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Recent advances in technology, particularly with regard to the successful use of membranes for wastewater treatment applications, have provided the industry with many possible process combinations that did not exist just a few years ago. This paper focuses on the evaluation and subsequent pilot testing of a new membrane-based process for the reclamation of municipal wastewater. The Loudoun County Sanitation Authority (LCSA) provides water and sewer services to a rapidly growing population in northern Virginia. In response to a rapid growth in flows from the service area, LCSA currently is planning for the construction of the Broad Run Water Reclamation Facility (WRF). The facility will be required to provide extremely high levels of treatment for the removal for nutrients, organics, suspended solids, turbidity, and coliforms to protect aquatic life in the watershed and to protect downstream drinking water sources. Initially, the facility will treat between 6 and 12 million-gallons-per-day (mgd). Ultimately, the treatment capacity of the facility may exceed 30 mgd. Both conventional and membrane-based advanced waste treatment (AWT) processes were evaluated for the proposed Broad Run WRF. The following four AWT processes were evaluated for the project: high-lime post-treatment; multi-point alum addition; post-secondary microfiltration; and, membrane bioreactor (MBR) with immersed membranes. The membrane bioreactor process was chosen as the recommended process. MBRs were shown to be cost competitive with the other alternatives, will use less site area, have fewer unit processes, provide a pathogen barrier, and can produce effluent of excellent quality. The paper summarizes the objectives of the project, describes the process evaluation, provides details of the pilot design, and presents results of the subsequent pilot testing for the project. The pilot test showed that the MBR process could be configured to meet all treatment objectives for biological nutrient removal, removal of organics, and protection from pathogens. Implications for design of the final facilities are also discussed. Includes tables, figures.

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Edition: Vol. - No. Published: 01/01/2002 Number of Pages: 19File Size: 1 file , 240 KB