This document discusses the design and operation of a decentralized wastewater treatment plant in Chennai, India that uses biological treatment processes. The plant serves 55,000 people and uses principles of carbon elimination, nitrification, and denitrification. It follows guidelines from ATV 131, the German technical standard for wastewater treatment plant design. The document outlines the treatment process, design considerations, and compares German and Indian wastewater treatment standards. It also analyzes how treatment plant size and volume requirements vary with influent temperature and population size.

1. Presented by:
Alex Tagbo
Shashank Giridhar
Sunil Kumar
1

2. Type of wastewater treatment
plant
 This plant is a decentralized one since chennai is a
very large city.
 The plant is designed to serve 55000 people.
 It is a pilot project and its main purpose is research
and development.
 The water from the plant is sent to the river or could
later be processed to drinking water.
2

3. Principles of biological elimination of
pollution
 Elimination of organic matter
org. C + O2 →Biomass + CO2 +H2O
 Nitrification
NH4 →NO3 / NO2
 Denitrification
NO3 / NO2→N2
3

4. Technical realization of the principle
 In the first process we eliminate carbon.
 The second step is the nitrificaton process where
ammonia is converted into nitrogen di- oxide and
nitrogen tri-oxide.
 The next stage is the denitrification process, where
nitrogen di-oxide and tri-oxide are converted into
nitrogen gas.
4

5. ATV 131
 ATV means Abwassertechnische Vereinigung
that is wastewater technical association in English.
 Using ATV 131, we can meet the achievable minimum
effluent requirement which correspond with the
requirements of the of the German waste water
ordinance.
5

6. Main objective of ATV 131
 Technical regulations for the selection of the most
practical procedure for carbon, nitrogen and
phosphorous removal and for the dimensioning of the
essential components and facilities of the plant.
6

7. Allgemeine Abwasser
 Verwaltungvorschrift uber die Mindestanforderungen
an das Einleiten von Abwasser in Gewasser .
 English translation of the above sentence is
“Administrative rules concerning the discharge of
waste water into water bodies based on minimum
requirements”.
7

8. Procedure for planning and dimensioning using ATV
Design criteria : flow rates and loads for different design cases,effluent
requirements
Other design constraints :
area,subsoil,hyraulics etc
Selection of the process,required sludge age,assumption of
sludge volume index
Design of the secondary settling tank
Design of the biological reactor
Optimum matching of
reactor and settling
tank
Optimised solution
End of dimensioning
8

9. Reactor constructions for biological
nitrogen removal
Post denitrification process Post aeration
Organic carbon
→ Nitrification → D → →
•The process is employed if the waste water has a low
C/N ratio.
•The denitrification tank is downstream from the
nitrification tank.
9

10. Pre-anoxic zone denitrification process
→→ → →
Denl. Nitrification
Internal recirculation Secondary
settling
Return sludge tank
•Waste water, return sludge and internal recirculation
flow are mixed in the denitrification tank.
10

11. Phosphorous Elimination
→ →→ →→
Anaerobic mixing
tank secondary settling
tank
Adenosine tri phosphate is broken down into adenosine
di phosphate and adenosine mono phosphate.
11

12. Specification table
CSB BSB Inorganic P
Nitrogen
Raw water dirt 120 60 11 2.5
Concentration 400-1000 200-500 40-90 10-20
mg/l
Required
quality
<1000 EW 150 40
1000-5000 EW 110 25
5000-20000 90 20 18
20000-100000 90 20 18 2
>100000 75 15 18 1
12

13. Differences between German and
Indian standards
13

14. 14

15. Summary of calculation for A-131
 Documentation of the project.
 Size class and treatment objectives.
 Specification of the process concerning the technical
realization.
 Overview and selection of loads.
 Dimensioning loads, flow rates, concentrations, peak
factors.
15

16.  Loading with the lowest temperature.
 Loading with the highest temperature.
 Selecting the type of sludge thickening, return sludge
and inflow secondary settling.
 Dimensioning of the tank.
 Details of the rotating blade scraper.
 Specifications related to nitrogen balance.
16

17.  Details regarding phosphorous removal.
 Dimensions of activated sludge tank.
 Operation specifications with lowest temperature.
 Operation specifications with highest temperature.
 Oxygen demand specifications.
 Alkalinity
17

18. Important technical aspects of
technology transfer
 Influence of the volume of basin depending on the
size of inhabitants.
 Dependence of volume of basin on produced waste
water per inhabitant per day.
 Influence of temperature on the volume of the basin
18

19. Influence of the volume of basin
depending on the size of inhabitants
Graph of Number of inhabitants Vs Loading
19

20. Graph of Total volume of the basin Vs Number of
inhabitants
20

21. Dependance of volume of basin on produced
waste water per inhabitant per day
21

22. 22

23. Influence of temperature on the
volume of the basin
23

24. Membrane technology
 Membrane technology utilizes a semipermeable
membrane for the
separation of suspended and dissolved
solids from water. There are two basic types of
membrane separation processes;
pressure-driven and electrically-driven.

25.  Pressure-driven processes use
hydraulic pressure to force water molecules
through the membranes.
 In the electrically-driven membrane
process, electric current is used to move
ions across the membrane.

26. Types of pressure driven membranes

28.  Settlement tanks are not required if membrane
technology is used, hence the space required will be
less.
 Settlement Tanks are a limiting factor for the
concentration for biomass in the aeration basin.
 The used basin volume for 100000 inhabitants without
membrane technology is 36653m3 , whereas with
membrane technology it is 18462m3 .

29. THANK YOU FOR YOUR
ATTENTION
29