green waste/biochar co-composting project update

Goals & Objectives

Demonstrate the techno-economic benefits of incorporating biochar into a green/food-waste C.A.S.P. (Covered Aerated Static Pile) composting process  

Measure over the course of the composting cycle:

  • Non-methane VOC (Volatile Organic Compounds) emissions during C.A.S.P. and curing phases
  • C/N ratio of compost
  • Nutrient availability, salt and chloride content of compost
  • Parameters to assess stability and maturity of compost
Benefits to Business:
  • Reducing VOC emissions would enable higher permittable facility throughput and increased tipping fee capture
  • Lower C/N ratio increases the mineralizable nitrogen content of the finished compost, reducing the need for chemical fertilizers
  • Reducing salt and chloride levels in the finished compost for a better performing and higher-value end product
  • Faster composting enables shorter curing time and reduced site inventory
C.A.S.P System at Napa Recycling
Napa Recycling, site of project

Project Pictures


Key Findings of Co-Composting with Biochar:

  • Reduced VOC Emissions
  • Reduced Curing Time To Achieve Compost Maturity
  • Increased NPK value of Finished Compost
  • Reduced Salinity of Finished Compost