FOOD WASTE AT

KOYAMBEDU MARKET

by Max Roy & Gokul Rajendran

Vendors at Koyambedu Market. Photo ©Mike Reid

Koyambedu Market in the city of Chennai, India, is the world’s single largest fruit and vegetable market. The market is wholesale, meaning most food sold is sold in bulk, bought by restaurants and grocery stores to resell to individual consumers.

Here, we trace the flow of the massive quantities of food through the market. Produce is grown all across India and shipped into Koyambedu by trains, buses, and trucks. By volume, the largest quantity of food is vegetables, followed closely by fruits, then by flowers, with food grains in a distant 4th.

In total, approximately 10% of the food going through Koyambedu is wasted at Koyambedu. While this may seem a relatively small percentage, the enormous amount of throughput means this accounts for over 200 tons of wastage daily.

Historically, this food waste was simply dumped on the streets and left to rot until it was moved to landfills by the city. Some improvements have already been made in the handling of food waste at Koyambedu; a biogas plant which converts food waste into electricity is the end destination of about 25% of the market’s waste. Additionally, about half a ton of waste is sent daily to orphanages, but half a ton is small compared to the total amount of food being lost. In the end, Koyambedu still produces about 150 tons of food waste daily which is still sent to landfill. We want to make a dent in that number.

Dumped fruits and vegetables outside of Koyambedu Market. Photo ©PlugInIndia

We propose tackling the waste at the source. Koyambedu market has notoriously poor options for storage of food. Most fruits and vegetables keep best in cold, humid conditions; the market, for the most part, is hot and poorly ventilated. In the 1990s, a single cold storage facility was constructed for the massive market complex. Today, it’s woefully inadequate, assuming it functions at all.

Because the market lacks any proper food storage, fruit and vegetables which aren’t sold immediately are very quickly thrown away. This is an unfortunate reality of selling produce, but can be alleviated through accessible adequate storage. Upon receiving shipments of produce, excess which is not expected to be sold quickly can be set aside in storage to wait and be brought out in the following days, still fresh. If we assume an increase from 90% to 95% successful sales of each shipment of produce, we can immediately reduce total waste by 100 tons.

Additionally, the biogas plant does not currently have the capacity to use all of the waste Koyambedu produces. We propose doubling the capacity to accommodate for the remaining waste, and achieve zero waste from the facility.

We suggest a total of 9 new storage facilities across the fruit and vegetable market areas. The market is divided in 3 major segments; the two at the left are vegetables, and the one at the right is fruits. Our storage comes in 3 types: Ventilation, Passive refrigeration, and Active refrigeration.

Ventilation

This type of storage is the most specialized. Certain root vegetables can be kept for almost a year through simple ventilation. A mesh is hung about a foot above the ground, and fans are placed onto the mesh to add airflow. This is good for Onions, Potatoes, and Garlic. This storage method uses 50 kWh/m2, and at a proposed 9000 m2, would use 450,000 kWh/Yr.

Passive Refrigeration

SkyCool is a refrigeration system which functions by radiating heat directly into space, instead of transferring it to the air. It works completely passively, and only needs the coolness to be transferred to the air which should be refrigerated. However, this method is not able to cool significantly below room temperature; therefore, it works best with produce that is most comfortable around 45-55 degrees Fahrenheit. We propose 27,000 m2 of this storage which uses 45kWh/m2, for a yearly total of 1,215,000 kWh/Yr

Active Refrigeration

This is the standard cold storage solution, using heat pumps to refrigerate a large area well below the ambient temperature. Many fruits and vegetables need temperatures close to freezing to keep well, and these facilities will be used for those. We propose 18,000 m2 of active refrigerated storage, at a rate of 200kWh/m2 and a total of 3,600,000 kWh/Yr.

Electricity Totals

For the proposed volume of cold storage, we need a total of 5,265,000 kWh/Yr. Currently, the biomethanation plant produces 250kW/hr for a day with 30 tons of waste. Expanding this to take in 100 tons, we reach 833 kW/hr, or a total of 7,300,000 kWh/Yr. This is greater than the storage energy demands, and the surplus can be used to either power other parts of the market, or be sold to the grid.

After our interventions, here’s what we anticipate a new waste flow looking like, with no more food being sent to landfill: