Full Description

The North Clackamas County Water Commission (NCCWC) owns and operates a 10MGD slow sand filter plant, constructed in 1998, and services a rapidly growingcommunity southeast of Portland, Oregon. The Oak Lodge Water District (OLWD) andthe Sunrise Water Authority (SWA) are the direct customers/owners of the NCCWC.Raw water for the plant is drawn from the Clackamas River, a normally low-turbiditysupply, subject to seasonal and periodic water quality challenges, including highturbidities, taste and odor (T the existing plant wasat full capacity and additional water was needed as quickly as possible to meet demands.In addition, SWA was looking for a treatment technology capable of operatingthroughout the year without shutdowns due to raw water quality. Since the slow sandplant has been operational, periodic shutdowns have been required when the river'sturbidity exceeds 10 NTU. Though schedule was a key driving force in the plant expansion, SWA regarded waterquality as high, if not a higher priority than schedule. For this reason, membranefiltration was recommended for plant expansion. To address the potential raw waterquality challenges, the membrane filtration plant was designed to allow for periodicaddition of powdered activated carbon (PAC) and/or alum or ACH (aluminumchlorohydrate). The expanded facility will be a unique combination of new and old,combining the earliest filtration technology - slow sand filtration, with the latest watertreatment technology - membrane filtration, operating in parallel. Through a fast-tracked and innovative process focused on partnership and cooperation,the project team was able to select the membrane supplier, complete the design, select the general contractor and break ground on construction in 10 months. A more traditional andconservative approach would likely have taken 18 months, or longer. This paper presentsdetailed descriptions of the following aspects of this project:to pilot or not to pilot lessons learned from the membrane procurement RFPprocess;pilot study results, and impacts on design; and,final design criteria and membrane building layout. Includes table, figures.

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Edition: Vol. - No. Published: 03/01/2005 Number of Pages: 6File Size: 1 file , 1.2 MB