Research On Utilization And Management Pattern For Rural Domestic Refuse

In this paper, characteristics of rural domestic refuse in Shi village of Fu Yang city were investigated, a recycle anaerobic-aerobic technology to dispose rural domestic refuse was studied, and an integrated management system for rural domestic refuse was initially explored. The main results of this research were summarized as follows:(1)Refuse component in developed rural area was close to the municipal solid waste. For example, in Shi village, organic kitchen refuse was the main component, accounted for 55% to 72%, and was affected by seasonal factors significantly. Plastic content was from 8.2% to 12.6%, which was also close to the municipal solid waste. The inorganic ash refuse proportion ranged from10% to14.9%, involving the fuel structure of Shi village, in which the proportion of using coal as fuel was only about 10%.(2)The anaerobic-aerobic technology was divided into anaerobic and aerobic two stages. In this paper, two parallel sets of two-phase bioreactor pilot devices named 1#,2# were studied in anaerobic stage, and then the anaerobic fermentation refuse was ventilated in laboratory in aerobic stage.(3)Two-phase bioreactor system had a good effect on refuse degradation. After running for 210 days. refuse settlement of 1#> 2# was up to 46.5% and 42.3%, respectively. Refuse organic carbon content and BDM decreased throughout the pilot process. In the end, refuse organic carbon content in upper, middle and lower layers of 1# dropped to 348.3g/kg (154d),265.8g/kg (210d) and 217.9g/kg (210d), 2# for the corresponding 336.5g/kg (154d),273.5g/kg (210d) and 220.1g/kg (210d), respectively. In the end, refuse BDM in upper, middle and lower layers of 1# dropped to 29.9% (154d),20.7% (210d) and 18.5% (210d), 2# for the corresponding 20.7% (154d),23.1% (210d) and 18.1% (210d). Refuse ammonia nitrogen content in middle and lower layers declined after firstly increasing. In the end, refuse ammonia nitrogen content in middle and lower layers of 1# was 834.3mg/kg and 366.3mg/kg, 2# for the corresponding 859.4mg/kg and 313.4mg/kg. Ammonia nitrogen of recirculated leachate was mainly accumulated in the upper and middle layers of refuse. From day 77 to day 154, ammonia nitrogen content of upper layer refuse was always on the rise, in 1# device rising to 1455.2mg/kg from 554.1 mg/kg, and in 2# device rising to 1477.5mg/kg from 567.4mg/kg. Refuse Cu and Zn content declined throughout the process. In the end, refuse Cu content in upper, middle and lower layers of 1# dropped to 211.3g/kg (154d),121.1g/kg (210d) and 69.3g/kg (210d), 2# for the corresponding 229.5g/kg (154d),123.2g/kg (210d) and 83.4g/kg (210d). In the end, refuse Zn content in upper, middle and lower layers of 1# dropped to 179.5g/kg (154d),107.3g/kg (210d) and 59.5g/kg (210d), 2# for the corresponding 166.5g/kg (154d),110.7g/kg (210d) and 72.3g/kg(210d).(4)C0D_Cr concentration and NH₄⁺-N concentration of leachate in two-phase bioreactor system gradually declined after rapidly rising firstly. In the end, COD_Cr concentration of 1#,2# was 8801.6mg/L and 9021.3mg/L, and NH₄⁺-N concentration of 1#,2# was 400.3mg/L and 383.5mg/L, respectively. COD _Cr and NH₄⁺-N removal efficiency in the methanogenic reactor firstly rised, then basically stabilized, and gradually declined at the end. COD_Cr removal efficiencies of 1#,2# were maximum to 57.9% and 55.3%, respectively. NH₄⁺-N removal efficiencies of 1#,2# were maximum to 16.8% and 15.9%, respectively.(5)Suitable parameter was intermittent aeration of 0.06m³/(min·m³). After aeration to three months , five months and seven months fermentative age refuse for 21 days, their water removal rates could reach 49.1%,45.3% and 44%, organic compound removal rates were 41.9%,24.8% and 13.1%, respectively. The optimal fermentative age for rural domestic refuse was three months and five months. After aeration for 21 days, there was a good a weight reduction of refuse. Deweighting rate of three months fermentative age refuse ranged from 31.7% to 37.2%, five months fermentative age refuse for the corresponding from 31.7% to 37.2%, and seven months fermentative age refuse for the corresponding 24.8% to 26.9%. As refuse weight and volume were reduced after aeration, concentration effect was found on major nutrient elements, such as total nitrogen, phosphorus, and potassium. Therefore, aeration could enhance fertilizer effect and utility value of the rural domestic refuse.(6)After aeration for 21 days, refuse pH values ranged from 7.5 to 8.5, water content was less than 35%, and organic compound was more than 20%, which could all meet the requirements of the urban garbage controlling standards for agricultural use. Total nitrogen, phosphorus, and potassium content were slightly lower than the standards. For example, total phosphorus content ranged from 1.87% to 2.49%, but the standard requires more than 3%. Therefore, it was necessary to add appropriate amount of inorganic nutrients for agricultural use. Anaerobic-aerobic technology had a good effect on innocuity,reduction and reclamation of rural domestic refuse.(7)In the paper, an integrated management system for rural domestic refuse was initially explored, rural domestic refuse firstly mixed collection, then centralized sorting, and divided into four categories of recycle matter, organic refuse, inorganic ash refuse, and hazardous refuse. Recycle matter was reclaimed, organic refuse was disposed by anaerobic-aerobic technology, inorganic ash refuse was backfilled to the low-lying in the village, and hazardous refuse was sent to a company with relevant qualification. Fixed investment of the integrated management system was 67500 yuan in Shi village, proposed to be solved by the government financial allocation. Operating cost of the integrated management system was 6740 yuan/year, proposed to be solved together by the revenue of 4740 yuan/year from the management system and the villagers refuse charges (8.3 yuan·year^-1·household^-1).