Top 10 viva/interview question on total solids present in water

Solids can be classified as either filterable or non filterable. Filterable solids may either be settleable or non settleable. Solids can also be classified as organic or inorganic.

The term “solids” is generally used when referring to any material suspended or dissolved in water or wastewater that can be physically isolated either through filtration or through evaporation.

Total solids present in water

Total Solids is the term applied to the material residue left in the vessel after evaporation of a sample and its subsequent drying in an oven at a defined temperature. Measurement of Solids can be made in different water samples (industrial, domestic and drinking water) and it is defined as residue upon evaporation of free water.

Thus, Total solids are nothing but summation of total dissolved solids and
total suspended solids.

Here are top 10 viva questions on the topic total solids present in water which are generally asked.

1. After Evaporation, the evaporating dishes needs to be.

a) weighed immediately
b) kept in air for cooling to room temperature
c) cooled to room temperature in a desiccator
d) cooled to a temperature less that 25ºC

2. Total Solids are referred to materials left after evaporation.

a) True
b) False

3. A sample was stored @ 4 ºC for 4 days. During the analysis, the temperature of the sample should be

a) maintained at 4 ºC
b) brought to room temperature
c) below room temperature
d) brought above room temperature by adding boiled distilled water

4. The determination of total solids in wastewater gives an idea about

a) the foulness of the sewage
b) pH of the sewage
c) temperature of the sewage
d) colour of the sewage

5. The evaporating dishes needs to be cleaned and dried at _______ to remove the existing organic content.

a) 100° C
b) 250° C
c) 450° C
d) 550° C

6. Sewage contains about 99% of _____.

a) water
b) solids
c) clay
d) microbes

7. Interference in the determination of total solids is due to ______.

a) Oil and Grease
b) Large water sample
c) Dissolved salts
d) Suspended salts

8. For analysis of total solids the sample used should be

a) homogeneous sample
b) supernatant of the sample
c) settled sample
d) clear sample

9. The sewage contain

a) suspended and dissolved solids.
b) no solids
c) only dissolved solids
d) only suspended solids

10. The major dissolved substances in natural water are comprised of

a) iron, manganese, silica and nitrate
b) calcium, magnesium, sodium, bicarbonate, sulfate and chloride
c) all anions
d) all cations

ANSWER KEY:
1) c
2) True
3) b
4) a
5) d
6) a
7) a
8) a
9) a
10) b

You can ask for explanation and discuss more questions on this topic in the comments section below.