Simple brick tank composting

No underground pits, no fancy or complex organic digesters or converters. Sierra Towers uses a strip of simple brick tanks built along the wall at the far corner of the apartment compound for composting. Located in Lokhandwala, Kandivali East, Mumbai, Sierra Towers, houses 250 families, and these compost tanks have been adequate to hold the wet waste of all the households.

Compost tanks at Sierra Towers, Jan 2016

Tray composting with cocopeat

Laburnum Block in Brigade Millennium is a relatively small apartment complex housing some 50-odd families. For many years, the households have been doing segregation of waste at source, with the wet waste being collected separately by the housekeeping staff.

About 5 years ago, during one of my visits to the block, the then President, Prof. Bhat, showed me the pits located at the periphery of the site, where composting was being done. This is the way many of us, with ground space around our homes, grew up. The wet waste would daily be put into a small pit and covered with a bit of soil. After the pit was filled we would grow plants over it. A new pit would be dug next to the old one to continue.

As the occupancy of the block increased, so did the waste generated, and the association started looking for an alternative method of composting. Mr Virendra Kumar, a resident of Laburnum Block, has shared the composting method that they are now following.

The kitchen waste from the households is collected and kept in bins. Stray plastic and other non-organic waste is removed.

Kitchen waste

Terrace composting

It has been a few years, more than five actually, since we tried composting on the terrace at Brigade Millennium Mayflower Block. Though this very successful pilot experiment has been written about here, I realised that the process has not been properly documented, so here goes!

The objective was to reduce the waste that went out of the 250-flat apartment block. The solution for wet waste was quite obvious, on-site composting.

Those of us from the apartment block who got involved with the project did quite a bit of research to arrive at a sensible, scalable model keeping in mind the existing infrastructure and constraints in the block. We visited a few working sites, read about various methods and engaged with waste management experts and service providers. With the help and guidance of Mr C. Srinivasan, a member of the Supreme Court of India’s Committee on Solid Waste Management, we decided on a method that overcame the lack of space on the ground. The terrace on the 15th floor was identified as a suitable location. Apart from a trolley that was specifically designed for the purpose, the method uses only natural resources – air, water, sunshine, manpower and bacteria present in cowdung/curd.

The trolley
4 ft x 3 ft x 3 ft. Fabricated with metal flats. Fitted with wheels for portability. Cost in 2010 – approx Rs 4,500.

My pots of gold

At a conservative estimate of 2.5 kg of wet waste per week, its more than 300 kgs! This is what my six compost pots have seen since we moved to Mumbai more than two years ago.

The pots are placed in an open balcony, and being on a high floor, there is good cross breeze. Inside, each pot is covered with a cardboard sheet (reused pizza box) so that the waste is not exposed.

Pots of gold

A Large Scale Composting Model

When segregating the wet waste from the dry becomes a habit (to the extent that soiled boxes, plastic packets and tetra packs also are cleaned/ rinsed and dried before going into the dry bin), it becomes difficult put all the waste into one dustbin, while visiting hotels and other homes. Often I’m tempted to carry my trash back to ensure it is handled appropriately. During a recent visit to Pune though, there was no such temptation. The friends we visited live in a large apartment complex called Camellia on the Baner-Pashan Link Road (about 300 apartments), and here segregation of the household waste at source is mandatory.