Decentralised Wastewater Treatment System at Centre for Science and Environment, New Delhi

Location: CSE, New Delhi
Scale: Institutional
Implementing organisation:
CSE and Vijay Vigyan Foundation, New Delhi
Designed Capacity: 8KLD
Operational since : 2006
Capital cost :  Rs 2-3 lakhs
The wastewater recycling system at CSE has been designed to treat 8000 litres per day. The components involved in treatment are a settler, a baffled reactor and a planted filter. The DWWT system receives 5000-6000 litres of wastewater evreday which is treated and stored in an underground sump. This treated wastewater is pumped and reused for gardening purpose in the CSE premises. 
The grey water from the kitchen and black water from the toilets goes to separate settlers for primary treatment. The settler is provided with a baffle wall which aids in controlling the inflow rate and cause effective separation of sludge and scum. Black water from the settler undergoes anaerobic treatment in the baffled reactor. The reactor consists of a series of chambers, in which the wastewater flows up-stream. On the bottom of each chamber activated sludge is retained. During inflow into the chamber wastewater is intensively mixed up with the sludge whereby it is inoculated with wastewater organisms, which decompose the contained pollutants.  The Biological Oxygen Demand or BOD reduction rate of the baffled reactor is about 80%. Grey water from the settler and black water from the baffled reactor  is mixed and goes to planted filter for secondary and tertiary treatment. Canna indica is grown on the planted filter for  for effective removal of nitrate and phosphate from the wastewater. Bottom slope is 1%. The flow direction is mainly horizontal. The main removal mechanisms are biological conversion, physical filtration and chemical adsorption. The final treated wastewater from the planted filter is stored in the 12000 litre capacity sump  This treated wastewater is pumped through 1HP automatic pump for gardening.
Centre for Science and Environment
41, Tughlakabad Institutional Area, New Delhi - 110062
Phone: +91 (011) 29955124/125 , Fax: +91 (011) 29955879