Study On The Treatment Of Integrated Tanning Wastewater

A great deal of protein, colorant, fatty acids, sulfide, chromium salt, and skin residue and so on. The raw materials were different. According to the discharge of Tannery Company in Da Lian, the process was designed. Two different craft were designed: coagulation-flotation system + SBR system and coagulation-flotation system + bio-contact oxidation system.Coagulation-flotation system: the results of the study on the stable time showed that when the pressure was 0.55MPa, the stable time was the longest. The pressure of gas-liquid pump was 0.55MPa. The diameter of micro-bubble was figured out about 35-45μm by means of Stokes' Expression in the pressure of 0.55MPa. Got the best dosages of orthogonal test in breakers: FeSO₄ was 2.66g/L, the wastewater pH value of adding alkaline NaAlO₂ waste liquid was 8, and PAM was 1mg/L, and got the best flow recycle ratio 225%. These parameters were used in the coagulation-flotation system. When COD was 7.70×10³mg/L, SS was 1.90×10³ mg/L, oil grease was 0.972×10³ mg/L,the experimental results showed that the average COD,SS,oil grease removal rate were beyond 85%,90%,99.5% respectively, and the shock resistances of experiments were also done.The experimental research of tannery wastewater by Sequence Batch Reactor (SBR) showed that reliable and stable treatment results could be achieved. The method of draining in the top and influent in the bottom was feasible. The speed of influent was 8L/h; the best ratio of draining was 3/5.Aeration time and aeration quantity has strong influence on treatment efficiency. When MLSS was between 4 g/L and 6g/L, the removal rate of COD was high. The draft parameter of the reactor: the time of influent (effluent) was 1.73h, aeration 6h, settle 1.5h. When the COD and NH3-N concentration of influent water was in level of 1000 mg/L and 70 mg/L. the removal rates of COD and NH3-N were 90% and 85% respectively.The experimental research of tannery wastewater by bio-contact oxidation process, the effect was stable. When the COD and NH3-N concentration of influent water was in level of 1000 mg/L and 70 mg/L. the removal rates of COD and NH3-N were 85% respectively. The process is easy to run and is a stronger suitable stress according to the shock resistances.