The Component Analysis Of Flue Gas Desulfurization Wastewater And Its Purification Technology

Because of the emissions of SO2of the fuel gas and coal, the atmospheric pollution is getting more and more worse. SO2is bad for health, and the acid rain is harmful for the environment. The "Twelve Five-Year" Plan clearly defined the SO2emissions reduction target of8%. The annes VI of73/78MARPOL (MARPOL Convention) of International Maritime Organization (IMO) has required that the emissions of SOx are controlled within6.0g/kwh. Therefore, the application technology of SO2emissions for marine diesel engine has great significance.The process of wet SO2reduction technology of marine diesel engine is simple, stable, highly efficient, etc. In Japan, WFGD occupies98%of the market, the statistics of United States and Germany are92%and90%respectively. Magnesium desulfurization process utilized MgO as a desulfurization agent which could absorb SO2to generate MgSO3and MgSO4. The key aspects of the process are the wastewater and its purification technology. Marine Diesel Engines Magnesium-based Wet FGD Wastewater (MDEM) contains suspended solids, nitrate, nitrite, sulfide, benzene, linear hydrocarbon, heavy metal compound, etc. Moreover, it contains high COD and has poor biodegradability characteristics. IMO has relevant regulations on pH, PAHs, turbidity, nitrate, additives, etc. However, there does not exist systemic and complete measures and purification technology.This paper studied the ingredients and purification technology on MDEM and established and partly improved a test method on NO2, NO-3, NH3-NH+4, COD, SO42-, SO32-, Mg2+, Cl-, turbidity and chroma; biological methods were used to reduce turbidity; biological and physical methods were combined to reduce chroma and determined its conditions; the optimal conditions of activated carbon’s adsorbing were determined; Heterotrophic Nitrification and Aerobic Denitrification (SND) technology was used on denitrification, and determined its conditions.The biofiocculant MBF03reduced turbidity and its average removal efficiency reached93.35%; the optimal conditions for decolorization were:activated carbon’s adsorbing chroma with acid dip, dosage160g/L, decolorizing time40min, decolorizing method still decolorization, and the average chroma declined from1400to281; in order to get SND strain to remove ammonia wastewater, the colony morphology was rob-shaped, gram-negative, the16SrDNA maximum similarity was99%of Halomonas meridiana strain PR51-13, named as Halomonas sp. L6, the best denitrification condition was SND, the optimal conditions for denitrification were:carbon source sucrose, C/N ratio10.0, pH8.0, temperature30℃, and the denitrification efficiency was87.5%.