Advanced treatment of wastewater generated by traditional Chinese medicine by coagulating sedimentation after oxidation with potassium ferrate

The objectives of the study were to test the effects of coagulation sedimentation after oxidation with potassium ferrate (CSOPF) in advanced treatment of wastewater from traditional Chinese medicine (TCMW) and to research kinetics of chemical oxygen demand (CODcr) and color removal by means of potassium ferrate oxidation. It was hoped to develop a feasible technology and provide technical support for TCMW factories. This study confirmed that implementing coagulating sedimentation after oxidation with potassium ferrate was very efficient for the advanced treatment of the secondary treatment effluent of TCMW. In this optimal situation, the performance of the CSOPF was stable, and the CODcr and the color in the effluent were always under 45and 25 mg L-1 respectively, which meet the strictest discharge standards of the discharge standard of water pollutes for pharmaceutical industry Chinese traditional medicine category (GB21906-2008)(DSWPPICTMC). Moreover, the experiment proved that the economic benefits of CSOPF implementation were striking because its operation cost is only 0.08380 US$ per m(3). Compared with the total cost of the existing wastewater treatment system in the sampled factory, the total saving of CSOPF implementation was 0.15845 US$ per m(3). Finally, the experiment confirmed that in potassium ferrate oxidation, the removal rate for COD can be described by C/C-0 = exp(-0.0421t) and the removal rate for color can be described by C/C-0 = exp(-0.0434t).