What is the impact of livestock manure on the environment and how to deal with it?
The newly discharged livestock manure contains harmful gases such as NH3, H2S and amine. If it is not removed in time, the odor will increase exponentially, and malodorous gases will lead to air pollution and mosquitoes and flies will breed. The long-term accumulation of livestock manure has increased the number of harmful bacteria in the environment. A large amount of high-concentration manure seeps into the soil where manure accumulates or flows, which will cause plants to grow crazy for a long time, or damage the roots of plants, and even lead to plant death. The infiltration of manure into groundwater will seriously exceed the nitrate nitrogen, hardness and total bacterial count in groundwater. According to the determination, when livestock manure flows into the pond and the ammonia content in the water reaches or exceeds 0.2 mg/L, it will be toxic to fish. If it flows into drinking water sources, it can become the source of disease transmission and reduce the disease resistance and production capacity of livestock and poultry. This not only affects the survival, growth and development of livestock and poultry, but also pollutes the environment and harms human health. \x0d\ Treatment of odor of livestock manure \x0d\ 1 Chemical neutralization and deodorization method \x0d\ Sprinkle a layer of calcium superphosphate on the padding of livestock houses, and the calcium superphosphate reacts with ammonia produced in the manure to generate odorless solid ammonium phosphate, which can reduce the emission and concentration of ammonia in the manure. Hydrogen peroxide, potassium permanganate, copper sulfate and acetic acid can be used to inhibit the activity of harmful bacteria through sterilization and disinfection, thus inhibiting and reducing the generation of harmful gases in livestock and poultry houses. Mixing 4% copper sulfate and appropriate amount of hydrated lime in the padding, or spraying 2% benzoic acid and 2% acetic acid on the padding can all play the role of deodorization. When sulfur is mixed into the filler, the pH value of the filler can be less than 7.0. This can inhibit the generation and emission of ammonia in feces and reduce the ammonia content in the air of livestock and poultry houses. \x0d\2 Acidifier deodorization method \x0d\ Ammonia in livestock manure can be adjusted by using acidifier, ammonia volatilization in pig manure will stop when pH=5, and acidifier can neutralize salty substances in livestock manure. Adding 20% calcium oxide to compost can reduce ammonia volatilization of 10%. It is also reported that the use of 1 1% sucrose can reduce the pH value of pig manure to 3.5 and reduce ammonia volatilization by 98%. Adding Lactobacillus plantarum and glucose to the manure can reduce the pH value of pig manure from 8 to 6 and reduce ammonia volatilization by 50%. The research shows that the addition of aluminum salt can reduce the pH value in feces and reduce the volatilization of ammonia. Adding aluminum sulfate to poultry manure can reduce ammonia volatilization by 99%. \x0d\ Reuse of Livestock and Poultry Manure \x0d\ 1 Biogas \x0d\ Biogas project is a systematic project which aims at reduction, harmlessness and resource utilization, implements clean production and integrates manure treatment, biogas production and resource utilization. It consists of pretreatment, anaerobic digestion, post-treatment and comprehensive utilization. The biogas produced after treatment can be used as energy for production or life after dehydration, desulfurization and impurity removal. Biogas residue is discharged regularly according to the situation and can be dried. Fermented biogas residue can directly kill bacteria and parasites, reduce the amount of biological sludge, and will not cause pests and diseases, so it can be used as high-quality organic fertilizer. Biogas slurry contains a variety of ammonia ions and microorganisms, as well as indoleacetic acid and gibberellin, which can sterilize and resist harmful bacteria. The results showed that the killing rates of biogas slurry to aphids, red spiders and yellow spiders were 95.25%, and other caterpillars were 99.40%. Therefore, biogas slurry can be used as a nutrient solution for pigs and a liquid organic fertilizer for farmland when it enters the post-treatment system. \x0d\2 Fertilization \x0d\ mainly adopts composting method. Poultry manure and solid organic waste, such as bedding grass, rice straw, rice husk, etc. Stacking according to a certain proportion, adjusting the proportion of carbon and nitrogen in compost materials, and controlling appropriate moisture, temperature, oxygen and pH value. Under the action of microorganisms, complex and unstable organic components in garbage are decomposed into simple and stable organic components. With the increase of composting temperature, pathogenic bacteria, eggs, maggots and pupae in compost materials are killed. When used in farmland, the treated materials can improve the soil and provide crops with nutrients. During the operation, we should pay attention to the following aspects: ① microbial strains, carbon-nitrogen ratio, pH value, temperature, water content, ventilation and maturity should be appropriate. ② Composting is the best way to make a covered dump. If it is stacked in the open air, it needs to be properly covered to prevent rain from washing away. In addition, we should also consider the problems of taking water, turning over space, ventilation and collecting fertilizer and water. (3) Composting equipment Composting equipment can be roughly divided into three types: traditional type (field accumulation type), ventilated static pile type and trough type. The difference between the first two is that air is provided in different ways during composting. As long as the surface of the heap or artificial heap is turned over to provide oxygen needed by aerobic microorganisms, the efficiency of the wild heap type is low; The tank is a kind of composting equipment, and the operation process of composting process (feeding and discharging mode, ventilation, etc.). ) is controlled by the main part of the equipment and can be regarded as semi-automatic production equipment (because the whole production process still needs to include the previous stage of material adjustment and subsequent decomposition). Considering the factors such as land and secondary pollution, tank composting equipment should be the future development trend. Good compost plays an important role in improving soil structure and fertility. Composting can not only treat livestock manure, but also treat other organic wastes, which is a good method integrating waste treatment and resource recycling. \x0d\3 Feed \x0d\ Livestock manure is not only a high-quality organic fertilizer, but also a good livestock feed resource. In particular, chicken manure contains a lot of undigested crude protein, B vitamins, mineral elements, crude fat and a certain amount of carbohydrates, which can be used as feed for poultry and aquaculture. However, livestock manure not only contains a lot of water, but also contains various bacteria, which need high temperature and high pressure, heating, sterilization and deodorization. To make manure into powder feed additive, it can only be a good feed resource after processing. The main methods of feeding livestock manure are drying, silage (anaerobic fermentation), aerobic fermentation and separation. \x0d\3. 1 drying method \x0d\ drying method is often used for feed treatment, especially chicken manure treatment. Drying methods can be divided into natural drying method and artificial drying method with or without artificial power. \x0d\3.2 Silage method \x0d\ Silage fermentation is a simple and economical method to treat solid organic wastes. Can balance the feed supply throughout the year. \x0d\3.3 Aerobic fermentation \x0d\ This method requires less investment and changes many characteristics of feces. The product can be used as animal feed. In the process of treatment, products need to be aerated, heated and dried, so a lot of energy is consumed. \x0d\3.4 Separation method \x0d\ At present, many pastures use flushing cleaning systems (especially pig farms), and the collected feces are mostly liquid or semi-liquid. If we use drying method and silage method to treat feces, it will consume too much energy and waste resources. The separation method is to select a certain washing speed to separate solid and liquid from livestock manure, and satisfactory results can be obtained.