Tests to find Total solids Suspended & Dissolved solid in water

The chemical analysis of water includes various parameters to be analysed. These parameters include totally analysing all the solids present in the water. Total solids [TS] in the water includes all the solid particles that are present in the water which might be visible or invisible to the naked eye. Classification of solids in water includes total solids, total suspended solids, and total dissolved solids. The process of measuring these solids is described here.

Solids are measured by gravimetry method. Suspended particles in the water includes the particles which are not dissolved but will be floating in the water. The suspended particles in the water can be separated by the process of filtration. The Total suspended solids [TSS] can be further classified as particles visible to the naked eyes (macro-particles), and invisible to the naked eyes (micro-particles).

Dissolved particles involved those particles which have been chemically mixed throughout the water. the dissolved particles cannot be separated by physical process like filtration from the water. Total dissolved solids [TDS] includes the dissolved solids plus the colloidal solids.

Total solid can be found by evaporating a sample of water and weighing the dry residue left. Where as the suspended solids can be found by filtering water sample through whatman filter paper.

total solids, suspended solids, dissolved solids, in water
total solids, suspended solids, dissolved solids, in water

Test to find Total solids :

Aim : To find the total solids present in the water.

Apparatus : 

  1. Empty container (gooch crucible)
  2. Oven for drying
  3. Weigh balance etc.,

Formulae :

Total Solids = ( W2 – W1) / V  ; mg/l

Procedure :

  • Take an Empty container of initial weight = W1
  • Add known volume of water in that container,  and let that volume be = V
  • Keep the container for oven drying at 103 degree to 104 degree Celsius for 4 to 5 hours
  • After oven drying,  let the weight of the container measure be = W2

Result :

The total solids in the water is found to be = _____ mg/l ; 

Based on nature of solids total solids includes, volatile solids (VS) and non-volatile solids (NVS);

PROBLEMS ON TOTAL SOLIDS:

A 50 ml of water sample is drawn on to empty container, whose initial weight found to be 92.468 grams. After oven drying water sample for 104° Celsius for 4 hours, final weight is found to be 92.492 grams. Find the total solids in the water sample tested.

Solution :-

Empty container’s initial weight = W1 = 92.468 g;

Weight of the container after oven drying = W2 = 92.492 g;

Volume of water = 50 ml = 50 × 10¯³ litres

Total Solids = ( W2 – W1) / V = ( ( 92.492 – 92.468) / 50 × 10¯³ ) × 1000 mg;

Total Solids = 480 mg/l;

Test to find Total Suspended Solids :

Aim : To find the total suspended solids present in the water.

Apparatus : 

  1. Empty container (gooch crucible)
  2. Filter papper
  3. Weigh balance etc.,

Formulae :

Total Suspende Solids = ( W2 – W1) / V  ; mg/l

Procedure :

  • Take a filter paper of pore size lesser than 1/1000mm and its weight be = W1 ;
  • Now pass a known volume of water = “V” ;
  • Keep filter paper for 104° Celsius for 4 hours;
  • Now that the weight of the filter paper be = W2 ;
  • The W2  weight of the filter paper consists of the dry mass of filter paper and mass of total suspended solids;

Result :

The total suspended solids in the water is found to be = _____ mg/l ;

PROBLEMS ON TOTAL SUSPENDED SOLIDS :

A 100 cc of water sample is passed through a papper whose initial weight was found to be 1.238g after oven drying the final weight measured to be 1.262g. Find total suspended solids in mg/l & μg/l;

Solution :-

100 cc = 100 cm³ = 0.1 litres

Total Suspende Solids = ( W2 – W1) / V 

= ( ( (1.262 – 1.238) × 10³ mg) / 0.1 )  = 240 mg/l

= 240 × 10³ μg/l = 240000 μg/l;

Test to find Total Dissolved Solids :

Total dissolved solids includes the dissolved solids plus the colloidal solids.

Aim : To find the total dissolved solids present in the water.

Apparatus : 

  1. Empty container (gooch crucible)
  2. oven for drying
  3. Weigh balance etc.,

Formulae :

Total Suspende Solids = ( W2 – W1) / V  ; mg/l

Procedure :

  • The initial weight of the empty dry container be = W1
  • A known volume of water is kept in the container, which is already passed through a filter paper whose pore size is smaller than the smallest size of the suspended particle. Let this volume be = V
  • After oven drying Final weight of the container will be = W2

Formulae :

Total dissolved Solids = ( W2 – W1) / Volume of filtered water added;

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