1

CIE4485

Wastewater Treatment

Dr.ir. J.G. Langeveld

7. Interactions between wastewater collection and treatment

29 novemberr2012

Challenge the future

DelftUniversity ofTechnology

CT4485 Wastewater Treatment Lecture: Interactions between wastewater collection and treatmentDr. Ir. J.G. Langeveld

2Interactions

Interactions within wastewater systems

sewer transport wwtp+

Effluent

Influent

CSO

DWF + runoff

Receiving waters

3Interactions

DWF variations: diurnal and week profile

Relatie neerslag - verpompt debiet gemaal De Laar

0

50

100

150

200

250

4-5

5-5

6-5

7-5

8-5

9-5

10-5

11-5

12-5

13-5

14-5

15-5

16-5

17-5

18-5

Datum

po

mp

deb

iet

(m3/

h)

0

5

10

15

20

25

30

35

40

45

50

nee

rsal

g (

mm

/d)

pompdebiet neerslag 240 per. Mov. Avg. (pompdebiet)

4Interactions

Annual profile

5Interactions

Impact transport system

DWA profiel

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00

Q/Q

gem

, NH

4/N

H4g

em

QNH4concNH4vracht

6Interactions

Impact pumping station

240 241 242 243 244 245 246 247 248-2000

-1950

-1900

-1850

-1800Verloop rioo lwaterstand in stelsel

tijd (d)

240 241 242 243 244 245 246 247 248-5000

-4800

-4600

-4400

-4200Verloop rioo lwaterstand bij rwzi

tijd (d)

7Interactions

WWF: storm event 29/30 October 2007

• Eindhoven Stad

• Dilution ~ factor 2

• Overall increase of loads during storm events

8Interactions

WWF dynamics: first flush?

0

100

200

300

400

500

600

700

800

900

1,000

29-10-2007 0:00 29-10-2007 6:00 29-10-2007 12:00 29-10-2007 18:00 30-10-2007 0:00 30-10-2007 6:000

2000

4000

6000

8000

10000

12000

14000

16000

CZV debiet

9Interactions

WWF dynamics: first flush??

0

100

200

300

400

500

600

700

800

900

1,000

29-10-2007 0:00 29-10-2007 6:00 29-10-2007 12:00 29-10-2007 18:00 30-10-2007 0:00 30-10-2007 6:0010

10.5

11

11.5

12

12.5

13

13.5

14

CZV niveau

10Interactions

• Normalization of concentration & flow

• Calculation of normalized load

• 24h moving average of loads Peak Load Factor

WWF: storm event 29/30 October 2007

11Interactions

12Interactions

WWF: analysis of PLF

• TSS highest followed by COD followed by CODf

• Differences between catchments

Contradicts earlier research (Kafi et al., 2008)

13Interactions

WWF: origin of additional pollutant loads

• total mass of pollutants (Mpt):

• in-sewer stocks (Mps)

• run-off (Mpr)

• dry weather flow (Mpd)

Gromaire et al., 2001

Mpt = Mps + Mpr + Mpd

14Interactions

• total mass of pollutants measured

• in-sewer stocks ???????

• run-off (Qwwf-Qdwf) * mean conc. Dutch stormwater

• dry weather flow measured, equal to DWF conc.

Gromaire et al., 2001

Mpt = Mps + Mpr + Mpd

WWF: origin of additional pollutant loads

15Interactions

• Mean contribution of in-sewer stocks 20-50%

• Gromaire et al. (2001) 50-60%

• Relative contribution in-sewer stocks larger for smaller catchment

WWF: origin of additional pollutant loads

16Interactions

Interactions within wastewater systems

sewer transport wwtp+

Effluent

Influent

CSO

DWF + runoff

Receiving waters

17Interactions

Impact on wwtp

PC SCASPT AT

18Interactions

Seasonal variation wwtp performance

19Interactions

Short term impacts wwtp performance

20Interactions

Short term impacts wwtp performance

21Interactions

Interactions in the real world

• Spring 2007: 6 weeks without precipitation finalized by storm event of 33 mm on May 7th and 8th

• Monitoring data available of wastewater system Eindhoven:• wwtp: flow and water quality• sewer system: CSO monitoring at CSO vd Heuvellaan and

Kosmoslaan: water level and samples for water quality• River Dommel: continuous oxygen measurements + sampling for

water quality

22Interactions

Monitoring locations Eindhoven area

23Interactions

Storm event May 7/8 2007

24Interactions

Flow river Dommel

01 Jan 01 Feb 01 Mar 01 Apr 01 May 01 Jun0

2

4

6

8

10

12

2007

Q i

n ri

ver

Dom

mel

[m3 /s

]

25Interactions

Influent monitoring: flow and COD

01 Apr 08 Apr 15 Apr 22 Apr 29 Apr 06 May

500700900

11001300

2007

CO

Deq

[m

g/L

]

1500

2000

2500

3000

3500

Q [

m3 /h

]

Q CODeq

26Interactions

Hydraulic performance during event

27Interactions

Hydraulic performance during event

Waterlevel influentpumping station

precipitation

Waterlevel CSO 2

Weir level CSO 2

28Interactions

Impact on wwtp performance during event

29Interactions

Impact on wwtp performance after event

Influent flow

Precipitation

30Interactions

Impact on receiving water quality

Precipitation

31Interactions

Interactions within wastewater systems:wastewater system optimisation

sewer transport wwtp+

Effluent

Influent

CSO

DWF + runoff

Receiving waters

32Interactions

• Network• Below groundlevel• Dirty• ‘simple pipes’• Over 100.000 km in NL.• Municipality• Focus on hydraulics• Service life 40-80 year• Up to 100* DWF

Sewer characteristics

33Interactions

• 1 clear location• visible• High tech• Microbiology/procestechnology• waterboard• Service life 20 year• Up to 3-4* DWF

wwtp characteristics

34Interactions

Example

35Interactions

Impact of storm event

36Interactions

Impact of timing of storm event

37Interactions

Impact of temperature

38Interactions

Impact of additional storage in sewer

39Interactions

Impact of storage on loads

Ammonium load(kg NH4-N)

Ntotal load(kg N)

CODbiodegradable load(kg COD)

Point ofdischarge

currentsystem

6 mm additionalstorage

currentsystem

6 mm additionalstorage

currentsystem

6 mm additionalstorage

CSO loadwwtp loadtotal load

133652

25860

23239262

4326330

15479

233

2595

12049

40Interactions

Impact of pumping capacity

41Interactions

Impact of pumping capacity on loads

Ammonium load(kg NH4-N)

Ntotal load(kg N)

CODbiodegradable load(kg COD)

Point ofdischarge

currentsystem

0.7mm/h

0.6mm/h

0.5mm/h

currentsystem

0.7mm/h

0.6mm/h

0.5mm/h

currentsystem

0.7mm/h

0.6mm/h

0.5mm/h

CSO loadwwtp loadtotal load

133652

142842

161935

23239262

24207231

29176204

15479

233

16474

238

19669

26449

42Interactions

Impact of pressure main

43Interactions

Impact of pressure main

154

200

354

154

97

251

154

79

233

23

268

291

23

236

258

23

239

262

13

118

131

13

49

62

13

36

49

CSO load

wwtp load

total load

24 h6 h current

system

24 h6 h current

system

24 h6 h current

system

CODbiodegradable load

(kg COD)

Ntotal load

(kg N)

Ammonium load

(kg NH4-N)

Point of

discharge

44Interactions

Conclusions of example

• Timing of storm event determines impact – diurnal pattern, seasonal variation

• wwtp is part of wastewater system: anything you do in one part influences the other parts

• The effect of measures for optimization in a wastewater system depends on the selected parameter