Department of Civil Engineering, University of Patras, Patras 26500, Greece.
Environ Sci Technol. 2010 Feb 1;44(3):971-7. doi: 10.1021/es902754n.
Two pilot-scale fractured aquifer models (FAMs) consisting of horizontal limestone slabs were employed to investigate the removal of biocolloids suspended in reclaimed wastewater. To better understand the behavior of real fractured aquifers, these FAMs intentionally were not "clean". The fracture apertures were randomly spread with soil deposits, and both FAMs were preflooded with reclaimed wastewater to simulate the field conditions of the Nardo fractured aquifer in the Salento area, Italy, where fractures are not clean due to artificial groundwater recharge. One of the FAMs was injected with secondary effluent from a wastewater treatment plant collected prior to the chlorination step and the other with exactly the same effluent, which was further treated in a commercial membrane reactor. Consequently, the organic and pathogen concentrations were considerably higher in the secondary effluent than in the membrane reactor effluent. Injected wastewater was continuously recirculated. Pathogen removal was greater for the secondary wastewater than the cleaner membrane reactor effluent. A simple mathematical model was developed to describe fracture clogging. The results suggest that the hydraulic conductivity of FAMs can be significantly degraded due to retention of viable and inactivated biocolloids suspended in reclaimed wastewater.
两段由水平石灰岩板组成的中试规模裂隙含水层模型（FAMs）被用于研究悬浮在再生废水中的生物胶体的去除。为了更好地了解真实裂隙含水层的行为，这些 FAM 并未被“清洁”。裂隙孔径随机散布着土壤沉积物，并且两个 FAM 都用再生废水预冲洗，以模拟意大利萨伦托地区的纳尔多裂隙含水层的现场条件，由于人工地下水补给，这些裂隙不干净。一个 FAM 中注入了氯化工序前收集的污水处理厂的二级出水，另一个则注入了经过商业膜反应器进一步处理的相同废水。因此，二级废水中的有机物和病原体浓度明显高于膜反应器出水中的浓度。注入的废水不断循环。对于二级废水，病原体的去除率高于更清洁的膜反应器出水。开发了一个简单的数学模型来描述裂隙堵塞。结果表明，由于再生废水中悬浮的有活力和无活力生物胶体的截留，FAMs 的水力传导率可能会显著降低。
