There have been a few posts in the past that have made reference to DEWATS systems in regards to the sewerage challenges the Project Sammaan team has faced. While some of these posts have shed a little light into what DEWATS is, we thought a more detailed presentation was in order.
A DEWATS system has 3 primary components:
Biogas Settler: The primary filtration point for the waste, this is a simple tank (similar to current septic tanks) that allow primary separation of solid and liquid waste under anaerobic conditions. Biogas that is generated by the microbial breakdown of the waste is collected and can be used as an energy source.
Anaerobic Baffled Reactor: This is the principal site for the treatment of the waste with an ‘active sludge blanket’ that allows for the breakdown of the dissolved and suspended waste particles. Wastewater typically stays in the reactor for up to 48 hours.
Planted Gravel Filter: The final step in the wastewater treatment is to pass it through a gravel bed with plants that aerobically remove and break down harmful chemicals and pathogens in the waste. This biological filtration and treatment is also supplemented by physical treatment through the use of gravel of varying grades, acting like a sieve to separate out unwanted particulates.
Apart from these three components, the DEWATS system also has a collection sump where the filtered treated water can be collected for use in activities like flushing and household cleaning where high levels of purification are not needed.
The Project Sammaan team strongly believes that DEWATS as a system is best placed to address the growing concerns regarding a sanitation solution and wastewater treatment in Odisha. While the singular disadvantage of DEWATS, it’s requirement for open space (especially for the gravel filter module) means that it cannot, as a system, be deployed in every toilet facility that we are constructing, we are currently working with CDD (The Centre for DEWATS Dissemination) to customize DEWATS systems for as many of the toilet locations as possible.
Look out for an update soon regarding the design of the DEWATS modules customised to the needs of our various toilet locations and user-ratios. We will also be featuring a ‘Partner Profile’ post on CDD and their work on Sammaan. In the meantime, if you would like to find out a little more about their work, you can visit their website here: http://www.cddindia.org/