BIOMASS Magazine: BioHiTech’s on-site technology eliminates the need for costly preprocessing at the biogas plant
One-third of the world’s food is wasted every year. In the U.S. alone, over $100 billion worth of food goes uneaten annually, with 98.4 percent, or more than 34 million tons, landfilled. Throughout North America, Green technology company BioHiTech Global Inc.’s subsidiary, BioHiTech America, is installing digestion technology that reinvents food waste management by focusing on processing the waste at its point of generation for easier, more cost-effective disposal. BioHiTech named its waste processor the Eco-Safe digester, an onsite aerobic digester that eliminates up to 2,400 pounds of food waste in a 24-hour period by converting it into a nutrient-neutral grey water that’s discharged through standard sewer lines. BioHiTech has been investigating further uses for the liquid slurry by testing the transportation and use of it in an anaerobic digestion (AD) facility. “BioHiTech teamed up with Natural Systems Utilities, Ridgewood Green RME LLC and the village of Ridgewood, New Jersey, to test a process that allows BioHiTech’s Eco-Safe digester to digest, tank and deliver the effluent from its Eco-Safe digesters to anaerobic digestion facilities anywhere in the world,” says Frank Celli, CEO of BioHiTech Global.

In order to test whether the effluent from the digester would be a good feedstock, the company installed a unit at a high-volume supermarket in New Jersey. “After testing by both BioHiTech and Natural Systems, it was determined that with some modifications to the settings on the Eco-Safe digester, the effluent would essentially complete the first step of AD, which is hydrolysis,” Celli says. He explains that hydrolysis is where the bacteria transform the particulate organics into liquid, and by adjusting the amount of microorganisms introduced into the system, the company can provide a viable feedstock that meets the needs of the AD facility.

“We’re looking to bring more of their material in on a longer-term basis,” says Richard Cisterna, executive vice president of business development with Natural Systems Utilities. Ridgewood Green—composed of NSU, American Refining and Biochemical, and Middlesex Water Company—entered into a public private partnership with the village of Ridgewood on the waste-to-energy project. The Ridgewood Green facility is located at the village’s wastewater treatment plant (WWTP), which includes a 20,000 gallon-per-day liquid waste receiving facility. Outside organic wastes are brought to the facility and codigested in two digesters with municipal biosolids that are generated at the WWTP. The resulting biogas is used in a combined-heat-and-power system with the capacity to generate 240 kilowatts of electricity and 1.5 million Btu per hour of thermal heat, equaling almost all of the WTTP’s required energy. Waste heat recovered from the engine is used to optimize the AD process by heating the sludge.

Only a few thousand gallons of BioHiTech’s effluent has been tested in the digesters, but once the company deploys more of its systems to generate material on an ongoing basis, NSU hopes to move beyond the trial period. “They need to know there is a viable outlet that creates sustainable products, which we’re doing by creating renewable energy,” Cisterna says. He adds that this demonstration will give BioHiTech the ability to deploy more of their systems at commercial facilities, especially in light of food waste generators’ obligation in certain jurisdictions to abide by legislation banning food waste from landfills. Currently, there are food waste diversion bans from landfills already in effect in Vermont, Rhode Island, Connecticut, Massachusetts, New York City and, according to Cisterna, it’s being proposed now in New York and New Jersey, states that NSU is very active in. “We are participating in promoting that,” he shares.
Since the Eco-Safe digester completes the hydrolysis step of the anaerobic process prior to arrival at the AD facility, Celli says this assists with blending other feedstocks into the process. “It breaks down the material and liquefies it so it’s more readily digestible by our anaerobic digesters,” Cisterna adds. The liquefied state also makes it easier to transport.
In a way, the system is geared toward enhancing a hub-and-spoke model of handling biogas feedstocks by predigesting food waste onsite at the source (the spoke) which can then be transported to a central AD plant (the hub) for energy generation. “The way it’s contemplated now is they would arrange for the hauling to pick up that liquid material from multiple locations, and they would haul the material to our facility at the waste water treatment plant,” Cisterna says.
According to Celli, tanking of the effluent will be done on a case-by-case basis. “The economics of distance to an AD facility and trucking the effluent have to add up to a positive,” he says. “We are working with customers who have sustainability goals to determine if the environmental benefits of producing energy are balanced with the distance and impacts of trucking.” In many instances, Celli adds, there are positive impacts, but for those where an AD plant is too far away, discharge to the sanitary sewer can accomplish many sustainability goals as well.
Prior to discharge into a sanitary sewer line or a collection tank, the digester weighs each increment of waste and allows users to qualify its type and origin, and then immediately transmits the data to BioHiTech Cloud. This “Software as a Service” analytics platform measures key metrics like utilization data, environmental impacts, costs savings, hour-of-day or day-of-week trends, waste categorization, as well as machine and digestion performance. “These metrics are providing the industry with an unprecedented level of transparency that not only helps to reduce the amount of waste generated, but also improves company-wide efficiency and profitability,” Celli says. The company also has an app called BioHiTech Cirrus, which provides easier access to real-time data.
BioHiTech has more than 300 units installed—nearly 400 if counting units under contract but not yet deployed—in 37 states and 13 countries, according to Celli. These customers span as many as 11 verticals, including prisons, followed by hospitality, grocery and restaurants as the largest portion of BioHiTech’s install base. Clients include The Cheesecake Factory, Federal Bureau of Prisons, Fairway, GE, and many others.
“In 2015 and the first quarter of 2016, BioHiTech Eco-Safe digesters have diverted over 5,500 tons of food waste from landfills; this does not include digesters that currently are not utilizing BioHiTech Cloud technology, therefore the number is substantially greater,” Celli says. “Through the use of BioHiTech Cloud technology, owners and managers of food processing establishments will be able to modify their solid waste management practices to reduce the amount of waste that is generated before disposal even becomes a factor.”