Which of the following radioactive wastes emits all α, β & γ rays and hence is the most hazardous of all radioactive emitters ?
(A) I-131
(B) Sr-90
(C) Au-198
(D) Ra-226
Deaeration of high pressure boiler feed water is done to reduce ___________________?
(A) Foaming from boilers
(B) Its dissolved oxygen content
(C) Its silica content
(D) Caustic embrittlement
The common pollutant generated in chlor-alkali industry and battery manufacture is ___________________?
(A) Mercury
(B) Brine
(C) Phosphate
(D) None of these
Permissible safe limit (TLV) of _____________ toxic gas is 100-1000 parts per million (ppm)?
(A) Highly
(B) Moderately
(C) Extremely
(D) Very extremely
The Killer gas which caused Bhopal gas tragedy in 1984 was________________?
(A) Phosgene
(B) Methyl isocyanate (MIC)
(C) Carbon monoxide
(D) Sulphur dioxide
Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removal ?
(A) By chemical coagulation
(B) In sedimentation tanks equipped with mechanical scrapper
(C) In vacuum filter
(D) In clarifiers
Removal of ______________ is accomplished by aeration of water?
(A) Dissolved gases
(B) Suspended solids
(C) Dissolved solids
(D) None of these
Which of the following pollutants, if present in atmosphere is detectable by its odour ?
(A) CO
(B) SO2
(C) NO2
(D) CO2
Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre) ?
(A) Lagooning
(B) Activated carbon adsorption
(C) Biological oxidation pond
(D) Chemical coagulation
Pick out the correct statement ?
(A) Chemical oxygen demand (COD) is a measure of chemically oxidisable organic matter present in water
(B) COD is determined by oxidising the organic matter present in water with potassium dichromate in cone, sulphuric acid solution at boiling temperature for specified time
(C) CO
(D) is related to BO