2. Urban Water Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Dresden, 2010 1Global water aspects 2Introduction to urban water management 3Basics for systems description 4Water transport 5Matter transport 6Introduction to water supply 7Water extraction 8Water purification 9Water distribution 10Introduction to wastewater disposal 11Urban drainage 12Wastewater treatment 13Sludge treatment

3. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 2 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

4. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 3 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

5. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 4 Type of water supply Typical consumption l/(Ca·d) Range l/(Ca·d) Communal water point distance > 1000 m distance 500 – 1000 m 7 12 5 – 10 10 – 15 Village well distance < 250 m 20 15 – 25 Communal standpipe distance < 250 m 30 20 – 50 Yard connection 4020 – 80 House connection single tap multiple tap 50 150 30 – 60 70 – 250 Typical domestic water demand

6. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 5 Average domestic water demand in Germany „Western Germany“DE

7. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 6 German drinking water consumption 2007

8. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 7 (Source: DREWAG GmbH (2002)) 80 Drinking water supply (Mio m³/a) 18751900200019801960 1940 1920 60 40 20 0 Water supply in Dresden 1875 – 1999

9. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 8 28% 34% 12% 6% 4% 2% 28% WC 34% bath/shower 12% washing cloths 6% personal hygiene 6% wash dishes 6% cleaning 4% watering 2% cooking/drinking 2% cleaning cars Composition of water consumption

10. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 9 Washing machineDish washer Manufactured(l/cycle) 1980125 – 17545 – 55 1985100 – 12530 – 40 199070 – 12520 – 30 200050 – 6012 – 15 201040 – 5010 – 12 Water use of household appliances

11. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 10 0 0,5 1 1,5 2 2,5 04812162024 Daytime (h) Q / Q m City Town Village Daily average Diurnal variation of water consumption

12. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 11 Water consumption in Dortmund, football world championship Italy-Germany, 11 July 1982 Extreme events of water consumption

13. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 12 Peak factors: peak day, peak hour (DVGW-W 400-1) Peak hour factor f h Peak day factor f d Inhabitants Peak factor

14. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 13 SymbolDefinitionFor dimensioning of Q d,m Mean daily consumptionWater budget, running costs, price Q d,max Maximum daily water consumptionWater extraction, water purification, storage Q h,m Mean hourly consumption = mean daily consumption Q h,max Maximum hourly consumptionDistribution system, storage Definition and application of peak factors

15. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 14 AgricultureDomestic Industry Others Africa 214 km³ Asia 2156 km³ Europe 512 km³ North America 680,8 km³ South America 166 km³ Oceania 33,6 km³ World 3760 km³ (Source: WRI (2001)) Water use

16. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 15 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

17. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 16 Q dw Dry-weather flow Q s Sewage flow Q ew Extraneous water flow Q dom Domestic sewage flow Q ind Industrial sewage water flow  all parameters are subject to distinct variations! Q dw = Q s + Q ew Q s = Q dom + Q ind Wastewater fluxes: dry-weather conditions

18. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 17 Groundwater infiltration Drainage water Spring and brook water Fountain water Cooling water Excess water from reservoirs  Extraneous water flow is variable Rule of thumb Extraneous water flow Q ew

19. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 18 Overflow structure Receiving water CSO Combined water storage WWTP Treated wastewater Sewage storage Urban drainage at wet-weather conditions (i)

20. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 19 Significance of rain events Rain runoff  decisive for sewer dimension WWTP operation is disturbed for a longer time period than rain event Rainwater is contaminated after runoff Sewer sediments are eroded Rain water causes overflow of sewage Urban drainage at wet-weather conditions (ii)

21. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 20 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality Department of Hydro Sciences, Institute for Urban Water Management Peter Krebs Urban Water

22. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 21 TSS Total Suspended Solids Filter with pore width 0.45 m Sedimentation VSS Volatile Suspended Solids Glow of TSS at 650°C volatile fraction is organic substance incl. biomass important for oxygen depletion TSS – VSS Non-organic solids Particulate compounds

23. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 22 BOD 5 biochemical oxygen demand in 5 days 5 days, 20°C, dark  reduction of O 2 -concentration bio-degradable organic substances dilution with O 2 -rich water, inoculation of biomass COD chemical oxygen demand Complete oxidation of org. substances to CO 2 and H 2 O Oxidation means potassium-di-chromate (K 2 Cr 2 O 7 ) in high temperature and acid environment all org. substances, not only bio-degradable COD can be balanced Parameters indicating oxygen consumption

24. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 23 NH 4 + Ammonium and NH 3 ammonia the total is measured equilibrium is depending on temperature and pH-value  Temp. and pH high  NH 3 -fraction higher Degradation of organic compounds  NH 4 + is released Nitrification to nitrate  oxygen depletion NO 3 - Nitrate and NO 2 - nitrite (NH 4 + + NH 3 )  NO 2 -  NO 3 - Nitrite is toxic to fish Nitrate is a problem in groundwater Nitrogen compounds

25. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 24 TKN total Kjeldahl Nitrogen Sum of organic N + ammonia-N) org. N in proteins Chemical oxidation of org. N  the released ammonia is measured N 2 nitrogen gas N 2 main fraction of atmosphere Hydrophobic Denitrification NO 3 -  N 2 Nitrogen

26. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 25 TOC total organic carbon DOC dissolved organic carbon Includes all organic compounds Measurement (  CO 2 ) expensive, accurate org. P part of DNA, RNA Analytics: org. P is mineralised, the product ortho- phosphate is measured TP, P tot total phosphorous DP dissolved phosphorous PO 4 –P ortho-phosphate Organic carbon and phosphorous

27. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 26 1,5 1,7 P tot 10 11 TKN 30354070 TSS 8090100120 COD 40455060 BOD 5 > 1.5 h1.0 – 1.5 h0.5 – 1.0 h Residence time in primary clarifierParameter After primary sedimentationRaw sewage Population equivalents in g/(Ca∙d)

28. Urban Water Chapter 2 Basics for system description © PK, 2010 – page 27 Diurnal variation of dry-weather loads