9.2 - Determination of Total Suspended and Total Dissolved Solids in p.p.m.

Materials and Apparatus Required

Chemicals

• Water sample (e.g., river or lake water)
• Anhydrous sodium carbonate (for TDS test)

Apparatus

• Filter paper (small-pore)
• Retort stand and clamp
• Filter funnel
• Beakers (250 cm³ and 1000 cm³)
• Drying oven
• Balance (precision to 0.01 g)
• Graduated cylinder (100 cm³)
• Evaporating dish
• Bunsen burner or hot plate

Safety Precautions

• Wear safety glasses throughout the experiment.
• Avoid contact with potentially toxic or polluted water samples.
• Handle hot equipment (oven, hot plate) with care to avoid burns.

Method

Determination of Total Suspended Solids (TSS)

1. Weigh the filter paper: Record the mass of a clean, dry piece of filter paper using a balance.
2. Filter the water sample: Pass 1 litre of the water sample through the filter paper set in a funnel.
3. Dry the filter paper: Place the filter paper in an oven set at approximately 105°C and allow it to dry overnight.
4. Weigh the dried filter paper: After drying, weigh the filter paper again and calculate the increase in mass.
5. Calculate the TSS: The mass of the suspended solids in the water is the difference in the mass of the filter paper before and after filtration.
6. The TSS concentration is calculated as mg/l (ppm).

Determination of Total Dissolved Solids (TDS)

1. Weigh the evaporating dish: Record the mass of a clean, dry evaporating dish.
2. Add the filtered water: Transfer 100 cm³ of the filtered water from the previous experiment into the dish.
3. Evaporate the water: Place the dish on a hot plate or in an oven set at 105°C until all water has evaporated and the solids remain.
4. Weigh the dish: After cooling, weigh the dish again to determine the mass of the dissolved solids.
5. Calculate the TDS: The difference in mass between the empty dish and the dish with dissolved solids gives the TDS in mg/l (ppm).

Results

Table of Results for Total Suspended Solids

Measurement	Value
Mass of dry filter paper before use	1.42 g
Mass of dried filter paper after use	1.60 g
Mass of suspended solids	0.18 g
Volume of water sample	1 litre
Total suspended solids (TSS)	180 ppm

Table of Results for Total Dissolved Solids

Measurement	Value
Mass of clean evaporating dish	99.05 g
Mass of dish after evaporation	100.54 g
Mass of dissolved solids	1.49 g
Volume of water sample	100 cm³
Total dissolved solids (TDS)	14,900 ppm

Example Questions with Answers