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The Water Environment Research Foundation (WERF) presented a conference workshop at WEFTEC 2003 in Los Angeles, CA entitled “Designing a Better Primary Clarifier” (WERF, 2003). This workshop presented preliminary results for WERF project 00-CTS- 2 entitled “Determine the Effect of Individual Wastewater Characteristics and Variances on Primary Clarifier Performance”, also known as the Primary Clarifier Performance Project (PCPP). WERF has not yet released a final report for this project (June, 2004). This paper presents a review of technical aspects of the WERF PCPP providing a comparison to data in the literature, including:

Project Foundations

Surface Overflow Rate Impact on Clarifier Performance

Fundamental Equations

Dispersed Suspended Solids Testing

Settling Velocity Distribution Testing

The paper concludes that the WERF PCPP would benefit from rigorous consideration of the fundamentals of primary clarifiers consistent with Hazen (1904). Engineers designing primary clarifiers should exercise caution when applying WERF PCPP techniques and apply an in-depth evaluation before utilizing the data.

The application of numerical solutions, ideally suited to primary clarification, combined with image analysis techniques presently under development and an improved understanding of flocculation should lead to an improved understanding of primary clarifiers to improve on the results of the WERF PCPP.

Document Type: Research Article


Publication date: January 1, 2004

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  • 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 These proceedings are not peer reviewed.

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