Solid waste management and liquid waste management cannot be separated given flow of sewage in open drains. Solid waste management is an integral part of the sanitation system.
Devanahalli : The Sanitation Safety Plan Trial and Fecal Sludge Management
The WHO has been piloting a planning process called the Sanitation Safety Planning (SSP) process as a vehicle for implementation of the 2006 WHO Guidelines for Safe Use of Wastewater Excreta and Greywater in Agriculture and Aquaculture. The Sanitation Safety Planning approach recognizes that the underlying objective of all sanitation engineering and investment is to protect public health. This approach is a health risk management approach with an emphasis on safe use of human waste. It assists in identifying and managing health risk across the entire sanitation chain (“from toilet to table”) and guide investments in sanitation where it will have the greatest public health impact.
The Devanahalli Town was identified as one of the trial towns for piloting this approach. The SSP was conducted by the Devanahalli Town Municipal Council under the leadership of the Karnataka Urban Water Supply and Drainage Board. The WHO entrusted Biome Environmental Trust to facilitate the trial planning with hand holding support and connecting the municipal council to resource partners. St Johns Medical College was a health partner in the identification of health risks across the sanitation chain.
The system boundary for the SSP was the Town Municipal council boundary – covering a population of around 30,000 people. This SSP was completed in 2014.
Description of Sanitation Chain in Devanahalli: Devanahalli is dependent completely on groundwater which is a scarce resource. Some sixty odd borewells (many of which have gone dry) are the source of water for devanahalli. This water is pumped to overhead tanks which is then piped and supplied to Devanahalli town. Water supply pipes in many places run parallel to or in the drains. Water supply is intermittent and not adequate to meet the demands of the town. Private tankers are also observed to provide water supply as a supplemental source.
Devanahalli town suffers from acute water shortage especially during summer time. Devanahalli does not have piped sewage or Sewage treatment plants. Devanahalli has combination of pit toilets and untreated sewage (black water) flows in open drains. Greywater also flows in open drains. The open drains are meant to be stormwater drains for the town.
While there is door to door collection of solid waste, segregation of solid waste does not yet exist. Solid waste is “dumped” in pre-identified land in an unscientific manner. Identifying appropriate land for scientific landfill has been a great challenge for Devanahalli town. A lot of solid waste finds its way also to open drains. Therefore there is a lot of sewage stagnation in drains.
A Vacuum truck operated by the town municipal council empties pits. Private vacuum trucks providing the same service are observed too. Farmers divert waste water from open drains to use for agriculture irrigation. Furrow irrigation is used to irrigate crops with waste water. Farms are irrigated with a mix of waste water and fresh water depending on availability of fresh water. Crops grown with waste water irrigation include root vegetables (carrot and beetroot), finger millet, vegetables such as knool kol, beans, bottlegourd, and leafy vegetables such as coriander, mint and spinach. Private Vaccuum trucks also deposit fecal sludge in certain farms for use as fertilizer. This fecal sludge is composted for 6-8 months before use of it as fertilizer to grow crops such as grapes, Ragi, flowers, spinach and coriander.
Organic solid waste composting is not done by farmers yet but conversations indicate their willingness to compost organic solidwaste in their farms if assurance of segregated waste is provided.
Important Conclusions from the SSP Trial: Solid waste management and liquid waste management cannot be separated given flow of sewage in open drains. Solid waste management is an integral part of the sanitation system. Source segregation and good solid waste management is essential to de-risk health risks from sewage in drains. Drain cleaning and sanitary workers cleaning the drains represent the highest health risk and exposure group to this risk. Water supply being contaminated by flowing sewage in drains represents also a high health risk with the entire community being an exposure group for this risk.
There is great potential for reuse of composted organic solid waste as a fertilizer as farmers are willing to use the same given assurance of segregation. It is possible to use farmer’s lands as places for solid-waste/fecal sludge composting. Combination of Farmer hygiene and irrigation practices, choice of crops, washing of produce with fresh water before going to markets and culture of peeling and washing of vegetables before consumption represents significant control measures to de-risk hazards presented by waste water irrigation.
Farmer / consumer health surveys support that as of today these represent relatively lower risks. Working with farmers to implement protocols of how to apply waste-water irrigation can lower risks even further. Fecal sludge use by farmers currently is after a 6-8 month period of composting by mixing human fecal sludge with other forms of organic fertilizer (eg: cow dung) and soil. This de-risk health risks presented by fecal sludge use. Working with farmers to implement protocols of how to apply fecal sludge can lower risks even further.
Implementing SSP Trial improvement plans: Currently the following are undertaken as steps towards implementing improvements in the sanitation system towards better public health: Solid-waste Source segregation drive is being undertaken with land allocated for solid-waste/fecal sludge co-composting. Here demonstration of safe composting will be done. Separate dry waste collection and recycling is also being planned. A registry of all farmers in Devanahalli, their land and crops is being done for outreach and communication and exploration of protocol implementation.