February 17, 2009 | General

The Art Of Composting Fish Waste

BioCycle February 2009, Vol. 50, No. 2, p. 19
Washington State facility purchases fish waste to process into a high value end product.
Rhodes Yepsen

LOCATED on 62 acres on the Olympic Peninsula, across the Puget Sound from Seattle, Washington, North Mason Fiber Co., Inc (NMFC) composts about 56,000 tons/year of organic material, including over 1,300 tons of fish waste. This potentially tricky feedstock requires diligent processing, but yields premium quality finished compost.
NMFC opened in 1989 to recycle downed, nonmerchantable timber, sorting and processing into hog fuel and chips. In 2001, Robert W. Dressel, Jr., owner and operator of NMFC, installed a state-of-the-art storm water system for the 28-acre paved operating pad. NMFC continued to expand and improve its site, and in 2003 obtained one of the first solid waste handling permits for composting under Washington State’s new regulations. “We use aerated static piles (ASP) to process a range of materials, including preconsumer food waste, yard trimmings, manure, scrap wood and fish waste,” says Dressel. The facility’s permitted capacity is 80,000 tons/year.
Yard trimmings, wood waste and preconsumer food waste are delivered to the site. “The haulers service supermarkets, the U.S. Navy and municipal curbside collection,” notes Dressel. “We get yard trimmings mixed with all types of preconsumer food waste, including whole watermelons. Currently, more than two dozen supermarkets are serviced, including large box stores.”


NMFC is permitted to accept Type 3 feedstocks, which includes postconsumer food waste and fish waste. “In fact, we’re the only composting facility permitted in Washington State to process certain types of fish,” Dressel observes. “We handle material from up to 40 different fisheries, from all over Washington State. Rather than charging a tipping fee, we bid for the fish waste against pet food companies, and it can be quite competitive. However, the fish are very clean, with absolutely no contamination.”
Because the fish waste is fresh, and potentially odorous, material handling is monitored very closely. “We cannot just have fish just show up, but rather it comes on a schedule,” explains Dressel. “Each tote is taken off the truck, mixed with other feedstocks and blended into the compost pile within 5 minutes. Fish waste produces a temperamental compost mix – it needs to be blended just right, and is active for a long time, taking one or two years to be finished.”
NMFC has two Peterson grinders, a 6700 horizontal, and a smaller 4700 model for processing feedstocks. After grinding and blending, materials are placed into positively aerated static piles (ASP), and topped with a biofilter of at least 18 inches of composted overs. It remains in ASP for up to six months. The facility produces over 20,000 cy/year of finished fish waste compost, marketed as Oly Mountain Organic Fish Compost. It also produces about 60,000 cy/year of Oly Mountain Organic Compost, without fish waste.
Finished compost is screened in a 628 McCloskey trommel and sold in bulk. “However, we recently purchased a Rotochopper Go-Bagger 250, and plan on expanding into bagged products in 2009, for wider distribution,” notes Dressel. “Our facility is located right on the rail line of the Puget Sound Pacific, which sets us up for easy shipping of bagged material. We also produce four types of bark mulch and topsoil blends, and have recently started bagging and shipping those as well.”

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