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Han L.,Tsinghua University | Liu W.,Tsinghua University | Chen M.,Tsinghua University | Zhang M.,Beijing Technology and Business University | And 3 more authors.
Water Research | Year: 2013

The removal of natural organic matter (NOM) in term of CODMn by up-flow biologically activated carbon filter (UBACF) and down-flow biologically activated carbon filter (DBACF) was investigated in a pilot-scale test. The impacts of the molecular weight distribution ofNOM on its degradation by the UBACF and DBACF were evaluated. The relationship between biodegradation and the microbial properties in the UBACF and DBACF were approached as well. The feed water of the UBACF and DBACF were pumped from the effluent of the rapid sand filtration (RSF) of Chengnan Drinking Water Treatment Plant (CDWTP), Huaian, Jiangsu Province, China. When the adsorption was the dominant mechanism of NOM removal at the initial stage of operation, the CODMn removal efficiency by the UBACF was lower than the DBACF. However, with the microbes gradually accumulated and biofilm formed, the removal of CODMn by the UBACF increased correspondingly to 25.3%, at the steady-state operation and was approximately 10% higher than that by the DBACF. Heterotrophy plate count (HPC) in the finished water of the UBACF was observed 30% higher than that of the DBACF. The UBACF effluent had higher concentration of detached bacteria whereas the DBACF harbored more attached biomass. The highest attached biomass concentration of the UBACF was found in the middle of the GAC bed. On the contrary, the highest attached biomass concentration of the DBACF was found on the top of the GAC bed. Furthermore, a total of 9479 reads by pyrosequencing was obtained from samples of the UBACF and DBACF effluents. The UBACF effluent had a more diverse microbial community and more even distribution of species than the DBACF effluent did. Alphaproteobacteria and Betaproteobacteria were the dominant groups in the finished water of the UBACF and DBACF. The higher organic matter removal by the UBACF was attributed to the presence of its higher biologically activity. © 2013 Elsevier Ltd. Source


Han L.,Tsinghua University | Liu W.,Tsinghua University | Wang Z.,Tsinghua University | Sun R.,China Water Industry Investment Co. | And 2 more authors.
Qinghua Daxue Xuebao/Journal of Tsinghua University | Year: 2012

The flow in ozone-biological activated carbon (O 3-BAC) filters was analyzed to investigate the effect of upflow and downflow BAC filters for contaminant removal to optimize the operating conditions and improve drinking water quality. The results show that the upflow BAC filter effluent COD Mn is 1.6 mg/L with a 38% removal ratio of sand filter effluent COD Mn, 10% higher than that of the down-flow BAC filter. The upflow BAC filter's effluent turbidity is 0.55 NTU, which is 15% higher than that of the down-flow BAC filter. The average head loss remained at 40 cm for 30 days, which effectively extends the backwash cycle. Satisfactory results were obtained using the design parameters to run the device, which means, that an upflow BAC has some advantages over the traditional downflow BAC. Source

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