The Great Lakes hold roughly 20% of the world’s fresh water, and provide a drinking water source for more than the 30 million people who live near the lakes in the U.S. and Canada. Since 1997, Siemens Water Technologies has provided or will be providing membrane technology to over 35 Great Lakes’ water treatment plants, to ensure high quality drinking water for these communities.

The treatment consists of low-pressure membrane systems that help municipalities meet the filtration requirements of the Long Term 2 Surface Water Treatment Rule (LT2SWTR). The purpose of the LT2 rule is to reduce illness linked with the contaminant Cryptosporidium and other disease-causing microorganisms in drinking water. Low-pressure membranes offer reliable treatment with unmatched ease of operation, while delivering greater than 4-log removal of Cryptosporidium, Giardia and bacteria, over 2-log virus rejection and a silt density index of less than 2.0, regardless of storm-driven turbidity events.

“Generally speaking, Great Lakes water is very low in total organic carbon (TOC), color and other regulated compounds, such that membrane filtration can produce LT2SWTR-compliant water for potable use when operating in a direct filtration process,” says Russ Davis, Technical Sales Manager for Memcor Products at Siemens Water Technologies. “This is a plus, since an upstream coagulation/flocculation/settling process prior to filtration is not needed, thus saving space, simplifying operations and reducing costs.”

The membrane systems for these 35 treatment plants encompass a capacity range from small package plants supplying State/National Parks or power plants, to mid-size systems supplying communities of around 30,000 people, to large systems serving regional utilities that supply water to more than 100,000 people. Of the 35 plants, 14 are on Lake Michigan, 13 on Lake Huron, 5 on Lake Superior, 2 on Lake Erie and 1 on Lake Ontario. These systems are either in operation, are being designed, or have been designed and are now under construction.

In many cases, these systems have been used to upgrade or expand aging conventional filtration systems. For example, in April 2009 Siemens was awarded a multi-million dollar contract to provide a Memcor CS submerged membrane system for the City of Highland Park, Illinois, a North Shore Chicago suburb that serves around 60,000 people. When completed in 2013, this system will replace the original filtration plant and increase the plant’s rated treatment capacity from 21 million gallons per day (MGD) to 30 MGD, with no change in building footprint. The city chose the Memcor submerged membrane system following a 12-month pilot study and competitive procurement process, whereby Siemens’ Memcor CS technology was shown to provide the best value.

To ensure that the Great Lakes remain sustainable, there are a number of organizations engaging in restoration efforts. Recently, President Obama announced the new Great Lakes Restoration Initiative, the largest, most serious commitment to Great Lakes restoration in U.S. history. Led by the EPA, the initiative seeks to: stop invasive species from entering the lakes; clean up beaches; remove toxic pollution; and restore fish and wildlife habitat. The initiative will build upon five years of work by the Great Lakes Interagency Task Force (IATF) and guided by the Great Lakes Regional Collaboration Strategy. Another organization, The Alliance for the Great Lakes, formerly called the Lake Michigan Federation, works to conserve and restore the lakes through policy, education and local efforts aimed at preserving the Great Lakes region as a national treasure.

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