Typical technical models and cases of rural organic waste resource utilization
For the implementation of the rural residential environment renovation of the promotion action plan for five years (2021-2025) "deployment requirements, improve the rural perishable rubbish, toilet waste and other organic waste harmless treatment and resource utilization level, strengthen the practical technology supply, agriculture NongCunBu, national rural revitalization of the bureau in the provinces, autonomous regions and municipalities directly under the recommended on the basis of, Through expert evaluation and field verification, four typical technical models and seven typical cases of rural organic waste resource utilization were selected for reference.
I. Model of reactor composting technology
Reactor composting is to put organic wastes such as perishable garbage, human and animal feces, and crop straw into an integrated closed reactor for aerobic fermentation. Common box-type reactor, vertical silo reactor, horizontal drum reactor. After pretreatment, such as impurity removal, crushing and mixing, the water content was adjusted to 45%-65%, and the raw materials were put into the reactor for high temperature composting. The fermentation temperature of the reactor compost should be above 55℃ for no less than 5 days to achieve the inactivation effect of pathogenic bacteria. The fermentation products can be returned to the field after maturity, and also used to produce organic fertilizer and cultivation substrate. The technology mode has a high level of automation, which is convenient for the collection and treatment of pollutants such as odor and leachate, but the construction cost is higher than that of simple compost.
Typical case 1: Qujiang District, Quzhou City, Zhejiang Province. The case covers about 11,000 people in four villages. It was put into operation in 2019 and mainly deals with kitchen waste and other organic wastes. The designed processing capacity is 5 tons/day, leaving some space for expansion. Currently, the actual processing of organic wastes is 1.2 tons/day. In terms of investment and construction, the government invested 2.7 million yuan to build a perishable waste treatment station, which mainly includes workshop, composting reactor, garbage sorting and storage facilities, fertilizer making equipment, leachate treatment equipment, deodorization equipment, etc., covering an area of 2,530 square meters. In terms of operation and management, cleaners guide villagers to sort garbage and put perishable garbage into temporary storage points, which will be collected by cleaners and transported to treatment stations. The third party is responsible for the operation, maintenance and maintenance of the treatment station, and the cost is borne by the government. There are 2 workers, and the comprehensive operation cost is about 220 yuan/ton. In terms of resource utilization, it can produce about 140 tons of organic fertilizer annually, which is used for surrounding landscaping, and the leachate is processed to the municipal pipe network after reaching the standard.
Typical Case 2: Doumen District, Zhuhai City, Guangdong Province. The case covers about 4,000 people in six villages. It was put into operation in 2019, mainly dealing with kitchen waste, crop straw and other organic wastes. The designed treatment capacity is 0.5 tons/day, and the actual treatment of organic wastes is 0.3 tons/day. In terms of investment and construction, the government invested 580,000 yuan to build kitchen waste treatment stations, purchase composting reactors and homogenizing mixing equipment, covering an area of 91 square meters. In terms of operation and management, a point system is adopted to guide villagers to conduct garbage classification, and garbage classification supervisors guide garbage classification, collect kitchen waste and transport it to treatment stations. The kitchen waste was sorted, crushed, dehydrated and pretreated, then put into the reactor for composting. The third party is responsible for the operation, maintenance and maintenance of the treatment station, and the government will bear the cost. The comprehensive operation cost is about 330 yuan/ton. In terms of resource utilization, organic fertilizer and cultivation substrate can be produced about 25 tons per year, which is mainly used for fertilizing surrounding flowers and seedlings.
Two, heap retting technology mode
Compost retting is the use of perishable garbage, crop straw, human and animal feces and other organic wastes by static compost retting. Fermentation time is usually not less than 90 days. The main facilities for the pile retting pool or pile retting equipment, should have rain, seepage and other functions. The technical mode is simple to operate, low construction and operation cost, but the fermentation cycle is long, odor and flies control measures need to be taken.
Typical case 3: Guangze County, Nanping City, Fujian Province. The case covers about 1,100 people in a village. It was put into operation in 2016, mainly dealing with kitchen waste, crop straw, mushroom residue and other organic wastes. The designed treatment capacity is 0.18 tons/day, and the actual treatment of organic waste is 0.13 tons/day. In terms of investment and construction, the village collective invested 27,000 yuan in the construction of solid-liquid separation platform, stratified fermentation tank, leachate fermentation tank, canopy, etc., covering an area of 60 square meters. In terms of operation and management, the villagers classify garbage, put the kitchen waste to the collection point in the village, and then transport it to the treatment station by the cleaner. After impurity removal and solid-liquid separation, kitchen waste is mixed with other organic waste, put into a stratified fermentation tank, add microbial agent, and rotate the driving device regularly to realize material agitation and layer change in the fermentation tank. The village collective is responsible for the operation, maintenance and maintenance of the treatment station, employing 1 worker, and the comprehensive operation cost is about 215 yuan/ton. In terms of resource utilization, the annual yield of organic fertilizer is about 24 tons, which is mainly used by surrounding farmers for free, and the leachate is stored and fermented and returned to the field for use.
Typical Case 4: Donggang District, Rizhao city, Shandong Province. The case covers about 350 people in 1 village. It was put into operation in 2019, mainly dealing with kitchen waste and other organic wastes. The designed treatment capacity is 0.15 tons/day, and the actual treatment of organic wastes is 0.11 tons/day. In terms of investment and construction, through the village collective self-financing, corporate sponsorship, government subsidies and other investment of 50,000 yuan, the construction of perishable waste treatment station, mainly including pretreatment facilities, decay bin, leachate storage tank, collection vehicle, grinder, covers an area of 450 square meters. In terms of operation and management, the villagers classify garbage, the cleaners regularly collect and transfer kitchen waste, and the tail vegetables and crop straw are delivered to the treatment station by the villagers themselves. After sorting, crushing, mixing and other pretreatment, the organic wastes were sealed and composted by using loess. The third party is responsible for the operation, maintenance, management and maintenance, and the cost is borne by the government. One person is employed, and the comprehensive operation cost is about 130 yuan/ton. In terms of resource utilization, the output is transported to the field after screening and further ripening, which can produce about 20 tons of "soil fertilizer" annually for vegetable and fruit cultivation.
Three, anaerobic fermentation collaborative treatment technology model
Anaerobic fermentation co-treatment is to put the organic wastes such as human and animal manure, crop straw, perishable garbage, vegetable and other organic wastes into anaerobic fermentation tank for treatment after crushing, removing impurities, conditioning and other pretreatment, which can produce biogas and marsh fertilizer. Wet and dry anaerobic fermentation are common, requiring raw material pretreatment facilities, feeding equipment, gas storage cabinets, storage facilities for marsh manure, etc. Biogas can be used as clean energy after purification and purification, and biogas fertilizer can be returned to the field for use or production of organic fertilizer. This technology mode has a high resource utilization rate, but has high technical requirements for stable operation and safety management, and is suitable for areas with sufficient raw material supply, large demand for clean energy and strong capacity of farmland consumption. From a practical point of view, perishable wastes and toilet manure can generally be co-processed by relying on the existing anaerobic fermentation facilities of livestock and poultry manure, and the pretreatment, feeding and other supporting equipment should be improved according to the actual situation.
Typical case 5: Liangzhou District, Wuwei City, Gansu Province. The case covers about 80,000 people in 17 towns and townships in the region. It was put into operation in 2016. It mainly deals with livestock and poultry manure, and co-deals with perishable garbage, toilet manure, vegetable tail, crop straw and other organic wastes. The designed treatment capacity is 820 tons/day, and the actual treatment of organic wastes is 350 tons/day. In terms of investment and construction, it has invested 91 million yuan in the form of self-financing by enterprises and government subsidies, and built five stations in the whole district with a total volume of 22,000 cubic meters of anaerobic tanks, mainly including semi-underground integrated anaerobic fermentation tank, fully enclosed dry-wet dual-feeding system, and biogas residue and biogas slurry treatment system, covering an area of 53,000 square meters. In terms of operation management, the company is responsible for collecting fecal waste, rural perishable garbage, crop straw and tail vegetables from farms within 15 kilometers of the treatment station, and putting raw materials into fermentation tanks for treatment after pretreatment. Employ 10 people, the comprehensive operation cost is about 180 yuan/ton. In terms of resource utilization, about 13.5 million cubic meters of biogas can be produced annually, of which about 1.45 million cubic meters can be supplied to surrounding areas through pipe networks, and the rest of the biogas can be used for power generation. About 120,000 tons of marsh manure can be produced annually, which can be used to sell or guide farmers to "trade waste for fertilizer".
Typical case 6: Suining County, Xuzhou City, Jiangsu Province. The case covers about 4800 people in one village. It was put into operation in 2017. It mainly deals with livestock and poultry manure, and co-deals with perishable garbage, crop straw and other organic wastes. The designed treatment capacity is 34 tons per day, and the operation is basically full load at present. In terms of investment and construction, the government invested 5.9 million yuan in the construction of solar anaerobic fermentation tank, gas storage tank, biogas purification system, biogas pipe network and biogas slurry storage tank, covering an area of 6,530 square meters. In terms of operation and management, the "trinity" operation and maintenance system of raw material collection, daily management and protection, and gas supply has been established. Perishable garbage is collected by the cleaner and sent to the treatment station. Livestock and poultry waste is collected and transported by a third party. The third party is responsible for the operation and maintenance of the treatment station, with 3 workers, and the comprehensive operation cost is about 110 yuan/ton. In terms of resource utilization, it can produce about 500,000 cubic meters of biogas annually to supply gas to 1,200 surrounding households. It can produce about 1750 tons of biogas residue and 9400 tons of biogas slurry, which are used for planting vegetables and fruit trees around it.
4. Technical model of earthworm culture and treatment of organic waste
Earthworm farming treatment is to mix livestock and poultry waste, perishable garbage, crop straw and other organic wastes in a certain proportion, after high temperature fermentation pretreatment, the earthworm abdominal digestion to achieve high value utilization. Earthworm manure can be used to produce organic fertilizer or return to the field, and the finished earthworm can be used to extract earthworm active protein. Raw material pretreatment equipment, juvenile worm breeding facilities, breeding sites, etc. This technology mode has high resource utilization rate and good economic benefit, but it requires supporting land for earthworm breeding and pollution prevention and control measures, which requires higher requirements on breeding technology, management level and climate conditions. In addition, some places are also exploring the treatment of rural organic waste by breeding black gadflies and cockroaches.
Typical Case 7: Jinghai District, Tianjin. The case covers about 30,000 people in 34 villages. Put into operation in 2011, it mainly deals with organic wastes such as livestock and poultry manure, crop straw, tail vegetables and kitchen waste. The designed treatment capacity is 140 tons/day, and the actual treatment of organic waste is 110 tons/day. In terms of investment and construction, the cooperative invested 3.1 million yuan to build an earthworm breeding production workshop, and purchased grinding machine, earthworm harvester, electric sprayer, etc., covering an area of 560 square meters. At the same time, 600 mu of forest base was transferred for earthworm cultivation under the forest. In terms of operation and management, the surrounding farms will transport livestock and poultry waste to the treatment station and pay a certain fee. The rural perishable waste and free-range manure will be collected and transported by a social service organization, and straw and other auxiliary materials will be purchased by agreement. The cooperative is responsible for operation, maintenance and maintenance, employing 30 workers, and the comprehensive operation cost is about 75 yuan/ton. In terms of resource utilization, about 10,000 tons of earthworm manure can be produced annually and sold as fertilizer. The annual yield of fresh earthworms is about 150 tons, which is used for fishing and deep processing of earthworm products.
There are many technological modes of rural organic waste resource utilization. In addition to the above four modes, some places are also actively exploring new technologies and new modes. In the process of promoting the utilization of rural organic waste resources, local measures should be taken in accordance with local conditions, scientific demonstration, and the selection of technology models suitable for local natural conditions, economic development level and villagers' living habits. No matter what kind of technology mode is adopted, it should be on the premise of harmless treatment and safe utilization to achieve green and low-carbon cycle development. If it is used to produce commercial organic fertilizer, it should comply with relevant standards such as Organic Fertilizer (NY525-2021) to avoid adverse effects on agricultural production and ecological environment.