Phytorid based DWWTs at Rainbow Drive Society, Bangalore

Site visit by: Sumit Gautam, Mahreen Matto, Chhavi Sharda, Bhitush Luthra, Ridhima Gupta and Bhavik Gupta Date of last visit: 31 / 07/ 2017

Location: Rainbow Drive, Bangalore  
Scale: Community 
Implementing Agency: Petrichor (Private Company)
Technical Consultant: NEERI 
Date of Operation: October, 2014

Designed Capacity:  250 KLD
Capital cost: INR 55 lakhs
O&M cost (including electricity): INR 10,000 per month

Phytorid, is a natural technology which involves creating constructed wetlands (using plants such as Elephant Grass, Canna etc.) which are normally found in natural wetlands and have effective filtration and treatment capability. The technology is a subsurface flow system in which wastewater is applied to cell/system filled with porous media such as gravel and stones. The plant Canna indica are grown on the media. The hydraulics are maintained in such a manner that wastewater does not rise to the surface retaining a free board at the top of the filled media.

The system consists of three zones :

• Inlet zone comprised of gravels and different sizes of stones

• Treatment zone consist of same media as in inlet zone with plant species and Outlet zone

The system with a capacity to treat 250 KL of waste water has following components;

• Anaerobic baffle reactor (8m * 8m * 4m depth)

• Reed bed of 100ft x 30ft x 2.5m depth

• 300 tons of variously sized aggregates has been placed in this system and 900 plants (3 each at 300 spots of various nitrate removing species) have been planted.

As per the back calculation done by the RWA, the phytorid system was expected to offset its investment in approximately 3 years. Operational costs dropped drastically, as against the INR 1 lakh per month maintenance costs (for the STPs), the new system only cost INR 10,000 per month (including electricity).

The treated water is piped back to the existing households in the colony for horticulture purposes.

The treated wastewater meets PCB standards. This treated water adds to sustainability of groundwater in the localcity as freshwater is not used for horticulture purposes. The reduction on the treated effluent for the Total Suspended Solids(TSS) varied from 70% to 80%, BOD from 78% to 84%, Nitrogen from 70% to 75%, Phosphorus from 52% to 64% and faecal coliform from 90% to 97%.

Mr. K.P. Singh
Resident
Rainbow Drive
Bangalore
kpsingh06@gmail.com

Mr. S.  Vishwanath
Principal Architect and Managing Director
Biome Environmental Solutions
Bangalore
zenrainman@gmail.com