Pretreatment of hypersaline mustard wastewater with integrated bioreactor

A full-scale experimental study of treating mustard wastewater by the integrated bioreactor with designed scale of 1 000 m(3)/d is conducted combined with a demonstration project. The systematical researches on the efficiency of combined operation conditions of anaerobic-aerobic and anaerobic-aerobic-flocculation as well as chemical phosphorus removal of hypersaline mustard wastewater are conducted. The optimal operation condition and parameters in pretreatment of mustard wastewater in winter (the water temperature ranges 8-15 degrees C) are determined: the anaerobic load is 3.0 kg (COD)/(m3 . d), the average COD and phosphate concentration of the inflow are respectively 3 883 mg/L and 35.53 mg/L and the dosage of flocculent (PAC) is 400 mg/L. The anaerobic-aerobic-flocculation combined operation condition and postpositive phosphorous removal with ferrous sulfate are employed. After treatment, the COD of the effluent is 470 mg/L and the average phosphate concentration is 5.09 mg/L. The effluent could achieve the third-level of Integrated Wastewater Discharge Standard (GB 8978-1996).