Monitoring and maintaining the integrity of immersed ultrafiltration membranes used for pathogen protection

2002 ◽  
Vol 2 (5-6) ◽  
pp. 307-311
Author(s):  
P. Côté ◽  
J. Cadera ◽  
N. Adams ◽  
G. Best
Keyword(s):  
Drinking Water ◽  
Membrane Filtration ◽  
Ultrafiltration Membranes ◽  
Vacuum Decay ◽  
Integrity Monitoring ◽  
Pressure Decay ◽  
Decay Test ◽  
Conventional Technology ◽  
Water Borne

Membrane filtration has become the preferred alternative to conventional technology to remove water-borne pathogens in the preparation of drinking water. This paper presents the integrity monitoring and maintenance options for the ZeeWeed® immersed membrane. Results from two versions of air-based tests, a pressure decay test and a vacuum decay test are presented and shown to be conservative when compared to challenge results from independent studies.

Monitoring membrane integrity using high sensitivity laser turbidimetry

2001 ◽  
Vol 1 (5-6) ◽  
pp. 273-276 ◽  
Author(s):  
A. Banerjee ◽  
M. Lambertson ◽  
J. Lozier ◽  
C. Colvin
Keyword(s):  
Drinking Water ◽  
Membrane Filtration ◽  
Membrane Integrity ◽  
High Sensitivity ◽  
Particle Counter ◽  
Pressure Decay ◽  
Particle Counting ◽  
Decay Test ◽  
Microfiltration Membranes ◽  
Decay Testing

Membrane filtration plants for drinking water typically use pressure decay testing in conjunction with particle counting and turbidity to monitor membrane integrity. Pilot plants offer the capability of monitoring permeate quality with both intact and intentionally compromised membranes. We compare data from a particle counter, a pressure decay test and a laser turbidimeter on pilot plants from two different manufacturers of microfiltration membranes.

Coagulation/flocculation/ultrafiltration for natural organic matter removal in drinking water production

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Water Production ◽  
Cellulose Acetate Membranes ◽  
Wide Range ◽  
Drinking Water Production

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.

Viruses and Water: Problems, Detection, and Control

1993 ◽  
Vol 27 (7-8) ◽  
pp. 127-133 ◽  
Author(s):  
H. Dizer ◽  
J. Dürkop ◽  
A. Grohmann ◽  
H. Kopecka ◽  
J. M. López-Pila
Keyword(s):  
Drinking Water ◽  
Surface Waters ◽  
Membrane Filtration ◽  
Wastewater Treatment Plants ◽  
Health Hazard ◽  
Primary Source ◽  
Detection Methods ◽  
Secondary Effluent ◽  
Naturally Occurring ◽  
Water Problems

Secondary effluent of wastewater treatment plants contains a high number of viruses and other pathogens, which pose a health risk to the population, (especially when receiv ng waters are used for bathing and swimming, or for growing shellfish. In areas with a high density of population, where drinking water supply is dependent on surface waters and contaminated rivers are the primary source of drinking water, failure of the filtration or of the disinfection step, or of any other “barriers” supposed to warrant safe potable water, will increase the risk of health hazard for the consumer. We have compared the efficiency of viral elimination in secondary effluent by flocculation, uv rradiation and membrane filtration taking naturally occurring, or additionally seeded f2 phages, as indicator for viruses. Flocculation decreased the number of phages present in secondary effluent by more than two logs. If combined with uv irradiation, the elimination reached five additional logs. Membrane filtration eliminated essentially all naturally occurring phages. Improvement of the quality of surface waters calls for a refinement of detection methods for viruses. We have found that the polymerase chain reaction (PCR) might be used for detecting viruses in surface waters.

scholarly journals One-step removal of lead from water using an electricity-free and sustainable membrane filtration

2021 ◽  
Vol 27 (4) ◽  
pp. 166-172
Author(s):  
Junwei Zhang ◽  
Yan Tung Lo ◽  
Hao Guo ◽  
Chuyang Tang
Keyword(s):  
Drinking Water ◽  
Removal Efficiency ◽  
Membrane Filtration ◽  
High Water ◽  
Water Safety ◽  
Drinking Water Contamination ◽  
Emergency Situations ◽  
Drinking Water Safety ◽  
Effective Removal ◽  
Volumetric Loading

Lead (Pb) is a typical contaminant in water with adverse effects on human health. Hong Kong’s incident of drinking water contamination by Pb in 2015 caused severe public concerns regarding drinking water safety. Conventional treatment methods for Pb removal generally require electricity, chemical dosage, and considerable time and space, which significantly restrict their use for rapid water purification under emergency situations. In this study, a polyvinyl alcohol/polyacrylic acid (PVA/PAA) composite nanofibrous membrane was developed for the rapid and effective removal of Pb from water. The PVA/PAA membrane had a high water permeability of 550 L/m2/h/kPa - 710 L/m2/h/kPa, which allowed the filtration to be driven by gravity (e.g. with a water height of 10.0 cm). The membrane showed consistently high removal efficiency of Pb (> 95%) with a volumetric loading up to 3000 L/m2. This high removal efficiency was attributed to the combined effects of complexing and electrostatic attraction between Pb and PAA. An esculent citric acid was used to regenerate the exhausted PVA/PAA membrane. The regenerated membrane maintained its removal efficiency of Pb over a five-cycle filtration. These results imply that the PVA/PAA composite membrane can be repeatedly used in electricity-free filtration devices for rapid elimination of Pb under emergency situations.

scholarly journals Aeromonas detection and their toxins from drinking water from reservoirs and drinking fountains

2007 ◽  
Vol 6 (1) ◽  
pp. 117-123 ◽  
Author(s):  
Maria Tereza Pepe Razzolini ◽  
Marisa Di Bari ◽  
Petra Sanchez Sanchez ◽  
Maria Inês Zanoli Sato
Keyword(s):  
Drinking Water ◽  
Aquatic Ecosystems ◽  
Membrane Filtration ◽  
Biochemical Characterization ◽  
Toxin Production ◽  
Health Concern ◽  
Public Health Concern ◽  
Emerging Pathogen ◽  
Pathogenic Potential ◽  
Drinking Water Samples

Aeromonads are inhabitants of aquatic ecosystems and are described as being involved in intestinal disturbances and other infections. A total of 200 drinking water samples from domestic and public reservoirs and drinking fountains located in São Paulo (Brazil), were analyzed for the presence of Aeromonas. Samples were concentrated by membrane filtration and enriched in APW. ADA medium was used for Aeromonas isolation and colonies were confirmed by biochemical characterization. Strains isolated were tested for hemolysin and toxin production. Aeromonas was detected in 12 samples (6.0%). Aeromonas strains (96) were isolated and identified as: A. caviae (41.7%), A.hydrophila (15.7%), A.allosacharophila (10.4%), A. schubertii (1.0%) and Aeromonas spp. (31.2%).The results revealed that 70% of A. caviae, 66.7% of A. hydrophila, 80% of A. allosacharophila and 46.6% of Aeromonas spp. were hemolytic. The assay for checking production of toxins showed that 17.5% of A. caviae, 73.3% of A. hydrophila, 60% of A. allosacharophila, 100% of A. schubertii, and 33.3% of Aeromonas spp. were able to produce toxins. The results demonstrated the pathogenic potential of Aeromonas, indicating that the presence of this emerging pathogen in water systems is a public health concern.

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