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The Tecumseh Water Treatment Plant (WTP), constructed in 1958, is a conventional treatmentplant that treats raw water from the Peche Isle Channel in Lake St. Clair near the mouth of theDetroit River. The design capacity of the plant is 27.3 MLD. The treatment train includescoagulation, upflow clarification and granular media filtration. The plant also occasionally usespowdered activated carbon (PAC) to control trace levels of atrazine. In addition, the plantcurrently discharges its filter backwash to the lake and is therefore required to limit the totalsuspended solids concentration in its waste discharge to the lake to below 25 mg/L. The rawwater is characterized by high turbidity, ranging from less than 1 NTU to greater than 100 NTU,low TOC, with occasional high color and high coliform counts. Lake St. Clair is a popular summervacation spot and the surrounding water body is used for a number of recreational water activitiesduring the warmer weather which can result in high fecal coliform concentrations in the sourcewater.Due to both the age of the facility, and expected demand increases in the future, the WTP is inneed of major upgrades. For instance, the existing upflow solids contact clarifier does notconsistently perform well during high turbidity events and can limit the plant capacity to 19.5 MLD.Plant upgrades are also necessary to meet the anticipated disinfection requirements of newregulations. The Town considered several alternatives to improve its finished water quality whilemeeting anticipated higher demand for water. Implementation of microfiltration (MF)/ultrafiltration (UF) membrane filtrationoffers several advantages over conventional treatment such as increased finished water quality,smaller foot print, ease of expansion and high-level of automation. Therefore the Town wanted toimplement membrane filtration to meet all of its objectives. Due to space constraints dictated bylimited land availability and to limit the financial burden to its consumers, the Town investigatedthe possibility of directly treating the raw water with membrane filtration. To address theoccasional color and taste occurrences, several of the existing conventional filters would bemaintained downstream of the membrane filtration and be used as granular activated carbonbeds. The existing clarifier would be modified to treat backwash water from the membrane filtersto meet the allowable suspended solids concentration limit upon discharge.This paper presents the approach the Town of Tecumseh had taken to implement membranefiltration into its existing plant, in particular the results of the pilot study that was conducted toinvestigate the feasibility of membrane filtration in treating raw water without any pretreatmentand the membrane procurement process based on pilot results and their incorporation into theexisting plant. Includes tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 7File Size: 1 file , 320 KB