I found this very informative article which talks about the existing sewage treatment processes undertaken by Bangalore Water Supply and Sewerage Board (BWSSB) and also the design of a Sewage treatment plant which could be installed in apartment complexes to start solving issues at a smaller scale. Some excerpts ..
... "The Bangalore sewer system has not kept up with the expansion of the city. Many localities still posses open sewers and like the map above indicated BWSSB itself diverts domestic sewage into storm water drains in the natural valleys. To add to this residents who build houses, in the new muncipal zones, are asked to build their own sewage treatment plant. This has led to plethora of problems propagated by a lack of compliance, thought, and non-functioning or improper-functioning of the sewage treatment plants. There are now companies that will come to your house and pump sewage out in a truck. They usually download it at the nearest lake bed." ...
.. "In the enlarged Bangalore muncipality area, BBMP, the BWSSB has thrown its hands up. It has asked all apartments to build their own sewage treatment plant. I presume with some guidelines on the quality of treated water. These apartments are then allowed to run the treated sewage water into the nearest lake, storm water drain (natural or otherwise). I am not sure if this is well thought out or this rampant development of Bangalore has caused this chaos. I live in one such apartment complex where we have our own sewage treatment plant. The treated water from the plant is not good enough to drink or bathe in but is enough to do landscape (65000 litres per day ); good enough for car wash (15000 litres per day ); more than good enough to use it for flushing (30000 litres per day ). This still leaves about 20000 litres of treated water which is let out on a daily basis."
Read the full article for understanding the basics of a sewage treatment plant ..
I have been voluntarily involved with many NGOs in India since 2002. I strongly believe that all of us can do more by coming together, sharing ideas and working together to address social issues! A techie by training - I have a Bachelor of Technology from IIT Bombay and Masters of Science from U.....read more