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New biogas digester for zero waste vertical farm

November 6, 2012  By Brandi Cowen

A new biogas digester will provide heat and power for Chicago's first net zero waste vertical farm. (Courtesy of Plant Chicago, NFP/Rachel Swenie.)

A 5,000 ton per year biogas digester will fuel the combined heat and power system in Chicago’s first net zero waste vertical farm and food business.

Known as The Plant, the project is located in a former meatpacking facility. One-third of the 93,500 square foot building will house aquaponic growing systems; the remaining two-thirds of the space will host sustainable food businesses, offering low rent, low energy costs and a shared, licensed kitchen.



Thanks in part to $1.5 million in funding provided by the Illinois Department of Commerce and Economic Opportunity, The Plant will install an anaerobic digester and a CHP system. According to The Plant’s website:


“By 2014, the completely enclosed, odourless anaerobic digester will consume 27 tons of food waste a day, including all of the waste produced in the facility and by neighbouring food manufactuers. The digester will capture all of the methane from that waste, and the methane will be burned in a combined heat and power system to produce 400 kW of electricity, plus all the process heat needed for an onsite craft beer brewery. Excess heat will be used in an absorption chiller to regulate the building’s temperature.”


The Plant will operate on a closed loop, aquaponic system. Tilapia fish raised on site will produce ammonia-based waste that can be filtered to separate nitrates from solid waste. The nitrates can then be used to feed vegetables growing in hydroponic beds.


“By absorbing the nitrates, the plants clean the water, which is returned to the fish. The Plant will sell both the fish and the vegetables to local food markets and restaurants, and will do so at a profit,” the project website explains.

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