Water/Wastewater Laboratory Calculations - Basic Mathematics for Water and Wastewater Operators - page 242

Water

Total Solids

= Fixed solids (inorganics)

= Volatile solids (organics)

FIGURE 16.3 Composition of wastewater.

Note: When the term biosolids is used, it may be understood to mean a semiliquid
mass composed of solids and water. The term solids , however, is used to mean dry
solids after the evaporation of water.

The percent total solids and percent volatile solids are calculated as follows:

Totalsolidsweight
Biosolids

%Total solids = ×100 (16.14)

sample weight

Volatilesolidsweight
Tot

%Volatile solids = ×100 (16.15)

al solidsweight

■ Example 16.17
Problem: Given the information below, determine the percent solids in the sample
and the percent of volatile solids in the biosolids sample.

Biosolids Sample After Drying After Burning (Ash)

Weight of sample and dish 73.43 g 24.88 22.98

Weight of dish (tare weight) 22.28 g 22.28 22.28

Solution: To calculate the percent total solids, the grams total solids (solids after
drying) and grams biosolids sample must be determined:

Total solids

24.88 g (weight of total solids and dish)
-22.28 g (weight of dish)

2.60 g (weight of total solids)