Loading...
Filter Assessment Manual : Third Edition
McGlohorn, Greg South Carolina Department of Health and Environmental Control, Bureau of Water, Compliance Assurance Division, Drinking Water & Recreational Waters Compliance Section
McGlohorn, Greg
South Carolina Department of Health and Environmental Control, Bureau of Water, Compliance Assurance Division, Drinking Water & Recreational Waters Compliance Section
Files
Abstract
In 1993, a Cryptosporidium outbreak in Milwaukee, WI affected over 400,000 people. The local water plant’s filtered water turbidity was high, but actually below the regulatory limit. As a result of the outbreak, over 4,400 people were hospitalized and 69 people died. The Milwaukee outbreak highlighted the importance of filtration. Filtration serves as the last physical barrier against pathogens in a conventional surface water treatment plant. Filtration is the fundamental system in a water treatment process that removes suspended solids, including microorganisms such as Cryptosporidium oocysts and Giardia cysts. Protozoa such as Giardia cysts and Cryptosporidium oocysts have been one of the primary focuses of evolving drinking water regulations. Cryptosporidium, in particular, is resistant to standard disinfection practices such as chlorination. The phrase “shoot a little chlorine to it” simply will not do the trick when it comes to Cryptosporidium. Optimization beyond the current regulatory limit with respect to filtration has been one technique proposed for improving oocyst removal. Various studies have found that providing a consistent filtration process with effluent turbidities below 0.1 NTU is an important step in process optimization. In fact, studies have shown that by decreasing the filtered water from 0.3 NTU to 0.1 NTU, an additional log removal of cysts can be achieved. That means ten times (10x) more cysts can be removed by improving performance by 0.2 NTU! A variety of techniques in filter optimization have been implemented including monitoring with particle counters and dosing with filter aid polymer. Two techniques which take advantage of more traditional filter tests are filter surveillance and filter assessment programs.
Issue Date
2003-12
Keywords
Water filters--South Carolina--Handbooks, manuals, etc, Water--Purification--Equipment and supplies
Type
Manual
Rights
Records, documents, and information made available by the agencies of the South Carolina state government or its subdivisions are made accessible through the South Carolina State Library Depository and are protected under U.S. Copyright law (Title 17, U.S.C.) and South Carolina state law (Title 30 and 60, S.C.C.L.). Distribution rights are determined by the agency or author and users should contact the aforementioned for more information.
Digitization Specifications
This South Carolina State Document was either saved from a document available publicly online in PDF format or converted to PDF using Adobe Acrobat DC.