Heylen Camille, Oliveira Aguiar Alice, String Gabrielle, Domini Marta, Goff Nathaniel, Murray Anna, Asatekin Ayse, Lantagne Daniele
Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155, USA.
Department of Chemical and Biological Engineering, Tufts University, Medford, MA 02155, USA.
Membranes (Basel). 2021 May 20;11(5):375. doi: 10.3390/membranes11050375.
Hollow-fiber membrane filters (HFMFs) for household water treatment (HWT) can efficaciously remove disease-causing organisms in laboratory settings. However, lower effectiveness in use in low- and middle-income countries (LMICs) and humanitarian contexts (HCs) has been observed and attributed to membrane fouling and the associated cleaning. In LMICs/HCs, it is not possible to prevent and control fouling using commonly known methods (e.g., testing influent water, maintenance regimes), and the literature on fouling/cleaning of HFMFs distributed in LMICs is scarce. As such, controlled laboratory experiments were conducted to determine the efficacy of locally available (in LMICs/HCs) backwashing solutions at removing fouling using different influent waters and HFMF types. Four commonly distributed HFMFs were selected; fouling layers were developed by filtering three influent water compositions, representing LMIC/HC waters, for 10-days, and bleach, water, or vinegar backwashing solutions were used for daily backwashing. Filter performance indicators included: fiber mechanical properties (strain at break, break force), water quantity performance (flow), water quality performance (turbidity, ), and imaging. The study found fouling developed rapidly and altered mechanical properties and water quantity indicators within 200 h of filtration. Fouling did not decrease water quality indicators. Backwashing improved the filter's mechanical properties and water quantity performance, but it did not fully recover the initial performance. Additionally, recovery differed between backwashing solutions, and no universal cleaning recommendation appropriate for HFMFs in LMICs/HCs was identified. Overall, fouling development and control depended on HFMF type, influent water quality, and backwashing solution type; thus, caution before distributing HFMFs for long-term use in LMICs/HCs is recommended.
用于家庭水处理（HWT）的中空纤维膜过滤器（HFMF）在实验室环境中能够有效去除致病生物。然而，在低收入和中等收入国家（LMICs）以及人道主义环境（HCs）中使用时，其效果较低，这被归因于膜污染及相关的清洗问题。在LMICs/HCs中，无法使用常见方法（如检测进水、维护制度）来预防和控制污染，并且关于在LMICs中分发的HFMF的污染/清洗的文献很少。因此，进行了对照实验室实验，以确定当地可得的（在LMICs/HCs中）反冲洗溶液在使用不同进水和HFMF类型时去除污染的效果。选择了四种常见分发的HFMF；通过过滤三种代表LMIC/HC水的进水成分10天来形成污染层，并使用漂白剂、水或醋反冲洗溶液进行每日反冲洗。过滤器性能指标包括：纤维机械性能（断裂应变、断裂力）、水量性能（流量）、水质性能（浊度等）和成像。研究发现，污染迅速发展，并在过滤200小时内改变了机械性能和水量指标。污染并未降低水质指标。反冲洗改善了过滤器的机械性能和水量性能，但并未完全恢复初始性能。此外，不同反冲洗溶液的恢复情况不同，未确定适用于LMICs/HCs中HFMF的通用清洗建议。总体而言，污染的发展和控制取决于HFMF类型、进水水质和反冲洗溶液类型；因此，建议在LMICs/HCs中长期分发HFMF之前谨慎行事。
