Question

In domestic sewage, suspended solids, colloidal and dissolved materials constitute
A. 10%
B. 5.6%
C. 2.7%
D. 0.1%

Answer 1

Hint: Wastewater treatment is a process in which the dirty wastewater or sewage water is processed such that it can be discarded to rivers, seas, and the water cycle. Water waste or sewage is of three types domestic sewage, industrial sewage, and storm sewage.

Complete answer:
Cities and towns have sewerage systems to carry the wastewater from homes, hotels, industries, factories, and other places. This water is sent to the sewage treatment plant where the wastewater is treated and when considered to be safe, released into other water sources like rivers. The wastewater treatment goes through different stages where wastewater is treated to remove physical, chemical, and biological contaminants present in it. The wastewater is of three types: industrial sewage, storm sewage, and domestic sewage. Industrial sewage is the portion of water from factories and industries. Depending upon the nature of industries organic chemicals are found in sewage. Storm sewage contains all types of pollutants like organic material, suspended and dissolved materials while traveling over the ground. Domestic sewage contains a wide variety of suspended and dissolved components and impurities.
Domestic sewage constitutes more than 99.9% of water by weight and less than 0.1% of suspended solids and dissolved materials.
Hence, the correct option will be option D- 0.1%.

Note: Even though the percent of domestic sewage is less the types of impurities present in domestic sewage are very difficult to treat. Domestic sewage contains organic materials and plant nutrients along with a large number of disease-causing microorganisms.