urban water department of hydro sciences, institute for urban water management peter krebs dresden,...

Urban Water

Department of Hydro Sciences, Institute for Urban Water Management

Peter Krebs Dresden, 2010

1 Global water aspects

2 Introduction to urban water management

3 Basics for systems description

4 Water transport

5 Matter transport

6 Introduction to water supply

7 Water extraction

8 Water purification

9 Water distribution

10 Introduction to wastewater disposal

11 Urban drainage

12 Wastewater treatment

13 Sludge treatment

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


Peter Krebs

Urban Water







Peter Krebs

Urban Water


Type of water supplyTypical consumption

l/(Ca·d)Rangel/(Ca·d)

Communal water pointdistance > 1000 m distance 500 – 1000 m

712

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 tapmultiple tap

50

150

30 – 60

70 – 250

Typical domestic water demand


Average domestic water demand in Germany

124

135

147 146144

132129

127 126

122

80

90

100

110

120

130

140

150

160

1975 1979 1983 1987 1991 1995 1998 2001 2004 2007

Wat

er c

on

sum

pti

on

l/(

Per

son

day

)

„Western Germany“ DE


German drinking water consumption 2007

116

133

112

98

127133

123

100

128135

118 116

8590

133

90

122

0

20

40

60

80

100

120

140

160

Baden

-Wür

ttem

berg

Bayer

n

Berlin

Brand

enbu

rg

Brem

en

Hambu

rg

Hesse

n

Mec

klenb

urg-

Vorpo

mm

ern

Nieder

sach

sen

Nordr

hein-

Wes

tfalen

Rheinl

and-

Pfalz

Saarla

nd

Sachs

en

Sachs

en-A

nhalt

Schles

wig-Hols

tein

Thürin

gen

Deutsc

hland

Wat

er c

on

sum

pti

on

l/(

Per

son

day

)


(Source: DREWAG GmbH (2002))

80

Dri

nki

ng

wat

er s

up

ply

(M

io m

³/a)

1875 1900 20001980196019401920

60

40

20

0

Water supply in Dresden 1875 – 1999


28%

34%

12%

6%6%

6% 4% 2%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


Washing machine Dish washer

Manufactured (l/cycle) (l/cycle)

1980 125 – 175 45 – 55

1985 100 – 125 30 – 40

1990 70 – 125 20 – 30

2000 50 – 60 12 – 15

2010 40 – 50 10 – 12

Water use of household appliances


0

0,5

1

1,5

2

2,5

0 4 8 12 16 20 24

Daytime (h)

Q /

Qm

CityTownVillageDaily average

Diurnal variation of water consumption


Water consumption in Dortmund, football world championship Italy-Germany, 11 July 1982

Extreme events of water consumption


0

1

2

3

4

5

6

7

1000 10000 100000 1000000

Anzahl Einwohner

Fak

tor

.

Stundenspitzenfaktor fh

Tagesspitzefaktor fdmd

dd Q

Qf

,

max,

mh

hh Q

Qf

,

max,

Peak factors: peak day, peak hour

(DVGW-W 400-1)

Peak hour factor fh

Peak day factor fd

Inhabitants

Peak

fact

or


Symbol Definition For dimensioning of

Qd,mMean daily consumption Water budget,

running costs, price

Qd,maxMaximum daily water consumption Water extraction,

water purification, storage

Qh,mMean hourly consumption = mean daily consumption

Qh,maxMaximum hourly consumption Distribution system,

storage

md,dmaxd, QfQ

24

QfQfQ md,hmh,hmaxh,

dh

QQ md

mh, /24,

Definition and application of peak factors


Agriculture DomesticIndustry 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







Peter Krebs

Urban Water


Qdw Dry-weather flow

Qs Sewage flow

Qew Extraneous water flow

Qdom Domestic sewage flow

Qind Industrial sewage water flow

all parameters are subject to distinct variations!

Qdw = Qs + Qew

Qs = Qdom + Qind

Wastewater fluxes: dry-weather conditions


• Groundwater infiltration

• Drainage water

• Spring and brook water

• Fountain water

• Cooling water

• Excess water from reservoirs

Extraneous water flow is variable

sew QQ 50.Rule of thumb

Extraneous water flow Qew

)f( lengthpipeQew


Overflow structure

Receiving water

CSO

Combined water storage

WWTP

Treated wastewater

Sewage storage

Urban drainage at wet-weather conditions (i)


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)







Peter Krebs

Urban Water


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


BOD5 biochemical 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

COD chemical 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

Parameters indicating oxygen consumption


NH4+ Ammonium and NH3 ammonia

• 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 compounds


TKN total Kjeldahl Nitrogen

• Sum of organic N + ammonia-N)

• org. N in proteins

• Chemical oxidation of org. N the released ammonia is measured

N2 nitrogen gas

• N2 main fraction of atmosphere

• Hydrophobic

• Denitrification NO3- N2

Nitrogen


TOC total organic carbon

DOC dissolved organic carbon

• Includes all organic compounds

• Measurement ( CO2) expensive, accurate

• org. P part of DNA, RNA

• Analytics: org. P is mineralised, the product ortho-phosphate is measured

TP, Ptot total phosphorous

DP dissolved phosphorous

PO4–P ortho-phosphate

Organic carbon and phosphorous


1,51,51,51,7Ptot

10101011TKN

30354070TSS

8090100120COD

40455060BOD5

> 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)


0

10

20

30

40

50

60

70

00:00 04:00 08:00 12:00 16:00 20:00 00:00

Clock time (hh:mm)

CO

D-l

oa

d (

kg

/h)

0

1

2

3

4

5

6

7

NH

4-lo

ad (

kg/h

)

Daily average ofCOD and NH4

NH4-load

COD-load

Diurnal variation of dry-weather loads

urban water department of hydro sciences, institute for urban water management peter krebs dresden,...

Documents

urban water chapter

water transport

water distribution

water purification

global water aspects

system description pk

average domestic water

urban drainage