On February 5th, 2001, a 56-year-old retired cadre named Zhang Chengshao mixed the smelled wastewater from papermaking and purifying agent made of rust inhibitor liquid to produce clean water at a shabby laboratory in Shankou town of Tai'an City, Shandong Province. He solved the difficult problems of the waste steel and iron rust inhibitor and the wastewater from papermaking. His patent for treatment the wastewater produces benefit...

In October 1999, Zhang Chengzhao changed the waste steel and iron rust inhibitor into water purifying agent. Then he used it to treat the papermaking wastewater. After monitoring the treatment rate reached to over 65%. The water is crystal and clear in quality better then the state grade II emission standard and can be use for reproduction. Compared with the traditional method, the treatment of per ton of papermaking wastewater can reduce RMB1 of the cost and save water 5 million tons a year...