Tannery Wastewater Biological Treatment Of Ammonia Nitrogen

Leather wastewater pollute the water environments seriously for a long time. From the current status of the leather industry point of view, after biological treatment of leather wastewater, most of the pollution index can reach GB8978-1996 emission standards,which is called "Integrated Wastewater Discharge Standard".But NH4+-N is difficult to reach the standard for a long time, which is a very common phenomenon in the leather industry. Mainly because:①use lots of ammonium salt in leather production processes;②one of the tanning materials, the skin of animals contain NH4+-N, which enter into the wastewater in the treatment;③The protein in the skin of some animals will be separated in the process and decomposite a lot of NH4+-N release into the wastewater. These reasons often make NH4+-N increase not decrease after biological treatment of tannery wastewater.NH4+-N,as a nutrient pollutant in the water,may causes deterioration of water, ecosystem balance, eutrophication problems with a high leven, and is also harm to fish and other aquatic animals if the water environments worth.For this feature of the tannery wastewater, the issue studied the biological treatment technology intensively.Subject is about two biological treatment processes:The first research is A/O nitrogen removal process, which is divided into three experimental stage, Study about:①The remove effect of COD and NH4+-N in the secondary effluent of leather wastewater treatment process;②The remove effect of NH4+-N by the influence of COD and the intrinsic relationship between them;③The remove effects of COD and NH4+-N in the leather of raw wastewater process. MBR process for the removal of the second study of ammonia nitrogen, which is divided into two experimental stage, Study about:①Combine of anaerobic+MBR processes of the tannery raw wastewater about COD,NH4+-N removal efficiency;②Combine of anaerobic+MBR processes about the distribution of NH4+-N removal for leather wasterwater;③Combined of A/O+MBR processes about COD and NH4+-N removal efficiency of the tannery raw wastewater;④Combined of A/O+MBR processes of nitrogen removal;⑤The influent of NH4+-N loading to the effect of their removal.The results showed that:1,a simple A/O process of leather waste water or secondary effluent does not make NH4+-N reach the standard, for containing low concentrations of NH4+-N in the wastewater, biological cell through the use of physical means by itself can achieve the requirement of nitrogen removal;2, the combined of A/O+MBR processes (bio-reactor using bio-contact oxidation) can make COD and NH4+-N reach GB8978-1996 emission standards "Integrated Wastewater Discharge Standard"of leather wastewater effluent,and NH4+-N can reach Omg/L, the system can reach 94.1% of total nitrogen, nitrogen of the results is satisfactory.