Future Directions
Ammonia Elimination Technology
Ammonia is a common pollutant found in waste water discharged mainly from industrial productions like fertilizer producing, coking, ammonia synthesis, dying, pharmaceuticals, oil refining and petroleum engineering. The traditional biochemical treatment is an effective measure taken to reduce the COD and oil contents in the water but only possesses a limited effect in the elimination of ammonia which, as a result, is in general dealt with by dilution discharge, thus posing dangers to the environment and leading to water eutrophication and bringing toxic effects to the living of aquatic animals as well as difficulties in the pretreatment of both life and industry water. It is a clear state here to eliminate the ammonia in waste water.
Wet Catalytic Oxidation (CWO) is a water treatment technology developed in the 1980s. It is mainly used for the pretreatment of high-concentration non-readily degradable organic waste water and biochemical treatment of ammonia waste water and also for the treatment of toxic and hazardous industrial waste water. Under conditions of high temperature and high pressure, the dissolved molecule of the catalyst can oxidize the toxic and harmful materials in the water and produce the final target products as CO2, H2O and N2 and others. At present, both domestic and foreign related researches consider noble metals as a catalyst. Du Hongzhang and others have developed a noble metal catalyst with high oxidation activity and stability which is effective in the treatment of coking waste water with an elimination rate of 99% or more. Qin and others have developed a catalyst of Ru / Al2O3 which can realize an elimination rate of 99% given the condition of 503K, 15MPa, 12 pH, and 1500×10-6 . Noble metal catalysts exhibiting a good catalytic effect and stability have got popular in industrial applications.