Q. Presence of a certain minimum quantity of flourine is desirable in potable water to prevent

View solution

Q. Death may occur, when SO₂ concentration in atmospheric air exceeds __________ ppm.

View solution

Q. Which of the following acts as a natural source of air pollution ?

View solution

Q. Higher concentration of CO₂ in atmosphere

View solution

Q. Permissible safe limit (TLV) of __________ toxic gas is 100-1000 parts per million (ppm).

View solution

Q. Radioactive substances present in the polluted water stream can be removed by

View solution

Q. Most of the bacteria in sewage are

View solution

Q. Which of the following is the most major constituents of air pollutants ?

View solution

Q. Shouting by a man at his full voice corresponds to a voice level of about __________ decibels.

View solution

Q. Carbonaceous particles having size less than 1 μm are called

View solution

Q. __________ substances present in sewage are removed in grit chamber during sewage treatment.

View solution

Q. Pick out the wrong statement pertaining to 'green house' for the plants.

View solution

Q. In water treatment, alum[Al₂(SO₄)₃] is used for the process of

View solution

Q. Pick out the one which is not a chemical coagulant.

View solution

Q. Presence of iron and manganese in water causes

View solution

Q. Septic tanks are used for the __________ of the deposited solids.

View solution

Q. The term Biological Oxygen Demand (BOD) is used in relation to

View solution

Q. The destruction of water-borne pathogens is termed as disinfection of water. Which of the following is a water disinfectant ?

View solution

Q. Disinfection of water is done to destroy pathogenic bacteria and thus prevent water-borne diseases. Disinfection of water may be done by the use of

View solution

Q. Which of the following processes is involved in the biochemical treatment of sewage effluents ?

View solution