Reading guidance：With rapid growth of the national sewage production and processing capacity, the sludge production has also increased, caused by the environmental pollution has caused a global common concern, sludge t

   With rapid growth of the national sewage production and processing capacity, the sludge production has also increased, caused by the environmental pollution has caused a global common concern, sludge treatment and disposal has become one of the important research topic nowadays.
   In current world, sludge treatment disposal of the mainstream technology of anaerobic digestion, aerobic composting, incineration, land use, in these technologies, anaerobic digestion with its remarkable sludge stabilization, energy has been attention at home and abroad.
   1. Technical principle of sludge anaerobic digestion technology
   Anaerobic digestion of sludge is a kind of sludge treatment process, which is used to decompose the organic substance in the sludge to reduce and stabilize the sludge.
   At present, the internationally recognized principle of anaerobic digestion and reaction process on a comprehensive three stage theory, by Bryant in 1979 according to the physiological characteristics of microbial population classification is proposed. They believe that the anaerobic digestion were divided into hydrolysis and acidification, acetic acid phase and methane phase, each stage is a linkage between effect, and has a unique microbial community. The hydrolytic acidification stage: in the stage of microorganisms including bacteria, protozoa and fungi, most of which absolute anaerobic bacteria and facultative anaerobic bacteria in the sludge, carbohydrate, protein, fat, cellulose and other non water soluble organic polymer in microbial enzymes hydrolyzed into soluble substances, converted into acetic acid, propionic acid, butyric acid and short chain fatty acid and ethanol, acetic acid and carbon dioxide. The main stages: the stage for microorganisms Hydrogen producing acetogenic bacteria and homoacetogenic bacteria, the hydrolytic acidification product into acetic acid. Methanation stage: methane bacteria is the main bacteria in this stage, belongs to anaerobic methane bacteria. Divided into two groups, a group of hydrogen and carbon dioxide into methane, another group of methane production of acetic acid decarboxylation according to the reaction temperature. The digestion, anaerobic digestion for mesophilic digestion and high temperature digestion, respectively, reaction temperature is 30 DEG to 35 DEG and 50 DEG to 55 DEG. In contrast, high temperature digestion than mesophilic digestion reaction speed, high organic load, high gas production rate, digester volume is small, the degradation of organic matter more thoroughly, the pathogenic bacteria killing rate is higher, but the energy consumption is relatively high, investment is large, difficult to control. Therefore, temperature is one of the important factors that affect the anaerobic digestion.
 2. Anaerobic technology development in foreign country
 3. Development of anaerobic digestion technology at home
   Compared with developed countries, development of anaerobic digestion technology lags behind. Until now, we haven’t made breakthroughs on anaerobic digestion technology. There are still many difficulties such as high production efficiency, reaction condition optimization and sludge control. Anaerobic digestion of professional equipment localization rate is low, the anaerobic digestion of key technology and equipment is still mainly rely on imports, Tianjin, Qingdao, Yantai, Haikou, Yongzhou, Hangzhou and other places sewage processing plant sludge anaerobic digestion of the mixing equipment from abroad.
  4. Development trend
  Our country has a large population, resources and energy relative shortage of anaerobic digestion technology of sludge resource and energy approach conforms to the national conditions of our country. Countries have also successively promulgated a series of policies and regulations to encourage the research and application of the technique and in the < Waste Resources of science and technology project of "Twelfth Five Year Plan" special plan, sewage treatment plant sludge anaerobic digestion technology listed as "Twelfth Five Year Plan" key research and vigorously promote the sludge treatment, disposal and recycling of the key technology. Visible, anaerobic digestion has huge market potential and favorable policy environment, will become the leading industry direction of sludge sludge treatment disposal technology of.
A. Anaerobic digestion technology of combination of organic wastes and sludge
    Our country produces every year the kitchen waste, municipal solid waste (MSW) huge number, its anaerobic digestion of the effect is not ideal, and the kitchen garbage and waste organic components and sludge mixed digestion can achieve "win-win" or "win win win", in our country has very important practical significance.
   B. Combination anaerobic digestion technology of high temperature and middle temperature
   At present, foreign countries have started to explore the combination of moderate and high temperature anaerobic digestion process, and it is proved that the high temperature anaerobic co digestion process possesses higher than single temperature digestion capacity. But research on the technology at home and abroad are not many, especially in our country, still no such reports.
  C. Anaerobic digestion technology with high solid content
    At present, garbage with high solid content has been widely applied to some developed countries such as Europe, America and Japan. 

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