Working toward a decision-support tool for municipal waste management By Dhivya Ravikumar | Tata FellowThis IAP, I spent three weeks in Muzaffarnagar, Uttar Pradesh focusing on understanding the waste streams of a typical household in a mid-sized city in India. A 3-6 hour drive from Delhi (depending on traffic and/or fog!), Muzaffarnagar has a population of about 400,000. While India is known for its megacities like Delhi and Mumbai, with populations between 15-20 million, 30% of India’s population live in cities with populations between 100,000 to one million people. Understanding the prevailing waste management architecture of these cities is vital in designing systems which adapt to meet the needs of the growing population with changing aspirations and consumer behavior.

There is a lack of bottom-up data on the composition and volumes of waste in India. In Muzaffarnagar, about 120 tons of waste is collected by the private waste management company, A2Z, every day. However, not all the city’s waste is collected (due to illegal dumping) and there is a diversity of waste generation sources (households, bulk generators, commercial establishments). The A2Z waste collectors use a tricycle cart for door-to-door collection of unsegregated waste from a total of 50,000 households.

To characterize and quantify municipal waste generation, we conducted waste audits in six pilot neighborhoods, spanning different socio-economic groups. From our preliminary analysis, we found that nearly 69% of the household waste is food waste. This is a much higher fraction when compared to developed countries such as the US, where around 37% of household waste is food waste. The large fraction of food waste present in household waste in India creates tremendous opportunities to utilize various waste-to-energy technologies and processes to create value from waste. Some of the waste utilization methods currently being applied in India include: composting, anaerobic digestion, incineration and RDF (refuse dried fuel).

Our next step is to scale up the data from the pilot neighborhoods to the city of Muzaffarnagar. This would provide data to test and develop a GIS-based decision support tool for the optimization of solid waste collection and transportation. Our tool aims to identify an effective solution for a particular city’s waste profile, which involves analysis of different technologies at varying scales of operations. Over the summer, we plan to explore collection strategies, such as incentivizing households to segregate their food waste, and also to study the impact of municipal waste policies on local waste generation.

MIT Tata Center Community JournalVol. 4 - March 2016 Environment

Eco-BLAC Bricks: Understanding durabilityBy Piyush Chaunsali | Postdoctoral Associate

India is the second largest producer of fired-clay bricks, accounting for around 10% of global production, and is estimated to be producing 150-200 billion bricks annually. The mixture of clay and water, when fired at high temperatures of 700-1100°C, becomes strong enough to be used as a building material. For centuries, the fired-clay brick has been the most popular building material in India due to its local availability and low cost. However, the manufacturing of these bricks results in significant air pollution due to the combustion of coal and biomass at high temperatures. Additionally, the depletion of clay from soil has negative impact on soil fertility.

The Eco-BLAC Brick project aims to utilize boiler ash, a by-product of the paper industry in India,

in making environmentally friendly bricks for construction. Considering the fact that the fired-clay brick has passed the test of time, it is not surprising that the project has met with challenges, both in developing a sustainable and durable alternative building material for masonry and in gaining adoption of that material.

But the interdisciplinary team of the MIT Tata Center, led by Professor John Ochsendorf and Assistant Professor Elsa Olivetti, has shown that it is possible to develop an environmentally friendly masonry material from boiler ash. The first formulation was created by Tata Fellow Michael Laracy and postdoc Thomas Poinot. The boiler ash, when activated by alkaline solution in the presence of clay and lime, results in a material with comparable strength to that of the fired-clay brick. This alkali-activation process results in the formation of sodium aluminosilicate hydrate gel, which has binding properties. Moreover, the use of high volume of boiler ash and low curing temperature (30-40°C), makes it more economically viable and environmentally friendly than the fired-clay brick.

With this foundation in place, current efforts by myself and Tata Fellow Hugo Uvegi are directed toward understanding the durability of Eco-BLAC bricks. During the last IAP, the MIT team with the help of its local partners in India was able to build a small wall (pictured at right) out of Eco-BLAC bricks.

Although durability is a broad term, the resistance (i.e., structural integrity) of a wall against exposure to the open environment will be an instrumental data point in assessing the brick’s long-term performance.

The Spring 2016 issue of Energy Futures magazine will include a feature on the Tata Center’s air quality sensor project. Here are some observations and outtakes from researching that story.

The most striking image I saw while in New Delhi this January to cover David Hagan’s work on low-cost, high-performance air quality sensors was one I failed to capture. It came while riding down Janpath in an auto-rickshaw: I had my camera out to shoot the iconic India Gate as we passed by – only it wasn’t there. Instead, I was confronted by a wall of milky white haze. Lutyen’s monument to the war dead, and one of the most enduring symbols of British rule, had been erased.

Three of us (David, myself, and Shriya Parekh) tooled around Delhi all day carrying a sensor. Starting from Connaught Place, we visited Khan Market, Hauz Khas village, and Nehru Place, watched the preparations for Republic Day, and breathed in a whole lot of unhealthy air. To be fair, in the afternoon the haze did lift a little bit, and we could see India Gate on the way back to our hotel. Wintertime is the nadir for air quality in Delhi. As David explains, Delhi is prone to “stagnation events. An inversion layer settles in,” trapping atmospheric pollutants. Partly because of these episodes, he says “Delhi is about 40% worse than Beijing.”

David has sensor prototypes set up in various locations around the city, including the Paharpur Business Centre in Nehru Place, which was built by an MIT alum and touts itself as the “greenest building in India.” While the air inside is clean, outside, where David’s sensors are located, it’s a different story. When we took them down to inspect, we found their intakes clogged with black grime. (One of David’s design requirements going forward is a robust filtration system.)

His goal is to eventually have a network of 120 sensors spread out across Delhi, which would make it possible to get specific data on localized pollutant and emissions patterns for the first time. There are currently only 20 official, regulatory-grade sensors in the city. That means 20 individual data points contolled by different parties with different agendas (the Indian government, the US Embassy, etc.). And these official sensors cost between $50,000-$100,000 each, making it prohibitive to expand the network. David’s sensors run about $1,000 each, and are much more compact in size, so deploying a dense network is feasible.

PM 2.5 levels are one of the standard measures used to evaluate air quality (though David calls it “a pretty useless, arbitrary metric,” arguing for a more holistic view of atmospheric chemistry). For what it’s worth, Delhi’s PM 2.5 levels run between 150-1,000 micrograms per cubic meter, as opposed to a high of just 12 micrograms per cubic meter in Manhattan. One of David’s targets is “to generate a better data set for epidemiologists” studying the effects of PM 2.5 and other particulate matter.

“It could be a sustainable public good,” he says, “one of the primary purposes of the Tata Center.”

Assessing Delhi’s air quality

Stories and photos © MIT Tata Center. Contact: btmiller@mit.edu

By Ben Miller

World Water Day

tatacenter.mit.edu

March 22nd was the UN’s World Water Day. To mark the date, we asked some of our researchers working in the water domain to answer the following question:

What is one impact you hope to make in water access and sustainability?