Guidelines for Grit Sampling and Characterization

Water Environment Federation (WEF) Task Force. WEF Press, 601 Wythe Street, Alexandria, VA 22314-1994, USA. 2016, 105 pp., $125, softcover. ISBN: 978-1-57278-330-0.

This special publicationis a typical example of how a group of water professionals unselfishly compile their knowledge and experience together for dissemination to their colleagues. 

Thirty-five environmental engineers and scientists formed a Grit Sampling and Characterization Task Force and jointly prepared this special publication. It was conducted under the leadership of task force chair Kendra Sveum and vice chair Lucas Botero under the direction of the Municipal Design Subcommittee of the Technical Practice Committee in which 30 more water professionals helped review the manuscript before its publication. The work of these  volunteers is especially noteworthy because grit sampling and characterization are small, narrow subjects, which are normally ignored by engineers and managers.

In this publication, the currently used grit sampling and characterization methods are introduced and reviewed, and modeling and expectations are discussed.

The book consists of four chapters. Chapter 1 introduces the grit characteristics; historical and current definitions of wastewater solids; and the roles of service utilities, consulting engineers, testing companies, and grit removal equipment manufacturers. Chapter 2 describes the various methods and equipment used for obtaining a grit sample, such as bucket sampling, single-point pumped sampling, multiple-port vertical sampling, vertically integrated slotted sampling, manifold pumped sampling, siphon cross-channel sampling, and complete influent mixing/sampling. Chapter 3 covers various methods for pretreatment, solids determination, settling velocity determination, grit particle size and shape analysis, and calculations. Chapter 4 focuses on international practices, design/operational expectations, grit characterization modeling, and future expectations. 

This book is meant for utility owners, consulting engineers, and grit equipment manufacturers who want to understand the implications and selection of a grit sampling and characterization method for proper grit chamber design and grit removal optimization. The book is not intended to address various types of grit removal equipment and grit slurry processing equipment, evaluate the equipment performance, or discuss the grit removal and slurry processing costs.

For further improvement of this excellent publication, practical examples should be added in Chapter 3, Section 5 “Calculations,” so licensed wastewater operators with a high school education can be included as intended readers. Normally, operators at a resource recovery facility will operate the grit chambers and take grit samples for analysis.

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Lawrence K. Wang and Mu-Hao Sung Wang are a professor and consultant, respectively, at the Lenox Institute of Technology (Newtonville, N.Y.).

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