Woźniak Piotr, Gryta Marek
Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, ul. Pułaskiego 10, 70-322 Szczecin, Poland.
Membranes (Basel). 2025 Mar 1;15(3):71. doi: 10.3390/membranes15030071.
An ultrafiltration (UF) installation was used to separate the actual wastewater from a car wash. Following these studies, the plant was washed several times; however, severe membrane fouling was observed during the filtration of sterile deionised (DI) water. As a result, the permeate flux decreased by more than 50% after 5 h of the UF process. The source of the fouling was the release of deposits, particularly bacteria, from the surfaces of plant elements such as pipes and pumps. The paper presents the effectiveness of biofilm removal from the surface of the equipment during a cyclically repeated washing process. Chemical washing was carried out using acid solutions and alkaline cleaning solutions containing NaOH (pH = 11.5-12). After installation cleaning, the filtration tests were carried out using DI water as a feed. It was determined how biofouling, which develops under these conditions, reduces permeate flux. Despite 3 h of installation washing, there was a 50% reduction in flux after 10 h of UF. Repeating the installation wash (4 h) resulted in a similar decrease in flux after 4 days of UF. Stabilisation of the flux at a level of 500 LMH was achieved after an additional 5 h of washing, including application of hot (323-333 K) alkaline cleaning solutions. The number of bacteria in the biofilm collected from the surface of the membranes, the pump inlet and the surface of the polyvinyl chloride (PVC) hoses forming the pipeline was also investigated. Despite repeated chemical cleaning, the number of bacteria on the pump and hose surfaces was 50-100 CFU/cm. Studies were carried out to determine which bacterial species survived the chemical cleaning of the installation. Gram-positive and Gram-negative bacteria were determined, and taxonomic characteristics of the isolated bacteria were identified.
使用超滤（UF）装置分离来自洗车场的实际废水。在这些研究之后，对该装置进行了多次清洗；然而，在过滤无菌去离子（DI）水期间观察到严重的膜污染。结果，在超滤过程5小时后，渗透通量下降了50%以上。污染的来源是管道和泵等装置部件表面沉积物的释放，特别是细菌的释放。本文介绍了在循环重复清洗过程中从设备表面去除生物膜的有效性。使用酸性溶液和含有NaOH（pH = 11.5 - 12）的碱性清洗溶液进行化学清洗。装置清洗后，使用DI水作为进料进行过滤测试。确定了在这些条件下形成的生物污染如何降低渗透通量。尽管对装置进行了3小时的清洗，但在超滤10小时后通量仍降低了50%。重复装置清洗（4小时）导致在超滤4天后通量出现类似的下降。在额外5小时的清洗后，包括应用热（323 - 333 K）碱性清洗溶液，通量稳定在500 LMH的水平。还研究了从膜表面、泵入口以及构成管道的聚氯乙烯（PVC）软管表面收集的生物膜中的细菌数量。尽管进行了反复的化学清洗，但泵和软管表面的细菌数量仍为50 - 100 CFU/cm²。开展研究以确定哪些细菌种类在装置的化学清洗后存活下来。确定了革兰氏阳性菌和革兰氏阴性菌，并鉴定了分离细菌的分类特征。
