Sewage Sludge Analytical Methods and Sampling Procedures
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Analytical Methods
40 CFR Part 503, promulgated in 1993, identified allowable methods to be used for four categories of pathogens, inorganic pollutants, and some physical and aggregate properties of sewage sludge. The list of allowable methods was updated in 2007 when EPA promulgated an update to 40 CFR Part 503. The EPA also recommends certain methods for unregulated pollutants in sewage sludge.
Regulated Pollutants Found in Sewage Sludge
|
Pollutant |
Methods Source |
Methods Number |
Reference |
|---|---|---|---|
| Enteric Viruses | “Standard Practice for Recovery of Viruses From Wastewater Sludges”, 1992 Annual Book of ASTM Standards: Section 11 - Water and Environmental Technology, ASTM, 1916 Race Street, Philadelphia, PA 19103-1187. | ASTM D 4994-89 | Method |
| Fecal Coliform | “Standard Methods for the Examination of Water and Wastewater”, 18th Edition, 1992, American Public Health Association, 1015 15th Street, NW, Washington, DC 20005. | Part 9221 E | 9221 E (1992) is no longer available. 9221 E (2017) |
| “Standard Methods for the Examination of Water and Wastewater”, 18th Edition, 1992, American Public Health Association, 1015 15th Street, NW, Washington, DC 20005. | Part 9222 D | 9222 D (1992) is no longer available. 9222 D (2017) | |
| 40 CFR Part 136, Guidelines Establishing Test Procedures for the Analysis of Pollutants | EPA Method 1680 | Method | |
| 40 CFR Part 136, Guidelines Establishing Test Procedures for the Analysis of Pollutants | EPA Method 1681 | Method | |
| Helminth Ova | Yanko, W.A., “Occurrence of Pathogens in Distribution and Marketing Municipal Sludges”, EPA 600/1-87-014, 1987. National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161 (PB 88-154273/AS). | Yanko, 1987 | Method |
| Salmonella sp. bacteria | “Standard Methods for the Examination of Water and Wastewater”, 18th Edition, 1992, American Public Health Association, 1015 15th Street, NW, Washington, DC 20005 |
Part 9260 D |
9260 D (1992) is no longer available. 9260 D (2017) |
| Kenner, B.A. and H.P. Clark, “Detection and enumeration of Salmonella and Pseudomonas aeruginosa”, Journal of the Water Pollution Control Federation, Vol. 46, No. 9, September 1974, pp. 2163-2171. Water Environment Federation, 601 Wythe Street, Alexandria, Virginia 22314. | Kenner and Clark, 1974 | Method | |
| 40 CFR Part 136, Guidelines Establishing Test Procedures for the Analysis of Pollutants | EPA Method 1682 | Method | |
| Specific oxygen uptake rate | “Standard Methods for the Examination of Water and Wastewater”, 18th Edition, 1992, American Public Health Association, 1015 15th Street, NW, Washington, DC 20005. | Part 2710 B | 2710 B (1992) is no longer available. 2710 B (2017) |
| Total, fixed, and volatile solids | “Standard Methods for the Examination of Water and Wastewater”, 18th Edition, 1992, American Public Health Association, 1015 15th Street, NW, Washington, DC 20005. | Part 2540 G | 2540 G (1992) is no longer available. 2540 G (2017) |
| Inorganic pollutants | “Test Methods for Evaluating Solid Waste, Physical/Chemical Methods”, EPA Publication SW-846, Second Edition (1982) with Updates I (April 1984) and II (April 1985) and Third Edition (November 1986) with Revision I (December 1987). Second Edition and Updates I and II are available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 (PB-87-120-291). Third Edition and Revision I are available from Superintendent of Documents, Government Printing Office, 941 North Capitol Street, NE, Washington, DC 20002 (Document Number 955-001-00000-1). | SW-846 6010 | SW-846 6010 is no longer available. SW-846 6010D |
| SW-846 7061 | SW-846 7061 is no longer available. SW-846 7061A | ||
| SW-846 7000A | SW-846 7000A is no longer available. SW-846 7000B | ||
| SW-846 7470 | SW-846 7470 is no longer available. SW-846 7470A | ||
| SW-846 7471 | SW-846 7471 is no longer available. SW-846 7471B |
Nitrogen
Currently there are no required methods in Part 503 for analyzing nitrogen in sewage sludge. In the absence of a requirement, the operator should ensure that the method selected is appropriate for the sewage sludge matrix as many methods are written for analysis of aqueous samples. A sample preparation may be appropriate for solid or semi-solid samples. States, Tribes, or territories may have required or approved methods for nitrogen that the lab should check with.
Per- and Polyfluoroalkyl Substances (PFAS)
The EPA recommends using EPA Method 1633 to measure 40 PFAS analytes, including PFOA and PFOS, in sewage sludge. EPA Method 1633 finished multi-lab validation and was finalized in January 2024. The EPA signed a new proposed Method Update Rule (MUR), MUR 22, on December 6, 2024. This action proposed to promulgate EPA Method 1633, among other methods, into 40 CFR Part 136.
Though not currently a regulated pollutant in 40 CFR Part 503, in December 2022, the EPA released a memorandum recommending pretreatment best management practices to reduce PFAS sources, along with quarterly monitoring of influent, effluent, and sewage sludge using EPA Method 1633.
- Read the EPA memo: Addressing PFAS Discharges in NPDES Permits and Through the Pretreatment Program and Monitoring Programs
Studies and Guidance Related to Biosolids Methods and Sampling
The POTW Sludge Sampling and Analysis Guidance Document was developed to provide guidance on implementing a sampling and analysis program, information gathering and permit compliance to POTW operators, engineers, managers, chemists and permit writers.
The purpose of the following study was to determine whether biosolids samples can be held for 24 hours without significant change in bacterial densities for these analytes.
The following document is not regulatory in nature and is only intended to serve as a guide to pathogen and vector attraction reduction, including detailed information on sampling procedures and methods.