THE USE OF ALTERNATE MICROBIOLOGICAL INDICATORS OF WATER TREATMENT PLANT PERFORMANCE
Previous studies have shown that current microbial indicators used to evaluate the performance of water treatment plants cannot be correlated with the removal of certain pathogens such as Giardia, Cryptosporidium and enteric viruses. To meet water quality standards established by federal agencies, various methods have been developed in order to assess existing treatment facilities for their capacity in treating drinking water and to obtain the required treated water quality. As part of an investigation conducted in Puerto Rico to improve the quality of the drinking water, a pilot study approach was adopted and involved the installation of a pilot plant. The pilot plant was installed in the largest Caribbean water treatment plant, the Sergio Cuevas Water Treatment Plant located in San Juan, Puerto Rico (100 MGD). The treatment units found include a coagulation-flocculation- sedimentation unit, dual-media filters, micro-filtration units, ozonation contact columns as well as a biological filtration unit. The clarification unit can be operated under two different flocculation and settling modes: typical conventional flocculation with lamellar settling and micro-sand ballasted flocculation with lamellar settling. Two identical filtration skids, each equipped with two 8-inch filtration columns, are found at the pilot plant site. One skid is used for conventional mono or dual-media filtration and the another skid is used for biological filtration. The micro-filtration units consist of two different membrane technologies found on the market: pressure vessels and submerged membranes. The ozonation unit consists of an ozone generator, two contact columns connected in series for ozone transfer. Included in the study is the evaluation of the physical bacterial removal through the different treatment steps described. To do so, Bacillus subtilis spores and coliphages are being used as alternate indicators of treatment plant performance because they may more closely mimic the removal of enteric pathogens during treatment processes. The procedure consists of injecting of Bacillus subtilis spores, and coliphages and to evaluate the percent removal at each treatment stage. Molecular fingerprinting is being carried out to track the seed bacteria through the system. Preliminary results have shown a removal range of 76.6-99.9 percent of Bacillus subtilis spores depending on a type of treatment. The ease as well as the apparent specificity of detection of the aerobic Bacillus spores indicate that these microorganisms may be an excellent alternative to currently used indicators of water treatment efficiency.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: 2001-01-01
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.
WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Learn about the many other WEF member benefits and join today
- Ingenta Connect is not responsible for the content or availability of external websites