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Biosolids Sampling Guide

The Wastewater Treatment Plant Operators Guide to Biosolids Sampling Plans

Residuals are the organic, nutrient-rich residues removed from wastewater during the treatment process. If these residuals are of sufficient quality, they may be applied to farmland as a fertilizer. Such residuals are often called biosolids.

Before biosolids can properly be land applied, samples must be analyzed in a laboratory to determine if they comply with state and federal land application regulations. If decisions on compliance are to be accurate and credible, it is vital that those doing the sampling are doing it the right way.

In 2006, NEIWPCC published The Wastewater Treatment Plant Operators Guide to Biosolids Sampling Plans. The manual covers proper sample collection, handling, and documentation procedures; laboratory and detection limit considerations; and data reporting.

The guide also emphasizes the benefits of pre-planning for sampling events including the development of a comprehensive sampling plan, and offers guidelines for the solicitation of laboratory services. All of this should be particularly helpful for staff at small- to medium-sized treatment plants, who often aren’t experienced at sampling residuals and may be unfamiliar with working with laboratories.

This publication was the product of a thorough development process that included extensive review by peers and technical experts.

PLEASE NOTE: We are aware that the holding time for mercury is incorrectly listed as 6 months in the Federal Sludge Analytical Requirements table in Appendix B and D of the printed edition. The correct holding time for mercury is 28 days. We have revised the downloadable edition to reflect the proper mercury hold time.

To order a hard-copy, download an order form. For more information, contact Jennifer Lichtensteiger of NEIWPCC at