- The Philadelphia Water Department (PWD) recently issued a request for information (RFI) about potential ways to co-digest food scraps at either of its two "water pollution control plants." PWD is specifically looking to accept pre-processed, liquefied material and would likely start with a demonstration project before scaling up.
- These two PWD facilities are set up to capture biogas for on-site use and create Class A biosolids that can be turned into fertilizer pellets. PWD already co-digests aircraft deicing fluid through a partnership with the Philadelphia International Airport and has determined that excess capacity is available, creating "a prime opportunity for food waste."
- The RFI includes multiple pages of specifications about the quality of expected material and the experience of any potential vendor. PWD would expect all contaminants to be removed; would not accept commercial or industrial fats, grease or oil; and would need a vendor that could deliver the liquefied material to their facilities directly.
The Philadelphia Streets Department estimates that 228,000 tons of food are discarded in the city every year, making this portion of the waste stream a key component of multiple city initiatives. In 2015, the city began requiring certain commercial generators to divert their food scraps and last year Mayor Jim Kenney established a goal of "zero waste" by 2035. As part of that goal, Kenney established a 16-member Zero Waste and Litter Cabinet to develop a detailed plan by September. Discussions and hearings have been ongoing in the months since.
Philadelphia's previous mayor mandated the installation of in-sink disposers for new residential construction — a concept which has been gaining more traction in other cities too — but this new proposal could lead to a significant expansion in material diversion. Co-digestion has been receiving renewed focus from industry associations and is currently on display at various levels in multiple cities. Waste Management's CORe system is one of the pre-processing options being used to create a liquefied feedstock and the company could be among the list of potential vendors responding to Philadelphia's RFI.
The city has made it clear that this is an early, non-binding step toward a potential co-digestion project though reaffirmed that food waste diversion is "critical" to achieving its 2035 goal. An information session will be held on July 6 and RFI responses are due by August 4.