Determination of volatile matter reduction in sludge is complicated because of the changes occurring during sludge digestion.
The calculation used to determine percent volatile matter (VM) reduction is
[%VMin – %VMout] X100
% of Volatile Matter Reduction (VM) = ——————————-
[%VMin – (%VMin X % VMout)]
Using the digester data provided below, Determine the percent volatile matter reduction for the digester.
Raw Sludge Volatile Matter = 72%; Digested Sludge Volatile Matter = 51%
According to the afore said formula, % VM (reduction) =59%