| Controlling the biostability and disfection by products(DBPs) is pivotal for ensuring water quality and safety. The research of biostability and DBPs control with ozone/biofilter is necessary and makes for engineering application as the extensive use of ozone/biofilter. Ozone enhanced Upward-flow zeolite/BAC multi-layers biological filter(UMBF) is an improved technology for low temperature and high ammonium nitrogen drinking water treatment based on ozone/biofilter. T his paper studied the efficiency of Ozone enhanced UMBF for biostability and DBPs control.Optimizations of assimiable organic carbon(AOC) and biodegr adable dissolved organic carbon(BDOC) measurement method were conducted through influence analysis of key factors with sand filtration effluent used as experimental water. T he results show that AOC achieved excellently with bacteria from the same source u sed for inoculation, 5% volume set as inocluation volume, and 24 hours’ cultivation time. And BDOC3 measurement was optimized with bacteria from the same source used for inoculation, 1.0×105 cells/m L set as inocluation concentration, 25 degree centigrade c hose as inocluation temperature, and 7.0±0.2 selected as cultivation p H.The efficiency of ozone enhanced UMBF for biostability control was investigated through a long-term sampling and monitoring with each treatment units. Results show that, ozone oxidation increased AOC and BDOC value, with a pecent of 32.00% and 24.73% achieved, while conduced to enhance the ability of subsequent biological filter for AOC and BDOC removal. Comparison of biological filter with different filter medium was conducted, which showed that zeolite/BAC filter is a little inferior to BAC filter in the degradation of AOC, BDOC and DOC, yet presented a more stable effluent quality. Two-stage BAC filters were designed with different influent modes and the comparison result s showed that gravity-flow filter yield a better removal efficiency of AOC, BDOC and DOC than up-flow filter, yet up-flow filter tend to be more stable in the removal of organic carbon. The overall result indicates that ozone enhanced UMBF contributes to a biostability of low temperature drinking water.The efficiency of ozone enhanced UMBF for DBPs control was also analysed. Results show that, ozone oxidation slightly decreased the disfection by products formation potential(DBPFP), simultaneously TCMFP, BDCMFP, DCAAFP and TCAAFP value reduced 24.50%, 12.53%, 11.00% and 27.11% respectively, while interestingly increased 72.14%, 33.03%, 5.77% and 28.84% respectively after the primary biological filter. No significant difference was found in the influence of DBPs precursors control between zeolite/BAC filter and BAC filte r. TCM precursors were the dominating DBPs precursors controlled by the two-stage BAC filter, with a removal ratio of 58.50% and 61.6 3% achieved by up-flow and gravity-flow filter respectively. When comparing the removal efficiency of HAA precursors, DCAAFP and TCAAFP were significantly reduced by gravity-flow filter, with a removal ratio of 62.67% and 38.62% respectively, which was superior to up-flow filter. T he overall result demonstrates that ozone enhanced UMBF yields a good removal efficiency of DBPs for low temperature drinking water. |
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