The Research Of Magnesia Wet Flue-gas Desulfurization Wastewater Biological Purification Treatment Technology

After more than 10 years of research and development of the magnesia wet flue gas desulfurization technology in China, the reliability of the process, the economy of the construction and operation as well as the feasibility of desulfurization byproducts resources have been widely recognized. Magnesia wet flue gas desulfurization technology is a kind of technology using magnesium oxide as desulfurizer, to absorb sulfur dioxide and generate magnesium sulfite and a small amount of magnesium sulfate, the key of which is waste water discharge and purification in desulfurization process. Magnesium was the main method with the aid of seawater act as auxiliary in Magnesium Base-seawater Marine Flue Gas Desulfurization(M&S FGD). M&S FGD wastewater contains a large number of nitric oxide, sulfur oxides, heavy metal compounds, ect. Moreover, it contains high salt concentration, COD and has poor biodegradability characteristics. Since ammonia and heavy metal compounds as the water main pollutants should get widespread attention, the research of the method of removing ammonia and heavy metal form M&S FGD wastewater is important.This paper analyzed ammonia, nitrate, nitrite, sulfate, sulfite, calcium, magnesium, chloride, COD, heavy metals, color and turbidity in the M&S FGD wastewater; screening efficient denitrification strain by simultaneous nitrification and denitrification technology for M&S FGD wastewater nitrogen removal; investigation unit approaches to heavy metals removement in M&S FGD wastewater,and focused on the study of microbial flocculant removement of heavy metals, the poly-y-glutamic acid (y-PGA) produced by Bacillus pumilus are employed to remove heavy metals in M&S FGD wastewater; comprehensive treatment M&S FGD wastewater. After comprehensive treatment the NH3-N concentration reduced from 604.00 mg/L to 12.00 mg/L; the initial NO;-N concentration reduced from 16.09 mg/L to 1.04 mg/L; the 1 NO;-N concentration reduced from 196.120 mg/L to 0.32 mg/L; the Zn2+, Cr3+, V5+, Cd2+, Pb2+, Ni2+concentration reduced from 0.26,0.34,8.28,0.87,2.54,101.67 mg/L to 0.06, not detected,1.04,0.05,0.42,11.39 mg/L. Provide suitable biological purification treatment technical methods for Magnesium Base-seawater Marine Flue Gas Desulfurization wastewater.