selected community.3. Geographic Information System Analysis:4. Population density to determine the requirements placed in the sewer network.5. Estimation of required lengths in the sewer network based on remote sensing.6. Identification of available areas for the potential location of wastewater and sewage

sludge treatment facilities.7. Wastewater quality standards and sludge quality parameters.8. Selection of the most suitable wastewater and sewage sludge treatment

technologies.9. CBA Calculation10. Estimation of economic benefits associated with the treatment solutions: 11. Calculation of cost-recovery capabilities, especially in terms of operating and

maintenance costs.

Status Quo Rio de Janeiro: Sanitation

9

Collected wastewater 39,28 %

Treated wastewater 15,58 %

Visão Geral do Estado do Rio de Janeiro*

Total Municipalities5564

Municipalities < 20.000inhabitants (73% do total)

4062

Wastewater Treatment in small municipalities

55%

Wastewater Treatment by Septic Tanks in Small Municipalities

52%

Sanitation Statues Brazil*

*Source: de Sa Salomao, A. L., et al. (2012) baseado no IBGE 2010

**SNIS 2010 . Sistema Nacional de Informacoes sobre saneamento

Statues Quo: Sewer Collection and Treatment

10*Source: de Sa Salomao, A. L., et al. (2012) baseado no IBGE 2010

**SNIS 2010 . Sistema Nacional de Informacoes sobre saneamento

0 50 10025 Kilometers

±

Prepered by:Jaime A. CardonaContact: [email protected]

Population Distribution

IBGE CENSO 2010

TIPO

RURAL

URBANO

GIS-Based Analysis

11

• Regional Analysis of Wastewater Treatment connection degree.

• Spatial location of existing centralized wastewater treatment plants

• Location of critical areas for rural sanitation• Preliminary hydro-modelling for gravity lines sewer

networks

It is planned the establishment of a Decision Support Systems based on Muli-Criteria Analysis for location and operation of semi-central ( cluster ) wastewater treatment and Reuse solutions for the Rio Dois Rios Basin

Basin Rio dois Rios- Brasil

GIS-Based Analysis

12

• Regional Analysis of Wastewater Treatment connection degree.

• Spatial location of existing centralized wastewater treatment plants

• Location of critical areas for rural sanitation• Preliminary hydro-modelling for gravity lines sewer

networks

It is planned the establishment of a Decision Support Systems based on Muli-Criteria Analysis for location and operation of semi-central ( cluster ) wastewater treatment and Reuse solutions for the Rio Dois Rios Basin

Sanitation Infrastructure: On-site cesspits users in Nova Friburgo Municipality

Cavallo, L ( 2014 ) . INTECRAL Sanitation Group

Case Study Rural SanitationBarracão dos Mendes (BDM)

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• Hydro-Topographic model development• Sanitation Survey

• Water Supply sources• Wastewater treatment infrastructure• Potential site for wastewater treatment plant


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• Socioeconomic Survey• Population / Current and Future expected• Willingness to accept wastewater treatment

projects• Waterborne diseases incidences ( Diarrhea),

based on statistical records

•Water consumption•Water source ( well, spring)•Inhabitants per household•Number of toilets•Existing wastewater infrastructure•Water quality •Existing sewer network

Example questions

Survey N=105 Households, 71 answered

Date : 25-29 January 2014


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• Socioeconomic Survey• Population / Current and Future expected• Willingness to accept wastewater treatment



2014 2024** 2034**

Isolated buildings 150 750 788 827

Cluster settlement 110 550 578 606

Total Buildings 260 1300 1365 1433

* Assuming 5 Inhabitants per building

** Assuming 5% population growth each 10 Years. Source J.Saraiva (2014)

ItemFlow Rate

(m3/d)

Population

Equivalent (PE)

Isolated buildings 32,60 827

Cluster settlement 23,91 606

Total 56,51 1433

*** Based on BOD load rate of 50 gr/c.d : Source ( ABNT-Associação Brasileira de Normas Técnicas: NBR 13969 de 1997)

Average water

consumption**** (l.c.d)271

Average wastewaterª flow

(l.c.d)217

**** Based on water consumption survey condcuted on Barracons dos Mendes. Cluster settlement (n=14 )

ª Assumed return factor = 80%

Current and Projected Population* Item Buildings

Not water supply tariff


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• Socioeconomic Survey• Population / Current and Future expected• Population Density• Willingness to accept wastewater treatment




17



• Socioeconomic Survey• Population / Current and Future expected• Pupulation Density• Willingness to accept wastewater treatment



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Diagnosis Wastewater Problematic

Lack of sewer network Superficial water Irrigation

Wells Cesspits

Groundwater

D -3 Case Study Rural SanitationBarracão dos Mendes (BDM)

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Lack of sewer network

High dependence on water springs for supply domestic and agricultural demand

Good water quality in the microbasin (Respondent Perception)

50% of the respondents use water filters (Family consumption)

Non official water payment (Absence of water operator)

• 55 Survey were conducted (Residents and Farmers)

0

10

20

30

40

50

60

70

80

90

100

BSM RG FS SN SV

Very good Good Regular Bad Very bad

BS: Barracão dos MendesRG: Rio GrandeFS: Florandia da SerraSN: Serra NovaSV: Serra Velha

53% consider to do not need a better wastewater treatment system 47% consider to need better wastewater treatment

Water extraction

Oxygen input

Filter effect Environment

improvement for microorganisms

Structure / material

stabilization

Decentralized Sanitation and Reuse Solutions (DESAR)

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1-Accomplish of resolution 357 from 2005, which was enacted by the National Environmental Council (Conselho Nacional do Meio Ambiente) CONAMA. The applicable standard is DZ 215.R4 from 2007 in respect to BOD. The BOD load rate applied in our case (201 to 1000 users) must achieve 65% of BOD and TSS removal.2-The WASTES solution observes the procedures and Brazilian legal requirements for sludge use and disposal, including restrictions and precautionary measures. Resolution 375, issued in 2006 by the Brazilian National Environment Council (CONAMA 2006), regulates only the concentration of heavy metals and some pathogens.

Sludge Dry Reed Beds2Vertical flow CW1

Economic Assessment based on Costs Benefit Analysis CBA

21

𝑁𝑃𝑉 =

𝑡,𝑖

𝑇,𝑁𝐵𝑖,𝑡 − 𝐶𝑖,𝑡(1 + 𝑟)

CBA* Application

where, Bi is the value of the benefit item i, and Ci is the value of the cost of item i. The Net Present Value NPV is the difference between Cost and Benefits. If the result of the calculation is NPV>0, then the project is economically viable, while the project is not viable in economic terms if the value is NPV<0.

*Pearce (2006)

Benefits estimations*

Nutrient Content in sewage sludge in kg/t.a (dry matter)**

Nitrogen (N) Phos-phorus (P) Potassium (K)

1390 kg.a-1 970 kg.a-1 128 970 kg.a-1

**Andreoli et al. (2007)

Items Total Benefit in R$ Assumptions

Avoided Costs of BOD5 Discharges a 11,000 Discharge fee for kg/BOD5 = 0,0763 R$/kg from CEIVAP (2014); uptake water for irrigation = 0,0109 R$/m3 from CEIVAP (2014)

Avoided Costs of Uptake Water for Irrigation b 4000 According to the flow rate and typical values for UASB + aerobic post treatment from Andreoli et al. (2007)

Avoided Costs of Sludge Transportation and Disposal c

26,000 Sludge transportation assumed from previous estimations in the country from (Quintana et al. 2012) estimated in R$11,84/t

Benefits for Nutrients contents as Fertilizer d 41.000 Derivate from local survey including fertilizer prices for mineral fertilizer costs NPK

*Benefits associated to DESAR infrastructure presented in Net Present Value for a 20-year project life span and a 12% discount rate (Ministerio da Cidades 2011). Values in Brazilian reals R$ October 2014 (1R$=0.4073 USD). Design data: PE = 1000; Flow Rate =130m3/d; BOD5=350 mg/l

Values in Brazilian Reals R$ October 2014 (1R$ =0.4073USD)

Costs Estimations*

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Item Value in R$ AssumtionTotal Capital Costs a 660,000 Including the treatment train UASB+VFCW+SDRB. Construction Costs UASB based on (von

Sperling & Salazar 2013); CC of VFCW and SDRBs using C= 1650,4*Q0,697 (Cardona 2005); Sewer Network costs based on own calculations using satellite images and digital elevation models.

Total Land Costs b 25,000 Land Requirements: UASB = (0,05 m2.c-1 ) based on von Sperling (1996); VFCW = (1 m2.c-1) from Hoffmann et al. (2011); SDRM = (0,3 m2.c-1) from (Uggetti et al. 2011) ; land costs assumed to be 20 R$/m2 based on local survey.

Total O&M Costs c 111,000 Operating and Maintenance costs: UASB = (15 R$/c.a) according to (Jordao & Volschan2009); VFCW and SDRB assuming (0.5 US$/c.a) based on (Koottatep et al. 2001).

*Costs in Brazilian Real R$ 2014 associated with DESAR infrastructure presented in Net Present Value for a project life span of 20 years and a discount rate of 12%. Design data: PE = 1000; Flow Rate =130m3/d; BOD5=350 mg/l Values in Brazilian Reals R$ October 2014 (1R$ =0.4073USD)


CBA in NPV after 20 years of operation

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*Costs in Brazilian Real R$ 2014 associated with DESAR infrastructure presented in Net Present Value for a project life span of 20 years and a discount rate of 12%. Design data: PE = 1000; Flow Rate =130m3/d; BOD5=350 mg/l Values in Brazilian Reals R$ October 2014 (1R$ =0.4073USD)


Costs and Benefits Values in R$Net Present Value NPV -713.817Total O&M Costs after 20 Years Operation 111.031Total Benefits after 20 years operation 81.537Recovery Costs associated to O&M Costs 73%

CBA- Results

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R$ 10.749

R$ 40.724

R$ 4.387

R$ 25.676

Avoided Cost BOD5 Discharges Nutrients recovered and used as fertlizer Avoided costs water uptake Avoided Costs of conventional sludgetreatment and disposal

R$ 0

R$ 5.000

R$ 10.000

R$ 15.000

R$ 20.000

R$ 25.000

R$ 30.000

R$ 35.000

R$ 40.000

R$ 45.000


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Conclusions

• The DESAR solution responds to the need to improve the current sanitation situation in small communities worldwide as a contribution to food security development.

• CBA is a powerful tool in displaying the total benefits of sanitation projects. Monetization of additional economic benefits is possible; including environmental benefits associated with Avoided the cost of uptake-water and payments for BOD5 discharge.

• The use of these integrative methodologies proves attractive in the generation of new incomes in the field of local water and sanitation, green practices, and the promotion of an integrative approach that combines wastewater treatment with the reuse of nutrients in rural areas worldwide.

• Small Urbanized Rural Settlements SURUS require a detailed and interdisciplinary planning in order to guarantee the application of adapted and sustainable wastewater treatment and reuse solutions.

• Sludge treatment locally can benefit the reduce and the costs recover capabilities of DESAR solutions

Contact

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BDZ An der Luppe 2

04178 Leipzig

Tel. (0049) 341 – 4 42 29 79

Fax (0049) 341 – 4 42 17 48

Jaime A. Cardona : [email protected]

www.bdz-abwasser.de

mailto:[email protected]

http://www.bdz-abwasser.de/

Reuse-oriented decentralized wastewater and sewage sludge treatment...

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