Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly _____________ substances?

Related Mcqs:

1. Inhalation of silica dust by human being during hand drilling in mica mining, lead & zinc mining, silica refractory manufacture and in foundries causes___________________?

   A. Asphyxiation (suffocation) B. Shortness of breath C. Tuberculosis D. All A., B. and C....

2. Oilish impurities present the effluent discharged from the electroplating industry is normally not removed by _____________________?

   A. Chemical coagulation B. Floatation & skimming C. Centrifugation D. Ultra filtration...

3. Suspended solid present in the waste water generated in blast furnace gas cooling and cleaning plant is removed by__________________?

   A. Biological oxygen pond B. Radial settling tank (thickener) using coagulant (lime & ferrous sulphate) C. Lagoons D. Filtration...

4. The amount of chemical coagulant added for treatment of polluted water ______________ with increase in temperature of the polluted water to be treated?

   A. Decreases B. Increases C. Remain constant D. May increase or decrease; depends on the chemical characteristics of polluted water...

5. Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes_______________?

   A. Foaming B. Odour nuisances C. Undesirable plant growth D. Turbidity...

6. The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by_________________?

   A. Biological oxygen pond B. Aerated lagoons C. Trickling filters D. Gravity separator having oil skimming devices...

7. Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by________________?

   A. Natural aeration of water stream B. Photosynthetic action of algae C. Both A. & B. D. Neither A. nor B....

8. Radioactive substances present in the polluted water stream can be removed by_________________?

   A. Biological oxygen treatment B. Coagulation and filtration C. Adsorption in ion exchange materials D. None of these...

9. Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of _____________ present in it?

   A. Coal ash B. Potassium cyanide C. Ortho-xylene D. None of these...

10. 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...