Study On Mechanism Of High Temperature Composting Of Livestock Manure And Its Application

A series of experiments were carried out aiming at full use of solid offal from industry and agriculture. Livestock manure, maize straw, furfural dreg and mushroom dreg were chosen as raw materials and packing materials in composting experiments to study the influence of different bacterial and different packing materials on the general nature, dynamic change of main nutrients, bio-chemical characteristics, humic characteristics, and decomposition status of compost. The results are as follows.1. Temperature influences compost quality directly. When the compost temperature was kept within 55-60C over 3 days, the pathogens in the compost were killed. After 10 days of temperature within 55-60C, the quality of the compost became stable. The moisture content of raw materials and oxygen concentration influenced aerobic-compost reaction rates. The ideal compost body moisture content was between 40-60% and the ideal compost body oxygen concentration was 5-15%.2. During composting, the absolute content of every nutrient dropped. The variation tendency of their relative content are obviously different. Namely the total C relative content presents the downward trend with the compost process, the content of total nitrogen shows different variation tendency based on different packing materials. In composting incubation experiments certain amount of nitrogen loss has been found which can be reduced by addition of some organic or inorganic additives, such as bentonite, super-phosphate, maize straw, etc. Ventilation or pile turning increased nitrogen loss, among them superphosphate is best. The content of total potassium and total phosphorus increased respectively in various degrees with the compost process.3. The compost pH value increased at first, and then decreased, and then tended to increase, leading to slight alkaline finally. In the course of composting, EC value showed downward trend. Peroxidase activity correlated negatively with compost pile temperature. To certain extent the urine enzyme activity was positively correlated with temperature.4. The decrease of total humic acid, free-form humic acid and water soluble humic acid of compost after composting, and the increase of the ratio of humic acid to organic carbon proved obvious trend of carbon humification in the compost course. Increase of HA/FA indicated that high-temperature compost helps to produce Humo acid, and therefore improve humus quality.5. The total carbon, C/N, NH4+- N, water soluble carbon, and WSC/TN of pile body showed downward trend during composting, while the indexes, such as HA/FA, CEC/TOC, and seed germination percentage etc. tended to rise. C/N, NH/- N, HA/FA, seed germination percentage can be chosen as indexes to reflect extent of compost decomposition. Water-soluble carbon, WSC/TN, and CEC/TOC is general indexes indicating extent of compost decomposition.6. Both furfural dreg and mushroom dreg can be taken as packing material for livestock manure compost, which can be more suitable for the factorial production of organic fertilizer compared with maize straw.7. The whole composting process in factorial production can be separated into 4 main stages, i.e., pretreatment of raw materials, first-fermentation, second-fermentation and post-treatment. Differentcompost pile turners have their own advantages and disadvantages, among which mill-cutter-pile-turner has high work efficiency, high energy conservation and relatively low cost8. Due to a large number of aboriginal microorganism in compost raw materials, composting process and quality can't be affected by addition of exterior microorganism.