Reality of residential wastewater organic and hydraulic loads - - PowerPoint PPT Presentation

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

• Dr. Anne CAUCHI

Technical Department VEOLIA WATER

Reality of residential wastewater

• rganic and hydraulic loads

Consequences with respect to testing small WWTP for CE marking

Anne CAUCHI Expert Eaux Usées et Boues

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Stake

Be sure having SWWTP suited to real organic and hydraulic loads Question 1: are organic and hydraulic loads for individual house

well-known? Standard EN 12566-3+A1 fix the daily volume per inhabitant and the range of concentration of this volume : Solution : measurements

Question 2 : what are the best design values?

Solution : propositions witch have to be discussed

150 to 500 BOD5 concentration (mg O2/L) 150 Daily volume (L/ inh.)

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

waste water from individual houses: how to sample ?

Punctual sampling ?

NO (totally random)

Proportional sampling ?

NO (not rather precise)

Sampling from total daily volume :

YES The best way to obtain 24h average sample

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Présentation électronique

4 -

Application

equipment is gathered in a mobile unit

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Présentation électronique

5 -

each site is equipped with a

200L buried tank upstream to the purification plan

In this tank, all the waste

water from the house is rejected (moving T-square) First waste water collecting tank

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Présentation électronique

6 -

Application

a 1m3 storage tank is installed

near the collecting tank

A pump is placed in the collecting

tank to transfer waste water into the storage, as soon as they are produced

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Présentation électronique

7 -

After 24h, the residual volume of

water witch is still at the bottom of the tank is aspired

There Is no more waste water in

the collecting tank (can be 20% of the total pollution). End of the daily collect : pumping the residual volume

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Présentation électronique

8 -

horizontality is verified, height can be read

Measurement of the daily volume

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Présentation électronique

9 -

The 24h sampling can be done

Total volume collected is

well mixed between each elementary samples, to realise finally the 24h sample

Analysis are made in

accredited laboratory

Parameters :

SS, COD, BOD5, NTK, NH4, NO2, NO3, Pt

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Results

138 “24h” samples for 7 days running minimum each house Some for 14 days, one for 21 days Occupiers :

Permanent home Active and retired persons With or without children/baby From 2 to 8 persons Different standing

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Distribution of daily volumes per inhabitant

• ne inhabitant uses less

than 90 litres by day

Reasonable bounds

values are 45

• 135 L/inh.d

average between those

bounds : 81 L/inh.d

Descriptive statistics of the daily volume (L/inh)

135 45 244 16 86 138 90% 10% maximum Minimum Average Samples 0.2 0.4 0.6 0.8 1 50 100 150 200 250

Daily volume L/inh.d

accumulated frequency

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

BOD5 Concentrations in daily volumes

Descriptive statistics

• f the daily BOD5

concentration (mgO2/L)

1230 268 3380 120 667 138 90% 10% maximum Minimum Average Samples

Concentration of BOD5 is

higher than 650 mg O2/L

Reasonable bounds values

are 270 1230 mg O2/L

Average between those

bounds : 600 mg O2/L

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 500 1000 1500 2000 2500 3000 3500

BOD5 of daily sample (mg O2/L)

accumulated frequency

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Comparison with BOD5 Concentrations from European notified laboratory

BOD5 Influent from 8 notified laboratories

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 100 200 300 400 500 600 700 800 900 1000 mg O2/L

network from a block of flats Average : 445 mg O2/L urban network Average : 296 mg O2/L

urban network produce influent with a diluted BOD5concentration

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

At the beginning, the same organic load to be treated Individual house V< 90L/inh.d BOD5> 600 mg O2/L Urban network V > 150 L/EH.d BOD5< 300 mg O2/L

BY-PASS

A SWWTP has to treat concentrated influent SWWTP is tested with diluted influent

How to take this into account ?

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Days after days : not the same loads

Daily hydraulic load (L/inh)

50 100 150 200 250 300 1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 101 106 111 116 121 126 131 136

Daily Organic load (g BOD5/L)

20 40 60 80 100 120 140 160 180 200 1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 101 106 111 116 121 126 131 136

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Relation between volume and BOD5 concentration?

High volume is not necessary

associated to low concentration

Low volume is not necessary

associated to high concentration Illustration : regression graph Its necessary to detail the composition of the daily sample

Water use is precisely take down

during each 24h collection

Daily volume(L) vs BOD5 (mgO2/L) 50 100 150 200 250 300 1000 2000 3000 4000 DBO5 Daily volume

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

Split up a daily pollution

The pollution of one inhabitant can be break up into following

principal components parts :

• bathroom (shower…)
• Kitchen (preparation of meals, dishes)
• Toilets (human excreta)
• Laundry (washes)
• Other activities

Each components is not “full” each day : examples

Inhabitant pollution - day « X »

showers WC dishes washings

Theoretical Total inhabitant pollution

showers

• ther

WC meals dishes washings showers WC dishes washings

Inhabitant pollution - day « Y »

meals

• ther
• ther

meals

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems” Munich, Germany, 8-9 May 2012

First data to think about

What could be the best choice for design rules : weekly average rather

than daily ? 21 90 4.3 16 140 8.6

54

Organic load (g BOD5/inh.d) 51 125 2.5 50 160 3.2

88

Hydraulic load (L/inh.d) 10% 90% 90%/10% Min Max min/max

Average

Weekly average