Facultative Stabilization Ponds: Mechanism of Purification
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Questions and Answers

What is the purpose of the aerobic layer in a facultative stabilization pond?

  • To stabilize sewage organics through algal photosynthesis (correct)
  • To promote odour evolution
  • To create anaerobic conditions at the bottom
  • To convert dissolved organic matter to methane

    • Why is oxygen supplied in the top aerobic layer of a facultative pond?

  • To encourage anaerobic reactions
  • To promote methane formation
  • To oxidize non-settleable and dissolved organic matter (correct)
  • To enhance odour evolution

    • Which factor does NOT affect pond design according to Prof. H.K.Mapari?

  • Wastewater characteristics and fluctuations
  • Algal growth patterns and their variation
  • Temperature
  • Industrial waste disposal methods (correct)

    • What happens to the end products of partial anaerobic decomposition in a facultative stabilization pond?

    <p>They escape the pond as bubbles</p> Signup and view all the answers

    Which process takes place in the lower layers of a facultative stabilization pond?

    <p>Conversion of dissolved and suspended organics to methane</p> Signup and view all the answers

    What kind of conditions prevail at the bottom of a facultative pond?

    <p>Anaerobic conditions</p> Signup and view all the answers

    What happens to the depth of the aerobic layer in a facultative pond as the organic loading increases?

    <p>It decreases</p> Signup and view all the answers

    What is the primary reason for the decrease in photosynthetic activity of algae in a facultative pond?

    <p>Greater turbidity</p> Signup and view all the answers

    What is the consequence of an imbalance between the activities of methane bacteria in a facultative pond?

    <p>Accumulation of organic acids</p> Signup and view all the answers

    What role does solar radiation play in algal growth and oxygen production in a facultative pond?

    <p>It converts solar energy to chemical energy in algae</p> Signup and view all the answers

    How is the permissible areal organic loading for a pond related to its latitude according to the Bureau of Indian Standards?

    <p>It increases with increasing latitude</p> Signup and view all the answers

    What determines the pond efficiency in sewage treatment for dispersed flow?

    <p>Dispersion numbers</p> Signup and view all the answers

    Why are aquatic plant systems like duckweed and hyacinth ponds classified as free floating growths?

    <p>They float on the water's surface</p> Signup and view all the answers

    What happens if the second step of organic matter gasification in a facultative pond does not proceed satisfactorily?

    <p>&quot;Methane bacteria inhibition&quot;</p> Signup and view all the answers

    What is one of the major adverse health effects associated with air pollution?

    <p>Respiratory symptoms</p> Signup and view all the answers

    Why has it been difficult to document the health effects of ambient air pollution?

    <p>Methodological problems in assessing exposure</p> Signup and view all the answers

    In what type of societies is air pollution a serious problem due to inefficient and smoky fuels used for heating and cooking?

    <p>Traditional and societies with crude household energy sources</p> Signup and view all the answers

    What is a significant property that can be affected by air pollution according to the text?

    <p>Visibility</p> Signup and view all the answers

    Why have some rapidly developing countries not invested sufficient resources in air pollution control?

    <p>Prioritization of other economic and social needs</p> Signup and view all the answers

    What has been partially successful in controlling particulate and gaseous emissions in much of the developed world?

    <p>Emission reduction technology</p> Signup and view all the answers

    Which body part might experience mucosal irritation due to high levels of air pollution?

    <p>Nose and throat</p> Signup and view all the answers

    What is a characteristic symptom of high levels of air pollution according to the text?

    <p>'Wheezy chest'</p> Signup and view all the answers

    What major effect does air pollution have on human health according to recent studies?

    <p>Major impact on respiratory health</p> Signup and view all the answers

    What is the purpose of septic tanks?

    <p>To settle sewage solids anaerobically</p> Signup and view all the answers

    Which of the following is an example of an aquatic plant commonly used in ponds for wastewater treatment?

    <p>Water hyacinths</p> Signup and view all the answers

    What is a characteristic of constructed wetlands?

    <p>They are man-made for treatment of wastewater, mine drainage, and storm drainage.</p> Signup and view all the answers

    What is the function of a cesspool?

    <p>To leach wastewater into porous soils</p> Signup and view all the answers

    How often are water-tight cesspools cleaned?

    <p>Once every 6 months</p> Signup and view all the answers

    What is the primary unit of measurement for air pollutants concentration?

    <p>$rac{ng}{m3}$</p> Signup and view all the answers

    How is the relationship between ppm and mg/m3 affected by the molecular weight of the pollutant?

    <p>It inversely proportional to the molecular weight</p> Signup and view all the answers

    What defines air pollution according to the text?

    <p>$Concentration$ of substances in undesirable levels</p> Signup and view all the answers

    How often should a septic tank be de-sludged?

    <p>$Once$ every 1-5 years</p> Signup and view all the answers

    What is the role of seepage pits in wastewater management?

    <p>To decompose fine suspended solids and leach effluent into sidewalls</p> Signup and view all the answers

    What is the primary source of sulfur dioxide (SO2) as mentioned in the text?

    <p>Combustion of coal and oil</p> Signup and view all the answers

    Which compound is responsible for reducing visibility and increasing the risk of respiratory diseases when present in large concentrations as per the text?

    <p>Nitrogen oxides (NO and NO2)</p> Signup and view all the answers

    What is the color and odor associated with nitrogen dioxide (NO2) mentioned in the passage?

    <p>Reddish-brown with a sharp odor</p> Signup and view all the answers

    Which source has contributed significantly to lead (Pb) levels in the atmosphere in the past before its gradual elimination worldwide?

    <p>Leaded gasoline combustion</p> Signup and view all the answers

    Inhalation of enough particulate matter (PM) over time increases the risk of which health condition according to the text?

    <p>Chronic respiratory disease</p> Signup and view all the answers

    What type of emissions can cause lung cancer due to arsenic release as per the text?

    <p>Emissions from lead smelters</p> Signup and view all the answers

    Which pollutant can affect various body systems including blood, kidneys, and nervous system when exposed to?

    <p>Lead (Pb)</p> Signup and view all the answers

    'Tropospheric ozone' is primarily formed as a secondary pollutant due to photochemical reactions involving which compounds?

    <p>$NO_2$ and VOCs</p> Signup and view all the answers

    What can lead to headaches, dizziness, unconsciousness, and even death when inhaled at high concentrations as per the text?

    <p>$CO$</p> Signup and view all the answers

    Which pollutant is colorless but has a suffocating, pungent odor according to the text?

    <p>Sulfur dioxide (SO2)</p> Signup and view all the answers

    What are Hazardous air pollutants (HAPS) known for?

    <p>Causing cancer and serious health effects</p> Signup and view all the answers

    Which of the following is an example of a toxic air pollutant?

    <p>Benzene in gasoline</p> Signup and view all the answers

    What is a geogenic source of indoor air pollution?

    <p>Radon</p> Signup and view all the answers

    Which type of air pollutants are emitted directly into the atmosphere by sources like power-generating plants?

    <p>Primary air pollutants</p> Signup and view all the answers

    What is the main effect of sulfur dioxide on the respiratory system?

    <p>Broncho constriction</p> Signup and view all the answers

    Which industry emits perchlorethlyene, a toxic air pollutant?

    <p>Dry cleaning facilities</p> Signup and view all the answers

    What is a common contributor to indoor pollution according to the text?

    <p>Environmental tobacco smoke (ETS)</p> Signup and view all the answers

    Which of the following sources can emit radioactive elements like uranium into the atmosphere?

    <p>Coal-fired power plants</p> Signup and view all the answers

    What type of air pollutants are formed as a result of reactions between primary pollutants and other elements in the atmosphere?

    <p>Secondary air pollutants</p> Signup and view all the answers

    Which ion remains a major constituent of air pollution capable of forming acid according to the given text?

    <p>Sulfate ion</p> Signup and view all the answers

    What phenomenon is caused by the emission of acid aerosols like sulfur dioxide and sulfates?

    <p>Acid rain</p> Signup and view all the answers

    Which chemical species are primarily responsible for causing acid precipitation?

    <p>SO2 and Sulfates</p> Signup and view all the answers

    What effects do oxides of nitrogen have on the respiratory tract?

    <p>Increased incidence and severity of bacterial infections</p> Signup and view all the answers

    Which source contributes significantly to the release of PM10 particulates into the air?

    <p>Wind blowing soil into the air</p> Signup and view all the answers

    What distinguishes PM2.5 from larger particulates in urban air pollution?

    <p>Presence of acid forming chemicals like sulfate and nitrate</p> Signup and view all the answers

    Which compound is a secondary pollutant created by the oxidation of NO under sunlight conditions?

    <p>Nitrogen Dioxide (NO2)</p> Signup and view all the answers

    What are the guideline levels for exposure to nitrogen dioxide according to WHO standards for 24 hours?

    <p>$150 μg/m^{3}$ ($0.08$ ppm)</p> Signup and view all the answers

    What is the primary contributor to respirable particles indoors in developed countries?

    <p>Tobacco smoke</p> Signup and view all the answers

    'Particulate matter (PM 10)' consists mostly of which material?

    <p>$Carbon-containing material$</p> Signup and view all the answers

    'Particulate matter (PM 2.5)' contains a larger amount of which chemicals compared to larger particles?

    <p>$Sulfate and nitrate$</p> Signup and view all the answers

    Which air pollutants are strongly suggested to cause an increase in deaths in affected cities?

    <p>PM2.5 and ozone</p> Signup and view all the answers

    What are the health risks associated with ozone, PM2.5, and sulfate pollution according to the text?

    <p>Higher rates of deaths from heart disease</p> Signup and view all the answers

    Why are hydrocarbons like aromatic compounds included among the criteria air pollutants?

    <p>Due to their role in photochemical smog formation</p> Signup and view all the answers

    What is a notable characteristic of lead as a trace metal pollutant according to the text?

    <p>It can cause nerve damage and learning disabilities</p> Signup and view all the answers

    What is one unexpected finding of research on particulate air pollution according to the text?

    <p>The effect on deaths is continuous from high to low pollution levels</p> Signup and view all the answers

    What factor is believed to be responsible for the high rates of respiratory disease in northern Chinese cities according to the text?

    <p>A combination of air pollution, cigarette smoking, and viral infections</p> Signup and view all the answers

    Why are hydrocarbons like benzo(a) Pyrene considered potent carcinogens?

    <p>They are biologically active and irritating</p> Signup and view all the answers

    What percentage of lead in ambient air is believed to come from the combustion of leaded petrol?

    <p>~80-90%</p> Signup and view all the answers

    'There is no obvious level below which the public is clearly protected' refers to the continuous effect of which pollutant on deaths?

    <p>$PM2.5$</p> Signup and view all the answers

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