With annual precipitation of 1 000–1 500mm, Lake Taihu gets fair amount of rain but not enough to meet the growing demands of industries located on the lake (chemical, metal, printing, dying industries) and the rapidly growing population. Since the last major algae bloom in April 2007, licence to operate has only been given to industrial plants that control their effluent discharges and air emissions tightly and reduce their water intake from the lake. This environment, together with a national policy on sustainable water resource management under the China 12th five-year plan of 2011-2015 has led to the implementation of the most rigorous zero liquid discharge treatment.
Operational since May 2015, the wastewater treatment process produces annually 231 000 m3 of treated effluent collected from the Flue Gas Desulphurisation (FGD) process and cooling tower blow-down and reused in the boiler feedwater purification system. The softening pretreatment sludge is disposed of in a landfill and salts from the process are dried to >95.5% solids and sold to the local chemical industry, cutting the wastewater discharge to zero.