Cradle to Gate
Identity ID
aa977426-2b0c-4f3e-9d97-b621d3b8a2b3
Waste treatment
Associated ID
8a1d1483-702d-484b-8c0e-d39fa04b1e63
Included activities starts
Included activities ends
Description
Composting technology has a simple process and is easy to manage, enabling local utilization of kitchen waste. However, due to its relatively small processing capacity, it is mainly applied in rural and township areas. A solar greenhouse in a certain area of China (daily processing capacity 1. 5 t/d), with a composting period of about 30 days and a compost yield reaching 20% of the incoming waste. The solar greenhouse structure typically features an inclined transparent glass surface on the sun-facing roof, effectively utilizing solar energy to accelerate composting. Additionally, the composting facility is equipped with ventilation and heating pipe systems, supplying oxygen and heat to the materials piled inside to promote aerobic microbial respiration and metabolism, thereby accelerating temperature rise and material maturation. The process flow of sunlight room composting: The pretreatment process involves sorting out inorganic impurities and crushing and pressing kitchen waste to produce uniformly sized, moderately moist biodegradable material, thereby enhancing compost quality. After pretreatment, microbial inoculants are added to improve composting efficiency, and the material is then shoveled into composting chambers. Chamber temperature and humidity are adjusted according to loading capacity, and aerobic composting fermentation is enhanced through measures such as heating and humidification. After composting, the product undergoes impurity removal and secondary grinding to produce fertilizer suitable for agricultural cultivation, landscaping, and other applications. The main gaseous pollutants generated during the composting process are H2S, NH3, and SO2. A photocatalytic pollutant treatment unit is used for odor removal from composting off-gas, achieving a removal efficiency of up to 90%. As this composting facility is located in a rural area, a complete wastewater treatment system is not established; thus, the wastewater pollutant concentrations are estimated based on composting effluent volumes and pollutant levels reported in the literature. The produced fertilizer complies with the Organic Fertilizer Standard (NY525-2012) and the Bio-organic Fertilizer Standard (NY884-2012).
Activity Description
Composting technology is a simple and easily managed method for treating kitchen waste, particularly suitable for rural and township areas. Solar greenhouses utilize transparent glass slopes and solar energy to accelerate the composting process, while equipped with ventilation and heating systems to promote aerobic microbial activity and speed up material maturation. Pretreatment includes sorting, crushing, and pressing to form compost-suitable materials. During fermentation, compost quality is controlled by adjusting temperature and humidity. The final product, after purification and grinding, can be used as fertilizer in agriculture and landscape gardening. Gaseous pollutants generated during composting are treated using photocatalytic technology, achieving removal efficiencies as high as 90%.
Process Description
kitchen waste on a dry basis: average organic matter content of 80–100%, crude protein 14–30%, and crude fat 15–30%; on a wet basis: moisture content 70–90%, oil content 3%, and salt content 1%.
Time period
2022
2026
Geography
China
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
Aerobic composting. Aerobic composting is a process that, under aerobic conditions, utilizes aerobic microorganisms to decompose the organic matter in kitchen waste into soluble organic substances, which then enter microbial cells to participate in metabolism, ultimately forming humus fertilizer. The aerobic composting process generally consists of three stages: pretreatment, microbial fermentation composting, and post-treatment of the product. During the pretreatment stage, materials such as crop straw, sawdust, and rice husks are typically added to adjust the carbon-to-nitrogen ratio. Aerobic composting has advantages such as a simple process, low cost, and ease of operation, and it converts organic matter into organic fertilizer. Therefore, it is one of the mainstream technologies for kitchen waste treatment and utilization worldwide. However, composting requires a large land area and a long processing time, and the generated odors and leachate can cause environmental pollution. If kitchen waste contains excessive impurities, the quality of the compost will be poor, necessitating continuous improvements. Currently, composting technologies are trending toward miniaturization and specialization, leading to various methods primarily based on solar-powered composting and machine-assisted composting. Within solar composting sheds or machines, temperature and humidity can be better controlled to accelerate composting, while effectively managing secondary pollution such as wastewater and odors.