Practical experiences from membrane filtration plants for humic substance removal

2000 ◽  
Vol 41 (10-11) ◽  
pp. 33-41 ◽  
Author(s):  
H. Ødegaard ◽  
T. Thorsen ◽  
E. Melin
Keyword(s):  
Molecular Weight ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Organic Molecules ◽  
Basic Design ◽  
Treatment Efficiency ◽  
Membrane Cleaning ◽  
Membrane Flux ◽  
Practical Experiences ◽  
Membrane Treatment

Humic substances are high molecular weight, organic molecules that give the water a yellow/brownish colour. They are normally removed from water by coagulation. During the last 10 years around 70 membrane filtration plants for drinking water supply have been built in Norway. The paper outlines the basic design of these plants and gives information on choice of membrane, treatment efficiency, membrane flux, membrane fouling, membrane cleaning and disposal of wastes as well as general operating experiences. It is concluded that the owners of the membrane filtration plants are quite satisfied and that the method will be used in increasingly larger plants.

scholarly journals Effect of Pre-Oxidation on Coagulation/Ceramic Membrane Treatment of Yangtze River Water

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 369
Author(s):  
Shengji Xia ◽  
Xinran Zhang ◽  
Yuanchen Zhao ◽  
Fibor J. Tan ◽  
Pan Li ◽  
...  
Keyword(s):  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Separation ◽  
Membrane System ◽  
Coagulation System ◽  
Fouling Control ◽  
Filtration System ◽  
Membrane Treatment

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.

Particle count and size alteration for membrane fouling reduction in non-conventional water filtration

2004 ◽  
Vol 50 (12) ◽  
pp. 273-278 ◽  
Author(s):  
A. Adin
Keyword(s):  
Activated Sludge ◽  
Ferric Chloride ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Positive Impact ◽  
Iron Chloride ◽  
Particle Count ◽  
Membrane Flux ◽  
Total Particle ◽  
Stirred Cell

If coagulation is not completely successful and produces aggregates which are too small, fouling may increase. In some cases, a deep-bed filter could perhaps provide a solution. The paper examines these effects using experimental results for different waters. Activated sludge effluents, stormy seawater containing microalgae and spent filter backwash water (SFBW) were coagulated by alum or ferric chloride. Sand filtration tests were carried out. Tests were performed in a membrane filtration stirred cell, filtration pilot plant equipped with SDI analyzer (seawater) and pilot UF plant (SFBW). For activated sludge effluent, alum residual ratio curves of turbidity and total particle count (TPC) followed one another. With ferric chloride, low coagulant dosage showed negative turbidity removal. Contact granular filtration reduced membrane fouling intensity. Increasing the dose resulted in higher improvement in membrane flux. For seawater, a filter run period under storm conditions reached 35 hours with satisfactory filtrate quality. An iron chloride dose of 0.3 mg/l during normal conditions and 0.5 mg/l for stormy condition should be injected, mixed well before the filters, while maintaining 10 m/hr filtration rate and pH 6.8 value. For SFBW, alum flocculation pretreatment of SFBW was effective in reducing turbidity, TPC, viruses and protozoa. SFBW settling prior to flocculation did not enhance turbidity and TPC removal. The largest remaining particle fraction after alum flocculation was 3-10 μm in size, both Cryptosporidium and Giardia are found in this size range. Coagulation enhanced the removal of small size particles, a positive impact on reducing membrane fouling potential.

Membrane fouling propensity after adsorption as pretreatment in rainwater: a detailed organic characterisation

2008 ◽  
Vol 58 (8) ◽  
pp. 1535-1539 ◽  
Author(s):  
L. Sabina ◽  
B. Kus ◽  
H.-K. Shon ◽  
J. Kandasamy
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Building Blocks ◽  
Fulvic Acids ◽  
Humic And Fulvic Acids ◽  
Removal Efficiencies ◽  
Hydrophilic Compounds ◽  
Hydrophobic Fraction

Organic characterisation in rainwater was investigated in terms of dissolved organic carbon (DOC) and molecular weight distribution (MWD) after powdered activated carbon (PAC) adsorption. PAC adsorption was used as pretreatment to membrane filtration to reduce membrane fouling. The MW of organic matter in rainwater used in this study was in the range of 43,000 Da to 30 Da. Each peak of organic matter consisted of biopolymers (polysaccharides and proteins), humic and fulvic acids, building blocks, low MW acids (hydrolysates of humic substances), low MW neutrals and amphiphilics. Rainwater contained the majority of hydrophilic compounds up to 72%. PAC adsorption removed 33% of total DOC. The removal efficiencies of the hydrophobic and hydrophilic fractions after PAC adsorption were 50% and 27%, respectively. PAC adsorption was found to preferentially remove the hydrophobic fraction. The majority of the smaller MW of 1,100 Da, 820 Da, 550 Da, 90 Da and 30 Da was removed after PAC adsorption. The MFI values decreased from 1,436 s/L2 to 147 s/L2 after PAC adsorption. It was concluded that PAC adsorption can be used as a pretreatment to membrane filtration with rainwater.

scholarly journals Adsorption-Enhanced Ceramic Membrane Filtration Using Fenton Oxidation for Advanced Treatment of Refinery Wastewater: Treatment Efficiency and Membrane-Fouling Control

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 651
Author(s):  
Haotian Mu ◽  
Qi Qiu ◽  
Renzhen Cheng ◽  
Liping Qiu ◽  
Kang Xie ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Removal Rate ◽  
Refinery Wastewater ◽  
Cake Filtration ◽  
Treatment Efficiency ◽  
Combined Process ◽  
Direct Filtration ◽  
The Impact

With the development of the refining industry, the treatment of refinery wastewater has become an urgent problem. In this study, a ceramic membrane (CM) was combined with Fenton-activated carbon (AC) adsorption to dispose of refinery wastewater. The effect of the combined process was analyzed using excitation–emission matrix (EEM), ultraviolet-visible (UV-vis) and Fourier transform infrared spectroscopies (FTIR). Compared with direct filtration, the combined process could significantly improve the removal of organic pollution, where the removal rate of the COD and TOC could be 70% and the turbidity removal rate was above 97%. It was found that the effluent could meet the local standards. In this study, the membrane fouling was analyzed for the impact of the pretreatment on the membrane direction. The results showed that Fenton-AC absorption could effectively alleviate membrane fouling. The optimal critical flux of the combined process was increased from 60 to 82 L/(m2·h) compared with direct filtration. After running for about 20 d, the flux remained at about 55 L/(m2·h) and the membrane-fouling resistance was only 1.2 × 1012 m−1. The Hermia model revealed that cake filtration was present in the early stages of the combined process. These results could be of great use in improving the treatment efficiency and operation cycle of refinery wastewater.

Influence and mechanism of different molecular weight organic molecules in natural water on ultrafiltration membrane fouling reversibility

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 83456-83465 ◽  
Author(s):  
Weiguang Sun ◽  
Jun Nan ◽  
Jia Xing ◽  
Jiayu Tian
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Natural Water ◽  
Weight Distribution ◽  
Membrane Fouling ◽  
Organic Molecules ◽  
Ultrafiltration Membrane ◽  
Ultrafiltration Membrane Fouling ◽  
Different Molecular Weight

To investigate the influence of different molecular weight distribution to UF membrane fouling, NOM in natural water was fractionated into five components based on their size and their potential to develop the membrane fouling was conducted.

RO filtration of biologically treated textile and dyeing effluents using ozonation as a pre-treatment

2010 ◽  
Vol 62 (4) ◽  
pp. 751-758 ◽  
Author(s):  
H. Y. Wang ◽  
Y. T. Guan ◽  
T. Mizuno ◽  
H. Tsuno
Keyword(s):  
Organic Matter ◽  
Membrane Fouling ◽  
Quality Parameters ◽  
Dyeing Wastewater ◽  
Improve Performance ◽  
Membrane Cleaning ◽  
Membrane Flux ◽  
Flux Decline ◽  
Pre Treatment ◽  
Water Purity

Bench-scale experiments were conducted to investigate the application of ozonation pre-treatment for biologically treated textile and dyeing wastewater to improve performance of the RO process. Based on ozonation experiments, four specific ozone consumptions (SOC), 0, 0.3, 0.6, 4.0 mg O3/mg DOC0 were chosen for study of the effects of ozonation on the reverse osmosis (RO) process. Membrane flux was recorded. Also, the permeate water quality parameters such as TOC, conductivity were analyzed. In addition, fouled membrane cleaning was studied. The study further examined the nature and mechanisms of membrane fouling using scanning electron microscopy (SEM) and the energy dispersive X-ray spectrometer (EDS). The effect of ozonation on RO filtration was found to depend on SOC. The study revealed that significant improvement can be achieved in the efficiency of RO filtration by employing ozonation with 0.6 mg O3/mg DOC0 SOC. Although the product water purity slightly decreased, the ozonation pre-treatment showed advantages at 0.6 mg O3/mg DOC0 SOC for the following: (i) mitigation of flux decline due to membrane fouling; (ii) improvement in foulants cleanability. In addition, hypotheses were put forward to explain the reasons from the aspect of organic matter characteristics changed by ozonation, such as changing on functional groups and molecular weight of organic matter.

Effect of Modified Diatomite Addition on Sludge Properties for Membrane Fouling Alleviation in Submerged Membrane Bioreactor

2011 ◽  
Vol 233-235 ◽  
pp. 680-683
Author(s):  
Shuo Liu ◽  
Yan Ping Liu ◽  
Bao Zhen Wang ◽  
Ji Fu Wang
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Submerged Membrane Bioreactor ◽  
Sludge Properties ◽  
Sludge Particle ◽  
Modified Diatomite

To alleviate the membrane fouling in membrane bioreactor, a kind of modified diatomite was used as anti-fouling agent to examine the effect on sludge properties in submerged membrane bioreactor for synthetic domestic wastewater treatment. Three submerged membrane bioreactor setups were operated under fixed membrane flux 21.9m3/m2·h, meanwhile, modified diatomite was added into each membrane bioreactor with dosage of 0mg/L, 1000mg/L and 2000mg/L respectively. Sludge particle size, extracellular polymeric substances and molecular weight distribution were characterized as the activated sludge properties in this study. The experiment results showed that with the increase of modified diatomite dosage, the number of sludge particle size less than 10μm was declined, however, the number between 10–20μm was increased correspondingly. Total extracellular polymeric substances and big molecular weight substances were decreased remarkably with modified diatomite addition dosage of 1000mg/L. The results indicated that addition of modified diatomite could effect of sludge properties in submerged membrane bioreactor. Therefore, membrane filtration performance could be improved by modified diatomite adding which alleviate membrane fouling directly.

Recycling of spent filter backwash water using coagulation-assisted membrane filtration: effects of submicrometre particles on membrane flux

2010 ◽  
Vol 61 (8) ◽  
pp. 1923-1929 ◽  
Author(s):  
Chihpin Huang ◽  
Jr-Lin Lin ◽  
C. L. Wu ◽  
C. P. Chu
Keyword(s):  
Particle Size ◽  
Fractal Dimension ◽  
Zeta Potential ◽  
Pore Size ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Treatment Plant ◽  
Membrane Flux ◽  
Filter Backwash Water

Membrane separation technology has been widely used for recycling of spent filter backwash water (SFBW) in water treatment plant. Membrane filtration performance is subject to characteristics of the particles in the SFBW. A bench-scale microfiltration (MF) coupled with pre-coagulation was set up to evaluate the recovery efficiency of SFBW. Effect of particle size distribution and zeta potential of the coagulated SFBW on the membrane filtration as well as the coagulation strategies were investigated. Pore clogging was more severe on the membrane with 1.0 μm pore size than on the membrane with 0.5 μm pore size due to the fact that submicrometre particles are dominant and their diameters are exactly closed to the pore size of the MF membrane. Pre-settling induced more severe irreversible fouling because only the submicrometre particles in the water become predominant after settling, resulting in the occurrence of more acute pore blocking of membrane. By contrast, pre-coagulation mitigates membrane fouling and improves membrane flux via enlarging particle size on membrane surface. The variations of zeta potential in response to coagulant dosing as well as fractal dimension were also compared with the performance of the subsequent filtration. The result showed that pre-coagulation induced by charge neutralization at the optimum dosage where the zeta potential is around zero leads to the optimal performance of the subsequent membrane filtration for SFBW recycling. At such condition, the fractal dimension of coagulated flocs reached minimum.

scholarly journals Decentralised, small-scale coagulation-membrane treatment of wastewater from metal recycling villages – a case study from Vietnam

2020 ◽  
Vol 82 (10) ◽  
pp. 2125-2133
Author(s):  
Lan Thu Tran ◽  
Anh Tien Do ◽  
Tuan Hung Pham ◽  
Kim Thanh Nguyen ◽  
Hung Cong Duong
Keyword(s):  
Heavy Metals ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Combined Treatment ◽  
Small Scale ◽  
Water Recovery ◽  
Metal Recycling ◽  
Beneficial Reuse ◽  
Pre Treatment ◽  
Membrane Treatment

Abstract Effective treatment of wastewaters laden with heavy metals is critical to the sustainable social and economic growth of metal recycling villages in Vietnam. Currently, most wastewaters from metal recycling villages in Vietnam are directly discharged, posing great threats to the environment and human health. In this study, a small-scale combined coagulation-membrane filtration treatment of wastewater collected from a metal recycling village in Vietnam was experimentally investigated. The experimental results manifested the technical viability of the combined coagulation-membrane filtration process for the treatment of the heavily polluted metal recycling wastewater for beneficial reuse. In this combined treatment process, coagulation using ferric chloride (FeCl2) served as a pre-treatment prior to the microfiltration (MF)/reverse osmosis (RO) process. Under the optimised conditions, coagulation at the dosage of 0.2 g FeCl2 per 1,000 ml wastewater removed more than 90% of heavy metals (i.e. most notably including aluminium and chromium) from the wastewater, reducing the aluminium and chromium concentrations in the wastewater from 548.0 to 52.3 mg/L to 32.6 and 1.7 mg/L, respectively. The MF treatment of the wastewater following the coagulation further removed suspended solids and organic matters, rendering the wastewater safe for the subsequent RO filtration with respect to membrane fouling. Given the efficient pre-treatment of coagulation and MF, the RO process at the controlled water recovery of 50% was able to effectively treat the wastewater to potable water.

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