Method SM 2540E

Fixed and Volatile Solids Ignited at 550°C

This method is for the determination of fixed and volatile solids ignited at 550°C.  The residue that is ignited is obtained from solid matter suspended in drinking water, surface water, saline water as well as domestic and international wastewater using Standard Methods B, C, or D.  The residue is ignited to constant weight at 550°C. The remaining solids represent the fixed total, dissolved, or suspended solids while the weight lost on ignition is the volatile solids.

This determination is useful in control of wastewater treatment plant operation because it offers a rough approximation of the amount of organic matter present in the solid fraction of wastewater, activated sludge, and industrial wastes. ‘‘Fixed solids’’ is the term applied to the residue of total, suspended, or dissolved solids after heating to dryness for a specified time at a specified temperature. The weight loss on ignition is called ‘‘volatile solids.’’

The range for the method is up to 20,000 mg/L.

(Standard Methods)


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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   Preferably do not hold samples more than 24 hours. In no case hold sample more than 7 days. Bring samples to room temperature before analysis.
Preservatives:   Refrigerate samples at 4°C from sample collection to analysis.
Required Preps:   Use resistant-glass or plastic bottles, provided that the material in suspension does not adhere to container walls.
Collection Method:   Grab sampling
Analytical Methodology:   Gravimetric

Analyte List*

Analyte Formula CAS Number Detection Limit
Fixed Solids
Volatile Solids

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.