Preliminary Study On Static And Intermittent-dynamic Of Small-scale Composting Of Solid Waste In Rural Area

Rural solid waste has always been an issue of living environment management in rural areas.However,due to the scattered sources of waste generation and the high cost of collection and transportation,its treatment and disposal have not been properly resolved.In the context of new countryside construction and waste classification,rural areas are gradually advancing the “dry and wet” classification of solid waste.Some rural areas have explored the formation of a new model of “wet and dry” classification of rural waste as the main line,and “wet waste” composting on the spot,which can greatly reduce the cost of collection,transportation and treatment and is an important way to realize the reduction,harmlessness,and recycling of rural solid waste.However,the existing research mainly focuses on the treatment and disposal of solid waste in cities.There is little research on the process of composting rural wet waste on-site and a lack of necessary standards or technical documents for the operation of small-scale composting facilities in rural areas.How to improve the composting conditions of rural waste based on the characteristics of perishable waste in rural areas and the favorable conditions of crops such as straws and other crops is the key to ensuring the popularization and application of aerobic composting technology in rural areas.Based on a large number of preliminary surveys and literature reviews,this thesis takes Hufang Town,Mingxi County,Fujian Province and Xiaogang Village,Fengyang County,Anhui Province as the research area,and a two-year experiment of static composting and intermittent-dynamic composting of rural perishable waste was carried out(focusing on primary composting).The main results are as follows:From the perspective of temperature,both static composting and intermittent-dynamic composting have good heating effects in the primary fermentation stage,and can effectively achieve harmlessness(static composting can be maintained at a temperature above 55 ℃ for at least 5 days,and intermittent-dynamic composting can be maintained at 65 ℃ for 3 to 4 days).Intermittent-dynamic composting has a faster heating rate(65 ℃ within 12 hours)and a higher fermentation temperature(above 70 ℃),while static composting takes 1 to 2 days to reach 55 ℃.In addition,the pile height and moisture content in the static compost have a significant impact on the heating effect of the pile.Under certain conditions(pile height: 0.8～1.4 m,moisture content: 59%～77%),as the pile height increases,the heating rate is slower,but the heat preservation effect is better;high moisture content leads to a slower heating rate,but it is easier to get a higher fermentation temperature and maintain a high temperature for a longer time.On the contrary,the lower the moisture content,the faster the temperature rise of the pile.but it is not conducive to the maintenance of high temperature.In contrast,the intermittent-dynamic composting pile has a good heating effect,which has little to do with the moisture content and pile height.Due to the heating of the lower layer materials,the upper layer materials can often heat up quickly.Finally,there is temperature stratification in the static compost pile.The higher the water content of the pile,the more obvious the temperature stratification.In addition,the upper pile tends to heat up faster(up to 55 ℃ within 24 hours)and the pile temperature is higher(above 70 ℃);The temperature distribution in the intermittent-dynamic composting pile is relatively uniform,and t no temperature stratification is observed.From the perspective of reduction,both composting devices have good reduction effects,and the mass reduction is maintained at about 30%.The intermittent-dynamic composting has a better volume reduction,and the maximum volume reduction rate is49.47%(Static composting is 36.30%).From the perspective of dewatering effect,intermittent-dynamic composting is better,basically keeping above 40%,up to 54.33%,while static composting is kept between 22% and 49%.From the perspective of compost products,static composting can achieve harmless after 7 days of primary fermentation.After 30 days of static composting,the compost products are decomposed,and the seed germination index can reach up to 160%(the rest of the batches are maintained above 90%),indicating a strong potential for resource utilization and a possible directly utilization in the field,which suggests that the composting process is mature.This study uses static and intermittent-dynamic small-scale composting devices to successfully carry out a large number of aerobic composting experiments in the rural area of Fujian and Anhui province,respectively,and obtain many reliable and practical process parameters and technical indicators.To a certain extent,this thesis provides a basis for the selection of different composting processes,project implementation and standardized operation in rural areas.