The dhalaos, built unscientifically, are now a health hazard. Instead of yielding valuable compost, they have turned into foul-smelling heaps of rotting garbage.
A SDMC composting pit at a dhalao
Composting pits made by South Delhi Municipal Corporation at the various dhalaos [local waste collection centres] in Dwarka have been rendered useless. The horticultural waste and wet waste dumped in them remain unattended, highlighting yet another failure of the corporation.
“The pits are useless — they are neither of the right size nor scientific. The ones at the dhalaos in Sector 11 and 12 make a mockery of the waste-management claims of the corporation,” said PK Jain, a resident of Sector 12.
The pits were constructed just after the new corporation came to power in April 2017. Many feel they were rashly built to draw mileage under the Clean India Mission.
Arvind Rudra , an environmental expert, also a resident of Harmony Apartments in Sector 4, explained to City Spidey, “We are constructing compost pits along dhalaos, which receive mixed waste. This waste has to be first segregated and then put inside the pits. But sometimes, even this basic process falters. What we are presently making are brick-walled pits sized 3 m x 1.2 m x 1 m, with some holes in walls to facilitate air transfer.”
He continued, “This is where we are going wrong. The pits soon become ‘anaerobic’ zones, or an area devoid of any oxygen. The waste needs to be brought in contact with atmospheric oxygen for composting to happen. But due to ‘compaction’ in the pit, there’s no space for aeration, and thus, the waste will only become more and more foul smelling.”
According to experts, waste needs to be wet (initially 50 per cent moisture) and needs to be shuffled or turned regularly to expose different layers to the atmosphere. It also has to be done in a cool place to facilitate the growth and sustenance microorganisms that will convert the waste to compost. It also needs to be dried and shredded in small pieces to accelerate this conversion.
According to Rudra, waste containing oil or fat needs to be segregated and treated in a different way, as the process and time taken for raw vegetables and garden waste to turn into compost is different from the manner in which cooked grease-stained waste is turned into compost.
All these technical details are missing from the compost pits made by the corporation. “Let’s not waste public resources for unscientific and non-standard practices, especially in areas where established procedures and domain knowledge already exists,” lashed out Rudra.
Composting is an established process practiced all over the world with great results — turning biodegradable waste into micronutrient-rich compost. If done efficiently, it results in a rich resource, but if left to rot, it becomes an environmental hazard. “Due to anaerobic conditions it can lead to the release of methane gas, which is a risk to the surrounding environment.”
