He Yue, a professor from China’s Tianjin University, recently said that, according to the China’s Sludge Treatment and Disposal Market Analysis Report, China’s annual urban sewage treatment capacity is equivalent to the total storage capacity of the Three Gorges Reservoir. However, 80 percent of the sludge from this "reservoir" is not dealt with, easily causing secondary pollution to the environment. "A large amount of toxic and harmful sludge has become a time bomb for the urban environment." He said that the sludge contains nitrogen, phosphorus, potassium, heavy metals, parasite eggs, and germs. It will not only endanger the environment of the underground water, rivers, and farmland, but also human health through the food chain. "China’s sewage treatment industry has developed rapidly, but the byproduct sludge has not been disposed of reasonably and safely." He said, this "sewage reservoir" produces nearly 22 million tons of dewatered sludge annually, of which only 20 percent receives the necessary processing. It has been estimated that by 2020 China will see as much as 60 million tons of sludge per year.
Source: People’s Daily, March 4, 2013