How to deal with the farm livestock manure is environmentally friendly?

In recent years, the rapid development of livestock and poultry farming, and gradually formed a series of specialized production, and at the same time also brought a series of environmental problems, such as in 2000, Beijing, large-scale farms produce livestock and poultry manure 600 × 104t, plus intensive production of rinse water, wastewater discharges amounted to 3,000 × 104t / a. According to the monitoring, farm wastewater COD exceeds the standard of 50-60 times, BOD exceeds the standard 70-80 times, SS exceeds the standard 12-20 times, if untreated discharge will form a serious surface source pollution around the city. According to the monitoring, the COD of farm wastewater exceeds the standard by 50-60 times, the BOD exceeds the standard by 70-80 times, and the SS exceeds the standard by 12-20 times, and if it is discharged on the spot without treatment, it will form a serious surface source pollution around the city. Deal with farm manure is to ensure that the farm reasonable environmental requirements, but also to avoid contamination of the surrounding environment and cause public nuisance laws and regulations, while the rational use of manure can also be turned into a treasure to produce certain economic benefits.

1, composting - livestock farm manure treatment method

Composting technology is a manure treatment method in the natural environment conditions will be crop residues and farm manure composting and fermentation for crop growth when used. Composting as a traditional biological treatment technology has been improved over the years, and is now moving towards mechanization, commercialization, and increasing equipment efficiency.

2, anaerobic treatment - livestock and poultry farm manure treatment methods

Currently used to deal with manure in the farming industry, many anaerobic process, which is more commonly used are the following:

① anaerobic filter (AF)

1969 by Young and McCarty was first put forward, in 1972, foreign countries began to be applied in the production. China in the late 1970s began to introduce and improve the biogas production rate of up to 3.4m3/(m3?d), methane content of up to 65%.

② upflow anaerobic sludge bed (UASB)

1974 by the famous Dutch scholars Lettinga, etc., put into use in 1977 in foreign countries. 1983 Beijing Institute of Environmental Protection Science and other domestic units conducted a cooperative study, and the improvement of the relevant technical indicators, and its removal of organic wastewater COD can reach 90%. The removal rate of COD from organic wastewater can reach 90% or more.

③ Sludge bed filter (UBF)

It is a combination of UASB and AF, with short hydraulic retention time, high gas production rate, high COD removal rate.

④Two-stage anaerobic digestion

Proposed by Ghosh in 1971, the biogas fermentation process is divided into two stages of acidification and methanization, which are carried out in two digesters. It is characterized by the fact that a large amount of anaerobic activated sludge (with excellent settling performance and biological activity) can be retained in the digester, which improves the load and gas production rate in the digester.

⑤ Ascending sludge bed reactor (USR)

is a kind of anaerobic digester, with high efficiency, process simplicity and other advantages, has been often used in the disposal of swine, chicken manure wastewater, the device gas production rate of up to 4m3/(m3?d), COD removal rate of more than 80%.

3, aerobic treatment - livestock and poultry farm manure treatment methods

① Aeration

In the 1970s, Japan used aerobic intermittent aeration technology for pig wastewater for effective management, and developed a series of related equipment. In recent years, Australia has developed a variety of simple and practical shallow jet aeration devices on the traditional blast aeration devices. Overall, the aerobic technology in the field of pollution control in the aquaculture industry is moving towards the direction of high efficiency, practicality, economy and ease of operation.

② contact oxidation

Contact oxidation technology has long been used to deal with a variety of different concentrations of organic wastewater, the essence of which is the use of filler microorganisms on the oxidative decomposition of organic matter, so as to achieve the purification of sewage. Britain in recent years, the use of contact oxidation technology for pig slurry treatment, and the development of structure and performance of the new filler is very good, its removal rate of COD of more than 90%, the BOD also has a high removal effect.

③SBR

Sequencing batch activated sludge method is an intermittent activated sludge process improved and developed based on the traditional Fill-Draw system, which has attracted much attention from many scholars in recent years, and is now widely used in the treatment of municipal sewage, food processing wastewater and so on. Test results show that swine manure water after solid-liquid separation, anaerobic digestion two-stage treatment into the SBR aerobic system, its removal rate of COD up to 70%, the removal rate of BOD up to 80% or more, the effluent can meet the discharge standards.

4, anaerobic - aerobic combination - livestock and poultry farm manure treatment method

To realize the complete disposal of manure in the aquaculture industry, anaerobic process alone can not yet reach the standard discharge and utilization of waste requirements, must be carried out in-depth treatment or follow-up treatment, which requires aerobic and anaerobic process combined together with the use of some of the domestic farms have been Started to notice the superiority of the combination of the two processes.