How are volatile solids (VS) measured in sludge analysis?

The measurement of volatile solids (VS) in sludge analysis is conducted by heating a sample to a specific temperature to burn off the organic material. This process involves drying the sample first and then igniting it in a high-temperature furnace, usually at around 550 degrees Celsius. The difference in weight before and after combustion indicates the amount of volatile solids present in the sample, with the loss being attributed to the burn-off of organic materials. This method allows for an accurate assessment of the organic fraction of the solids present in sludge, which is important for various applications in wastewater treatment and management.

The other methods mentioned do not accurately measure volatile solids; weighing the wet sample does not account for the organic content, measuring chemical oxygen demand assesses the oxygen required to oxidize organic matter but does not quantify solids directly, and a biological assay evaluates the biological activity rather than quantifying solids.