Wei Ruoqi, Li Yu-e
# 2010 Vancouver
China being the world’s most populous country produces the highest volumes of sewage and waste water and due to rapid increase in industrialization this volume is rising fast. According to the statistics from the National Ministry of Construction, by the end of 2007, the water consumption of the 665 cities in China had reached 50.2 billion cubic meters every year and the corresponding total sewage volume was more than 40 billion tons every year. These figures only cover the major cities and the waste from China’s 34,000 towns in rural areas is undoubtedly much higher. So what about the operational condition of the sewage and drainage systems in China? According to an investigation of the domestic network in 76 cities representing a total length of urban sewage pipes of 180 thousands km, more than 60% of them were laid before 1980 and these were mainly old generation concrete pipes, cast iron pipes, ceramic pipes etc. There are a large number of problems with these old piping systems, such as pipe wall erosion, joint leakage, pipe cracks and damage and blockages, all of which have resulted in groundwater pollution.
