Wastewater and Drinking Water Treatment -Theoretical and Legal Aspects

Wastewater and Drinking Water Treatment:

Theoretical and Legal Aspects

Jelena RozovaEC TraineeDG REGIO Cohesion Fund Closure

October 25, 2013

Agenda1. Wastewater Treatment2. Sludge Treatment3. Drinking Water Treatment4. Frequently Asked Questions

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Agenda1. Wastewater Treatment

• Definitions, content, origin• 91/271/EEC Urban Wastewater Treatment Directive• Wastewater treatment steps

2. Sludge Treatment3. Drinking Water Treatment4. Frequently Asked Questions

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What is wastewater?

Wastewater is…•Combination of the liquid or water-carried wastes

Wastewater types…•Household and municipal wastewater•Industrial wastewater (cooling and process water)•Agricultural wastewater•Rainwater overflows•Infiltrated water

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Wastewater constituentsNutrients•Nitrogen N, phosphorus P and carbon C

Heavy metals•Industrial/commercial wastewater (Zn, Cu, Cr etc.)

Suspended solids•Solid particles in suspension

Biodegradable organics•Mostly carbohydrates, fats and proteins

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Wastewater constituentsPathogens•Viruses, bacteria, protozoa

Priority pollutants•Proved or suspected to be carcinogenic, mutagenic, toxic or teratogenicity compounds

Refractory organics•Not easily removed during conventional treatment pollutants (phenols, pesticides, surfactants etc.)

Dissolved inorganics•Pollutants from household activities (Ca, Na, sulphate etc.)

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Some wastewater related problemsHuman and wildlife acute and chronic health risks

Brain and nervous systemEndocrine system disruptionToxicityCancer etc.

Drinking water source contaminationInfiltrated wastewater from sewage leaks into groundwaterDischarge of untreated wastewater into surface water

Poor ecological and chemical water statusEutrophication

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Eutrophication

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Urban Wastewater Treatment Directive (91/271/EEC)

Aims to…•Protect the environment from the adverse effects of wastewater discharges

Concerns…•Collection, treatment and discharge of urban wastewater•Treatment and discharge of certain industrial wastewaters

Requires…•Certain level of treatment (primary, secondary or tertiary) depending on the sensitivity of receiving area

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Definitions in UWWTDDomestic wastewater•Wastewater from residential settlements and services originating mostly from human metabolism and household activities

Industrial wastewater•Any wastewater discharged from any trade or industry, other than domestic wastewater and run-off rainwater

Urban wastewater•Domestic wastewater OR mixture of domestic and industrial wastewater AND/OR run-off rainwater

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Definitions in UWWTDSensitive areas•Freshwater bodies, estuaries and coastal waters which are eutrophic or may become in the near future if protection measures are not taken•Surface freshwater used for abstraction of drinking water which could contain 50 mg/L of nitrate (Directive 75/440/EEC)•Areas where further treatment is necessary to satisfy other Directives

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Definitions in UWWTDOne population equivalent 1 p.e. "The organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day"

Generated load = "size" of agglomeration expressed in p.e.1 p.e. means pollution load produced by 1 person within 24 hours and takes into account

• Resident and non-resident population• Industries covered by Art.11 UWWTD• Industrial wastewater from small and medium enterprises• All remaining urban wastewater

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Important Articles in UWWTD

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Wastewater treatment steps

Wastewater FlowRaw

wastewaterTreated

wastewater

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Collecting systems

Collecting systems are systems of conduits which collect and conduct urban wastewaterInclude: pipelines, collection basins, pumps, vacuum systemsDesign considerations: population to be connected, industrial and urban flows, peak flows, ground type, land profile

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Collecting systems

Collection systems in place (Art. 3 UWWTD)agglomerations > 2000 p.e. (normal waters)agglomerations > 10 000 p.e. (sensitive areas)

Avoid excessive costs in design, construction and maintenance regarding (Annex I A)

• volume and characteristics of wastewater• prevention of leaks• limitation of overflows pollution

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Pre-treatment

Pre-treatment is the removal of coarse solids, floating solids and sand using mechanical processes

Bar screens Grit chamber17

Pre-treatment

Pre-treatment of industrial wastewater prior entering collecting systems is required in order to (Annex I C)

• protect health of workers• protect environment• ensure proper operation of treatment plant• ensure safe disposal of sludgeSpecific authorisation from competent body is neededDepending on industrial wastewater quality pre-treatment

might mean not only mechanical, but also secondary treatment 18

Primary treatment

Primary treatment is physical and/or chemical process during which suspended solids are removed by passing wastewater through settlement or flotation tanks

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Primary treatment

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Floating oil

Settle-able solids

Secondary treatment

Secondary treatment is a biological treatment during which wastewater passes through tanks where bacteria "eat" pollutants and transform them into sludgeSecondary treatment in place (Art. 4 UWWTD)

agglomerations > 2000 p.e. (freshwaters and estuaries waters)

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Secondary treatment

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Tertiary treatment

Tertiary treatment is the advanced treatment involving•Nutrients removal (advanced N and P removal)

• Biological treatment• Physico-chemical treatment (sand filters, chemical addition)

•Disinfection (reduction and/or inactivation of pathogens)ChlorinationUltraviolet (UV) radiationOzone treatment

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Wastewater limit values in UWWTD

ParameterType of waters

Normal waters Sensitive WatersBOD5 25 mgO2/L 25 mgO2/L

Minimum % of reduction 70 - 90% 70 - 90%COD 125 mgO2/L 125 mgO2/L

Minimum % of reduction 75% 75%TSS 35 mg/L 35 mg/L

Minimum % of reduction 90% 90%Total Nitrogen

10 000 - 100 000 p.e. - 15 mg/L (70 - 80%)

>100 000 p.e. - 10 mg/L (70 - 80%)Total Phosphorus

10 000 - 100 000 p.e. - 2 mg/L (80%)>100 000 p.e. - 1 mg/L (80%)

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Wastewater treatment plant example

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Typical wastewater treatment process train

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Agenda1. Wastewater Treatment 2. Sludge Treatment

• Definitions, source, types of disposal• Sludge treatment processes• 86/278/EEC Sewage Sludge Directive

3. Drinking Water Treatment4. Frequently Asked Questions

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Sludge definitionSludge is…Residual sludge, whether treated or untreated, from urban wastewater treatment plant

Sludge sources• Primary settling tank (primary treatment)• Secondary settling tank (2nd part of secondary treatment)

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Sludge treatmentMost common sludge treatment process train

1. Pre-thickening2. Anaerobic digestion (~30 days, presence of

anaerobic bacteria)3. Post-thickening4. Mechanical dewatering5. Disposal (e.g. incineration)

After treatment next goals achievedReduced volume of the materialReduced odoursKilled pathogens

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Sludge treatment at WWTP

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10 digesters at Hamburg WWTP

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Sewage Sludge Directive 86/278/EEC

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• Addresses both pathogen reduction and potential for accumulation of persistent pollutants in soils

• Sets • no limits for organic contaminants• limit values for 7 heavy metals in sludge and in soil

(cadmium, copper, nickel, lead, zinc, mercury and chromium)

• Calls for the use of treated sludge, however no specific treatment processes are outlined

Sludge disposal options

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Incineration (most widely used)LandscapingAgriculture •Decreasing due to contamination of crops•Restrictions for use on grassland, fruit and vegetable cropsLandfilling •Forbidden in Germany since 2006 due to high amount of organic contaminants

Agenda1. Wastewater Treatment 2. Sludge Treatment3. Drinking Water Treatment

• 98/83/EC Drinking Water Directive• Drinking water treatment steps

4. Frequently Asked Questions

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Drinking Water Quality Directive (98/83/EEC)

Establishes…•Strict water quality standards for water intended for human consumption

• 2 microbial parameters• 27 chemical parameters• 19 indicator parameters

Requires…•Member states to monitor drinking water quality•Comply with limit values "at the tap"

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Range of application in drinking WTP

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Tertiary treatment - Ozonation

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Tertiary treatment – Adsorption

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Tertiary treatment – Nanofiltation

Agenda1. Wastewater Treatment 2. Sludge Treatment3. Drinking Water Treatment4. Frequently Asked Questions

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Questions answered in presentation1. Explanation of different wastewater treatment steps and how WWTP works

in principle 2. Requirements and limit values that need to be achieved by Member States

(UWWTD)3. Explanation of definition "1 population equivalent"4. Safe disposal of sludge 5. Explanation of most important Articles in UWWTD6. Obligations for industries regarding pre-treatment of discharged

wastewater into collecting systems7. Links to different directives is in Annex I of this presentation8. In which cases wastewater should be treated with more stringent limit

values?

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I. Modernisation of networks and WWTPs

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WWTP and sewage modernisation is needed to

• increase the treatment capacity due to increasing number of residents

• comply with limit values if the aging treatment plant cannot produce positive results anymore

• eliminate/reduce leakages in networks

Facts that need to be presented by MS

• wastewater treatment plant capacity before and after modernisation• compliance with UWWT Directive and if necessary with other

Directives• proof of leakage reduction

II. Alternative treatment stepsIt is possible to apply alternative treatment step with lower investment and operational costs, if…

•Effluent still complies with UWWTD and other Directives (e.g. Bathing Water Directive)•There is no additional environmental benefit of applying more expensive treatment facilities

BUT…•MS still have to have in place collection systems and secondary treatment in place for certain load generated in agglomeration•Need to double check if MS actually complies with limit values

It strongly depends on details of certain project!

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III. Combined sewers VS separate collection systems?

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III. Combined sewers VS separate collection systems?

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Combined sewers overflow consequences during heavy rains:

•Potential health hazards in contact with wastewater•Malfunction of WWTP•Poor quality of water treatment•Environmental pollution

Questions and topics for detailed research

1. Which parts of projects related to renovation of WWTP and networks are financed by Cohesion Fund?

2. The UWWTD intermediary and final targets of The Accession Treaty ensuring compliance with the provisions of Article 3

3. What if planned WWTP capacity is less in the beginning of the project operation?

4. Global approach to de-polluting receiving waters e.g. river basin management approach

5. Elaborate technicalities of Pollutants which affect process, plant and the effluent quality

6. Enforcement of the relevant directives: role of environmental inspection authorities

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•Thank you for your attention!

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Annex 1. Directives, regulations and other documents91/271/EEC Urban Wastewater Treatment Directive

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1991:135:0040:0052:EN:PDF

Terms and Definitions of the Urban Waste Water Treatment Directive

http://ec.europa.eu/environment/water/water-urbanwaste/info/pdf/terms.pdf

80/778/EEC Directive related to the quality of water intended for human consumption and its revision


98/83/EC Directive on the quality of water intended for human consumption


76/160/EEC Directive concerning the quality of bathing water


2006/7/EC Directive concerning the management of bathing water quality and repealing Directive 76/160/EEC


86/278/EEC Directive on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture


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Annex 1 (continued). Directives, regulations and other documents2000/60/EEC Directive establishing a framework for Community action in the field of water policy


75/440/EEC Directive concerning the quality required of surface water intended for the abstraction of drinking water


2008/105/EC Directive on environmental quality standards in the field of water policy


80/68/EEC Directive on the protection of groundwater against pollution caused by certain dangerous substances


2006/118/EC Directive on the protection of groundwater against pollution and deterioration


76/464/EEC Directive on pollution caused by certain dangerous substances discharged into the aquatic environment of the Community


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Annex 1 (continued). Directives, regulations and other documents2006/11/EC Directive on pollution caused by certain dangerous substances discharged into the aquatic environment of the Community (codified version)


78/659/EEC Directive on the quality of fresh waters needing protection or improvement in order to support fish life


91/692/EEC Directive on the quality of fresh waters needing protection or improvement in order to support fish life (codified version)


2006/113/EC Directive on the quality required of shellfish waters (codified version)


2008/56/EC Directive establishing a framework for community action in the field of marine environmental policy (marine Strategy Framework Directive)


648/2004/EC Regulation on detergents

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2004:104:0001:0035:en:PDF

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Annex 1 (continued). Directives, regulations and other documents

91/676/EEC Directive concerning the protection of waters against pollution caused by nitrates from agricultural sources


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Annex 2.

Principal constituents of concern in wastewater treatment

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Wastewater and Drinking Water Treatment -Theoretical and Legal Aspects

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