Auroville is situated on a large plateau, about 65 metres above sea level, sloping gently towards the Bay of Bengal. The absence of rivers or major lakes makes it necessary to draw water needs from underground for its present population of 1500 people. If the projected growth rate towards a small city of 50,000 people is to be achieved and sustained, wastewater treatment will be an essential part of the overall city water use.
Years of experimentation
The Auroville community has been experimenting with small scale wastewater recycling systems for over fifteen years. During that time pilot systems were built, experience was gathered, and the operating skills with such plants improved.
In the mid-eighties the first experiments with recycling of wastewater took place. Absence of specialised literature and proper guidance made the small household pioneer plants more of an exercise in trial and error learning. A dedicated group maintained the interest in the subject and relied for expert advice and information mainly on visiting experts from western countries. During the nineties the preferred choice for recycling domestic wastewater shifted towards treatment systems called planted filters. With such natural functioning systems one could obtain a high quality effluent. The large space requirement for this kind of system was not viewed as a disadvantage since the treatment systems can be beautifully landscaped into any environment, even urban.
Root zone treatment systems
From 1995 to 1998 Auroville participated in a European Union funded project on Decentralised Wastewater Systems (DEWATS) The project was executed by BORDA (Bremen Overseas Research and Development Association), and gave Auroville the opportunity to research and develop horizontal planted filters, also called constructed wetlands or root zone treatment systems. Access to expertise in the technology proved extremely beneficial for further growth and development. Four specially designed research plants were constructed and tested under the project.
At present Auroville operates nearly sixty treatment systems for recycling domestic wastewater, from small individual households to communities and small industrial units, producing effluent with similar characteristics to domestic wastewater.
The use of horizontal planted filters for decentralised wastewater treatment in Auroville, an overview and description.