Abushaban Almotasembellah, Salinas-Rodriguez Sergio G, Pastorelli Delia, Schippers Jan C, Mondal Subhanjan, Goueli Said, Kennedy Maria D
Water Management Department, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands.
Environmental Engineering and Water Technology Department, IHE Delft Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands.
Membranes (Basel). 2021 Feb 27;11(3):167. doi: 10.3390/membranes11030167.
In this study, the removal of particulate, organic and biological fouling potential was investigated in the two-stage dual media filtration (DMF) pretreatment of a full-scale seawater reverse osmosis (SWRO) desalination plant. Moreover, the removal of fouling potential in two-stage DMF (DMF pretreatment) was compared with the removal in two-stage DMF installed after dissolved air floatation (DAF) (DAF-DMF pretreatment). For this purpose, the silt density index (SDI), modified fouling index (MFI), bacterial growth potential (BGP), organic fractions and microbial adenosine triphosphate (ATP) were monitored in the pretreatment processes of two full-scale SWRO plants. Particulate fouling potential was well controlled through the two stages of DMF with significant removal of SDI15 (>80%), MFI0.45 (94%) and microbial ATP (>95%). However, lower removal of biological/organic fouling potential (24-41%) was observed due to frequent chlorination (weekly) of the pretreatment, resulting in low biological activity in the DMFs. Therefore, neutralizing chlorine before media filtration is advised, rather than after, as is the current practice in many full-scale SWRO plants. Comparing overall removal in the DAF-DMF pretreatment to that of the DMF pretreatment showed that DAF improved the removal of biological/organic fouling potential, in which the removal of BGP and biopolymers increased by 40% and 16%, respectively. Overall, monitoring ATP and BGP during the pretreatment processes, particularly in DMF, would be beneficial to enhance biological degradation and lower biofouling potential in SWRO feed water.
在本研究中，对一座大型海水反渗透（SWRO）海水淡化厂的两级双介质过滤（DMF）预处理工艺中颗粒、有机和生物污垢潜在物质的去除情况进行了研究。此外，还比较了两级DMF（DMF预处理）与溶解气浮（DAF）后安装的两级DMF（DAF-DMF预处理）中污垢潜在物质的去除情况。为此，在两座大型SWRO工厂的预处理过程中监测了淤泥密度指数（SDI）、改良污垢指数（MFI）、细菌生长潜力（BGP）、有机组分和微生物三磷酸腺苷（ATP）。通过DMF的两个阶段，颗粒污垢潜在物质得到了很好的控制，SDI15（>80%）、MFI0.45（94%）和微生物ATP（>95%）均有显著去除。然而，由于预处理过程中频繁（每周）加氯，导致DMF中的生物活性较低，生物/有机污垢潜在物质的去除率较低（24-41%）。因此，建议在介质过滤前而不是像许多大型SWRO工厂目前的做法那样在过滤后进行氯中和。将DAF-DMF预处理的总体去除情况与DMF预处理的情况进行比较表明，DAF提高了生物/有机污垢潜在物质的去除率，其中BGP和生物聚合物的去除率分别提高了40%和16%。总体而言，在预处理过程中，特别是在DMF过程中监测ATP和BGP，将有助于增强生物降解并降低SWRO进水的生物污垢潜在风险。
