With the ceaselessly rise of Chinese urban wastewater treatment rate, the yield of sewage sludge is
also increased dramatically. In 2009, there are 1992 urban sewage treatment plants in operation, and the
treated wastewater amount is 28 billion m3, which produced 20.05 million tons of sludge with 80% water
content. And it is estimated that the amount of sludge will soon exceed 30 million tons 0. In addition to
the large amount, pathogenic bacteria and microorganism in sludge may pollute the food chain; open
dumping of sewage sludge will emit stink smell and other pernicious gases, which surely include NOx,
the famous green house gas 0, 0; if sludge discharge without further treatment, heavy metal in sludge could cause cultivated land degradation irreversible and may move into the food chain, do harm to
environment safety and human health0, 0. So in China sewage sludge treatment and disposal has become
one of the major environmental problems. But high water content of sewage sludge is the critical problem
for its further treatment and disposal, deep dehydration is necessary 0.
With the ceaselessly rise of Chinese urban wastewater treatment rate, the yield of sewage sludge isalso increased dramatically. In 2009, there are 1992 urban sewage treatment plants in operation, and thetreated wastewater amount is 28 billion m3, which produced 20.05 million tons of sludge with 80% watercontent. And it is estimated that the amount of sludge will soon exceed 30 million tons 0. In addition tothe large amount, pathogenic bacteria and microorganism in sludge may pollute the food chain; opendumping of sewage sludge will emit stink smell and other pernicious gases, which surely include NOx,the famous green house gas 0, 0; if sludge discharge without further treatment, heavy metal in sludge could cause cultivated land degradation irreversible and may move into the food chain, do harm toenvironment safety and human health0, 0. So in China sewage sludge treatment and disposal has becomeone of the major environmental problems. But high water content of sewage sludge is the critical problemfor its further treatment and disposal, deep dehydration is necessary 0.
การแปล กรุณารอสักครู่..