International Biomass Conference & Expo: Digesting food processing residues

By Lisa Gibson
Posted May 6, 2010, at 8:12 a.m. CST

It takes a team of companies with a variety of expertise to implement an anaerobic digestion (AD) project at a food processing facility, according to Dave Konwinski, founder and chief executive officer of Onsite Power Systems Inc.

Feedstock management, along with monitoring and operating might be the most crucial elements of project development, he told attendees of the International Biomass Conference & Expo. "We really have to look at where the customer sits; what kinds of incentives there are," he said. The company's pathway to commercialization of its AD system started with extensive testing that included system analysis, design and feedstock.

AD offers economic opportunities in waste recovery as well as renewable fuels production, Konwinski said. "It offers the customer a way to deal with the waste stream and turn it into a revenue stream," he said.

Scott Christian, process engineer with ADI Systems, discussed ADI's Anaerobic Membrane Bioreactor (AnMBR) for high suspended solid waste. The system uses a physical membrane barrier to separate solids, liquids and gases, distinguishing it from conventional AD systems. AnMBR fits in a compact space, he said, achieves complete retention of biomass and consistently produces a superior-quality effluent. The company has 15 full-scale systems operating in Japan and recently established its first in the U.S. at Ken's Foods near Boston, Mass. It can be set up for distilleries, municipal solid waste (MSW) processing or food processing facilities.

The main benefits of organics recycling for food processors are cost savings and an improved environmental profile, which can drive sales, according to Paul Sellew, co-founder and CEO of Harvest Power Inc. Local development is essential for successful projects, Sellew said, along with product marketing. The company deals with AD technologies, advanced composting and distributed biomass gasification. "Europe has really taken the lead in anaerobic digestion of organic feedstocks," he said, comparing the process to the stomach of a cow.

The Sacramento, Calif., Municipal Utility District generates 61 percent of its renewable energy portfolio this year from biomass systems that include digesting dairy wastes, MSW and agricultural wastes, among others, according to senior project manager Valentino Tiangco. Dairy farms are ideal places for AD systems and 151 operating in the U.S. produce 374,000 megawatt hours of energy, he cited.

SMUD is working to develop gas and NOx cleanup systems, along with a biogas-fueled low emission engines generator demonstration, both on dairy farms. The utility recently received $5 million from the U.S. DOE for five projects, four of which are biomass based.