The correct answer is A. 90 %.
Sewage is a mixture of wastewater from homes and businesses, as well as stormwater runoff. It contains a variety of materials, including water, organic matter, inorganic matter, and pathogens. The water content of sewage is typically around 90%. The remaining 10% is made up of the other materials mentioned above.
The water content of sewage is important because it affects the treatment process. Sewage treatment plants use a variety of methods to remove the pollutants from sewage, and the water content of the sewage affects the efficiency of these methods. For example, some treatment methods, such as filtration, are more effective when the water content of the sewage is high.
The water content of sewage is also important because it affects the disposal of the treated sewage. Treated sewage can be discharged into surface waters, such as rivers and lakes, or it can be used for irrigation or other purposes. The water content of the treated sewage affects the amount of land that is required for disposal, and it also affects the quality of the receiving water body.
In conclusion, the water content of sewage is an important factor in sewage treatment and disposal. The water content of sewage affects the efficiency of the treatment process and the amount of land that is required for disposal.