Coupling continuous sand filtration to ultrafiltration for drinking water treatment: Improved performance and membrane fouling control

2018 ◽  
Vol 567 ◽  
pp. 18-27 ◽  
Author(s):  
Yuanqing Guo ◽  
Langming Bai ◽  
Xiaobin Tang ◽  
Qiaojin Huang ◽  
Binghan Xie ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Drinking Water Treatment ◽  
Sand Filtration ◽  
Fouling Control ◽  
Improved Performance

Pretreatment Process of Nanofiltration for Silting Density Index Reduction in Drinking Water Treatment System

2013 ◽  
Vol 777 ◽  
pp. 467-471 ◽  
Author(s):  
Liang Wang ◽  
Ying Chun Li ◽  
He Zhao ◽  
Zhao Hui Zhang ◽  
Bin Zhao ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Sodium Dodecyl ◽  
Drinking Water Treatment ◽  
Hybrid Process ◽  
Transmembrane Pressure ◽  
Sand Filtration ◽  
Density Index ◽  
One Year

Calcium ions, magnesium ions, and silicate were the main reasons for the high silting density index (SDI) of natural waters. Therefore, they posed serious membrane fouling problems in the nanofiltration (NF) system, which restricted the wide application of this excellent drinking water treatment technology. In this study, the sand filtration and the micro-flocculation/sand filtration hybrid process were investigated as the pretreatment process of NF for SDI reduction. Compared with the sand filtration, the hybrid process of micro-flocculation/sand filtration was more effective for SDI reduction. When polyaluminium chloride (PAC) was used as the flocculant at a dose of 10 mg/L and the filtration rate of the sand filter was controlled at 10 m/h, the SDI value in the effluent of the pretreatment process maintained below 3. As a result, the subsequent NF system stably ran for one year. 68% CODMn was removal by NF. The membrane fouling during the operation was quite slight as the transmembrane pressure (TMP) increased by 17% after one-year use. Chemical cleaning with sodium tripolyphosphate (2%) and sodium dodecyl benzene sulfonate (0.25%) at 6 months interval could effectively recover the flux loss of the NF membrane.

scholarly journals Natural organic matter removal by ion exchange at different positions in the drinking water treatment lane

2013 ◽  
Vol 6 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
E. R. Cornelissen ◽  
L. C. Rietveld
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Drinking Water Treatment ◽  
Biological Stability ◽  
Sand Filtration ◽  
Slow Sand Filtration

Abstract. To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m−3), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.

scholarly journals Coagulation/flocculation prior to low pressure membranes in drinking water treatment: a review

2020 ◽  
Vol 6 (11) ◽  
pp. 2993-3023
Author(s):  
Tyler A. Malkoske ◽  
Pierre R. Bérubé ◽  
Robert C. Andrews
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Drinking Water Treatment ◽  
Low Pressure ◽  
Floc Properties ◽  
The Impact

Coagulation/flocculation has been grouped into three typical configurations and the impact of each examined in terms of floc properties and membrane fouling.

scholarly journals Improving chemical cleaning of fouled membranes in a drinking water treatment plant

2019 ◽  
Vol 19 (8) ◽  
pp. 2330-2337
Author(s):  
Susumu Hasegawa ◽  
Yasuhiro Tanaka ◽  
Naokazu Wake ◽  
Ryosuke Takagi ◽  
Hideto Matsuyama
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Membrane Fouling ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Chemical Cleaning ◽  
Water Treatment Plants

Abstract Recently, membrane filtration systems have become increasingly common in drinking water treatment plants. In this industry, preventing membrane fouling is of utmost importance. Many studies on the relationship between raw water components and membrane fouling have been performed in laboratory conditions. However, very few studies have analyzed the components of foulants on the fouled membrane as operated in actual drinking water treatment plants. By analyzing these components in plant-conditions, membrane fouling will be more effectively prevented. In this study, we analyzed the components of foulants extracted with 0.1 N NaOH from a fouled membrane operated in a drinking water treatment plant in Japan. Our analysis revealed that the main foulants were humic substances. In order to dissolve the accumulated humic substances, additional chemical cleaning was attempted with 500 ppm sodium hypochlorite. As a result, it was found that humic substances were dissolved and filtration resistance significantly decreased. Additionally, the removal of inorganic foulants was also greater after chemical cleaning with 500 ppm sodium hypochlorite, as inorganic foulants trapped within humic substances were released to the membrane surface as hydroxides by the additional sodium hypochlorite cleaning and were dissolved by the periodic citric acid cleaning.

scholarly journals Application of Coagulation–Membrane Rotation to Improve Ultrafiltration Performance in Drinking Water Treatment

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 643
Author(s):  
Hongjian Yu ◽  
Weipeng Huang ◽  
Huachen Liu ◽  
Tian Li ◽  
Nianping Chi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Drinking Water Treatment ◽  
Permeate Flux ◽  
Organic Removal ◽  
Cake Layer ◽  
The Impact

The combination of conventional and advanced water treatment is now widely used in drinking water treatment. However, membrane fouling is still the main obstacle to extend its application. In this study, the impact of the combination of coagulation and ultrafiltration (UF) membrane rotation on both fouling control and organic removal of macro (sodium alginate, SA) and micro organic matters (tannic acid, TA) was studied comprehensively to evaluate its applicability in drinking water treatment. The results indicated that membrane rotation could generate shear stress and vortex, thus effectively reducing membrane fouling of both SA and TA solutions, especially for macro SA organics. With additional coagulation, the membrane fouling could be further reduced through the aggregation of mediate and macro organic substances into flocs and elimination by membrane retention. For example, with the membrane rotation speed of 60 r/min, the permeate flux increased by 90% and the organic removal by 35% in SA solution, with 40 mg/L coagulant dosage, with an additional 70% increase of flux and 5% increment of organic removal to 80% obtained. However, too much shear stress could intensify the potential of fiber breakage at the potting, destroying the flocs and resulting in the reduction of permeate flux and deterioration of effluent quality. Finally, the combination of coagulation and membrane rotation would lead to the shaking of the cake layer, which is beneficial for fouling mitigation and prolongation of membrane filtration lifetime. This study provides useful information on applying the combined process of conventional coagulation and the hydrodynamic shear force for drinking water treatment, which can be further explored in the future.

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