[Featuring PBEA Member Phildelphia Water Department and PBEA Director Paul Kohl]
Everytime you throw scraps of vegetables or leftover food into your garbage disposal, the organic matter gets liquefied and transported through Philadelphia’s sewage system to water pollution control plants, where they’re then transformed into energy.
Water waste plants in southwest and northeast Philadelphia break down that liquified organic matter through an anaerobic digestion process to create biogas and biosolids. The resulting gas is then combusted to generate electricity and heat, and the solids are turned into little pellets of fertilizer or fuel.
According to Philadelphia’s Office of Sustainability, the biogas cogeneration plant in the Northeast Water Pollution Control Plant currently creates 34 million kilowatt hours of energy annually — the equivalent to installing solar energy in more than 5,800 houses — which can provide up to 85 percent of all the electricity used by the water treatment facility.
But there’s capacity — and the necessity — for more.
In June, the Water Department issued a food waste co-digestion Request For Information (RFI) to solicit ideas and possible business plans from potential vendors and evaluate possible scenarios for accepting pre-processed food waste.
“We were considering doing the direct decomposition of food in our anaerobic digesters, so the RFI is: Does anyone wants to do that with us?” Philadelphia Water Department’s Paul Kohl said. “We received interest, people showed up for the informational meeting, people are asking questions. So yes, there’s interest in the market place.”