CHENNAI: Ours is one of the few countries in the world where people still get into sewers to check and unclog them. There are sewage tankers that are seen around town very often. We have an unparalleled level of tolerance with sewage, its handling and treatment. So let’s talk sewage; it is not as dirty as it connotes!
The city has grown from having open drains in the 1800s into one with a planned sewage system in 1914. Since then the network has grown into five zones with pumping stations covering the city. Why do we still encounter sewage tankers on our main roads you may ask? It is because many newer parts of the city are still outside the utility limits and rely on alternate methods for dealing with their daily waste water.
Water is a scarce resource, and it is sustainable to recycle sewage water. Larger developments often have their own sewage treatment plant (STP) as part of their green initiatives. When using an STP, water is treated so that it can be effectively reused for landscaping or flushing needs.
As a resident of an area unconnected to a sewer system, it is my responsibility to handle my sewage is. The most effective way to handling this for a small scale residence or in rural areas is to have a small septic tank with a soak pit.
The septic tank is a watertight box, usually made of concrete or fiberglass, with an inlet and outlet pipe. Wastewater flows from the home to the septic tank through the sewer pipe. The septic tank treats the wastewater naturally by holding it in the tank.
The wastewater forms three layers inside the tank. Scum on top, sludge at the bottom and grey water in the middle. While the grey water percolates through the leach pit and is bio-filtered by gravel and soil, the solids have to be periodically pumped out. That is when the sewage tanker comes on to our roads!
As a proud owner of an on-site sewage facility, here are some ways in which you can extend the life of the system and put off pumping as long as possible! The first thing to do is to design the system so there is a different tank for sewage and another for waste from toilets and kitchens.
This reduces the amount of solids drastically, with the wash basin and shower water soaking into the ground directly. Fats, oils and grease from the sink are hard for the natural microbes to break down. Disinfectants and cleaners take long to break down. One must be restrained too with the use of disinfectants and cleaning chemicals, especially the drain unclogging ones. They can contaminate the sub soil with unwanted chemicals.
Flushing the toilet with cloth, plastic, empty tubes and bottles clog the drain and sewage pipes. And lastly, talk to your sewage tanker operator to ensure they discharge the waste in an approved area and not dump surreptitiously where no one is watching!
(The writer is an architect, urban designer, dancer and chief designer at Shilpa Architects)