Cranfield Water Science Institute, Cranfield University, Bedfordshire, UK.
Scottish Water, Edinburgh, Scotland, UK.
Water Res. 2020 May 1;174:115613. doi: 10.1016/j.watres.2020.115613. Epub 2020 Feb 15.
Operational and financial constraints challenge effective removal of natural organic matter (NOM), and specifically disinfection by-product (DBP) precursors, at remote and/or small sites. Granular activated carbon (GAC) is a widely used treatment option for such locations, due to its relatively low maintenance and process operational simplicity. However, its efficacy is highly dependent on the media capacity for the organic matter, which in turn depends on the media characteristics. The influence of GAC media properties on NOM/DBP precursor removal has been studied using a range of established and emerging media using both batch adsorption tests and rapid small-scale column tests. DBP formation propensity (DBPFP) was measured with reference to trihalomethanes (THMs) and haloacetic acids (HAAs). All GAC media showed no selectivity for specific removal of precursors of regulated DBPs; DBP formation was a simple function of residual dissolved organic carbon (DOC) levels. UV was found to be a good surrogate measurement of DBPFP for an untreated water source having a high DOC. Due to the much-reduced concentration of DBP precursors, the correlation was significantly poorer for the coagulation/flocculation-pretreateed water source. Breakthrough curves generated from the microcolumn trials revealed DOC removal and consequent DBP reduction to correlate reasonably well with the prevalence pores in the 5-10 nm range. A 3-6 fold increase in capacity was recorded for a 0.005-0.045 cm/g change in 5-10 nm-sized pore volume density. No corresponding correlation was evident with other media pore size ranges.
操作和财务方面的限制给偏远地区或小型站点有效去除天然有机物 (NOM) ，尤其是消毒副产物 (DBP) 前体带来了挑战。对于这些地点，颗粒活性炭 (GAC) 是一种广泛使用的处理选择，因为其维护成本相对较低且工艺操作简单。然而，其效果高度依赖于有机物质的介质容量，而这又取决于介质特性。已经使用一系列已建立和新兴的介质，通过批量吸附测试和快速小型柱测试，研究了 GAC 介质特性对 NOM/DBP 前体去除的影响。通过参考三卤甲烷 (THMs) 和卤乙酸 (HAAs) 来测量 DBP 形成倾向 (DBPFP)。所有 GAC 介质对特定去除受管制 DBP 的前体均无选择性；DBP 的形成是残留溶解有机碳 (DOC) 水平的简单函数。发现 UV 是未经处理的高 DOC 水源 DBPFP 的良好替代测量值。由于 DBP 前体的浓度大大降低，对于混凝/絮凝预处理水源，相关性明显较差。从小柱试验生成的穿透曲线表明，DOC 的去除和随之而来的 DBP 减少与 5-10nm 范围内普遍存在的孔合理相关。在 5-10nm 大小的孔体积密度中，0.005-0.045cm/g 的变化可记录到容量增加 3-6 倍。对于其他介质孔尺寸范围，没有明显的相应相关性。
