Experimental Study Of Tungsten Smelting Iron Salt Flocculation + SNdNMBR Wastewater Treatment

With the rapid development of economic, tungsten smelting technology at home and abroad is becoming more and more mature. But it will produce the As/NH4+-N-containing wastewater in W metallurgy accompanying the composition of ATP, which would cause serious harm to the aquatic environment, vegetation and human health. Therefore, to seek out a new and efficient tungsten smelting wastewater treatment technology is extremely urgent.In this article, the iron salts flocculation+SNdNMBR integrated system approach to processing of W metallurgy wastewater. Research on the removal of As/NH4+-N in wastewater is made. Studies have shown as follows:(1) When the wastewater is pretreated with FeCl3·6H2O of Fe/As=2, pH=7-8, the PAM dosage of about6mg/L,the As concentration in effluent wastewater is0.458mg/L. Secondly, with removed of As through the adsroption and degradation by activated sludge, the As concentration can be controlled between0.34-0.39mg/L in wastewater through the MBR, which can meet the national emission requirements.(2) Acclimating sludge with the median ammonia nitrogen concentration method, controlling DO=1.5mg/L, HRT=8h, T=30℃, no adjusting for pH, the trial run in C/N=1.5source condition then it is found that the system removal effect on COD, NH4+-N, TN is better, the respectively removal rate of93.4%,73%and52%,and the shock load experiment proved that the system is running stable, shock load capability is good.(3) Observing the running situations which are different from the DO, C/N, HRT, pH, the MLSS, continuously monitoring the COD,NH4+-N, TN concentration in effluent water,it is found: DO=1mg/L, HRT of8h,SRT of about30-40d,C/N of1.5-2.0, the system can achieve better SNdN effects, and a good treatment effect. This moment, inspect the reation conditions of systems under the different pH,it found that:when the pH was about7-8,the system is best for the removal of COD and NH4+-N, which is fully consistent with the pH value of iron salts flocculation process envisaged As.(4) Moreover, under the condition of SNdN effect mechanism analyzing, based on the Monod equation and experimental data elicited the kinetic model of SNdNMBR systemr with W metallurgy wastewater:It can provide model analysis for SNdNMBR on treatment for W metallurgy wastewater in post, at the same time it is found that in the kinetic constant determination process, the substrate saturation of NO3-N concentration KD constant value is much larger than the conventional single-stage activated sludge, which illustrated that the rat of SNdNMBR system is higher than traditional activated sludge process.