1. Total Solids PresentationBy
Douglas Rittmann, Ph.D., P.E.
Water/Wastewater Consultant
Presented to
UTEP Lab Class On
February 28, 2006

2. Total Solids 1. General Discussion
A well mixed sample is evaporated in a weighed dish and
dried to constant weight in an oven at 103O to 105O C.
Interferences – Hygroscopic minerals require prolonged drying
& rapid drying. Disperse oil and grease and floating material.

3. Total Solids 2. Apparatus a. Evaporating Dishes – 100 ml capacity
1. Porcelain, 90 mm diameter
2. Platinum dishes – generally satisfactory for all purposes
3. High Silica Glass
b. Muffle Furnace for operation at 550OC
c. Steam Bath
d. Dessicator – dessicant with color indicator
e. Drying oven for operation at 103 – 105 degrees C.
f. Analytical Balance capable of weighing to 0.1mg
g. Wide Bore Pipets

4. Total Solids 3. Procedure
If volatile solids to be determined, ignite dish at 550OC for
1 hour or if only total solids to be determined, heat dish
at OC for 1 hr. Store and cool dish in dessicator
until needed. Weigh before use.
Sample analysis:
*Choose sample volume = residue between 2.5 & 200 mg.
*Stir sample volume with magnetic stirrer.
*Pipet sample volume from center of container
*Dry sample at degrees C. for at least 1 hour
*Cool dish in dessicator and weigh after constant weight is obtained
*Be alert to weight change due to air exposure.
*Analyze at least 10% of samples in duplicate.
*Duplicate samples should agree within 5% of average weight.

5. Total Solids 4. Calculation Mg total solids, L = (A – B) X 1000
sample volume, ml
Where A = weight of dried residue + dish, mg, and
B = weight of dish, mg.
5. Precision
Single laboratory duplicate analyses of 41 samples of
Water and Wastewater samples were made with a standard
deviation of differences of 6.0 mg/L

6. Questions?