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Building blocks for a cleaner Mumbai

Our garbage continues to cause us problems. But what if we could find a way to use it constructively?

March 27, 2016 08:42 am | Updated November 17, 2021 06:18 am IST - Mumbai

Mumbai, 29/01/2016: Aerial view shows the landmark Twin towers and south and central mumbai engulf in the smog.

Photo: Prashant Nakwe

Mumbai, 29/01/2016: Aerial view shows the landmark Twin towers and south and central mumbai engulf in the smog.

Photo: Prashant Nakwe

Twice this year, garbage fires in Deonar have attracted media attention across the country. While the situation now makes for front page news, the malaise affecting Mumbai’s largest dumping ground is not new.

While the fire and associated smoke cloud are causing respiratory ailments in citizens living downwind of Deonar, it is nothing compared to the disease and misery afflicting those living in the vicinity of the dumping ground every day. The blame for this situation lies in many places, but more so with us.

Every resident of Mumbai is required by law to segregate their waste into ‘dry’ and ‘wet’ bins, but a miniscule number of us follow the law. We have all allowed this situation to happen right under our noses.

We have heard our Chief Minister stating recently, that the government has decided to switch to scientific processing of waste, and has issued instructions to all civic bodies for the segregation of waste at source. These two initiatives are at the core of waste management.

The CM has also clarified that the plan was to process and recycle waste at the site. Why then has an innovative in-house solution by a team from the Municipal Corporation of Greater Mumbai (MCGM), been abandoned to the rubbish heap of history?

In 2001, I visited the Deonar dumping ground for the first time. It was a defining moment for me. Not because of the smell, the sight of the human misery, or even the sheer mountain of garbage. It was because I was witness to the birth of a ground-breaking solution to the city’s garbage problem.

Foundations of an idea

The idea was to use decomposed garbage, officially termed Municipal Solid Waste (MSW), which is always available in huge quantities at the dumping ground, to create solid bricks which can be used for construction and other masonry activities. These bricks are structurally as good as traditional bricks, but their production process is far less damaging to the environment. While conventional bricks are manufactured from fertile topsoil layers, these ‘MSW bricks’ are made from waste. They not only reduce the garbage in the landfills, but are also more cost-effective. I can personally attest to the durability of the MSW bricks, having used them for community improvement projects in my area. As long as humankind exists, there will always be a steady generation of raw material required for making these bricks. The demand for these will also be constant, as the construction of houses will increase.

This unique project was the brainchild of SS Shinde, now Joint Municipal Commissioner, and was led by GB Chaudhari from Veermata Jijabai Technological Institute (VJTI). Other members of the team included AK Jain, who at the time was Additional Municipal Commissioner and is now the Mumbai Information Commissioner, Dr PP Bhave, lecturer, civil engineering, VJTI, and AY Mukadam, who is now retired, an executive engineer at the MCGM.

The project was conceived when MCGM realised that with the constant increase in Mumbai’s solid waste generation, the existing dumping grounds, which are already at super-saturated levels, could not accommodate vast amounts of garbage much longer. The situation was compounded by the lack of low-lying areas which could be converted into new dumping grounds. Existing landfill sites too suffered from several problems, such as ground water contamination, disease and pollution in surrounding areas, and environmental damage.

As we can all clearly see, these factors have worsened since 2001.

The research team found that contemporary methods of disposing of MSW — sanitary landfilling, composting, incineration and pyrolysis — mainly dealt with raw MSW. What if decomposed MSW, which is available in huge quantities at the dumping ground, could create a useful product? If such a production process was in place, it would automatically create space for more waste. Knowing that the MSW disposed of at landfill sites gets naturally converted and degraded within six months to 10 years or more (depending on its composition), the research team zeroed in on the construction of bricks made from decomposed MSW as a product.

One of the main reasons for picking bricks in particular was the ready availability of a market. In 2009, it was estimated that around 350 truckloads, each with 5,000 bricks, came into the city every day. Today, this number would have surely increased.

A solid solution

Over the next few months, several experiments were conducted at the Deonar dumping ground. The initial procedure involved the quarrying of decomposed matter and the removal of plastic, metal and rags, to avoid pollution, and the sieving of the remaining soil to segregate fine-grain material. This was mixed manually with soil brought from agricultural fields, and moulded into brick blocks, which were then burned in bhattis with the use of coal. (Later batches saw a great deal of experimentation with the composition and techniques, and eventually eliminated the use of agricultural soil.)

The bricks were then tested, and found to be technically sound. To manufacture 1,000 bricks, about 3 to 3.5 metric tonnes of decomposed garbage were consumed (which then created that much more space in the dump for fresh garbage). The cost of production of the bricks, while conducting the studies, was found to be around Rs 1.5 to Rs 4 per brick, for the small quantities manufactured during the tests; with larger numbers and the resulting economies of scale, it was estimated that the cost could be brought down to Re 1 to Rs 1.2 per brick.

Bricks that currently come into the city are currently made in rural areas, and use fertile agricultural topsoil full of nutrients; its removal degrades the soil in those areas for generations to come.

Despite the obvious advantages of this project it has been consistently kept on the backburner and hidden from the public. The reasons are… up for speculation.

While I fervently hope that this very useful and low-cost solution is implemented, another aspect of waste management needs equal attention: the decentralisation of waste processing. By this, I mean the collection, treatment and conversion of MSW at the municipal ward level, to absorb the generation of waste close to its point of generation and its reuse and recycling in close proximity.

Decentralised systems offer an alternative approach to waste management, and can provide various resources, such as biodegradable waste used as fertilizers for gardens and parks.

For this to succeed, capacity building of the municipality is crucial. The duties and responsibilities of the municipality as well as those of citizens need to be clearly defined. The rules regarding segregation of waste must be strictly enforced.

To do this, the Advance Locality Management scheme of the municipality must be strengthened.

With this two-fold approach — bringing down the amount of waste sent to the dumping ground and utilising the existing waste at the dumping ground to produce MSW bricks — we can successfully begin to tackle the Deonar problem.

How garbage can be converted into bricks:

* Draw samples of MSW by taking trial pits and bores

* Analyse samples for physical, chemical and microbiologial properties

* Design mix of MSW, agricultural soil and fly ash

* Make sample bricks, test them for compressive strength and water absorption

* For manufacturing 1,000 bricks, 3-3.5 mt of decomposed garbage needs to be consumed

*Cost of production: Rs 1.5-4 per brick. Can fall to Rs 1-1.2 with greater quantity

Points to ponder:

* We can begin to tackle the Deonar problem by bringing down the amount of waste sent to the dumping ground and utilising the existing waste to produce musicipal solid waste (MSW) bricks

* Decentralised systems offer an alternate approach to waste management and can provide various resources such as fertilisers in the case of gardens and other biodegradable waste

* For this to succeed, duties and responsibilities of the municipality and citizens need to be clearly defined. Rules regarding segregation of waste must be strictly enforced.

* The municipality's Advance Locality Management scheme should be strengthened

About the author

Indrani Malkani is a civic activist and volunteer who firmly believes in working in partnership with statutory authorities towards achievable goals. Her model school bus service, which she conceived and implemented in 2002, is now the model on which Maharashtra has based its Policy of Transportation of School Children. She is actively involved in issues related to ALMs, disaster management, road safety, electoral systems, and of course waste management. She has recently started a web portal, togethervcan.in, designed to provide citizens with information that helps them deal with challenges themselves. She is the Managing Trustee of V Citizens Action Network, and a 2015 Ashoka Fellow.

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