Co-processing paths of agricultural and rural solid wastes for a circular economy based on the construction concept of “zero-waste city” in China

The treatment and utilisation of agricultural and rural solid wastes are important initiatives to advance high-quality agricultural development and improve rural living environment in a concerted manner. We identified the general background and need of agricultural andrural solid wastes in China, and elucidated the main sources and classified the agricultural and rural solid wastes; we grouped the wastes according to their source, value, components, and form, and described the basic characteristics of agricultural and rural solid wastes, namely, diversity, spatio-temporal fluctuations, and consistency of collection. Based on this, the technical pathways of agricultural and rural solid waste co-processing were systematically summarised for a circular economy based on the construction concept of ‘zero-waste city’ in China, including conversion to fertilisers and energy, value enhancement, and volume reduction. Three main models were developed, namely, the mixed fermentation of agricultural and rural solid wastes for fertiliser production, mixed pyrolysis/gasification/incineration for energy production, and urban-rural integrated waste treatment. Subsequently, we systematically analysed the main framework, fundamental characteristics, and applicable scenarios of the three models. We established the foundations and strategies for the co-processing and efficient utilisation of agricultural and rural solid wastes.