Question

Data taken on solids contents of a water sample are given below. All sample were 500 mL aliquots

Residue in evaporating disk after 4 h at 105 °C = 50 mg

Residue in evaporating disk after 4h at 550 °C = 30 mg

Residue on filter after drying at 105 °C = 10 mg

Net ash content (tare subtracted) after drying residue at 550 °C = 5 mg

Determine the concentrations of total solids, total volatile solids, volatile dissolved solids and volatile suspended solids.

Answer 1

For all, use V = 50 mL

Note that there are 4 species:

- Total solids... will be the addition of all solids

- Volatile solids = those not present in ash, yet volatil material

- suspended solids = willl be filtered

- volatile suspendedsolid concentration = use ash content = 11 mg per 50 mL = 0.22 mg/mL

For suspended + volatile solids use the GFC residues = 12 mg per 50 = 0.24 mg/mL

for volatile solids = 36 mg / 50 = 0.72 mg/mL

for volatile suspended solids = 34/50 = 0.68 mg/mL