2种填料BAF深度处理印染废水沿程污染物变化规律研究

针对某印染工业园区污水处理厂二级生化处理出水,采用处理规模为15 t·d-1的中试试验,研究了活性炭填料和悬浮填料曝气生物滤池沿程的污染物浓度变化,探讨了用低价、轻质悬浮填料替代活性炭的可行性.结果表明,在进水COD和色度分别为50.2 mg·L-1和58倍时,活性炭和悬浮填料曝气生物滤池最终出水COD和色度分别为35.0 mg·L-1、18倍和44.3mg·L-1和26倍,均可达到城镇污水厂污染物排放标准(GB 18918-2002)中的一级A排放标准要求,但是悬浮填料曝气生物滤池达标所需沿程的高度为2 400 mm,高于活性炭曝气生物滤池的1 800 mm.悬浮填料曝气生物滤池对色度、总氮、氨氮的去除效果及沿程变化趋势与活性炭曝气生物滤池相仿,但COD去除效果不佳,主要是与其生物量少有关.因此,用悬浮填料替代活性炭在该污水厂是可行的,但仍需要对填料大小和材质进行优选,增大生物量,必要时可考虑使用活性炭和悬浮填料的组合工艺减少造价成本.

Variation of Pollutants Along the Height of Two Media BAF During Advanced Treatment of Dyeing Wastewater

A pilot-scale process with the capacity of 15 t·d^-1 was applied for treatment of the secondary biological effluent from a dyeing industrial park wastewater treatment plant. We studied the variation of pollutants along the height of two media biological aerated filter (BAF), investigated the feasibility of the cheaper and lighter suspended media to substitute activated carbon. The results showed that while the influent average COD and color were 50.2 mg·L^-1 and 58 times, the effluent average COD and color of activated carbon and suspended media BAF were 35.0 mg·L^-1, 18 times and 44.3 mg·L^-1, 26 times, and both of the effluent met the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), while it met the first level A criteria at the height of 2400 mm in suspended media BAF, higher than the height of 1800 mm in activated carbon BAF. The removal variation of color, TN and ammonia along the height of suspended media BAF is similar to the activated carbon BAF, but with a low removal efficiency of COD, mainly related to its less biomass. Therefore, suspended media to substitute activated carbon is feasible to the wastewater treatment plant, but the size and material of the media still need to be optimized, and to enhance the biomass, the hybrid process of suspended media with activated carbon BAF may be used to reduce the cost if it is necessary.