Pretreatment Of Coking Wastewater With Anaerobic Sequencing Batch Reactor (ASBR)

The anaerobic pretreatment of coking wastewater with the laboratory-scale Anaerobic Sequencing Batch Reactor (ASBR) at a constant temperature of 35 was studied. The BMP (Biochemical Methane Potential) was assayed. The results showed that the maximal efficiency of COD conversion into methane for anaerobic treatment of coking wastewater was 41.9%. The ASBR was seeded with granulated solids that were cultivated with synthetic wastewater containing sucrose Before the pretreatment of coking wastewater, 225 days' acclimation was needed. Three fundamental technological factors affecting anaerobic pretreatment of coking wastewater in the ASBR, such as the ratio of fill time and reaction time (Tf/Tr), the strength of mixing and the pattern of the intermittent mixing were evaluated through the orthogonal test. The optimal of technological parameters were studied. The result of the orthogonal test showed that when the coking wastewater was pretreated with ASBR, the optimal T/Trwas 0.5, the optimal strength of mixing was 300mlgas/min(1.5m3gas/m3reactor d), the optimal pattern of the intermittent mixing was mixing 100s every 45min. The cycle of operation was 24h, where the feed time was 7.2h, the react time was 14.3h, the settle time was 2 Oh, the decant time was 0.5h respectively. The MLSS in the ASBR was 22.9g/L. At coking wastewater influent of COD from 416 to1304mg/L, the organic loading rate (OLR) from 0.17 to 0.54gCOD/L d, the removal efficiency of COD was from 30% to 40% and the SS of effluent was no more than 150mg/L during the stage of steady operation.