Tuesday, March 16, 2021

Water and sanitation in Devanahalli: Fecal Sludge Treatment Plant

 Part 3: Fecal Sludge Treatment Plant

Devanahalli Fecal Sludge Treatment Plant is the first of its kind in the country. FSTP is functioning from the year 2015. FSTP is implemented by Consortium of DEWATS Dissemination (CDD) Society with the funding from Bill and Melinda Gates foundation. According to CDD's report "Insights from Fecal Sludge Management in Devanahalli", FSTP was implemented to facilitate scientific dumping of fecal sludge and to end open dumping of fecal sludge causing health and environmental hazards. FSTP converts fecal sludge into co-compost which is sold to farmers.

CDD was looking after FSTP for a duration of one year. From 2016 to till date TMC is managing the FSTP entirely with technical guidance from the CDD. The plant manager, civil engineer is from the outsourced private company who was appointed in 2019.

ABS system


Finances of FSTP: The capital cost of FSTP is Rs.8,000,000. The land belonged to TMC and thus capital cost excludes the land cost. Major cost of maintenance of FSTP is on paying the manpower. FSTP has one manager, one plant operator and 3 workers collecting wet waste. Rs. 15,000 is the salary paid to four workers. This makes about Rs.180,000 per annum. 

Operational capacity: According to CDD's report FSTP is designed to treat 6000litres of FS in a day and FSTP is currently operating at 1/3rd of its capacity. According to TMC in a day 3000litres of fecal sludge is collected in the FSTP (this could be a single trip or 2-3 trips having around 1000litres capacity). In 2020, Government owned honey sucker has just made 12 trips a year whereas private owned honey sucker made 333 trips. 

Co-compost: Fecal sludge compost is mixed with Municipal wet waste in 1:3 ratio to create co-compost. Co-compost is suggested to balance the Nitrogen level where E-Coli and Fecal Coli growth (could grow when applied to soil) can be permanently stopped when mixed with wet waste. CDD experimented the efficiency of co-compost by applying it on to the plants grown in the FSTP premises. Only after the results were proved to be good co-compost was sold to the farmers. Co-compost is sold to farmers at Rs.7 per kilogram. Currently there are 10-12 farmers buying co-compost in smaller quantities and 5-6 farmers buying in tons. There are mixed opinions from farmers using co-compost, few find the co-compost is not giving good results and few say they are benefitted. There are farmers who are reluctant to buy co-compost because it is fecal sludge and famers who bought co-compost without being aware it is fecal sludge never returned to buy. Co-compost is generally used for rose and grapes which are best suited as the farmers suggest. Yearly 200-250 tons of co-compost is generated. When FSTP was just started, advertisements on co-compost and FSTP was made using print media and on auto rickshaws. 

Monitoring of FSTP: TMC has been monitoring FSTP for almost two years. There are no challenges currently faced by TMC in maintaining the FSTP because of the efficient worker Mr. Rajkumar. Rajkumar has been working in FSTP since its inception. He brings every small or major issue into TMC's notice which reduces TMC’s burden. Environmental Engineer Miss. Nethravathi gives all the credit to Rajkumar for the success of FSTP by saying "if Rajkumar wasn't there we would have neglected FSTP in all the bundles of works we handle."TMC is now planning to train other worker to reduce the dependence on only one worker.

Records: A ledger is regularly maintained by Rajkumar which contains all the details of honey suckers. The details include, date, government or private, name of the driver, contact number, quantity of fecal sludge and its sludge and water ratio, type of pit toilet and dept, Valve one or two, time of flow to BioGas digester, weight of solid waste in kg etc.

Wastewater disposal: Commercial units have created big tanks to hold grey water in the areas where there are no storm water drains. Wastewater(grey water) from these tanks are emptied by honey suckers and allowed to discharge in farmers fields since it has nutrients beneficial for agricultural fields. 

TMC on-field checks: TMC makes frequent field visits. TMC officials stop the honey suckers and check the type of sludge (grey water from commercial units or fecal sludge) and where they are emptying frequently.

Penalty on honey suckers: TMC is putting fines on the honey suckers who are disposing fecal sludge in open spaces. Honey Sucker operator Mr.Ramesh was fined Rs.5000 for dumping in a farm field. 

Biogas Digester: Biogas Digester has been very inefficient since day one. it was supposed to fulfill the cooking needs of Rajkumar. It would take two hours to cook rice using the limited biogas generated. Rajkumar approached CDD and asked them to provide an alternate fuel source. He has got a gas cylinder from CDD and cooking and now he says, he has put the air out option in the biogas digester always open which would generate no gas!

Wet waste: Wet waste is collected from 10 wards currently. FSTP does not aim to be a complete solution for wet waste and thus total wet waste generated is not fully utilized in FSTP. Currently there are 4 complete wet waste composts and one partial compost under TMC.

- Rakshitha M L

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