Petro-chemical wastewater treatment by biological process

In order to study the feasibility of treating petro-chemical wastewater by the combination of anaerobic and aerobic biological process, a research of treating wastewater in UASB reactor and aeration basin has been conducted. The test results shows that under moderate temperature, with 5.2 kgCOD/(m³.d) volumetric load of COD_Cr in the UASB reactor and 24h of HRT, 85% removal rate of BOD₅ and 83% of COD_Cr and 1.34 m³/(m³.d) volumetric gas production rate can be obtained respectively. The aerobic bio-degradability can be increased by 20%-30% after the petro-chemical wastewater has been treated by anaerobic process. As Ns=0.45 kgCOD/(kgMLSS.d), HRT=4h in the aeration tank, 94% removal rate of BOD₅, 93% of COD_Cr , 98.8% total removal rate of COD_Cr and 99% removal rate of BOD₅ can be reached.