Abstract
In Vietnam, more than 50 % of municipal solid waste is biodegradable solid waste, in which food waste, including kitchen waste and the leftover, is the main component. The mixing of domestic waste in collection and treatment has brought significant environmental consequences. The waste separation policy towards strategic goals in waste management has posed many challenges for the locality in implementation. This study aims to develop a pilot of the thermal composting system to optimize the household organic waste composting process. The pilot has a volume of 12 L, a bottom heating system, and a temperature measurement and monitoring system. The system operates on a batch mechanism; the first batch is started with the addition of sawdust substrate at a rate of 1/3 of the volume of food waste. From the 2nd batch onwards, 1/3 of the compost product is kept in the system to mix with the raw materials. The heating system only provides a temperature of 40 °C during the first 2 d of the treatment. The results show that the thermal-composting system is activated quickly in the first 2 d, and the treatment process is highly effective in the next 3 d with temperatures ranging from 60 to 70 °C. The pile volume decreased rapidly by 50 % within 5 d of treatment and stabilized gradually in the last 2 d. After 7 d of treatment, the compost has a temperature of about 40 °C with a moisture content of 31.3 %. Compost products have high organic content (57.8 %), low nutrient content, and heavy metal content below the allowable threshold in microbial organic fertilizers standards (TCVN 7185:2002). Efficiency in home composting with a shortened retention time of 7 d, simple operation, and friendly compost quality are the outstanding results of this applied research. This study provides a practical product for implementing new waste management regulations in Vietnam. It also awakens the potential to promote the municipal organic solid waste recycling system, contributing to reducing the waste to landfills and mitigating greenhouse gas emissions towards a waste circular economy.
