300 likes | 384 Vues
Dive into the basics of urban water management with a focus on water supply, purification, distribution, wastewater disposal, and treatment processes. Understand parameters, consumption patterns, and quality considerations for efficient systems.
E N D
Department of Hydro Sciences, Institute for Urban Water Management • Global water aspects • Introduction to urban water management • Basics for systems description • Water transport • Matter transport • Introduction to water supply • Water extraction • Water purification • Water distribution • Introduction to wastewater disposal • Urban drainage • Wastewater treatment • Sludge treatment Urban Water Peter Krebs Dresden, 2010
Peter Krebs Department of Hydro Sciences, Institute for Urban Water Management Urban Water 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality
Peter Krebs Department of Hydro Sciences, Institute for Urban Water Management Urban Water 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality
Type of water supply Typical consumptionl/(Ca·d) Rangel/(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 40 20 – 80 House connection single tap multiple tap 50 150 30 – 60 70 – 250 Typical domestic water demand
Average domestic water demand in Germany „Western Germany“ DE
80 60 Drinking water supply (Mio m³/a) 40 20 0 1875 1900 1920 1960 1980 2000 1940 Water supply in Dresden 1875 – 1999 (Source: DREWAG GmbH (2002))
28% WC 34% bath/shower 2% 2% 4% 6% 12% washing cloths 28% 6% 6% personal hygiene 6% 6% wash dishes 6% cleaning 4% watering 12% 2% cooking/drinking 34% 2% cleaning cars Composition of water consumption
2,5 City Town Village 2 Daily average 1,5 m Q / Q 1 0,5 0 0 4 8 12 16 20 24 Daytime (h) Diurnal variation of water consumption
Extreme events of water consumption Water consumption in Dortmund, football world championship Italy-Germany, 11 July 1982
Peak factors: peak day, peak hour Peak hour factor fh Peak factor Peak day factor fd (DVGW-W 400-1) Inhabitants
Africa 214 km³ Asia 2156 km³ Europe 512 km³ World 3760 km³ North America 680,8 km³ South America 166 km³ Oceania 33,6 km³ Agriculture Industry Domestic Others Water use (Source: WRI (2001))
Peter Krebs Department of Hydro Sciences, Institute for Urban Water Management Urban Water 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality
Wastewater fluxes: dry-weather conditions Qdw Dry-weather flow Qs Sewage flow Qew Extraneous water flow Qdw = Qs + Qew QdomDomestic sewage flow Qind Industrial sewage water flow Qs = Qdom + Qind all parameters are subject to distinct variations!
Extraneous water flow Qew • Groundwater infiltration • Drainage water • Spring and brook water • Fountain water • Cooling water • Excess water from reservoirs Extraneous water flow is variable Rule of thumb
Sewage storage Overflow structure CSO WWTP Treated wastewater Combined water storage Urban drainage at wet-weather conditions (i) Receiving water
Urban drainage at wet-weather conditions (ii) Significance of rain events • Rain runoff decisive for sewer dimension • Rainwater is contaminated after runoff • Rain water causes overflow of sewage • Sewer sediments are eroded • WWTP operation is disturbed for a longer time period than rain event
Peter Krebs Department of Hydro Sciences, Institute for Urban Water Management Urban Water 2 Basics for system description 2.1 Water consumption 2.2 Wastewater fluxes 2.3 Parameters to characterise water quality
Particulate compounds TSS Total Suspended Solids • Filter with pore width 0.45 m • Sedimentation VSSVolatile Suspended Solids • Glow of TSS at 650°C • volatile fraction is organic substance incl. biomass • important for oxygen depletion TSS – VSSNon-organic solids
Parameters indicating oxygen consumption BOD5biochemical oxygen demand in 5 days • 5 days, 20°C, dark reduction of O2-concentration • bio-degradable organic substances • dilution with O2-rich water, inoculation of biomass CODchemical oxygen demand • Complete oxidation of org. substances to CO2 and H2O • Oxidation means potassium-di-chromate (K2Cr2O7) in high temperature and acid environment • all org. substances, not only bio-degradable • COD can be balanced
Nitrogen compounds NH4+Ammonium and NH3ammonia • the total is measured • equilibrium is depending on temperature and pH-value Temp. and pH high NH3-fraction higher • Degradation of organic compounds NH4+is released • Nitrification to nitrate oxygen depletion NO3-Nitrate and NO2-nitrite • (NH4+ + NH3) NO2- NO3- • Nitrite is toxic to fish • Nitrate is a problem in groundwater
Nitrogen TKNtotal Kjeldahl Nitrogen • Sum of organic N + ammonia-N) • org. N in proteins • Chemical oxidation of org. N the released ammonia is measured N2nitrogen gas • N2 main fraction of atmosphere • Hydrophobic • Denitrification NO3- N2
Organic carbon and phosphorous TOCtotal organic carbon DOC dissolved organic carbon • Includes all organic compounds • Measurement ( CO2) expensive, accurate TP, Ptottotal phosphorous DP dissolved phosphorous PO4–P ortho-phosphate • org. P part of DNA, RNA • Analytics: org. P is mineralised, the product ortho-phosphate is measured
Population equivalents in g/(Ca∙d) Raw sewage After primary sedimentation Parameter Residence time in primary clarifier 0.5 – 1.0 h 1.0 – 1.5 h > 1.5 h BOD5 60 50 45 40 COD 120 100 90 80 TSS 70 40 35 30 TKN 11 10 10 10 Ptot 1,7 1,5 1,5 1,5
70 7 60 6 NH -load 4 50 5 COD-load 40 4 -load (kg/h) COD-load (kg/h) 30 3 4 COD NH Daily average of and NH 20 2 4 10 1 0 0 00:00 04:00 08:00 12:00 16:00 20:00 00:00 Clock time (hh:mm) Diurnal variation of dry-weather loads