Q1: Dilution method of disposing off sewage, is not preferred to

ANS:C - when diluting water is used for water supply near the point of sewage disposed

The dilution method of disposing of sewage involves mixing sewage with a large volume of water to reduce its concentration and potential impact on the environment. However, this method is not preferred under certain conditions due to environmental and health concerns. The statement "when the diluting water is used for water supply near the point of sewage disposed" is not preferred for the dilution method. When diluting water used for sewage disposal is also utilized for water supply near the point of discharge, there's a risk of contaminating the water supply with sewage-related pollutants. This can pose significant health hazards to the population relying on the water supply for drinking, cooking, and other domestic uses. Therefore, the dilution method of disposing of sewage is not preferred when the diluting water is used for water supply near the point of sewage disposal. The other conditions mentioned in the options do not necessarily pose the same level of risk and may not conflict with the dilution method's application.