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

2013 ◽  
Vol 13 (3) ◽  
pp. 790-797 ◽  
Author(s):  
B. Kus ◽  
Jaya Kandasamy ◽  
S. Vigneswaran ◽  
H. K. Shon ◽  
G. Moody

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.

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.


2011 ◽  
Vol 11 (1) ◽  
pp. 23-29 ◽  
Author(s):  
P. M. Huck ◽  
S. Peldszus ◽  
C. Hallé ◽  
H. Ruiz ◽  
X. Jin ◽  
...  

Fouling remains one of the major constraints on the use of low pressure membranes in drinking water treatment. Work over the last few years has shown the importance of biopolymers (carbohydrates and protein-like material) as foulants for ultrafiltration (UF) membranes. The purpose of this study was to investigate at pilot scale the use of rapid biofiltration (without prior coagulation or ozone addition) as an innovative pretreatment to reduce fouling of UF membranes. The investigation was carried out on a water with a higher than average DOC and significant temperature variation. The biofilters, each operated at a hydraulic loading of 5 m/h, had empty bed contact times of 5, 10 and 15 minutes. The membrane unit was operated at a flux equivalent to 60 LMH at 20°C. The investigation confirmed the encouraging results obtained in an earlier smaller scale study with essentially the same water. Increased biofiltration contact time (i.e. increased bed depth) led to lower rates of hydraulically irreversible fouling. The initial biofiltration backwash procedure, involving air scour as is common in chemically assisted filtration, led in some cases to an increased rate of membrane fouling immediately after the backwash. An alternative backwashing strategy was developed, however the feasibility of operating with this approach over very long periods of time needs to be confirmed. To assist in full-scale implementation of this “green” and simple pretreatment, the design and operating conditions for the biofilters should be optimized for various types of waters. It is expected that biofiltration pretreatment will be of particular interest for small and/or isolated systems where a higher initial capital cost may be acceptable because of operational simplicity and reduced chemical requirements.


2013 ◽  
Vol 13 (2) ◽  
pp. 479-485 ◽  
Author(s):  
B. Kus ◽  
Jaya Kandasamy ◽  
S. Vigneswaran ◽  
H. K. Shon ◽  
G. Moody

The characterisation of rainwater in metropolitan Sydney and in rural New South Wales was undertaken. The results showed that factors such as the lack of vehicular traffic, air pollution and urban contamination meant that rural rainwater water quality was better. The rain water collected in both metropolitan and rural areas generally complied with the 2004 Australian Drinking Water Guidelines except for parameters such as the pH in both the metropolitan and rural rainwater tanks and the turbidity, and lead levels from the metropolitan tanks. This paper also reports the results of a laboratory and a pilot scale study with a deep bed filter (granular activated carbon, GAC) and microfiltration (MF) hollow fibre membrane filter system used to treat raw rainwater collected from a metropolitan rainwater tank. The results of the laboratory experiment and pilot scale systems focus on the non-compliant parameters of the sampling program, i.e. turbidity, lead and dissolved organic carbon (DOC). It was found that rainwater treated by the GAC filter removed the majority of the turbidity and organic substances. The treatment system reduced the concentration of turbidity, lead and DOC to below the Australian Drinking Water Guidelines limits. The pilot plant experiment demonstrated that a GAC filter system and gravity driven membrane could result in low cost and low maintenance operation.


2020 ◽  
Vol 82 (10) ◽  
pp. 2125-2133
Author(s):  
Lan Thu Tran ◽  
Anh Tien Do ◽  
Tuan Hung Pham ◽  
Kim Thanh Nguyen ◽  
Hung Cong Duong

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.


2017 ◽  
Vol 8 (2) ◽  
pp. 176-191 ◽  
Author(s):  
Samia A. Aly ◽  
William B. Anderson ◽  
Peter M. Huck

Abstract The objectives of this research were to investigate biofiltration prior to ultrafiltration (UF) for treatment of secondary effluent. Biofiltration with and without prior in-line coagulation was assessed for UF membrane fouling reduction. Two parallel pilot-scale biofilters, each with different media (sand vs. anthracite), were operated under identical conditions at a hydraulic loading rate of 0.75 m/h. A component of this investigation included the in-line application of a 1.0 mg/L dose of ferric sulfate prior to an anthracite biofilter. All UF membrane fouling experiments were conducted at bench-scale at a constant flux of 32 L/m2h (LMH). The sand (BF1) and anthracite biofilters (BF2) removed on average 25 and 20%, respectively, of the biopolymer fraction of the effluent organic matter. Humic substances were less well removed at about 10%, while biofilter influent turbidity was reduced by 75 and 70% through BF1 and BF2, respectively. Feeding the UF membrane with biofilter effluent (no prior coagulant addition) substantially reduced both hydraulically reversible and irreversible membrane fouling by up to 60 and 80%, respectively. Hydraulically reversible and irreversible fouling were further reduced (up to 69 and 87%, respectively) by the integration of the in-line coagulation/biofiltration pre-treatment processes compared to biofiltration alone.


2006 ◽  
Vol 6 (4) ◽  
pp. 81-87 ◽  
Author(s):  
Hae-Nam Jang ◽  
Dae-Sung Lee ◽  
Min-Koo Park ◽  
Sun-Young Moon ◽  
Soo-Young Cho ◽  
...  

This study was performed to investigate the effects of flux and pre-treatment on the operation performance of a microfiltration drinking water treatment system through a pilot scale operation using lake water as raw water. The pilot plant had a capacity of 500 m3/day with a five membrane module and was operated for 1 year to carry out the experiments for the variation of filtration flux, physical cleaning conditions and pre-treatment conditions. Also, an experiment was performed when raw water with high turbidity flowed into the system as well as that pretreated with powdered activated carbon (PAC). When the MF system was operated with filtration flux of 2 m3/m2 day, it could not be operated more than 500 h due to the continuous TMP (Trans-membrane pressure) increase. In case of filtration flux of 1 m3/m2 day, the system could be operated continuously for more than 1300 hours without the increase in the TMP. During this experimentation period, raw water with high turbidity (above 400NTU) was fed into the membrane system. Therefore, the TMP increased by approximately 4.90 kPa compared to the TMP for the previous raw water with lower turbidity. In the case of the PAC pretreated membrane filtration process, the TMP tended to increase slightly. However, the TMP was reduced by performing coagulation and mixing after injecting PAC.


2001 ◽  
Vol 1 (5-6) ◽  
pp. 141-150 ◽  
Author(s):  
S. Sawada ◽  
I. Sumida ◽  
K. Matsumoto

The preliminary study investigated the effect of pre-ozonation of synthetic raw water (bentonite and humic acid) on membrane fouling. The results showed that humic acid, not bentonite, was the dominant factor in membrane fouling. When the synthetic raw water was pre-treated using ozone and activated carbon, stable operation was possible at twice the flux of membrane filtration without pre-treatment. Thus, ozone and activated carbon reduced the concentration of organic matter (humic acid), leading to an increase in flux. Secondly, an MF membrane filtration device with ozone tolerance was attached downstream of the ozone reactor so that residual ozone could reach the membrane surface. When water was treated with MF membrane filtration in the presence of ozone, the flux was stable at 4 m/d. The membrane filtration resistance increased when ozone was not injected, and decreased when it was injected. This phenomenon was repeatable. In the presence of ozone, organic matter that could accelerate fouling as decomposed and converted to less fouled materials, resulting in a suppression of fouling as well as facilitating removal of the fouling layer during back washing.


2003 ◽  
Vol 3 (5-6) ◽  
pp. 15-22
Author(s):  
P. Kouadio ◽  
M. Tétrault

Three colored surface water nanofiltration pilot-scale projects were conducted in the province of Quebec (eastern Canada), between November 2000 and March 2002, by the company H2O Innovation (2000) inc., for the municipalities of Lac Bouchette, Latulipe-et-Gaboury and Charlesbourg (now part of Quebec City). Results indicated that nanofiltration permeate quality has an advance on present drinking water regulation standard in Quebec, but important membrane fouling occurred. Fouling can be controlled by pretreatment and optimization of the operating conditions.


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