Phone and Address
Northern Recycling
P O Box 177
Napa,  CA  94559
Phone:  (530) 406-1614
Fax:  (530) 406-1751 
U.S. Composting Council






Composting Process

The windrow composting process is currently employed for the green material feedstock, which will continue as a planned expansion of the facility is completed. The facility is currently conducting a research project using post-consumer, residential co-collected organic materials or pre-ground green waste and commercial food waste (up to 40%), utilizing covered aerated static pile technology (up to 5,000 cubic yards) to determine and demonstrate the viability of using covered aerated static pile technology to process these selected food and green materials.

Windrow Composting

Upon completion of the grinding and moisture conditioning operations, the feedstock is then arranged into windrows using a front-end loader. The dimensions of the windrows are approximately 14 to 18 feet in width and vary in length, depending upon the type of windrow turning equipment utilized.

Covered Aerated Static Pile

ASP-compostingCovered ASP systems are designed as a cost-effective system for controlling potential environmental impacts (including storm water contamination and odors) and maintaining optimal pile conditions during composting. It combines a waterproof, synthetic fabric or finished compost cover with a computerized aeration control technology to optimize composting conditions for all types of feedstock.

Curing and Screening

Upon completion of the composting process, the compost product begins the curing process. The purpose of the curing process is to allow the material to stabilize in preparation for final screening. Upon completion of the curing process, the compost material is then processed through a series of mechanical screens to separate and remove materials according to size.

Testing and Shipment

Following the windrow composting process, the finished compost product is sampled and tested to verify compliance with metal and pathogen reduction provisions stipulated in state regulations. After successful completion of the aforementioned testing, the composted materials are transported off-site or held on site for further processing, including custom blending with soil, sand, gypsum or lime to create value-added products that may serve a broad array of markets. Material off haul is dependent on available markets and product demand; product may temporarily be stored during this time. The majority of this material is sold into local agricultural markets, while some compost is returned to the communities that send material to the facility.

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