What is the difference between a filter profile and a filter self-assessment?

A filter profile is only one required element of an individual filter self-assessment.  A filter profile is a graphical representation of individual filter performance over time.

The graphical profile is based on continuous turbidity measurements or total particle counts versus time for an entire filter run, from startup to backwash inclusively.  That includes assessment of filter performance while another filter is being backwashed.

The purpose of the filter profile is to identify transient events that cause spikes but are not truly related to turbidity increases.  Spikes in turbidity may be caused by trigger events such as pump changes and backwash cycles.  The run length during the filter profile should be representative of typical plant filter runs.  The profile should include an explanation of the cause of any filter performance spikes during the run. 

Filter self-assessments include filter profiles as part of the assessment but also look more intensively at the other aspects of media, such as general media conditions, hydraulic loading conditions, media design and actual conditions. 

The filter profile and the filter self-assessment are to be done by plant personnel, either on their own or in conjunction with technical assitance staff in the Drinking Water Branch, phone 502-564-3410.  If the water system relies on a consultant to do the filter profile or filter assessment, plant personnel must be actively involved.  Otherwise, the purpose of understanding what may be wrong with that particular filter is defeated.

For technical publications on filter assessments, refer to EPA's Guidance Manual for IESWTR Turbidity Provisions (EPA 815-R-99-010, April 1999, 216 pages).  To obtain copies of this publication, go to EPA's Publication Index.  Do a simple search for document number 815R99010, then follow the instructions to order the document.  Or, download the publication from EPA’s Web page on “Technical Guidance.”  Chapter 5 of this manual provides detailed guidance on conducting a filter self-assessment, including filter profiles, assessing hydraulic loading conditions and assessing support media. 

Susumu Kawamura's book titled "Integrated Design of Water Treatment Facilities" (ISBN 0471350931, September 2000) offers comprehensive coverage of water treatment processes, including filter self-assessment.  This book is especially geared toward professional engineers and college students who seek emphasis on the practical rather than principle, method rather than methodology.

Refer to the Microsoft® PowerPoint® presentations below for more detailed information on filtration.  If you do not have PowerPoint, a free PowerPoint viewer is available from Microsoft.

Filtration, Part 1.  The Fundamentals.  Presentation by Tim Wolfe, March 2003.  Topics include history of filtration, particle removal, unit filter-run volume, backwashing and tomorrow's filter challenges.

Filtration, Part 2.  Methods of Filter Coring.  Presentation by Tim Wolfe, March 2003.  Topics include filter coring methods and analyzing results of filter coring.