A novel integration of microwave catalytic oxidation and MBBR process and its application in advanced treatment of biologically pretreated Lurgi coal gasification wastewater

Laboratorial scale experiments were conducted in order to investigate a novel system integrating microwave catalytic oxidation (MCO) and MBBR process on advanced treatment of biologically pretreated Lurgi coal gasification wastewater. Results indicated that MCO with catalyst of MOs/SAC (sewage sludge based activated carbon which loaded Mn oxides) represented high efficiencies in eliminating bio-refractory compounds by generating OH∗, O2- and holes. GC-MS analysis indicated the MCO eliminated most bio-refractory compounds and improved the BOD5/COD from 0.08 to 0.48. Meanwhile, the integrated process exhibited efficient performance of COD, BOD5, TOC, NH4+-N and TN removals at a much shorter retention time of 8 h, with the effluent concentrations of 18.4, 2.3, 10.1, 3.2 and 10.6 mg/L, respectively, which all met class-I criteria of the Integrated Wastewater Discharge Standard. The total operating cost was 1.6 CNY/t. The integrated system was efficient, cost-effective and ecological sustainable and could be a promising technology for engineering applications.