O_3/BAC工艺深度处理某工业园区废水的效果

Effects and Mechanisms of Ozone/Biological Activated Carbon Process for Advanced Treatment of Industrial Park Wastewater

开展了规模为36 m3/d的中试研究,考察了不同臭氧投加量下臭氧/生物活性炭(O3/BAC)工艺深度处理某印染制革工业园区污水厂生化处理出水的效果,探讨了作用机理。当臭氧投量为25 mg/L时对COD、色度、TOC、UV254的去除效果最佳,去除率分别为17.4%、54.3%、14.7%和47.5%。在生物活性炭挂膜启动期间,系统对COD的去除率先下降后上升,32 d后稳定在50%左右。在生物活性炭稳定运行期间,系统进水COD和色度平均值分别为100 mg/L和112.5倍,出水值则分别降至50 mg/L和5倍,达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)中的一级B标准。臭氧将大分子的有机物降解成小分子有机物后被生物活性炭吸附和氧化,同时产生部分微生物胞外分泌物及其代谢产物,TOC和UV254在分子质量<1 ku区间的比例分别由进水的60.7%和58.8%增加至出水的66.8%和65.7%。

A pilot-scale hybrid process of ozone/biological activated carbon （O^3/BAC） with a ca- pacity of 36 m^3/d was applied for advanced treatment of secondary biological effluent from a dyeing and tannery park wastewater treatment plant. The pollutant removal performance was investigated at different ozone dosages , and the removal mechanism was discussed. The results showed that the optimal removal efficiencies of COD, color, TOC and UV254 were reached using ozone dosage of 25 mg/L, with the remov- al rates of 17.4%, 54.3%, 14.7% and 47.5%, respectively. During biofilm growth period, COD re- moval rate first decreased, then increased and finally stabilized at 50% after 32 d. When the BAC filterreached a stable period, the average COD and color were decreased from 100 mg/L and 112.5 times in the influent to 50 mg/L and 5 times in the effluent, and the wastewater quality met the first level B crite- ria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （GB 18918 - 2002）. The micromolecular organics degraded from macromolecular organics by ozone were absorbed and oxidized by BAC, meanwhile, some extracellular polymeric substances and metabolites were produced. The proportions of TOC and UV254 were increased from 60.7% and 58.8% in the influent to 66.8% and 65.7% in the effluent at the molecular weight of less than 1 ku.