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Broad Brook, CT, United States

Huang S.,University of California at Irvine | Voutchkov N.,Water Globe Consulting LLC | Jiang S.C.,University of California at Irvine
Desalination | Year: 2013

One of the challenges the seawater desalination industry faces today is reverse osmosis (RO) membrane biofouling. Traditional water quality parameters such as SDI and the RO feed water turbidity are inadequate at protecting the membrane from biofouling. This research investigated the environmental and water quality parameters in a Southern California desalination plant in order to develop a set of seawater desalination RO membrane biofouling indicators. Statistical analysis was performed on data collected onsite over two years. The relationships between operation parameters, rain precipitations, TOC, UV254, chlorophyll fluorescence in raw seawater and the performance loss of the RO desalination process are presented. The environmental triggers for accelerated RO membrane biofouling was further investigated by developing membrane fouling simulators at the desalination pilot plant. Biofouling was confirmed by confocal laser scanning microscopy investigation of membrane biofilm and live and dead bacterial cell counts. The results of this study indicated that biofouling was significantly correlated with water quality changes. Thus, chlorophyll fluorescence measurements can be used as a precursor for desalination membrane biofouling. © 2013 Elsevier B.V.

Voutchkov N.,Water Globe Consulting LLC
Desalination | Year: 2010

Two types of pretreatment systems are typically used to protect seawater reverse osmosis membranes from fouling: conventional granular media filtration and membrane filtration. While granular medial filtration is still a dominating seawater pretreatment technology, microfiltration and ultrafiltration membrane systems for seawater pretreatment have evolved rapidly over the past decade and may offer cost and performance benefits for the site specific conditions and challenges of a given seawater desalination project. This article presents a critical review of widely used conventional granular and membrane pretreatment technologies and addresses key factors, and issues which would need to be taken under consideration when selecting a seawater pretreatment system. © 2010 Elsevier B.V. All rights reserved.

Voutchkov N.,Water Globe Consulting LLC
Desalination | Year: 2011

This article discusses the available alternatives for ocean concentrate disposal, site specific factors involved in the selection of the most viable alternative for a given project, and the environmental permitting requirements and studies associated with their implementation. The article focuses on the three most widely used alternatives for ocean discharge of concentrate: direct discharge through new outfall; discharge through existing wastewater treatment plant outfall; and co-disposal with the cooling water of existing coastal power plant. Key advantages, disadvantages, environmental impact issues and possible solutions are presented for each discharge alternative. Results from recent salinity tolerance and toxicity study completed at the Carlsbad, California seawater desalination demonstration plant for a variety of sensitive marine organisms are presented. The practical implementation of this study along with other methods for analysis of the environmental impact of ocean discharges from large seawater reverse osmosis plants is illustrated with case study examples. © 2010 Elsevier B.V.

Zhang M.,University of California at Irvine | Zhang M.,Nankai University | Zhang M.,Tsinghua University | Jiang S.,University of California at Irvine | And 4 more authors.
Applied and Environmental Microbiology | Year: 2011

Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Cellulophaga based on 16S rRNA gene sequencing analysis. The 16S rRNA gene clone library of the SWRO membrane biofilm showed that a filamentous bacterium, Leucothrix mucor, which belongs to the gammaproteobacteria, accounted for nearly 30% of the clone library, while the rest of the microorganisms (61.2% of the total clones) were related to the alphaproteobacteria. 16S rRNA gene terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that bacteria colonizing the SWRO membrane represented a subportion of microbes in the source seawater; however, they were quite different from those colonizing the cartridge filter. The examination of five SWRO membranes from desalination plants located in different parts of the world showed that although the bacterial communities from the membranes were not identical to each other, some dominant bacteria were commonly observed. In contrast, bacterial communities in source seawater were significantly different based on location and season. Microbial profiles from 14 cartridge filters collected from different plants also revealed spatial trends. © 2011, American Society for Microbiology.

Birnhack L.,Technion - Israel Institute of Technology | Voutchkov N.,Technion - Israel Institute of Technology | Voutchkov N.,Water Globe Consulting LLC | Lahav O.,Technion - Israel Institute of Technology
Desalination | Year: 2011

The quality with which water is released from desalination plants is continuously increasing. Since desalination permeates are slightly acidic, contain very low buffering capacity and are very soft, post-treatment is always required. This paper reviews the knowledge accumulated in the last decades on desalination post-treatment processes. It covers fundamental chemistry aspects, required water quality criteria, advantages and disadvantages of currently applied processes, engineering and cost considerations, recent full-scale project experience and up-to-date research trends. © 2010 Elsevier B.V.

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