Analysis of raw materials and products characteristics from composting and anaerobic digestion in rural areas

Chinese food waste (FW) production is enormous which brings many economic and environmental benefits. There is an urgent need for proper and efficient treatment technology. Anaerobic digestion (AD) is a popular technology for centralized large-scale treatment of FW. Composting technologies including static composting (SC), forced aerated composting (FC), and machine composting (MC) have been applied in rural areas owing to their low cost and simplicity. The characteristics of products in different FW treatment are still unclear, preventing agricultural use of the products. In order to elucidate the properties of different samples and to realize the resource utilization of products, compost samples (FC, SC and MC) and AD biogas residue samples were collected on site. By analyzing the physicochemical properties (pH, moisture content, maturity, salinity, lignocellulose, etc.) and phytotoxicity, the quality of different products was evaluated to determine the most appropriate rural FW treatment technology. MC products showed poor performance in maturity, salt concentration and plant toxicity. SC products cannot be used due to phytotoxicity. High moisture content limited the prospects of AD products utilization. FC products were of good quality with 32.91% in organic matter loss, good performance in lignocellulose degradation, 6.76% in water-soluble salts, and 79.61% in germination index. FC technology is worth promoting in rural areas of China.