At the Laguna Compost Facility biosolids are mixed with bulking agents and turned into rich, marketable Class A compost. The process is clean, efficient and meets or exceeds all standards set by public health and environmental agencies. The mix is formulated from treated Class B biosolids, screened green waste and wood chips.
This agitated bed system is dependable, economical and environmentally sound. With 12 bins in full operation, up to 150 cubic yards of organic compost can be produced daily. Below is a picture of one of the agitators.
The pile is turned each day by an agitator. Starting at the rear of the bin, each pile is aerated and moved back 14 feet and then restacked behind the machine. Working from bin to bin, two agitators can process the entire facility in an 8 hour day.
Odorous air is extracted from the building by a series of ducts above the compost bins and pumped by high volume blowers to the biofilter adjoining the facility.
The above biofilter is a biological air treatment system that replaces conventional chemical air scrubbing units. Air is introduced into the biofilter by perforated pipes at the bottom of the bed. As the air travels upwards, it is evenly distributed through a layer of sized aeration stone. The air then moves through a three foot layer of medium made from wood chips. Living organisms in the medium consume ammonia and other odorous compounds before it reaches the surface.
After 14 days the compost is removed from the bins and screened to 3/8 of an inch by a rotary screen. Oversized material is returned to the process as a bulking agent.
The screened compost is then cured for 30 days as biological activities slow. After the curing process, the compost is sampled and analyzed to confirm pathogen reduction. The compost is approved for use in parks, schools, golf courses and gardens. Current production is approximately 12,000 cubic yards per year.
Watch the City's Biosolids Video