Coliform Removal Research Articles

Disinfection effect of a continuous-flow ultrasound/ultraviolet baffled reactor at a pilot scale

An ultrasound/ultraviolet (US/UV) baffled reactor was developed to fill the gap in ultraviolet (UV) disinfection associated with disinfection efficiency. According to the previously selected operational condition, a continuous-flow US/UV baffled reactor was continuously operated in a wastewater treatment plant at a pilot scale for nearly three months, and the disinfection influent and effluent were analyzed, including fecal coliforms, Escherichia coli, and fecal streptococci. The US/UV baffled reactor could guarantee a high effluent disinfection performance in terms of fecal coliforms removal even with the fluctuation of the secondary effluent. All the disinfected effluents satisfied the requirement of the “Pollutants Discharge Standard of Municipal Wastewater Treatment Plant in China” (fecal coliforms below 1000CFU/L for class 1A), and 87% of the tested fecal coliforms concentration in the disinfected effluent was below 100CFU/L, nearly eliminating all fecal coliforms. Further analysis of the E. coli and fecal streptococci showed the broad disinfection ability and high disinfection efficiency of the US/UV baffled reactor. The flexibility of the specific energy consumption for the disinfection system depends on the water quality.

Optimized Design of a Hybrid Biological Sewage Treatment System for Domestic Wastewater Supply

This study is aimed at evaluating alternative designs of waste stabilization ponds (WSPs) and constructed wetlands (CWs) for Kaputiei Housing Estate consisting of 2000 low cost housing units in Kenya. The entire analysis was carried out by simulating the effectiveness and purification efficiencies of WSPs and CWs in terms of Biological Oxygen Demand (BOD) reduction and faecal coliform (FC) removal under different scenarios of water treatment systems that included Re-sizing of the initial sewage treatment system, optimizing the design of the initial system and design of hybrid system for the estate. The graphic comparison of the simulated parameters under different scenarios showed that a hybrid design that combines both the WSPs and CWS provides an effluent BOD of 20 mg/l and 195 FC per 100 ml that meets the standard effluent discharge that is acceptable for unrestricted crop irrigation and thus will be reused in the housing estate for kitchen gardening and agroforestry.

Application of Ceramic Filter for Improvement of Pond Sand Filter’s Water Quality

Paying attention to the use of surface water a household type filter unit adding with existing Pond Sand Filter (PSF) is introduced as an alternative water supply option where groundwater is contaminated with arsenic/iron or excessive saline and freshwater aquifers are not available. The performances of existing PSFs are not satisfactory due to poor operation and maintenance, shorter filter run and poor treated water quality. In this study a simple and low cost ceramic filter unit consists of clay pot (10L-capacity), ceramic filter core, storage tank and wooden stand, were applied. The combined action of PSF with ceramic filter unit, the average total coliform and fecal coliform removal efficiencies were found to be 99.73% and 99.97% respectively. Moreover, the reduction efficiencies of turbidity, and color were also achieved to be 96.89% and 99.90% respectively. The average discharge rate of the filter was observed to be 3.0 lit/hr. In combination with PSF, this kind of ceramic filter would be a reliable and sustainable treatment option particularly appropriate for problematic area in Bangladesh.

Fly ash-amended pervious concrete pavement followed by bamboo bioretention basin with Dracaena sanderiana for urban stormwater runoff control

This study assessed the feasibility of pervious concrete pavement (PCP) followed by a bamboo bioretention basin (BBB) with Dracaena sanderiana for urban stormwater volume control and water quality enhancement. Two PCPs (nPCP and tPCP) having a permeability of ∼4.5mm/s were prepared with optimized mix designs. A control impervious concrete pavement (CP) was also prepared. Results showed that both PCP-BBB’s outperformed CP-BBB not only in runoff volume reduction, but also in pollutant removal; both PCPs removed a considerably high amount of pollutants, especially in fecal coliform and phosphate removal. tPCP-BBB improved water quality better than nPCP-BBB in terms of chemical oxygen demand and pH. Additionally, D. sanderiana grew healthier in tPCP-BBB than in nPCP-BBB. Production costs for tPCP and CP were similar, whereas nPCP production was twice as expensive.

Assessment of activated sludge, membrane bioreactors and vertical flow wetlands for upgrading sewage treatment works

ABSTRACTThis paper demonstrates that utilising a vertical flow (VF) wetland after a conventional activated sludge (CAS) delivers equivalent or better effluent quality to a membrane bioreactor (MBR) based on a side-by-side pilot trial. The CAS was operated under the solids retention times (SRT) of 6, 12, and 20 days, with the effluent from each pilot plant fed onto a soil aquifer treatment column to better understand their water reuse application potential. Results showed an upgraded CAS + VF system could deliver effluents with median values of 34 mgO2.L–1, 7 mg.L–1 and 1.9 mg.L–1 for organics, solids and ammonia nitrogen, respectively, which were statistically similar to those from the MBR. Water reuse standards were achieved by the upgraded system for most parameters, with the exception of total coliform removal. The upgraded system delivered superior metal removal when compared to the CAS. An economic analysis showed upgrading a CAS with a VF wetland was more favourable than investing in an MBR system for example works of 5000 and 50,000 population equivalents if the VF system was operated at hydraulic loading rates of 0.03 m.d–1 and 0.08 m.d–1, respectively. This was delivered for a tenth of the carbon footprint of the MBR treatment.

Effects of Eisenia foetida and Eichhornia crassipes in the removal of organic matter, nutrients and coliforms in domestic wastewater

Con el objeto de conocer la capacidad depuradora de un sistema biologico potencialmente aplicable como alternativa para la reduccion de la carga contaminante de efluentes residuales domesticos del municipio de San Juan del Cesar, se evaluo, a escala de laboratorio, el efecto del tratamiento con Eisenia foetida y Eichhornia crassipes , sobre la remocion de materia organica, de nutrientes y de patogenos. Durante un mes, se aplicaron tres tratamientos: T1: E. foetida (biofiltro dinamico aerobio de flujo vertical); T2: E. crassipes (sistema de flujo horizontal con plantas flotantes) y T3: E. foetida + E. crassipes (sistema en serie), empleando tiempos de retencion hidraulica de 24 h y caudales de 0,125L/min ( E. foetida ) y 0,020L/min ( E. crassipes ). Se determinaron las concentraciones de solidos totales (ST), solidos suspendidos totales (SST), turbidez, Demanda Bioquimica de Oxigeno (DBO 5 ), Demanda Quimica de Oxigeno (DQO), Nitrogeno Total, fosfatos, coliformes totales y Escherichia coli , en 30 muestras analizadas (10 para cada sistema). T1 fue mas eficiente en la remocion de DQO 69,2%, T2 elimino el 100% de SST, mientras que T3 reporto las mejores eficiencias de remocion, para la demas variables analizadas. Existen diferencias significativas p<0,05 en la remocion de materia organica, nutrientes y coliformes, en los tratamientos aplicados. La matriz de correlacion de Pearson indica que existe relacion directa p≤0,01 entre la remocion de ST y la disminucion de las concentraciones de DQO, coliformes totales y E. coli . Finalmente, la prueba de HDS Tukey confirmo que T3, excepto para DBO, resulto ser mas eficientes en el tratamiento, las variables analizadas p<0,05.

Continuous electrocoagulation process for the post-treatment of anaerobically treated municipal wastewater

The potential of continuous electrocoagulation (EC) process with aluminium electrodes for the post-treatment of upflow anaerobic sludge blanket (UASB) reactor-treated municipal wastewater was investigated. In order to optimise the performance, influence of three parameters affecting EC, namely, chemical oxygen demand (COD), current density (CD) and residence time in the reactor was studied using response surface methodology (RSM) with Box–Behnken design (BBD) employing real UASB reactor effluent. The results of the modelling study gave the following optimum conditions: influent COD concentration 274mg/L, CD 2mA/cm2 and residence time 5min; and predicted effluent COD, phosphate and turbidity values of 87mg/L, 0.59mg/L, and 12.6NTU, respectively. Confirmatory tests at these optimum conditions gave 90mg/L effluent COD, 0.57mg/L effluent phosphate and 15.2NTU effluent turbidity, which were in close agreement with the predicted results. At optimum conditions, high removals of BOD and suspended solids were also observed, with effluent BOD and suspended solids concentration of 34mg/L and 29mg/L, respectively. High total coliform and faecal coliform removals of 99.81% and 99.86%, respectively, were also obtained at these conditions. The study thus suggests EC as an attractive post-treatment option for UASB reactor-treated municipal wastewater.

Multilevel modeling of retention and disinfection efficacy of silver nanoparticles on ceramic water filters

This research examined how variations in synthesis methods of silver nanoparticles affect both the release of silver from ceramic water filters (CWFs) and disinfection efficacy. The silver nanoparticles used were stabilized by four different molecules: citrate, polyvinylpyrrolidone, branched polyethylenimine, and casein. A multilevel statistical model was built to quantify if there was a significant difference in: a) extent of silver lost, b) initial amount of silver lost, c) silver lost for water of different quality, and d) total coliform removal. Experiments were performed on location at Pure Home Water, a CWF factory in Tamale, Ghana using stored rainwater and dugout water (a local surface water). The results indicated that using dugout vs. rainwater significantly affects the initial (p-value 0.0015) and sustained (p-value 0.0124) loss of silver, but that silver type does not have a significant effect. On average, dugout water removed 37.5μg/L more initial silver and had 1.1μg/L more silver in the filtrate than rainwater. Initially, filters achieved 1.9 log reduction values (LRVs) on average, but among different silver and water types this varied by as much as 2.5 LRV units. Overall, bacterial removal effectiveness was more challenging to evaluate, but some data suggest that the branched polyethylenimine silver nanoparticles provided improved initial bacterial removal over filters which were not painted with silver nanoparticles (p-value 0.038).

Comparison of formation of disinfection by-products by chlorination and ozonation of wastewater effluents and their toxicity to Daphnia magna

This study compared the two most frequently used disinfectants (i.e., chlorine and ozone) to understand their efficiency in wastewater effluents and the ecotoxicity of disinfection by-products created during chlorination and ozonation. Four trihalomethanes (THMs) and nine haloacetic acids (HAAs) were measured from a chlorine-disinfected sample and two aldehydes (i.e., formaldehydes and acetaldehydes) were analyzed after ozonation. Chlorination was effective for total coliform removal with Ct value in the range of 30–60 mg-min/L. Over 1.6 mg/L of ozone dose and 0.5 min of the contact time presented sufficient disinfection efficiency. The concentration of THMs increased with longer contact time (24 h), but that of HAAs showed little change with contact time. The measured concentration of formaldehyde at the ozone dose of 1.6 mg/L and the contact time of 9 min showed the greatest value in this study, approximately 330 μg L−1, from which the corresponding ecotoxicity was determined using an indicator species, Daphnia magna. The ecotoxicity results were consistent with the toxicological features judged by occurrence, genotoxicity, and carcinogenicity. Both the disinfection efficiency as well as the DBP formation potential should therefore be considered to avoid harmful impacts on aquatic environments when a disinfection method is used for wastewater effluents.

Evaluating coagulant activity of locally available &lt;i&gt;Syzygium cumini&lt;/i&gt;, &lt;i&gt;Artocarpus heterophyllus&lt;/i&gt; and &lt;i&gt;Moringa oleifera&lt;/i&gt; for treatment of community drinking water, Uganda

Most rural communities in Africa are without access to treated water and therefore use the readily available unsafe water sources exposing them to water borne diseases. This calls for the need for action to search for affordable and simple solutions. This research therefore examined the effectiveness of readily available natural coagulants Syzygium cumini (Javaplum), Artocarpus heterophyllus (Jackfruit) and Moringa oleifera (Moringa) using ‘Jar Test’. Water turbidity and coliforms removal from community drinking water by seeds extracts of natural coagulants was examined. Turbidity removal increased with coagulants concentration in (solvents extracts water and NaCl). Optimal turbidity removal occurred at 40 mg/l coagulant concentration with low and medium turbidity raw water for both solvents extracts and at 60 mg/l for Na Cl extract with high turbidity water. Compared to alum [KAl (SO 4 ) 2 .12(H 2 O)], the turbidity removal effectiveness was: alum> Moringa oleifera > Artocarpus heterophyllus > Syzygium cumini , except for 1MNaCl extract where it was: alum> Artocarpus heterophyllus > Moringa oleifera > Syzygium cumini .Optimal turbidity removal was: Moringa oleifera 97.7%, Artocarpus heterophyllus 95.8% and Syzygium cumini 94.1%. The seed extracts were also effective as water disinfectants (Moringa>Jackfruit>Java plum). The use of Jackfruit and Java plum and Moringa, for water treatment is recommended. © 2015 International Formulae Group. All rights reserved. Keywords: Coagulant activity, Artocarpus heterophyllus , Moringa oleifera , Syzygium cumini , community drinking water treatment, turbidity removal

Integrated nitrogen removal biofilter system with ceramic membrane for advanced post-treatment of municipal wastewater

ABSTRACTThe pre-denitrification biofilm process for nitrogen removal was combined with ceramic membrane with pore sizes of 0.05–0.1 µm as a system for advanced post-treatment of municipal wastewater. The system was operated under an empty bed hydraulic retention time of 7.8 h, recirculation ratio of 3, and transmembrane pressure of 0.47 bar. The system showed average removals of organics, total nitrogen, and solids as high as 93%, 80%, and 100%, respectively. Rapid nitrification could be achieved and denitrification was performed in the anoxic filter without external carbon supplements. The residual particulate organics and nitrogen in effluent from biofilm process could be also removed successfully through membrane filtration and the removal of total coliform was noticeably improved after membrane filtration. Thus, a system composed of the pre-denitrification biofilm process with ceramic membrane would be a compact and flexible option for advanced post-treatment of municipal wastewater.

Anaerobic co-digestion of vegetable waste and swine wastewater in high-rate horizontal reactors with fixed bed

Considering the high waste generation that comes from agriculture and livestock farming, as well as the demand for natural gas, it is necessary to develop sustainable technologies which can reduce environmental impact. There is no available literature on the use of high-rate horizontal anaerobic reactors with fixed bed (HARFB) and continuous feed for the co-digestion of vegetable wastes (VW) and swine wastewater (SW). The aim of this work was to evaluate the reactor performance in terms of methane production, organic matter consumption, and removal of total and thermotolerant coliforms under different proportions of SW and VW, and organic loading rates (OLR) of 4.0, 5.2 and 11.0g COD (Ld)−1. The mixture of SW and VW in the proportions of 90:10, 80:20 and 70:30 (SW:VW) with those OLRs provided great buffering capacity, with partial alkalinity reaching 3552mgL−1, thereby avoiding the inhibition of methane production by volatile fatty acids produced during the fermentation process. Higher proportions of VW and higher OLR improved volumetric methane production with a maximum value of 1.08LCH4 (Ld)−1, organic matter removal rates up to 98% and total and thermotolerant coliform removal rates of 99% were also observed.

Mix design and pollution control potential of pervious concrete with non-compliant waste fly ash

Pervious concrete mix was optimized for the maximum compressive strength and the desired permeability at 7 mm/s with varying percentages of water-to-binder (W/B), fly ash-to-binder (FA/B), nano-iron oxide-to-binder (NI/B) and water reducer-to-binder (WR/B). The mass ratio of coarse aggregates in sizes of 4.75–9.5 mm to the binder was fixed at 4:1. Waste FA used in the study was not compliant with a standard specification for use as a mineral admixture in concrete. One optimum pervious concrete (Opt A) targeting high volume FA utilization had a 28-day compressive strength of 22.8 MPa and a permeability of 5.6 mm/s with a mix design at 36% W/B, 35% FA/B, 6% NI/B and 1.2% WR/B. The other (Opt B) targeting a less use of admixtures had a 28-day compressive strength and a permeability of 21.4 MPa and 7.6 mm/s, respectively, at 32% W/B, 10% FA/B, 0.5% NI/B and 0.8% WR/B. During 10 loads at a 2-h contact time each, the Opt A and Opt B achieved the average fecal coliform removals of 72.4% and 77.9% and phosphorus removals of 49.8% and 40.5%, respectively. Therefore, non-compliant waste FA could be utilized for a cleaner production of pervious concrete possessing a greater structural strength and compatible hydrological property and pollution control potential, compared to the ordinary pervious concrete.

Bioaugmentation Mitigates the Impact of Estrogen on Coliform-Grazing Protozoa in Slow Sand Filters.

Exposure to endocrine-disrupting chemicals (EDCs), such as estrogens, is a growing issue for human and animal health as they have been shown to cause reproductive and developmental abnormalities in wildlife and plants and have been linked to male infertility disorders in humans. Intensive farming and weather events, such as storms, flash flooding, and landslides, contribute estrogen to waterways used to supply drinking water. This paper explores the impact of estrogen exposure on the performance of slow sand filters (SSFs) used for water treatment. The feasibility and efficacy of SSF bioaugmentation with estrogen-degrading bacteria was also investigated, to determine whether removal of natural estrogens (estrone, estradiol, and estriol) and overall SSF performance for drinking water treatment could be improved. Strains for SSF augmentation were isolated from full-scale, municipal SSFs so as to optimize survival in the laboratory-scale SSFs used. Concentrations of the natural estrogens, determined by gas chromatography coupled with mass spectrometry (GC-MS), revealed augmented SSFs reduced the overall estrogenic potency of the supplied water by 25% on average and removed significantly more estrone and estradiol than nonaugmented filters. A negative correlation was found between coliform removal and estrogen concentration in nonaugmented filters. This was due to the toxic inhibition of protozoa, indicating that high estrogen concentrations can have functional implications for SSFs (such as impairing coliform removal). Consequently, we suggest that high estrogen concentrations could impact significantly on water quality production and, in particular, on pathogen removal in biological water filters.

Performance Evaluation of Alternative Disinfectants in Reducing Microbial Contamination of Vegetables Supplied from City of Kermanshah

Background: In recent decades, due to the scarcity of fresh water resources and high costs of wastewater treatment, cases of irrigation of cultivation of vegetables using raw sewage and polluted effluents or the use of human and animal faeces have been reported. Vegetables are important sources of exposure of human pathogenic pathogens such as fecal coliforms. The aim of this study was to evaluate the performance of three different disinfectant on several kinds of vegetables that would normally be released in Kermanshah. Methods: In this cross sectional study, 180 randomly selected vegetable samples were collected from mobile and fixed stores of vegetables in Kermanshah. Then, to evaluate the effectiveness of disinfectants in eliminating microbial samples, three types of disinfectants containing active ingredient Benzalconium chloride, were studied. Heterotrophic plate count (HPC) surface culture method, coliform count (VRBA) Violet Red Bile Agar purplate method and Yeast Glucose Chloramphemicole Agar (YGCA) surface culture method was used in order to count the microbial load. Results: The findings of this study suggest that the overall average performance of all three disinfectants was less than 75 and most disinfection efficiency was observed in two-fold concentrations of proposed by manufacturer. Based on the analysis of the resulting data, disinfectants examined in this study had an average efficiency of 76.13 for the removal of coliforms as an indicator of gram-negative bacteria and 100 for the removal of Streptococcus bacteria as indicators gram positive bacteria. Conclusion: Disinfection can not solely guarantees the maintaining the health of the consumer. We could have declared that recommended disinfection conditions and existing facilities can effectively reduce the microbial load of vegetables. However, preparing vegetables from safe and ensure proper burial are recommended. Moreover, consuming the raw vegetables in sensitive seasons and precarious conditions should be avoided.

Reactor performance and pathogen removal during wastewater treatment by vermifiltration

The application of vermifiltration could reduce the load of chemical and biological pollutants present in wastewater, reducing the pressure over water requirements and allowing the reclamation of the treated water. In the present study, vermifiltration has shown a great potential for chemical pollutants and pathogen removal in wastewater through the synergistic interactions of earthworms and microorganisms. The results of a pilot-scale study showed a higher percentage removal of biochemical oxygen demand (88%), chemical oxygen demand (78%), total suspended solids (83%) and log removal of fecal coliforms (2.61), fecal streptococci (2.50), Salmonella (2.20) and Escherichia coli (2.48) to the levels considered acceptable for reuse in irrigation purposes. Specifically, earthworms in the vermifilter were able to transform insoluble organic material to soluble form followed by selective digestion of the material to finer size, and further degradation by the microorganisms in the reactor. In vitro antimicrobial assay tests also showed that the present microflora had strong inhibitory efficiency against Staphylococcus aureus, E. coli, Pseudomonas aeruginosa and Klebsiella aerogenes. The observed inhibitory effect was found to be responsible for the phenomenon mentioned above, with release of antimicrobial substances by earthworms and associated microflora that showed antimicrobial potency against pathogenic bacteria. The kinetics evaluation showed the predominance of a first order removal model during vermifiltration.

Effect of geometry on the performance of integrated solar and hydraulic jump enhanced waste stabilization pond

The effect of surface area geometry on the performance of the integrated solar and hydraulic jump enhanced waste stabilization pond (ISHJEWSP) on the treatment of sewage wastewater was studied. The set-up consisted of eight numbers of experimental ponds with varying width. The enhanced ponds were constructed to enable the initiation of hydraulic jump. Three sets of these experimental ponds were constructed with varying locations of the points of initiation of hydraulic jump. The enhanced ponds were fitted with tilt frame, wrapped with aluminium foil paper. Wastewater samples collected from the inlet and outlet for varying inlet velocities were examined for physicochemical and biological characteristics for a period of nine months. The parameters examined were temperature, pH, detention time, dissolved oxygen, total coliform count, total suspended solids, E coli, algae concentration and biochemical oxygen demand. The efficiencies of the ISHJEWSPs with respect to these parameters fluctuated with variations in geometry, with the smallest ISHJEWSP in width giving the highest treatment efficiency. The research revealed that an ISHJEWSP with Length (L):Width (W):Depth (D) ratio of 1.0:0.3:0.2 is on average 1.1 times efficient than the solar enhanced pond (pond B); 1.3 times efficient than the hydraulic jump enhanced pond (pond C), 1.7 times efficient than the conventional WSP with the same L:W:D ratio for coliform removal. The use of flat plane reflector (aluminium foil paper) appeared to be a low-cost and practical system suited to raising the average temperature of the ISHJEWSP (Pond D) over those of the conventional WSP (Pond A) between 2.43 and 3.23°C within the period of the study. The results clearly shows that a designer looking for optimum geometry must avoid relatively low values of surface area aspect ratio (Length/Width) as this will reduce the specific effect of the solar reflector in the ISHJEWSP except where the solar reflector width spans the entire width of the ISHJEWSP. However, this must be balanced with other considerations such as ease of maintenance, construction cost and availability of land.

Performance assessment of modified biosand filter with an extra disinfection layer

Biosand filters (BSFs) have been used widely as an efficient, inexpensive, and appropriate point-of-use technology. Several organizations are promoting filters without adequate testing, which may not lead to sufficiently safe devices. The objective of this study was to evaluate the performance of a modified biosand filter (MBSF) with an extra disinfection layer (brass or zero valent iron (ZVI)) and three layers of underdrain in a range of parameters including Escherichia coli , total coliform, turbidity, pH, and dissolved oxygen. On average, a 91.29% reduction (log 1.43) in total coliform, 98.7% reduction (log 2.6) in E. coli and 88.71% reduction in turbidity were observed for the control. There was a 90.11% reduction (log 1.41) in total coliform, 98.2% reduction (log 2.25) in E. coli , and 88.5% reduction in turbidity for MBSF brass. A 96.93% reduction (log 1.81) in total coliform, 97.33% reduction (log 2.36) in E. coli and 91.5% reduction in turbidity for MBSF ZVI were observed. Adding brass as a disinfection layer in MBSF did not improve bacteria and turbidity removal rates. Adding ZVI as a disinfection layer gave better turbidity and total coliform removal relative to control and MBSF brass. Water quality remained within drinking water standards for all filters.

Using of Alternative Green Coagulant in the Treatment of Water Resources Different Micro-pollutants

Many studies approved the unique properties of potassium ferrate as coagulant, disinfectant and oxidant at the same time. This paper represents an attempt to use this properties to remove ammonia from water resources using single dose of ferrate and hence save energy of chlorine and alum dosing.potassium ferrate prove itself as a possible replacement of conventional chemicals by improving water quality; potassium ferrate by 30ppm dose achieve removal of ammonia, turbidity and total coliform by 92.2%, 82.1% and 99.99% respectively which is higher than using both alum and chlorine with doses 40 and 80ppm.

Applicability of a Reverse Osmosis (RO) Membrane to the Treatment of Wastewater Contaminated with Nitrite, Nitrate, Iron and Manganese

In recent times, the practice of reverse osmosis (RO) membrane technology has become a feasible alternative tool for the wastewater reclamation and reuse. In this research we investigated the applicability of a commercial polyamide RO element to the treatment of municipal sewage-based synthetic wastewater contaminated with nitrite, nitrate, iron, and manganese. The results showed that the RO element achieved the complete removal of BOD, COD, and total coliform. Besides, the ions rejection rates were 98% for iron, 97% for manganese, 93% for chloride, 80% for nitrite, 77% for nitrate, and 45% for ammonia, respectively. Although, dissolved matters in feed water did not cause any significant fouling, organic aggregates and inorganic particles like iron (Fe) colloids decreased the permeate flux of the membrane. The permeate flux of membranes fouled by organic aggregates was successfully recovered to 79% of the initial flux by backwashing from the concentrate port with sodium hydroxide (NaOH) solution at the concentration of 1,000 mg-NaOH/L. The efficiency of NaOH in permeate flux recovery was inferred to be owing to hydrolyzation and solubilization of organic matter by NaOH. On the contrary, the permeate flux fouled by Fe colloids was completely recovered, when backwashing with the deionized water was applied just after the fouling, which suggested that the membrane fouling by Fe colloids was mainly caused by the physical clogging in the membrane.