There’s a new player in town reducing the amount of food waste headed to the Frederick County landfill—actually a host of new players in the form of hungry microbes.
Frederick Memorial Hospital installed a BioHiTech EcoSafe digester, an aerobic food waste disposal system.The digester began processing food waste from the kitchen and patient rooms in February 2018. So far, it’s reduced the hospital’s food waste being landfilled by nearly five tons a month. Overall figures for waste from the hospital were unavailable. Diverting the leftover food from the cafeteria, what’s known as “front of house”, is a more complex feat and is not yet underway.
Emily Dyson, Director, Science Research and Development for BioHiTech, explained how the system works.
· Kitchen employees scrape the food waste during the dishwashing process into a 5-gallon bucket. When the bucket fills they dump the scraps into the digester.
· The system is housed in a steel container that resembles an industrial icemaker. The digester is maintained at between 105 and 115 degrees and has paddles to provide constant aeration which allows the microorganisms to reproduce at an optimum rate. The digester operates like a stomach and needs proper temperatures, oxygen, and bacteria to digester the food waste. BioHiTech uses a proprietary blend of microorganisms to facilitate digestion.
· The digester can handle everything except bones, large amounts of meat, raw dough and rice, corn husks, cobs and pineapple tops. That’s because the outer surfaces are too hard for critters that break down. If you wouldn’t eat it neither will the critters!
· After the digestion process, the discharged liquid heads to a FMH grease trap where anything that is not digested is skimmed and the rest of the liquid heads to the Frederick City Wastewater Treatment Plant.
The digester so far has diverted 37,621 lbs since the system was installed fin February. That’s removed it from landfill disposal and changed it to effluent treated by the Frederick water treatment system. The microorganism blend contains no surfactants or man-made enzymes (what is added to dish detergent so that dishes get clean quickly). This is because surfactants only temporarily break down fats, oils, and greases which can recongeal in the treatment process into “fatbergs” that clog sewage treatment operations. The microorganisms used in the digesters continue to eat away at the fats, oils and greases as they continue down the sanitary sewer line.
The added value of the EcoSafe digester, BioHiTech says, is its smart technology. The hospital’s chef, nutritionists and operations team all can use the BioHiTech app on their phones connected to the microcomputer in the digester. It can tell them at any moment how much waste has been digested for any given time period, as well as other metrics such as the equivalent drop in trash truck trips; carbon footprint and water used.
The EcoSafe digester was downsized from its originally installed digester because the data provided the hospital food and nutrition team info that helped them to tweak what they buy and put on the menu so that organic waste was significantly reduced (a followup story on this coming in July!). This helped the hospital cut their food waste by 200 pounds weekly.
BioHiTech sees the system complementing other organic waste diversion practices coming on line in the states where composting and anaerobic digestion are being required through regulation. “The digester is one element of the solution for organic waste,” she said. “There is not one technology that is going to work to solve the organic waste issue in the US.”