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

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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Household rainwater harvesting system – pilot scale gravity driven membrane-based filtration system

Water Science & Technology Water Supply ◽

10.2166/ws.2013.067 ◽

2013 ◽

Vol 13 (3) ◽

pp. 790-797 ◽

Cited By ~ 7

Author(s):

B. Kus ◽

Jaya Kandasamy ◽

S. Vigneswaran ◽

H. K. Shon ◽

G. Moody

Keyword(s):

Heavy Metals ◽

Drinking Water ◽

Organic Matter ◽

Membrane Fouling ◽

Membrane Filtration ◽

Rainwater Harvesting ◽

Membrane Filter ◽

Pilot Scale ◽

Treatment System ◽

Pre Treatment

This paper presents the results of a pilot scale study consisting of pre-treatment with a granular activated carbon (GAC) filter followed by membrane filtration. Detailed characterisation of rainwater tanks has highlighted that turbidity, dissolved organic carbon (DOC) and heavy metals, in particular lead, were not compliant with the 2004 Australian Drinking Water Guidelines (ADWG). Further, organic matter present in the water causes membrane fouling and leads to carcinogenic compounds upon chlorination. A GAC filter was used as a first step to remove dissolved organic matter (measured in terms of DOC) in particular and also to reduce the concentration, of turbidity and lead. Membrane filtration can remove any remaining solids reducing the concentrations of turbidity and microorganisms. In this study a pilot scale rainwater treatment system consisting of a gravity fed GAC filter and membrane filter (Ultra Flo) was operated for a period of 120 days. The performance of this system was assessed in terms of membrane flux and improvement in water quality measured against the 2004 Australian Drinking Water Guidelines. Determination of the flux especially in the later stages of membrane operation was important to be able to size the filters in a manner that meets the expected demand. The treatment system of GAC filter and membrane filter was effective in reducing the turbidity, DOC and heavy metals. The system reduced the turbidity to levels of 0.3–0.4 NTU, below the ADWG limit of 1 NTU. The concentration of DOC was reduced to below the 2004 Australian Drinking Water Guidelines limit of 0.2 mg/L. The concentration of lead was reduced to less than 0.005 mg/L, and below the ADWD limit of 0.01 mg/L. The concentrations of all other heavy metals were well within the ADWG limits. Further, the GAC filter removed a majority of the organic substances from raw rainwater collected from the roof. After the initial flux decline, the stable flux achieved was 0.47 L/m2/h consistently over the final 60 days of the experiment.

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A rapid small scale evaluation of ultrafiltration performance for surface water treatment at Alcantarilha's water treatment works (Algarve, Portugal)

Water Science & Technology Water Supply ◽

10.2166/ws.2004.0109 ◽

2004 ◽

Vol 4 (5-6) ◽

pp. 199-206

Author(s):

M. Ribau Teixeira ◽

H. Lucas ◽

M.J. Rosa

Keyword(s):

Water Treatment ◽

Membrane Fouling ◽

Conventional Treatment ◽

Apparent Molecular Weight ◽

Small Scale ◽

Hydraulic Permeability ◽

Scale Evaluation ◽

Surface Water Treatment ◽

Drinking Water Production ◽

Pre Treatment

A rapid small-scale evaluation of ultrafiltration (UF) performance with and without physical–chemical pre-treatment was performed to up-grade the conventional treatment used for drinking water production in Alcantarilha's water treatment works, Algarve, Portugal. Direct UF and pre-ozonation/coagulation/flocculation/sedimentation/UF (O/C/F/S/UF) were evaluated using polysulphone membranes of different apparent molecular weight cut-off (MWCO) (15–47 kDa). The results indicated that (i) UF is an effective barrier against microorganisms, including virus larger than 80 nm; (ii) for surface waters with low to moderate SUVA values, direct UF performance is equivalent or better than the conventional treatment in terms of residual turbidity, while UV254 nm and TOC residuals require the use of O/C/F/S/UF; (iii) the permeate quality improves with the membrane apparent MWCO decrease, especially for the direct UF, although the conventional treatment performance is never reached using UF; (iv) membrane fouling and adsorption phenomena are more severe in direct UF than in O/C/F/S/UF sequence (pre-ozonation decreases the membrane foulants by decreasing their hydrophobicity) and these phenomena increase with the membrane hydraulic permeability and, particularly, with the membrane apparent MWCO.

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

Membranes ◽

10.3390/membranes11050369 ◽

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.

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Characteristics of coagulation-flocculation of humic acid with effective performance of polymeric flocculant and inorganic coagulant

Water Science & Technology ◽

10.2166/wst.2003.0024 ◽

2003 ◽

Vol 47 (1) ◽

pp. 89-95 ◽

Cited By ~ 14

Author(s):

J. Yu ◽

D.D. Sun ◽

J.H. Tay

Keyword(s):

Humic Acid ◽

Membrane Fouling ◽

Membrane Filtration ◽

Molecular Size ◽

Aluminium Sulphate ◽

Fouling Control ◽

Effective Performance ◽

Water And Wastewater ◽

Pre Treatment ◽

Flocculation Process

Ferric chloride and aluminium sulphate as coagulants and positive charged flocculants PDDMAC ((PDDMAC = poly (diallyldimethylammonium chloride) were used for pre-treatment of water and wastewater for removing humic substance prior to RO membrane filtration. It was found that a combination of flocculant and coagulant enhanced the coagulation-flocculation process and humic acid removal. The optimum conditions of coagulation-flocculation were established in reference to the ratio of humic acid and coagulant. Zeta potential and the ratio of E4/E6 were investigated to explore the possible micro-mechanisms of coagulation-flocculation. The ratios of E4/E6 show the molecular size variations using different coagulants and flocculants, which are expected to benefit membrane-fouling control.

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UV and bacteriophages as a chemical-free approach for cleaning membranes from anaerobic bioreactors

10.1101/2020.08.03.234450 ◽

2020 ◽

Author(s):

Giantommaso Scarascia ◽

Luca Fortunato ◽

Yevhen Myshkevych ◽

Hong Cheng ◽

TorOve Leiknes ◽

...

Keyword(s):

Wastewater Treatment ◽

Membrane Fouling ◽

Membrane Filtration ◽

Membrane Bioreactor ◽

Combined Treatment ◽

Chemical Cleaning ◽

High Quality ◽

Anaerobic Membrane Bioreactor ◽

Membrane Biofouling ◽

Uv C

ABSTRACTAnaerobic membrane bioreactor (AnMBR) for wastewater treatment has attracted much interest due to its efficacy in providing high quality effluent with minimal energy costs. However, membrane biofouling represents the main bottleneck for AnMBR because it diminishes flux and necessitates frequent replacement of membranes. In this study, we assessed the feasibility of combining bacteriophages and UV-C irradiation to provide a chemical-free approach to remove biofoulants on the membrane. The combination of bacteriophage and UV-C resulted in better log cells removal and twice higher extracellular polymeric substance (EPS) concentration reduction in mature biofoulants compared to UV-C. A reduction in the relative abundance of Acinetobacter spp. and selected gram-positive bacteria associated with the membrane biofilm was also achieved by the new cleaning approach. Microscopic analysis further revealed the formation of cavities in the biofilm due to bacteriophages and UV-C irradiation, which would be beneficial to maintain water flux through the membrane. When the combined treatment was further compared with the common chemical cleaning procedure, a similar reduction on the cell numbers was observed (1.4 log). However, combined treatment was less effective in removing EPS compared with chemical cleaning. These results suggest that the combination of UV-C and bacteriophage have an additive effect in biofouling reduction, representing a potential chemical-free method to remove reversible biofoulants on membrane fitted in an anaerobic membrane bioreactor.SIGNIFICANCEAnaerobic membrane bioreactors can achieve high quality effluent with a reduced energy consumption. However, biofouling represents the main bottleneck for membrane filtration efficiency. Biofouling is commonly reduced through chemical treatment. These agents are often detrimental for the environment and health safety due to the formation of toxic byproducts. Therefore, we present a new approach, based on the additive antifouling action of bacteriophages infection and UV-C irradiation, to reduce anaerobic membrane biofouling. This new strategy could potentially delay the occurrence of membrane fouling by removing the reversible fouling layers on membranes, in turn reducing the frequencies and amount of chemicals needed throughout the course of wastewater treatment.

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Practical experiences from membrane filtration plants for humic substance removal

Water Science & Technology ◽

10.2166/wst.2000.0602 ◽

2000 ◽

Vol 41 (10-11) ◽

pp. 33-41 ◽

Cited By ~ 8

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.

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The Effect of Advanced Oxidation Pre-Treatment on the Membrane Filtration Parameters of Dairy Wastewater

Hungarian Journal of Industry and Chemistry ◽

10.1515/hjic-2017-0016 ◽

2017 ◽

Vol 45 (2) ◽

pp. 23-27 ◽

Cited By ~ 1

Author(s):

Mihály Zakar ◽

Ildikó Kovács ◽

Péter Muhi ◽

Erika Hanczné Lakatos ◽

Gábor Keszthelyi-Szabó ◽

...

Keyword(s):

Membrane Fouling ◽

Membrane Filtration ◽

Advanced Oxidation ◽

Treatment Method ◽

Organic Content ◽

Dairy Wastewater ◽

Limiting Factor ◽

Wide Range ◽

Pre Treatment ◽

High Degree

Abstract The dairy industry generates wastewater characterised by high levels of biological and chemical oxygen demands representative of their high degree of organic content; mainly carbohydrates, proteins and fats that originate from milk. Several investigations have been conducted into the reuse of dairy wastewater, e.g. membrane processes are a promising method to treat such wastewater. Earlier works have proven that with membrane filtration an appropriate degree of retention can be achieved and the permeate can be reused. However, membrane fouling is a limiting factor in these processes. Advanced oxidation processes (AOPs) are widely used in the fields of water and wastewater treatments and are known for their capability to mineralise a wide range of organic compounds. AOPs also exhibit some other effects on the filtration process, e.g. the microflocculation effect of ozone may play a significant role in increasing the elimination efficiency and causing a decreased level of irreversible fouling. By comparing ozone and Fenton pre-treatment (FPT) processes it can be shown that the fouling propensity of pre-treated pollutants does not depend on the pre-treatment method, while FPT was proven to be more efficient in improving the level of flux.

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Applying the coagulation and reverse osmosis for water recovery from evaporative water

Annals of Warsaw University of Life Sciences – SGGW Land Reclamation ◽

10.1515/sggw-2015-0003 ◽

2014 ◽

Vol 46 (4) ◽

pp. 291-300

Author(s):

Magdalena M. Michel ◽

Lidia Reczek ◽

Tadeusz Siwiec ◽

Piotr Rudnicki

Keyword(s):

Reverse Osmosis ◽

Organic Compounds ◽

Membrane Filtration ◽

Raw Material ◽

Feed Water ◽

Water Recovery ◽

Evaporative Water ◽

Water Turbidity ◽

A Value ◽

Pre Treatment

Abstract Applying the coagulation and reverse osmosis for water recovery from evaporative water. Evaporative water from the concentration of yeast slurry is a potential raw material for water recovery. It is characterized by low pH (4.6-6.3), increased turbidity (3.65-13.7 NTU), and high content of total organic carbon (356-754 mg/L). Its treatment in the volume coagulation process using NaOH and coagulant PIX 111, was studied. Water turbidity was lowered to a value below 1 NTU, but coagulation did not allow for the removal of organic compounds. Coagulation was effective at temperatures of 20 and 40°C. Pretreatment of the feed water for RO included alkalization, coagulation, sedimentation, and 5 μm fine filtration (variant I), as well as single 5 μm fine filtration (variant II as a blank). In variant I the feed with improved properties was achieved. Membrane filtration allowed for effective desalination of evaporative water, 98 and 73% conductivity retention was obtained, depending on the method of the feed pre-treatment. The organic compounds were removed less efficiently, at 94 and 84%, respectively.

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Potable reuse of wastewater effluent through an integrated soil aquifer treatment (SAT) - membrane system

Water Science & Technology Water Supply ◽

10.2166/ws.2003.0004 ◽

2003 ◽

Vol 3 (3) ◽

pp. 25-33

Author(s):

C. Jarusutthirak ◽

G. Amy ◽

D. Foss

Keyword(s):

Organic Matter ◽

Membrane Fouling ◽

Membrane Filtration ◽

Membrane System ◽

Wastewater Effluent ◽

Soil Aquifer Treatment ◽

Wastewater Reclamation ◽

Potable Reuse ◽

Barrier Membrane ◽

Membrane Treatment

Soil aquifer treatment (SAT) has been shown to provide significant reductions of wastewater effluent organic matter (EfOM). While SAT can renovate wastewater effluent to levels commensurate with potable reuse, SAT represents only a single treatment barrier. Membrane filtration has been demonstrated to be an alternative treatment process for wastewater reclamation. However, the performance of membrane filtration is significantly constrained by membrane fouling, reducing membrane productivity in terms of flux decline. Soil aquifer treatment (SAT) is used as a primary barrier in the reclamation system to remove a complex suite of chemical and biological contaminants in wastewater. This study of membrane filtration of SAT-source waters is intended to determine the benefits of the SAT system in terms of membrane fouling reduction with membrane filtration providing a secondary barrier. Membrane treatment of SAT-recovered water provides a multiple barrier exhibiting additional organic matter removal. Moreover, the SAT system also provides for storage of reclaimed water. The synergy between SAT and membrane treatment has led to the concept of an integrated SAT-membrane system for potable reuse.

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Detergent and Water Recovery from Laundry Wastewater Using Tilted Panel Membrane Filtration System

Membranes ◽

10.3390/membranes10100260 ◽

2020 ◽

Vol 10 (10) ◽

pp. 260

Author(s):

Nafiu Umar Barambu ◽

Derrick Peter ◽

Mohd Hizami Mohd Yusoff ◽

Muhammad Roil Bilad ◽

Norazanita Shamsuddin ◽

...

Keyword(s):

Environmental Sustainability ◽

Membrane Fouling ◽

Membrane Filtration ◽

Membrane Surface ◽

Aeration Rate ◽

Water Recovery ◽

Wastewater Reclamation ◽

Permeability Enhancement ◽

Filtration System ◽

Wastewater Filtration

Increasing global concern on clean water scarcity and environmental sustainability drive invention in water reclamation technology. Laundry wastewater reclamation via membrane technology faces the challenge of membrane fouling. This paper assesses a tilting-the-filtration-panel filtration system for the treatment of real laundry wastewater filtration aimed for water and detergent reuse. Results showed that the panel tilting significantly improved fouling control and enhanced permeability due to enhanced contact of air bubbles with the membrane surface, which induced continuous detachment of foulant from the membrane surface. The combination of aeration rate and tilting angle resulted in up to 83% permeability enhancement from 109 to 221.4 ± 10.8 (L/m2·h·bar). The system also offers 32% detergent recovery. Overall findings suggest that the system offers an attractive approach for both fouling management and detergent recovery and can potentially be applied under a simple setup in which filtration can be driven by gravity/hydrostatic pressure.

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