School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
Water Res. 2012 Jan 1;46(1):218-26. doi: 10.1016/j.watres.2011.10.050. Epub 2011 Oct 31.
Organic pollutants in reverse osmosis (RO) concentrates from wastewater reclamation are mainly comprised of low molecular weight biorefractory compounds. Generally, advanced oxidation methods for oxidizing these organics require a relatively high level of energy consumption. In addition, conventional adsorption removal methods require a large dose of activated carbon. However, the dose can be reduced if its full adsorption capacity can be used. Therefore, the combined technology of powdered activated carbon (PAC) adsorption and microfiltration (MF) membrane filtration was studied to develop a countercurrent two-stage adsorption process. A PAC accumulative adsorption prediction method was proposed based on the verification of a PAC multi-stage adsorption capacity equation. Moreover, the prediction method was amended for a more accurate prediction of the effluent quality because adsorption isotherm constants were affected by the initial adsorbate concentration. The required PAC dose for the accumulative countercurrent two-stage adsorption system was 0.6 g/L, whereas that of the conventional adsorption process was 1.05 g/L when the dilution factor(F) was 0.1 and the COD and DOC removal rates were set to 70% and 68.1%, respectively. Organic pollutants were satisfactorily removed with less consumption of PAC. Effluent from this combined technology can be further reclaimed by an RO process to improve the overall recovery rate to between 91.0% and 93.8% with both economic and environmental benefits.
反渗透（RO）浓缩液中的有机污染物主要由低分子量生物难降解化合物组成。通常，用于氧化这些有机物的高级氧化方法需要相对较高的能源消耗。此外，传统的吸附去除方法需要大量的活性炭。然而，如果可以充分利用其吸附能力，则可以减少剂量。因此，研究了粉末活性炭（PAC）吸附和微滤（MF）膜过滤的组合技术，以开发逆流两段吸附工艺。提出了一种基于 PAC 多级吸附容量方程验证的 PAC 累积吸附预测方法。此外，由于吸附等温线常数受初始吸附质浓度的影响，对预测方法进行了修正，以更准确地预测出水质量。对于累积逆流两段吸附系统，所需的 PAC 剂量为 0.6 g/L，而当稀释因子（F）为 0.1 且 COD 和 DOC 去除率分别设定为 70%和 68.1%时，传统吸附工艺所需的 PAC 剂量为 1.05 g/L。该组合技术可以很好地去除有机污染物，同时消耗更少的 PAC。反渗透（RO）工艺可以进一步回收该组合技术的出水，从而将总回收率提高到 91.0%至 93.8%，具有经济和环境效益。
