Discussion on Sludge Treatment Technology

According to the statistical data of the Ministry of Housing and Urban-Rural Development of People's Republic of China (MOHURD), up to the end of 2014, about 56% of the sludge got the harmless treatment through building materials, incineration, composting, and sanitary landfill, nearly half of the sludge failed to achieve harmless treatment, about 1/3 of the sludge adopted the "temporary way" for disposal, and over 10% of the sludge got unknown treatment111. The relevant data show that the investment of the sludge treatment in the developed countries accounts for 50% -70% of the total investment of sewage treatment plant, and in China, it only accounts for 20%-45% of the total. [...]the sludge treatment and disposal costs take up only a small proportion in the sewage treatment costs in China. According to some statistical reports, a treatment of 10 000 tons of sewage in the sewage treatment plants can produce 5-10 tons of sludge with the water content of 80%. [...]many countries in Europe and America, the application of sludge land mainly include 3 aspects: one is as the crops and pasture grass fertilizer in agriculture; two is as forest land, landscaping fertilizer in forest; three is as the improvement matrix for sandy wasteland, saline alkali land, abandoned mine in soil improvement. Because of the objective factors, such as transportation distance and operation difficulty, the amount of sludge in agriculture-oriented utilization is higher than that in forest and soil improvement.