This document provides an overview of wastewater and drinking water treatment from both a theoretical and legal perspective. It discusses key definitions and requirements related to wastewater collection, treatment according to the Urban Wastewater Treatment Directive, and sludge treatment and disposal according to the Sewage Sludge Directive. It also outlines the standards for drinking water quality established by the Drinking Water Directive and typical treatment steps. Finally, it addresses some frequently asked questions about topics like modernizing treatment infrastructure, alternative treatment options, and combined sewer systems.

1. Wastewater and Drinking
Water Treatment:
Theoretical and Legal
Aspects
Jelena Rozova
EC Trainee
DG REGIO Cohesion Fund Closure
October 25, 2013

2. Agenda
1.Wastewater Treatment
2.Sludge Treatment
3.Drinking Water Treatment
4.Frequently Asked Questions
2

3. Agenda
1.Wastewater Treatment
• Definitions, content, origin
• 91/271/EEC Urban Wastewater Treatment Directive
• Wastewater treatment steps
1.Sludge Treatment
2.Drinking Water Treatment
3.Frequently Asked Questions
3

4. 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
4

5. Wastewater constituents
Nutrients
•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
5

6. Wastewater constituents
Pathogens
•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.)
6

7. Some wastewater related problems
Human and wildlife acute and chronic health risks
Brain and nervous system
Endocrine system disruption
Toxicity
Cancer etc.
Drinking water source contamination
Infiltrated wastewater from sewage leaks into groundwater
Discharge of untreated wastewater into surface water
Poor ecological and chemical water status
Eutrophication
7

8. Eutrophication
8

9. 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
9

10. Definitions in UWWTD
Domestic 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
10

11. Definitions in UWWTD
Sensitive 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
11

12. Definitions in UWWTD
One 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
12

13. Important Articles in UWWTD
13

14. Wastewater treatment steps
Wastewater Flow
Raw
wastewater
Treated
wastewater
14

15. Collecting systems
Collecting systems are systems of
conduits which collect and conduct
urban wastewater
Include: pipelines, collection basins,
pumps, vacuum systems
Design considerations: population to be
connected, industrial and urban flows,
peak flows, ground type, land profile
15

16. 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
16

17. Pre-treatment
Pre-treatment is the removal of coarse solids, floating solids
and sand using mechanical processes
Bar screens Grit chamber
17

18. 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 sludge
Specific authorisation from competent body is needed
Depending on industrial wastewater quality pre-treatment
might mean not only mechanical, but also secondary
treatment 18

19. Primary treatment
Primary treatment is physical and/or chemical process during
which suspended solids are removed by passing wastewater
through settlement or flotation tanks
19

20. Primary treatment
20
Floating oil
Settle-able solids

21. Secondary treatment
Secondary treatment is a biological treatment during which
wastewater passes through tanks where bacteria "eat"
pollutants and transform them into sludge
Secondary treatment in place (Art. 4 UWWTD)
agglomerations > 2000 p.e.
(freshwaters and estuaries waters)
21

22. Secondary treatment
22

23. 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)
Chlorination
Ultraviolet (UV) radiation
Ozone treatment
23

24. Wastewater limit values in UWWTD
Parameter
Type of waters
Normal waters Sensitive Waters
BOD5 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%)
24

25. Wastewater treatment plant
example
25

26. Typical wastewater treatment
process train
26

27. Agenda
1.Wastewater Treatment
2.Sludge Treatment
• Definitions, source, types of disposal
• Sludge treatment processes
• 86/278/EEC Sewage Sludge Directive
1.Drinking Water Treatment
2.Frequently Asked Questions
27

28. Sludge definition
Sludge 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)
28

29. Sludge treatment
Most common sludge treatment process train
1. Pre-thickening
2. Anaerobic digestion (~30 days, presence of
anaerobic bacteria)
3. Post-thickening
4. Mechanical dewatering
5. Disposal (e.g. incineration)
After treatment next goals achieved
Reduced volume of the material
Reduced odours
Killed pathogens
29

30. Sludge treatment at WWTP
30

31. 10 digesters at Hamburg WWTP
31

32. Sewage Sludge Directive
86/278/EEC
32
• 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

33. Sludge disposal options
33
Incineration (most widely used)
Landscaping
Agriculture
•Decreasing due to contamination of crops
•Restrictions for use on grassland, fruit and vegetable crops
Landfilling
•Forbidden in Germany since 2006 due to high amount of
organic contaminants

34. Agenda
1.Wastewater Treatment
2.Sludge Treatment
3.Drinking Water Treatment
• 98/83/EC Drinking Water Directive
• Drinking water treatment steps
1.Frequently Asked Questions
34

35. 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"
35

36. Range of application in drinking WTP
36

37. 37
Tertiary treatment - Ozonation

38. 38
Tertiary treatment – Adsorption

39. 39
Tertiary treatment – Nanofiltation

40. Agenda
1.Wastewater Treatment
2.Sludge Treatment
3.Drinking Water Treatment
4.Frequently Asked Questions
40

41. Questions answered in presentation
1. 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 UWWTD
6. Obligations for industries regarding pre-treatment of discharged
wastewater into collecting systems
7. Links to different directives is in Annex I of this presentation
8. In which cases wastewater should be treated with more stringent
limit values?
41

42. I. Modernisation of networks and
WWTPs
42
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

43. II. Alternative treatment steps
It 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!
43

44. III. Combined sewers
VS separate collection systems?
44

45. III. Combined sewers
VS separate collection systems?
45
Combined sewers overflow consequences during heavy
rains:
•Potential health hazards in contact with wastewater
•Malfunction of WWTP
•Poor quality of water treatment
•Environmental pollution

46. 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
46

47. •Thank you for your
attention!
47

48. Annex 1. Directives, regulations and other documents
91/271/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
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1980:229:0011:0029:EN:PDF
98/83/EC Directive on the quality of water intended for human consumption
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1998:330:0032:0054:EN:PDF
76/160/EEC Directive concerning the quality of bathing water
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1976:031:0001:0007:EN:PDF
2006/7/EC Directive concerning the management of bathing water quality and repealing Directive
76/160/EEC
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:064:0037:0051:EN:PDF
86/278/EEC Directive on the protection of the environment, and in particular of the soil, when sewage
sludge is used in agriculture
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1986:181:0006:0012:EN:PDF
48

49. Annex 1 (continued). Directives, regulations and other documents
2000/60/EEC Directive establishing a framework for Community action in the field of water policy
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2000:327:0001:0001:EN:PDF
75/440/EEC Directive concerning the quality required of surface water intended for the abstraction of
drinking water
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1975:194:0026:0031:EN:PDF
2008/105/EC Directive on environmental quality standards in the field of water policy
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:348:0084:0097:EN:PDF
80/68/EEC Directive on the protection of groundwater against pollution caused by certain dangerous
substances
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1980:020:0043:0048:EN:PDF
2006/118/EC Directive on the protection of groundwater against pollution and deterioration
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:372:0019:0019:EN:PDF
76/464/EEC Directive on pollution caused by certain dangerous substances discharged into the aquatic
environment of the Community
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1976:129:0023:0029:EN:PDF
49

50. Annex 1 (continued). Directives, regulations and other documents
2006/11/EC Directive on pollution caused by certain dangerous substances discharged into the aquatic
environment of the Community (codified version)
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:064:0052:0059:EN:PDF
78/659/EEC Directive on the quality of fresh waters needing protection or improvement in order to
support fish life
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1978:222:0001:0010:EN:PDF
91/692/EEC Directive on the quality of fresh waters needing protection or improvement in order to
support fish life (codified version)
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1991:377:0048:0054:EN:PDF
2006/113/EC Directive on the quality required of shellfish waters (codified version)
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:376:0014:0020:EN:PDF
2008/56/EC Directive establishing a framework for community action in the field of marine
environmental policy (marine Strategy Framework Directive)
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:164:0019:0040:EN:PDF
648/2004/EC Regulation on detergents
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2004:104:0001:0035:en:PDF
50

51. 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
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1991:375:0001:0008:EN:PDF
51

52. Annex 2.
Principal
constituents of
concern in
wastewater
treatment
52