Schumacher J, Pi Y Z, Jekel M
Department of Water Quality Control, Secr. KF4, Fasanenstrasse 1A, Technical University Berlin, 10623 Berlin, Germany.
Water Sci Technol. 2004;49(4):305-10.
Groundwater recharge is becoming common in areas where the withdrawal of groundwater exceeds its natural recharge. Wastewater treatment plant (WWTP) effluent can be used for this purpose, but persistent organic compounds can only be partly removed during soil passage. This point was confirmed in degradation tests using soil columns in which the DOC of a membrane bioreactor (MBR) permeate could only be reduced by 15% and adsorbable organic iodine (AOI) by 2%. However, ozonation was found to improve biodegradation and at the maximum formation of biodegradable DOC at 2.5 mg O3/mg DOC0, the DOC values of MBR permeate (11-13 mg/L) could be reduced in aerobic degradation batch tests to the DOC of Berlin drinking water (3-5 mg/L). A combination of ozonation at 1.9 g O3/g DOC0 with soil passage could adjust DOC, UVA254, colour (436 nm) and the molecular DOC size distribution to drinking water ranges, but AOI was only reduced from 143 microg/L to 92 microg/L and remained high compared to tap water (2.2 microg/L). The extremely persistent X-ray contrast compound iopromide, which represents part of AOI, was spiked into MBR permeate at a low concentration. Iopromide was reduced by 88% during ozonation, but AOI only decreased by 23% indicating that a transformation, but not a mineralization, of iodinated organic compounds occurs.
在地下水开采量超过其天然补给量的地区，地下水回灌正变得越来越普遍。污水处理厂（WWTP）的出水可用于此目的，但持久性有机化合物在通过土壤时只能部分去除。这一点在使用土壤柱的降解试验中得到了证实，在该试验中，膜生物反应器（MBR）渗透液的溶解性有机碳（DOC）仅能降低15%，可吸附有机碘（AOI）降低2%。然而，发现臭氧化可改善生物降解，在臭氧投加量为2.5 mg O3/mg DOC0时可最大程度地形成可生物降解的DOC，在好氧降解批次试验中，MBR渗透液（11 - 13 mg/L）的DOC值可降低至柏林饮用水的DOC水平（3 - 5 mg/L）。臭氧投加量为1.9 g O3/g DOC0与土壤过滤相结合，可将DOC、UVA254、色度（436 nm）和分子DOC尺寸分布调整至饮用水范围，但AOI仅从143 μg/L降至92 μg/L，与自来水（2.2 μg/L）相比仍处于较高水平。将作为AOI一部分的极难降解的X射线造影剂碘普罗胺以低浓度添加到MBR渗透液中。碘普罗胺在臭氧化过程中降低了88%，但AOI仅下降了23%，这表明碘化有机化合物发生了转化，但并未矿化。
