Hotel saves $15,000 diverting food waste
The JW Marriott Marquis luxury hotel in Downtown Miami said it estimates an annual savings of $15,000 by using a biodigester to process its food waste. The hotel recently installed a biodigester in its banquet kitchen. The unit – an LFC (liquid food “composter”) manufactured by Power Knot LLC, of San Jose, Calif., converts solid food waste into drain-safe, odor-free wastewater in 24 hours, diverting 33.7 tons of food waste annually from landfills.
The hotel installed an LFC unit on a trial basis for several months to document food volume digested, reliability and the associated costs. Based on the results, the hotel installed a Power Knot model LFC-500 in the main stewarding area where dishes, tableware, glasses, pots, pans and kitchen utensils from the hotel’s four kitchens are washed. Staffers bring food waste from the hotel’s kitchens and restaurants to the LFC biodigester to be digested.
Despite the name “Liquid Food Composter,” the unit doesn’t actually compost the waste, but rather decomposes it into environmentally safe, nutrient-rich gray water, which meets or exceeds the city’s requirements to be piped into the municipal drain line.
The biodigester is a fully enclosed machine that digests food waste in a clean and odorless manner. A kitchen staffer opens the unit’s door at any time, adds food waste and closes the door. The rest is automatic. The vessel of the machine contains porous plastic “Powerchips” media that remain in the vessel, distributing a mixture of microorganisms and “Powerzyme” enzymes that accelerate the decomposition of solid food waste.
Slowly rotating mixing paddles maximize the contact between the food particles, aerobic bacteria, enzymes and air which, along with infusions of hot and cold water, accelerate the process of decomposition. The operation produces water, CO2, and heat to 108°F.
The CO2 created is part of the natural cycle of carbon generation from plants, which makes the process carbon neutral. Within 24 hours, the waste decomposes into gray water.
“I can get information online about how much food waste the machine is processing daily as well as how often the kitchen staff is adding waste, and a wealth of other useful data,” said Raymond Linares, Marriott’s director of engineering. “Through a touch screen, or remotely through a mobile device, staffers can view machine usage and performance in hourly, daily, weekly or monthly increments, as well as information on diagnostics and service schedules.
Linares said the biodigester has run continuously since 2015 and has been problem-free, requiring minimal scheduled maintenance. Measuring 75 x 47 x 64 inches, the machine can digest 1,100 to 2,000 pounds of solid food waste per day, which exceeds the waste volume generated by the kitchens. During 2017, the unit digested 67,470 pounds of solid food waste – a daily average of 187 pounds.
“The landfill waste problem will not take care of itself,” Linares said. “But if more hotels, schools, factories and facilities with restaurants or cafeterias do what we did, we can make a difference together in solving this problem.”Follow us on social media: