Pure water consists of h2o only, but in nature there is always other matter present in the water.
This matter may be dissolved gases, liquids and solids, some of which dissociates into ions.
It normally contains undissolved suspended matter. Some of the matter may be organic in nature and others, inorganic in nature. The sum of all matter other than water, dissolved or undissolved is referred to as TOTAL SOLIDS. Solid fractions can be classified into the following types
a. Settable solids (SETS)
b. Suspended solids (SS/TSS) – Comprises of insoluble matter, and contribute to turbidity
c. Dissolved Solids (DS/TDS) – Comprises of dissolved matter, and contributes to conductivity
d. Total Solids (TS)
e. Volatile Solids
f. Fixed Solids
