Treatment of Tannery Wastewater with Salt Tolerant Bacteria Basing on Different Culture Mediums

This study was done to access the influence of salinity on the treatment of tannery wastewater, activity of sludge and morphological characteristics of the salt-tolerant bacteria cultivated using tannery wastewater as culture mediums and intermittent aeration as method. The results indicated that， aerobic sludge which contained salt-tolerant bacteria was cultivated under the conditions of temperature of 35°C and pH = 8, the COD removal in simulated and actual tannery wastewater was more than 87% and 85% by the cultivated aerobic sludge, respectively. In addition, the morphological characteristics were related to the composition and concentration of the salt. The average generation time of bacteria was 24.6min ~ 28.6min when the concentration of MLSS was 2.0 ~ 3.0g/L and the concentration of pure NaCl was 1 ~ 5g/L. As the volume ratio of NaCl and Na2SO4 was 4:1 ~ 1:4 with the total concentration of 5g/L, the average generation time of bacteria was 30.8min ~ 39.7min. The relation equation between salt concentration and the average generation time of bacteria under the pure salt, composite salt and actual tannery wastewater conditions was also deduced through four assumptions. The results had significant application on tannery wastewater treatment with great reduction of pollution.