By Nripendra Kumar Sarma, Executive Engineer (PHE) in Umrongso PHE Division, Dima Hasao District, Assam
A Zero Waste Plan focuses on immediate responses to dealing with littering, indiscriminate dumping, waste burning etc., contributing to reduction in air pollution, water pollution and in the waste load going for dumping. It takes care of both bio-degradable and non-biodegradable waste, leaving little waste for the landfills.
Source Management of waste: Source management of household waste is the most prioritized options under a Zero Waste Plan. Under this, the mixing of dry, wet, and non-biodegradable waste from the household should be strictly avoided. The practice of segregating waste will stop indiscriminate dumping/littering; encourage segregation at source and home-based composting; and handing over of recyclable waste to collectors, the latter as an option for resource recovery.
Home composting options:
Garbage Pit: A simple earthen pit measuring 1m diameter and 1m depth can be used for dumping of biodegradable waste from households. Under this method, a layer of crushed dry tree leaves should be put on the waste from time to time. It acts as a cover, keeping insects and flies away. Once a pit is filled, it should be given a soil cover while another fresh pit should be dug nearby. The nutrient-rich decomposed waste can be used as compost in kitchen gardens as well as agricultural fields.
Pipe Composting: There are two options for pipe composting: (a) Pipes inserted into the ground surface; and (b) Pipes inserted either into big containers with soil-filled up or to rooftop kitchen garden.
a) Ground Surface Pipe Composting: For ground surface pipe composting, three PVC pipes measuring 2m length and 150-200 mm diameter need to be used. These pipes should be inserted into the ground, preferably near the kitchen, at minimum 1-2 metres apart, by keeping half their length underground. The underground portion of each pipe should remain open to earth and a few small holes should be made in their periphery for allowing leaching. Each pipe should remain covered with an inverted plastic packet (simple carry bag type), to avoid entry of rainwater and any other foreign materials into the pipe. Moreover, these plastic packets should have a few holes from the sides for passage of air.
In the absence of any sub-soil water, approximately 10-15 litres of water needs to be poured into the pipes to start the process. Then one mug of cow dung slurry and one or two handfuls of dry leaves should be added. All biodegradable waste generated daily in the household should be put into the pipe after shredding. Check that there is enough moisture and add one or two mugs of water if dry. Once the pipe is half full, add fresh cow dung slurry and leaves and continue the same procedure until the pipe gets full. At this point, again add fresh cow dung slurry and dry tree leaves and close pipe. From the next day, the same procedure must be followed for the second pipe and subsequently the third pipe. By the time the third pipe gets full, the contents of the first pipe would have decreased in volume and fully decomposed. It can be used as a rich fertilizer for plants.
b) Roof Top/Upper Floor Pipe Composting: As per this method, pipes should be inserted either into big containers with soil-filled up or to the raised earthen layer used for rooftop kitchen garden. In this process, the underground length of pipe may be lesser than that used for ground surface composting. A minimum of 300-450 mm length of pipe will serve the purpose, considering the lesser area surrounding the pipe.
The whole process is the same as that ground surface pipe composting, with only one exception Since the bottom of this system does not allow for any leaching of water, only cow dung slurry should be poured into these pipes and not water. Furthermore, in case of upper floor pipe composting, the container with the inserted pipe should be placed on a balcony exposed to direct sunshine at least for two / three hours a day.
Resource Recovery Option: Large scale processing of non-biodegradable waste can be done using the 5R principal – Reduce, Reuse, Recover, Recycle and Remanufacture (5Rs). Under this, Dry Waste Collection Centres should be established and prioritized at suitable locations, where all forms of dry waste can be collected on ‘Buy Back Approach’ as per market-based value offered by scrap dealers. Such centres can be set by NGOs that can also take care of O&M activities including sorting, storage etc. Scrap dealers need to be encouraged to lift different dry waste in segregated forms, for eventual transformation or recycling.