Reading guidance：This kind of disposal methods occupies a certain component in sludge disposal in the disposal of sewage sludge in agriculture, agricultural use of sludge also attracted the attention of some industry.

   This kind of disposal methods occupies a certain component in sludge disposal in the disposal of sewage sludge in agriculture, agricultural use of sludge also attracted the attention of some industry. But due to heavy metals and pathogenic microorganisms, agricultural use of sludge may have a potential threat to the environment. Therefore, treatment method of sludge disposal by agricultural processing stage must choose reasonable in the sludge, in order to more effectively achieve the safe agricultural use of sludge. According to the plant pollutant discharge standard of urban sewage treatment in China  (GB18918-2002) regulations, at the same time to ensure the safety of sludge, and better meet the requirements of sewage sludge, as much as possible to avoid the sludge applied directly destroy the soil environment influence the quality of crops, should be a reasonable choice of sludge treatment and disposal technology.
   Composting is a commonly used organic wastes treatment means, is widely used in sludge, treatment of livestock and poultry manure and other agricultural organic wastes, divided into two aerobic fermentation and anaerobic fermentation technology. Anaerobic fermentation process due to the complexity of the operation, need to invest a lot of money to build the digestive apparatus and supporting facilities, and there are not many China's relevant engineering experience, so that the operation of the difficulty of the larger, relatively speaking, aerobic fermentation of the operation is relatively simple, easy to run. Therefore, urban sludge dehydration can be disposed by aerobic hair fermentation composting of manure.
   Related studies have shown that, after aerobic composting treatment, proportion of stable state of heavy metals in sewage sludge, rather than the steady state proportion of heavy metals has increased, the biological effectiveness of heavy metals in sewage sludge decreased, and as the growth of the composting time, biological effectiveness decline more.In addition, the sludge in the process of composting temperature as high as more than 50 ℃, can reduce the moisture content in the sludge, and will carry bacteria in the sludge, eggs, and weed seeds kill, and composting time in half a month or more commonly, the sludge can be complex organic nutrients, into more easily by plants use of soluble nutrients and humus, improving its physical properties.
    Thus, it can be seen that compost method can not only effectively solidified and stabilized sewage sludge of heavy metals, but also in sterilization and optimization nutrients in sewage sludge, sludge reduction, stabilization, harmless, resource. Moreover, aerobic fermentation equipment investment and energy consumption were compared to anaerobic fermentation of low 1 / 3, is energy efficient composting process. Therefore, the composting process can be used as the preferred method of sludge pretreatment. Of course, aerobic fermentation has some limits its application problems to be solved, such as: poor handling, covering a large area. With the development of long time, sludge composting technology has been developed rapidly, the formation of sludge sludge compost 4 types of composting technology, and related research have concluded that the advantages and disadvantages of the four types, provides a theoretical basis for the use of sewage sludge composting. According to relevant data, to control the content of heavy metals in sludge composting sludge, the effect of killing pathogens. Therefore, experts recommend, in take the sludge utilization of agricultural resources disposal before using the method for the treatment of sludge compost. 

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