Al-Saedi Rasha, Smettem Keith, Siddique Kadambot H M
Department of Civil, Environmental, and Mining Engineering, The University of Western Australia, Perth, WA 6001, Australia; Department of Environmental Engineering, Mustansiriyah University, Baghdad, Iraq; The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia.
Department of Civil, Environmental, and Mining Engineering, The University of Western Australia, Perth, WA 6001, Australia; The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia; College of Science, Health, Engineering and Education, Murdoch University, Perth, WA 6150, Australia.
Sci Total Environ. 2019 Nov 15;691:360-366. doi: 10.1016/j.scitotenv.2019.07.036. Epub 2019 Jul 3.
The addition of biodegradable carbon sources to sand filters can enhance microbial activity but may lead to substrate clogging, a major operational problem. In laboratory-scale soil columns emulating vertical up-flow filters, the clogging effect of two readily biodegradable organic substrates-sucrose as a sugar source and ethanol as an alcohol source-were examined with coarse sand as the substrate medium. Wastewater without the addition of supplemental organics and a 'control' treated with tap water were monitored as references. Changes in saturated hydraulic conductivity were measured for all treatments over time. Other parameters that can influence the clogging rate, including temperature, dissolved oxygen, chemical oxygen demand, protein, and polysaccharides, were measured in the influent and effluent wastewater on a weekly basis. At the end of the clogging experiment, the main layer of each filter bed was separated into three sections and saturated hydraulic conductivity, organic matter content, and protein and polysaccharide concentrations were measured in each section. The rate of clogging development in the columns depended on treatment, with ethanol-treated cores clogging more quickly than sucrose-treated cores. Wastewater-treated cores took far longer to clog and the tap water control did not clog, but the saturated hydraulic conductivity declined by 60% over a year. Saturated hydraulic conductivity within the treated cores declined far less than the calculated decline in saturated hydraulic conductivities for the entire cores at the end of the experiment, indicating that clogging in the vicinity of the inlet plate by microbial mats was a major factor influencing the reduction in flow through the columns. To reduce bio-clogging in inlet filters, it may be advantageous to inject organic amendments directly into the bed, rather than pass them through the filters, as is usually the case.
向砂滤池中添加可生物降解的碳源可以增强微生物活性，但可能会导致基质堵塞，这是一个主要的运行问题。在模拟垂直上流过滤器的实验室规模土壤柱中，以粗砂为基质介质，研究了两种易生物降解的有机底物（蔗糖作为糖源和乙醇作为醇源）的堵塞效应。监测未添加补充有机物的废水和用自来水处理的“对照”作为参考。测量了所有处理随时间的饱和水力传导率变化。每周测量进水和出水废水中其他可能影响堵塞速率的参数，包括温度、溶解氧、化学需氧量、蛋白质和多糖。在堵塞实验结束时，将每个滤床的主要层分成三个部分，并测量每个部分的饱和水力传导率、有机物含量以及蛋白质和多糖浓度。柱中堵塞发展的速率取决于处理方式，乙醇处理的柱芯比蔗糖处理的柱芯堵塞得更快。废水处理的柱芯堵塞所需时间长得多，自来水对照没有堵塞，但饱和水力传导率在一年内下降了60%。处理后的柱芯内的饱和水力传导率下降远小于实验结束时整个柱芯饱和水力传导率的计算下降值，这表明微生物垫在入口板附近的堵塞是影响通过柱的流量减少的主要因素。为了减少入口过滤器中的生物堵塞，直接将有机改良剂注入滤床而不是像通常那样使其通过过滤器可能是有利的。
