Tuesday, October 21, 2014

Junasandra and Devarabisanahalli lake teams: Working out solutions

Google Maps with Inlets
The meeting started at 8:15am sharp -  unusually early for a Saturday morning. A group of  8 enthused people who live around the Junasandra lake were looking for help/advice on how they could go about rejuvenating the lake. Some homework had been done diligently -  inlets marked, lake marked on Google Maps, conversations with the BDA that is responsible for this lake,  some thoughts on how the lake could be taken up for rejuvenation. The key questions were around - how to identify/handle encroachment ? How/Where to get the relevant maps that mark the boundary of the lakes as well as the raja kaluves. What would be a good model for the lake ? Would it be ok to have boating ? Was it only to looked at as a place for bio diversity ? How would the maintenance of the lake be funded
Junasandra team - with Priya
First thoughts on lake improvement
2 points that came across quite strongly were that  1) it would be useful to have some place/document where a lot of this information about "how one could go about rejuvenating a lake" be available.  2) Even though all the infrastructure might be in place its only when the people come together, plan out their lake and then actually visit/use it that the lake actually comes to life.

What plant is this ? 
Junasandra + Devarabisanahalli team
Full Gazebo
The Devarabisanhalli lake team meeting was next. 9:15 sharp. Thanks to great time keeping by Priya. They had a different agenda. Their lake had overgrown with a certain kind of water plant. They got  a sample for us to see (need help with the identification of the plant).  There was waste water going into their lake from the nearby village as well as the neighbourhood and this had resulted in the growth of a "water hyacinth" like plant. There seemed to be very many more mosquitoes in their area and a few incidences of dengue. They were not sure as to what their next steps should be. How do they keep the sewage from coming in ? What do they do with the water that is already in the lake ? Was it likely that the lake was responsible for the rise in the number of mosquitoes ?  The 2 key questions from this group were around how to keep the lake free of sewage as well as prevent mosquito breeding.

The "Lakes Project" hopes to address some such queries

Saturday, October 18, 2014

Phytorid at Rainbow Drive, Sarjapura Road

Reed Bed
Rainbow Drive on Sarjapura Road with its 320+ recharge (with 400+ plots on 36 acres) wells is pretty much the oasis on Sarjapura Road where the borewells on their campus are able to yield sufficient water to fulfill their water demand. In addition to this they felt a need to recycle their waste water and use it appropriately.

The  2 existing STPs  of about 200KL capacity required about Rs 1 lakh per month for maintenance and repairs and the water was not of expected quality at all times. This meant that they evaluated various technologies for the replacement of their STP. SBT (from IIT Mumbai) was the technology that they first considered in detail and then decided to drop for various reasons. 

During implementation
Mr KP Singh - instrumental in the implementation
The technology that they finally decided upon was Phytorid from NEERI . This was to be implemented through a company called Petrichor (alumnus of IIT Guwahati). This decision came after a long study of the technical as well as financial implications of the system implementation. Involved visits to the various sites where Phytorid had already been implemented as well as several meetings with the vendors as well as NEERI. Once the committee made its recommendations it was placed before the larger resident group through several open houses that were held for all residents.  All queries (including ownership of land where the plant would be setup) were discussed and resolved with great diligence. The Phytorid plant was expected to offset its investment in about 3 years time. As against the 1 lakh maintenance costs for the older STP, the new Phytorid system is expected to cost only about Rs 10,000 per month for maintenance as there only 2 motors running at any given point in time and there are no moving parts requiring repair. The costs for setting it up so far has been about 55 lakhs. . The system with a capacity to treat 250 KL of waste water  has an anaerobic baffle reactor of 8m * 8m * 4m depth and a reedbed of 100ft x 30ft x 2.5m depth 300 tonnes 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.

Water coming out of the baffle filter
The system has just been commissioned for very controlled testing with some raw sewage as well as output from the existing STP and is seeming to work well. 

Visibly Clean water - at the outlet point
Once the treatment system stabilizes there is a plan to pipe this water back to the various houses for gardening. In the interim there are talks with a local organic farmer who will be willing to use this water for agriculture. With continuous recharge of ground water, frugal use of water , a sound tariff system that supports economic use , water education and now waste water treatment and reuse, Rainbow Drive is on its way to be a totally water sustainable layout.  The design through till implementation has been a labour of love for the core committee which is keenly looking forward to the performance of the system. Our best wishes to them