Study On The Treatment Of Ammonia-nitrogen From Coke Plant Wastewater

Coke plant wastewater is a kind of intractable waste water which is from the process of making coke. It contain high concentration of ammonia nitrogen and a number of toxic and difficult decompounded organic compounds. These brought severe harm to our environment and the health of human. So it is an important task for environmental researchers to find high efficiency and economical methods to remove ammonia nitrogen from coke plant wastewater. We find a new method for dispose ammonia nitrogen of coke plant wastewater. We adopt chemical precipitation method deal with high ammonia-nitrogen waste water, then use SBR+Biological contact oxidation deal with low ammonia-nitrogen waste water, finally,the water meet the standard.The chemical precipitation method with simple technology, fast reaction speed and high removal efficiency has been taken researched. Magnesium salt and phosphate salt are added into coke plant wastewater, and precipitation occurs at an optimal condition, to produce magnesium-ammonium-phosphate which is an insoluble compound and contains three nutrients of phosphorus,nitrogen and magnesium. Various factors affecting on ammonia nitrogen removal rate such as chemical precipitaters,pH value reaction temperature, dosages etc.are researched on this paper. The reagent choose Na₂HPO₄ and MgSO₄, and the best condition is n(P): n(Mg):n(N)=l : 1 : 1,pH=9, the rate of ammonia nitrogen remove has more than 94%. We find a method for magnesium- ammonium-phosphate purification, the purity of product is more than 90%, and it can use as a composite fertilizer.In detail the flowing are studied on SBR technology: test and study on SBR technology, finding the basic rule of groundmass degradation through studying in a test the changes of COD and ammonia nitrogen difficult to be degraded in coke plant wastewater. The result shows that the best operation cycle is 8.0 hours, the optimization operation mode is water feeding→anoxic churn up transitorily→aerobic aerated→anoxic churn up→aerobic aerated transitorily→sedimentation→water export and discharge mud→waiting. The let water can meet the standard if the concentration of ammonia nitrogen is less than 140mg/L.Biological contact oxidation is a method which is widely used in wastewater treatment. In this paper, we searched a fast velocity of bio-film domestication method, and choose a best packing material. The result shows that COD and ammonia-nitrogen be low of 15mg/l, The water can vent standard.