(a) Biogas Engineering Technology Biogas engineering technology mainly adopts the following modes in pig farm waste disposal practices: 1. Biogas (anaerobic) returning mode. Also known as the combination of agriculture and animal husbandry, according to the nutrient content of livestock and poultry manure sewage and nutrient requirements for crop growth, the waste water and manure produced by livestock and poultry farms are harmlessly treated and applied to farmland, orchards, vegetable gardens, nursery stock, and flower cultivation. Pasture and grassland, etc., to achieve the combination of planting and breeding, this approach applies to farms far from the city, the land is wide, surrounded by enough farmland. 2. Biogas (anaerobic) natural treatment mode. The anaerobic effluent is treated with natural treatment systems such as oxidation ponds, land treatment systems or constructed wetlands. Mainly uses aerobic decomposition oxidation (aerobic bacteria), anaerobic digestion (anaerobic bacteria) and photosynthesis (algae and aquatic plants) of algae symbiotic system in oxidation ponds, biological, chemical, physical fixation and degradation of land treatment systems. Functions, as well as artificial sewage treatment technology, wetland plants and microorganisms purify anaerobic effluent. It is applicable to areas that are far away from the city, have a wide land, and have low land prices. They have beaches, waste land, forest land, or low-lying land that can be used for the natural ecological treatment of manure. 3. Biogas (anaerobic) compliance discharge model. In other words, sewage from pig farms is treated with industrialized sewage treatment. The livestock and poultry manure treatment system of this method consists of pretreatment, anaerobic treatment (biogas fermentation), aerobic treatment, post-treatment, sludge treatment, and biogas. Purification, storage and use of other components. More complex mechanical equipment and more demanding structures are required, and their design and operation need to be performed by professionals with higher technical skills. It is suitable for the treatment of excrement on large-scale pig farms located in the suburbs of large cities, with developed economy and in tight land areas. This model is generally used for large scale farms. 4. Biomass energy use model. Mainly biogas power generation. Biogas from anaerobic fermentation processes is used to generate electricity, producing electricity and heat. The specific process is to collect the fresh excrement from livestock and poultry farms and put them into the anaerobic reactor through the feeding system. The flushing water in the livestock house is collected into the catchment and pumped into the front of the anaerobic reactor. Under the action of the stirring device inside the reactor, a high concentration of fermentation broth is formed. The manure is digested anaerobicly and the biogas produced enters the power generation system for power generation. The biogas slurry and biogas slurry are dewatered through a flat filter, and the separated biogas residue is used as organic fertilizer. The biogas slurry enters the storage tank as a liquid organic fertilizer and is directly applied to the farmland or discharged after being treated for compliance. Biogas power generation not only solves the problem of aquaculture waste disposal, but also generates a large amount of heat energy and electric energy, conforms to the environmental protection concept of energy recycling, and has good economic benefits. (B) Solid Manure Composting Technology Composting is the process of degrading organic matter in solid feces through the action of microorganisms under artificial control of moisture, carbon-nitrogen ratio, and ventilation conditions to make it mineralized, humified, and harmless. The high temperature during composting can not only kill various pathogenic microorganisms and weed seeds in the faeces, make the excrement harmless, but also generate effective nutrients that can be absorbed and utilized by plants, and have soil improvement and regulation. Composting is widely used due to its advantages such as low operating costs, large amount of processing, and no secondary pollution. The compost is divided into aerobic and anaerobic compost. The aerobic compost is a biochemical process that degrades the organics by the action of the obligate and facultative aerobic microorganisms. The aerobic compost has a fast decomposition rate, a short period, and a low odor, and the organic matter is fully decomposed; Oxygen compost is the process of degrading organic matter by the action of obligate and facultative anaerobic microorganisms. Anaerobic composting has a slow decomposition rate, a long fermentation period, and odors are easily generated during the composting process. At present, aerobic compost is mainly used. Pumpkin Kernel,Kernel Pumpkin Seed,Squash Seed Kernels,Roasted Pumpkin Seed Kernels Wuyuan county dafeng oil food co.,ltd , https://www.sundafengfoods.com