MIT Tata Center Community Journal
Vol. 4 - March 2016
Environment
Working toward a decision-support tool for
municipal waste management
By Dhivya Ravikumar | Tata Fellow
This 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.
Eco-BLAC Bricks: Understanding durability
By Piyush Chaunsali | Postdoctoral Associate
India is the second largest producer of firedclay 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 (3040°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 EcoBLAC 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.
Assessing Delhi’s air quality
By Ben Miller
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 autorickshaw: 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.”
Stories and photos © MIT Tata Center. Contact: btmiller@mit.edu
World Water Day
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?
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