SBR工艺用于焦化纳滤浓盐水生物脱氮

Biological denitrification for nanofiltration concentrate from coking wastewater by SBR process

以焦化废水超滤/纳滤/反渗透的“三膜法”深度处理工艺产生的高电导率纳滤（NF）浓盐水为研究对象,采用SBR脱氮工艺对NF浓盐水中有机污染物和总氮（TN）的去除性能进行了研究.实验结果表明,SBR脱氮工况为进水5min,缺氧搅拌8h,好氧曝气12 h,静置2h,出水5 min,闲置1 h 50 min,污泥浓度（MLSS）为3 000 mg/L左右时,TN平均去除率为45.45％,COD平均去除率为45.36％.通过烧杯实验研究了不同C/N比对反硝化脱氮效率的影响及其中氮形态的变化,在C/N为421时,出水TN可降低至14.8 mg/L,其中NO3--N为5.0 mg/L.研究结果证明,SBR可将电导率为12 000～ 16 000 μS/cm的焦化纳滤浓盐水TN降低至15 mg/L以下.

Organic pollutants and total nitrogen （TN） removal performances in NF concentrate with high conductivity from coking wastewater generated through ultrafiltration/nanofiltration/reverse osmosis processes by SBR denitrification were investigated in this study. The results showed that the average removal effieieneies of TN and COD were 45.45% and 45.36% , respectively, under the operational conditions, namely, 5 rain of inflow, 8 h of anoxic treatment, 12 h of aerobic treatment, 2 h of sedimentation, 5 min of outflow, 1 h and 50 min of i- dle, and MLSS concentration around 3 000 mg/L. The batch tests were employed in investigation of the effects of various C/N ratios on denitrification efficiency and transformation of nitrogen form, and the results showed TN and NO3- -N in effluent could be lowered to 14.8 mg/L and 5.0 mg/L, respectively, when C/N was set at 4/1. This study finally confirmed that less than 15 mg/L of TN could be achieved after treatment for NF concentrate whose conductivity was around 12 000 - 16 000 μS/cm by SBR process.