hey guys please answer my 3rd 4th 5th 6th 8th and 9th question.
Answers
3Answer: Oil and fats can clog the drains. In open drains, they block the pores in the soil and thus hamper the filtration by soil. Hence, oil and fats should not be released in the drain.
4Answer: The following steps are involved in clarifying wastewater:
Insoluble waste is removed by filtration and sedimentation processes.
Bacteria are allowed to grow through the process of aeration. Bacteria eat away human waste from the wastewater.
Chlorination is used to kill the germs in clarified water. After this step, the water becomes fit even for human consumption.
5Answer: The solid waste which settles at the bottom of the sedimentation tank is called sludge. The sludge is further treated by the process of aeration. This helps in growth of bacteria which eat away the human waste.
6Answer: Untreated human excreta contains many microbes which can cause deadly diseases; like cholera, diarrhea, jaundice and typhoid. The germs of these diseases can easily reach human population through insects and through contaminated food and water. Thus, untreated human excreta are a health hazard.
8Answer: Bar screens are large filters which are placed in the form of vertical screens. Large solid wastes; like sticks, pebbles, sand, cans, plastic bottles, plastic bags, etc. are filtered out when the wastewater moves through the bar screen.
9Answer: Sanitation and disease are closely related. Lack of sanitation leads to unhygienic conditions; which creates many communicable diseases. Maintenance of sanitation removes the chances of such diseases.