Coal gasification is an effective way to reduce coal pollution, but pollution caused by waste water generated in the gasification process on the environment. In this paper, different for the major pollutants in wastewater, its treatment, control technology, process were discussed, and recommendations. They introduced the gasification of useful substances in wastewater recycling, biological treatment methods, and the depth of treatment. Specifically introduced phenol and ammonia in wastewater recycling, using activated sludge, biological iron law, charcoal - bio - ferric process, anoxic - aerobic (A-O) method of wastewater treatment, activated carbon adsorption and coagulation precipitation depth treatment of wastewater.

keywords: Sulfuric acid gas system, the new shell and tube falling film evaporator, coal gasification,