Low-pressure membrane filtration of secondary effluent in water reuse: Pre-treatment for fouling reduction

2008 ◽  
Vol 320 (1-2) ◽  
pp. 135-142 ◽  
Author(s):  
Linhua Fan ◽  
Thang Nguyen ◽  
Felicity A. Roddick ◽  
John L. Harris
Keyword(s):  
Water Reuse ◽  
Membrane Filtration ◽  
Low Pressure ◽  
Secondary Effluent ◽  
Pre Treatment ◽  
Fouling Reduction

scholarly journals In-line coagulation assessment for ultrafiltration fouling reduction to treat secondary effluent for water reuse

2020 ◽  
Author(s):  
Samia A. Aly ◽  
William B. Anderson ◽  
Peter M. Huck
Keyword(s):  
Membrane Fouling ◽  
Water Reuse ◽  
Hollow Fiber Membrane ◽  
Secondary Effluent ◽  
Membrane Performance ◽  
Coagulant Dosage ◽  
Pre Treatment ◽  
Uf Membranes ◽  
Fouling Reduction ◽  
The Impact

Abstract Low pressure membranes are attracting attention for their potential to improve secondary effluent quality, but membrane fouling can limit their widespread applicability. In this study, in-line coagulation as pre-treatment to ultrafiltration (UF) was investigated using a bench-scale hollow fiber membrane at a constant flux of 33 L/m2 h. Membrane fouling was monitored by observing change in trans-membrane pressure when the membrane was fed with secondary effluent and in-line coagulated secondary effluent over a 24-h period. The impact of four coagulants at different dosages on reversible and irreversible membrane fouling and permeate quality was studied. It was found that in-line coagulation improved UF performance to varying degrees depending on coagulant type and dosage. Generally, higher reduction of fouling was achieved by increasing coagulant dosage within the 0.5–5.0 mg/L range investigated. Ferric-based coagulants were better than aluminum-based coagulants with respect to improving membrane performance for the secondary effluent investigated, even at low dosages (0.5 mg/L). Further investigations are required to determine how in-line coagulation affects removal of organic compounds through UF membranes.

Comparison of sand and membrane filtration as non-chemical pre-treatment strategies for pesticide removal with nanofiltration/low pressure reverse osmosis membranes

2014 ◽  
Vol 14 (4) ◽  
pp. 532-539 ◽  
Author(s):  
Krzysztof P. Kowalski ◽  
Henrik T. Madsen ◽  
Erik G. Søgaard
Keyword(s):  
Organic Matter ◽  
Reverse Osmosis ◽  
Membrane Filtration ◽  
Treatment Strategies ◽  
Low Pressure ◽  
Sand Filtration ◽  
Sand Filter ◽  
Pesticide Removal ◽  
Pre Treatment ◽  
Uf Membranes

Pilot plant investigations of sand and membrane filtration (microfiltration (MF)/ultrafiltration (UF)/nanofiltration (NF)/low pressure reverse osmosis (LPRO)) have been performed to treat groundwater polluted with pesticides. The results show that simple treatment, with use of aeration and sand filtration or MF/UF membranes, does not remove pesticides. However, by reducing the content of key foulants, the techniques can be used as a pre-treatment for nanofiltration and low pressure reverse osmosis that has proved to be capable of removing pesticides. It was found that a lower fouling potential could be obtained by using the membranes, but that sand filter was better at removing manganese and dissolved organic matter. The results indicate that combining aeration, sand filtration and membrane techniques might be a good option for pesticide removal without any addition of chemicals and minimized membrane maintenance.

Characterisation of RO fouling in an integrated MBR/RO system for wastewater reuse

2013 ◽  
Vol 67 (4) ◽  
pp. 780-788 ◽  
Author(s):  
J. Moreno ◽  
H. Monclús ◽  
M. Stefani ◽  
E. Cortada ◽  
J. Aumatell ◽  
...  
Keyword(s):  
Water Reuse ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Wastewater Reuse ◽  
Sewage Water ◽  
Attenuated Total Reflection ◽  
X Ray ◽  
Infrared Microspectroscopy ◽  
Pre Treatment ◽  
Inorganic Precipitation

Membrane filtration has gradually gained acceptance as the preferred pre-treatment for reverse osmosis (RO). In this paper, an integrated membrane bioreactor (MBR)/RO system for wastewater reuse treating real sewage water has been evaluated and the RO fouling has been characterised. The MBR achieved low values of organic matter, total nitrogen, PO43−, total organic carbon, turbidity and conductivity. Filtration with two different RO commercial membranes was performed after the MBR pre-treatment and the same average fouling rate (0.08 bar day−1) was noted. These results gained from the characterisation of the high quality MBR/RO permeate show its potential for water reuse. Inorganic precipitation appears to be the predominant form of fouling in the RO membranes. Calcium phosphate and alumino-silicates were identified by a scanning electron microscope combined with an energy dispersive X-ray and polysaccharides, amide and aliphatic structures were detected with attenuated total reflection infrared microspectroscopy.

scholarly journals Membranes coupled with physico chemical treatment in water reuse

2010 ◽  
Vol 61 (2) ◽  
pp. 513-519 ◽  
Author(s):  
W. S. Guo ◽  
R. Zhang ◽  
S. Vigneswaran ◽  
H. H. Ngo ◽  
J. Kandasamy
Keyword(s):  
Membrane Fouling ◽  
Water Reuse ◽  
Membrane Filtration ◽  
Ion Exchange Resin ◽  
Transmembrane Pressure ◽  
Long Duration ◽  
Pre Treatment ◽  
Refractory Organic Pollutants ◽  
Treated Sewage Effluent ◽  
Magnetic Ion

In this study, short-term experiments were conducted with different configurations of membrane hybrid systems to treat biological treated sewage effluent containing refractory organic pollutants: (i) submerged hollow fiber microfiltration (SMF) alone; (ii) spiral flocculator (SF)-SMF without settling; (iii) SF-PAC-SMF without settling and (iv) SMF with magnetic ion exchange resin MIEX® pretreatment. The results indicated that the pre-flocculation of SF could improve the mitigation of membrane fouling significantly even when the system was operated at a high membrane filtration rate. The transmembrane pressure (TMP) of SF-PAC-SMF only increased marginally (0.8 kPa over 8 hours). SF-SMF without the addition of powdered activated carbon (PAC) also took a relatively long duration for the TMP to increase. The TMP only increased by 2.5 kPa over 8 hours. The SF-PAC-MF system resulted in a high dissolved organic carbon (DOC) removal of more than 96%. When used as pre-treatment to submerged membranes, the fluidized bed MIEX® contactor could remove a significant amount of organic matter in wastewater. This pre-treatment helped to reduce the membrane fouling and kept the TMP low during the membrane operation.

scholarly journals Biological filtration with and without prior in-line coagulation to reduce UF fouling by secondary effluent

2017 ◽  
Vol 8 (2) ◽  
pp. 176-191 ◽  
Author(s):  
Samia A. Aly ◽  
William B. Anderson ◽  
Peter M. Huck
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Membrane Fouling ◽  
Loading Rate ◽  
Pilot Scale ◽  
Secondary Effluent ◽  
Biological Filtration ◽  
Treatment Processes ◽  
Pre Treatment ◽  
Fouling Reduction

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.

Optimization of phosphorus removal in secondary effluent using immersed ultrafiltration membranes with in-line coagulant pretreatment — implications for advanced water treatment and reuse applicationsA paper submitted to the Journal of Environmental Engineering and Science.

2009 ◽  
Vol 36 (7) ◽  
pp. 1272-1283 ◽  
Author(s):  
Joel Citulski ◽  
Khosrow Farahbakhsh ◽  
Fraser Kent
Keyword(s):  
Ferric Chloride ◽  
Water Reuse ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Hollow Fibre ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Ferrous Chloride ◽  
Treated Effluent ◽  
Pre Treatment

In-line addition of alum and ferric chloride was conducted at a hollow-fibre immersed ultrafiltration (UF) membrane pilot plant, using secondary effluent from a municipal wastewater treatment plant (WWTP) as the feed. The objective of such pretreatment was to remove phosphorus from the feed from an initial concentration of approximately 5 mg/L to below 0.3 mg/L. The simplified in-line coagulant addition process involved hydraulic mixing of the coagulant into the feed and subsequent flocculation, and a greatly reduced (12–14 min) flocculation time relative to conventional coagulation-flocculation-settling treatment. Both alum and ferric chloride effectively removed phosphorus to below the 0.3 mg/L threshold when applied as a pretreatment at optimized doses, both of which were below the WWTP’s current coagulant dose (as ferrous chloride). This simplified pre-treatment scheme provided consistent enhanced removal of phosphorus and organic compounds. These results suggest that simplified in-line coagulant addition in advance of immersed UF membranes enhances the ability to produce treated effluent suitable for water-reuse applications.

Leading the City of Baltimore into the 21st Century: Flexible Treatment Solutions and Integrated Raw Water Management

2010 ◽  
Vol 5 (4) ◽  
Author(s):  
J. L. Manuszak ◽  
M. MacPhee ◽  
S. Liskovich ◽  
L. Feldsher
Keyword(s):  
Water Management ◽  
Water Quality ◽  
Water Supply ◽  
Conceptual Design ◽  
Membrane Filtration ◽  
Treatment Plant ◽  
Low Pressure ◽  
Management Tool ◽  
Raw Water ◽  
The City

The City of Baltimore, Maryland is one of many US cities faced with challenges related to increasing potable water demands, diminishing fresh water supplies, and aging infrastructure. To address these challenges, the City recently undertook a $7M study to evaluate water supply and treatment alternatives and develop the conceptual design for a new 120 million gallon per day (MGD) water treatment plant. As part of this study, an innovative raw water management tool was constructed to help model source water availability and predicted water quality based on integration of a new and more challenging surface water supply. A rigorous decision-making approach was then used to screen and select appropriate treatment processes. Short-listed treatment strategies were demonstrated through a year-long pilot study, and process design criteria were collected in order to assess capital and operational costs for the full-scale plant. Ultimately the City chose a treatment scheme that includes low-pressure membrane filtration and post-filter GAC adsorption, allowing for consistent finished water quality irrespective of which raw water supply is being used. The conceptual design includes several progressive concepts, which will: 1) alleviate treatment limitations at the City's existing plants by providing additional pre-clarification facilities at the new plant; and 2) take advantage of site conditions to design and operate the submerged membrane system by gravity-induced siphon, saving the City significant capital and operations and maintenance (O&M) costs. Once completed, the new Fullerton Water Filtration Plant (WFP) will be the largest low-pressure membrane plant in North America, and the largest gravity-siphon design in the world.

Low-pressure membrane filtration with unconventional coagulation regimes

2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey
Keyword(s):  
Activated Carbon ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Cleaning ◽  
Sand Filters ◽  
Charge Neutralization ◽  
Floc Size ◽  
Filtration System ◽  
Pre Treatment

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.

Sign in / Sign up

Export Citation Format

Share Document