BRADENTON, FL, Dec. 17, 2008 -- Membrana is pleased to announce that the first full scale Aquifer Storage and Recovery (ASR) deoxygenation trial using Liqui-Cel® Membrane Contactors was commissioned in Bradenton, FL on Dec. 2, 2008.
ASR wells are commonly used in Florida and other areas of the world to capture and store excess wet season surface water for use during periods of low rainfall. It is suspected that the high dissolved oxygen concentration in the recharge water oxidizes naturally occurring arsenic bearing minerals such as pyrite in the ground, thereby initiating the arsenic mobilization process in the aquifer. As a result, the arsenic content in the recovered water is often higher than the EPA threshold of 10 parts per billion (ppb). The goal of the project is to determine if removal of dissolved oxygen helps control arsenic mobilization.
The Bradenton deoxygenation system consists of twelve Liqui-Cel 14x28 Membrane Contactors operating in combination mode with nitrogen (N2) sweep and vacuum. The nitrogen is provided by an on-site N2 generator. The water supply is city water that has been pre-treated with ultraviolet light and sodium bisulfite to reduce chloramines. The system is designed to reduce dissolved oxygen concentrations from approximately 8 parts per million (ppm) to less than 10 ppb at a flow rate of 1 million gallons per day (MGD). The actual measured residual oxygen content of the water is excellent and well under specification at 2.0 ppb.
This trial (Cycle Test 8) will consist of a 90 day recharge period where approximately 90 million gallons of deoxygenated water will be injected into the aquifer and then stored for 60 days prior to recovery. Recovery of the stored water will occur over a 60 day period. Arsenic concentrations will be monitored in the recovered water and compared to earlier tests that had high dissolved oxygen content of approximately 8 ppm to determine if arsenic concentrations have been reduced.
Since water resources are seriously strained in Florida due to a rapid population growth, the utilization of ASR wells offers a very important alternative for the water supply. Controlling arsenic mobilization is a major challenge for the use of ASR wells and this trial marks a very significant step in providing plentiful fresh water for Florida residents. This process will then be able to move forward and provide a sound solution to many other locations with similar fresh water supply issues.
The project is being managed by the Southwest Florida Water Management District and the City of Bradenton with funding contributions from the South Florida Water Management District, Peace River/Manasota Regional Water Supply Authority and the St. Johns River Water Management District.
Jones Edmunds & Associates of Gainesville, FL designed the deoxygenation system and is assisting the City of Bradenton with managing the project. The membrane degasification system was constructed by Hydropro Inc. of West Palm Beach, FL. Technical assistance with the design and review of the results of the field test are also being provided by the US Army Corps of Engineers, the Florida Geological Survey and the Florida Department of Environmental Protection.
Liqui-Cel® Membrane Contactors are used around the world for adding or removing oxygen (O2), carbon dioxide (CO2) and nitrogen (N2) to or from different liquids in the semiconductor, power, pharmaceutical, photographic, food and beverage, and many other industries. For example, it is known that O2 negatively impacts many processes; it is corrosive and can oxidize materials. In the power and industrial areas, piping and equipment are susceptible to corrosion. Specifically to the semiconductor market, high levels of O2 can cause lower wafer yields. Additionally, CO2 negatively impacts performance of EDI and Ion Exchange. The Liqui-Cel Contactors offer a modular solution for O2/ CO2 removal before these processes without chemicals.
Liqui-Cel Contactors are also used to add gasses to liquids to enhance megasonic cleaning. The beverage industry looks to membrane contactors for carbonation, nitrogenation and O2 removal. These reflect only a few examples of the variety of applications where the Liqui-Cel Membrane Contactors are used. New applications are constantly being developed.
Additionally, Membrana offers liquid ring vacuum pumps to complement the membrane contactors. Membrana´s Industrial Membrane Group also manufactures a variety of membranes used for filtration in various industries and applications.
Membrana GmbH is a wholly owned subsidiary of Polypore International Inc. (NYSE: PPO) which is a global high technology filtration company specializing in microporous membranes. Polypore's flat sheet and hollow fiber membranes are used in specialized applications that require the removal or separation of various materials from liquids, primarily in the ultrafiltration and microfiltration markets. Based in Charlotte NC, Polypore International Inc. is a global leader with manufacturing facilities or sales offices in nine countries serving six continents.