Sewage treatment: the process of purifying sewage in order for it to meet the water quality requirements for drainage or reuse. Sewage treatment is widely used in construction, agriculture, transportation, energy, petrochemical, environmental protection, urban landscape, Medical, catering and other fields, but also more and more into the daily life of ordinary people.

The topic of water pollution has been constantly raised, especially the problem of groundwater pollution. In Zhejiang, Hangzhou, Wenzhou, and other places, farmers or entrepreneurs have funded the director of environmental protection to go down the river to swim, so as to arouse people''''s concern about the severity of water pollution. Although each environmental protection director has chosen to silence or refuse, but the awareness of environmental awareness of the public awareness of water pollution has reached an unprecedented level of concern.

Surface water pollution is obvious, but groundwater pollution is shocking. Of China''''s 1.3 billion people, 70 percent of the population drink groundwater. More than 400 of the more than 660 cities use groundwater as a drinking water source. But according to reports, Ninety percent of the country''''s urban groundwater has been polluted.

Another set of data also shows that groundwater is facing severe challenges. In 2011, 857 monitoring wells in Beijing, Shanghai and other provinces and cities have been evaluated for water quality of 857 wells in the area, accounting for 2% of the monitoring wells of Class I and Class II, and of Class IV and Class V as many as 76.8 wells.

Among the nine provinces and cities, the best water quality is in Hainan Province, mainly in Class II; Shanghai, Beijing, followed by III; Heilongjiang and Jiangsu provinces have the highest proportion of Class IV water, while Jilin, Liaoning, Guangdong, Ningxia four provinces and regions generally only reached the level of category V.

The situation of water pollution is getting worse, which makes the sewage treatment and recycling industry receive unprecedented attention. In the past two years, the gross profit rate of each region has remained at about 70%, and even some areas have exceeded 100%. The industry has a great potential for development.