Biosolids Composting

Biosolids are nutrient-rich organic materials obtained from wastewater treatment and the word itself is an emotionless word frequently refers to several families of materials:  sludge, green waste and certain food processing wastes.

There is a growing battle between biofuels and composting for these source materials.  The compost advocates want to return these bio-materials to the soil to ensure longterm nutritive value and humus to the soil.  Biofuel advocates want to burn the biosolids to produce biodiesel and other fuels to reduce our dependence on petroleum and foreign sourcing.

Watch for this battle to play out in political regulations and the media.  One example of a diversified agricultural company who has been converting biosolids to both compost and biofules is McCarty Family Farms in California.

McCarthy Family Farms was established in 1991 to provide beneficial reuse Biosolids and Green Waste Management services to cities, municipalities, and special districts throughout California.

Liberty Composting, located in Kern County, California operates the worlds largest biosolids composting facility, permitted for more than 2,000 tons per day.

Biosolids are combusted at a temperature of 1,700 degrees in the preheater/precalciner. The combustion process releases ammonia which reacts with NOx in the gas stream, producing nitrogen and water. All ash and other residues are incorporated into the cement product. During periods when the cement plant is unable to co-fire biosolids, material is diverted to Liberty Composting. Co-firing biosolids with other fuels significantly reduces N0x emissions.