Prototype uses PVC baffles to treat domestic sewage

In order to replace expensive and complicated baffles in septic tanks, Rajesh TR, an innovator from Kerala has developed a prototype using baffles made of Polyvinyl chloride (PVC) pipes.

The septic tank is a combined sedimentation cum digestion tank where household sewage is treated. The lighter solids including grease and fat rise to the surface to form scum while the heavier solids settle down to form a sledge, which is gradually decomposed by bacteria. The liquid waste or effluent goes into the drain field and undergoes oxidation.

The baffle in a septic tank helps reduce the disturbance of the settled sludge and keep the solids and scum in the tank. In the conventional septic tank, two baffles made of concrete are used. However, in Rajesh's innovation, only one baffle made of PVC pipes is necessary.

The circular baffle which consists of three chamber works as a divider and filter.

Besides being cost effective, the system gives greater capacity for settling, digestion and storage of sludge and clearer, stench-free effluent through a simple manner.

The National Innovation Foundation (NIF) had sanctioned him Rs 62,500 to conduct a market survey of the prototype and has also applied for patent on his behalf.

"Normally used outlet arrangement of a conventional septic tank is a T shaped pipe. The Bureau of Indian Standards (IS-2470(part-I)-1985) also specifies such an arrangement for outlet system, which extends approximately one-third the depth of water in the septic tank. Under these circumstances, I had proposed the innovation and that could remove the requirement for a baffle system. Also that it is of better efficiency than the conventional system and would be most beneficial to those living in the rural or suburban areas," says Rajesh.

The technology has been licensed to Goa-based GMI Zarahk Moulders Pvt. Ltd.