Fish By-Product Composting

There are many fish farms, hatcheries and fish processing plants in the Puget Sound region. O2Compost has partnered with Northwest Fish By-Products, Inc. to demonstrate the technical and economic viability of composting salmon waste from Northwest fisheries. This is significant as conservative projections place salmon waste in Washington State at 30 million pounds per year, and growing.

The salmon waste is brought to the composting site in 1,000 pounds “totes” and is tipped onto a bed of previously blended bulking materials. Initially, the odor is moderate to strong, however the mix is immediately mixed and placed onto the aerated static pile and capped with a biofilter layer of horse manure and bedding. Within 30-minutes, all impacts from odor have been mitigated. A representative from the Health District has observed this process and approved it as an efficient process utilizing best management practices. Objectionable odors during fish by-product composting have been non-existent.

Within hours, the pile temperatures have consistently exceeded 131 degrees Fahrenheit, the minimum requirement for pathogen destruction, and within 3-days there is no evidence of fish remains. The fish by-product compost has no “fishy” odor, and will not attract cats, dogs or wildlife. It is nutrient-rich and full of beneficial microorganisms. The net results are beautiful and bountiful landscapes and vegetable gardens.