Facultative Stabilization Ponds: Mechanism of Purification

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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?

They escape the pond as bubbles Signup and view all the answers

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

Conversion of dissolved and suspended organics to methane Signup and view all the answers

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

Anaerobic conditions Signup and view all the answers

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

It decreases Signup and view all the answers

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

Greater turbidity Signup and view all the answers

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

Accumulation of organic acids Signup and view all the answers

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

It converts solar energy to chemical energy in algae 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?

It increases with increasing latitude Signup and view all the answers

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

Dispersion numbers Signup and view all the answers

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

They float on the water's surface Signup and view all the answers

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

"Methane bacteria inhibition" Signup and view all the answers

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

Respiratory symptoms Signup and view all the answers

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

Methodological problems in assessing exposure 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?

Traditional and societies with crude household energy sources Signup and view all the answers

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

Visibility Signup and view all the answers

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

Prioritization of other economic and social needs Signup and view all the answers

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

Emission reduction technology Signup and view all the answers

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

Nose and throat Signup and view all the answers

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

'Wheezy chest' Signup and view all the answers

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

Major impact on respiratory health Signup and view all the answers

What is the purpose of septic tanks?

To settle sewage solids anaerobically Signup and view all the answers

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

Water hyacinths Signup and view all the answers

What is a characteristic of constructed wetlands?

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

What is the function of a cesspool?

To leach wastewater into porous soils Signup and view all the answers

How often are water-tight cesspools cleaned?

Once every 6 months Signup and view all the answers

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

$rac{ng}{m3}$ Signup and view all the answers

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

It inversely proportional to the molecular weight Signup and view all the answers

What defines air pollution according to the text?

$Concentration$ of substances in undesirable levels Signup and view all the answers

How often should a septic tank be de-sludged?

$Once$ every 1-5 years Signup and view all the answers

What is the role of seepage pits in wastewater management?

To decompose fine suspended solids and leach effluent into sidewalls Signup and view all the answers

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

Combustion of coal and oil 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?

Nitrogen oxides (NO and NO2) Signup and view all the answers

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

Reddish-brown with a sharp odor 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?

Leaded gasoline combustion 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?

Chronic respiratory disease Signup and view all the answers

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

Emissions from lead smelters Signup and view all the answers

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

Lead (Pb) Signup and view all the answers

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

$NO_2$ and VOCs 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?

$CO$ Signup and view all the answers

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

Sulfur dioxide (SO2) Signup and view all the answers

What are Hazardous air pollutants (HAPS) known for?

Causing cancer and serious health effects Signup and view all the answers

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

Benzene in gasoline Signup and view all the answers

What is a geogenic source of indoor air pollution?

Radon Signup and view all the answers

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

Primary air pollutants Signup and view all the answers

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

Broncho constriction Signup and view all the answers

Which industry emits perchlorethlyene, a toxic air pollutant?

Dry cleaning facilities Signup and view all the answers

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

Environmental tobacco smoke (ETS) Signup and view all the answers

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

Coal-fired power plants 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?

Secondary air pollutants Signup and view all the answers

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

Sulfate ion Signup and view all the answers

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

Acid rain Signup and view all the answers

Which chemical species are primarily responsible for causing acid precipitation?

SO2 and Sulfates Signup and view all the answers

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

Increased incidence and severity of bacterial infections Signup and view all the answers

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

Wind blowing soil into the air Signup and view all the answers

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

Presence of acid forming chemicals like sulfate and nitrate Signup and view all the answers

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

Nitrogen Dioxide (NO2) Signup and view all the answers

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

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

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

Tobacco smoke Signup and view all the answers

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

$Carbon-containing material$ Signup and view all the answers

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

$Sulfate and nitrate$ Signup and view all the answers

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

PM2.5 and ozone Signup and view all the answers

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

Higher rates of deaths from heart disease Signup and view all the answers

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

Due to their role in photochemical smog formation Signup and view all the answers

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

It can cause nerve damage and learning disabilities Signup and view all the answers

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

The effect on deaths is continuous from high to low pollution levels 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?

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

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

They are biologically active and irritating Signup and view all the answers

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

~80-90% 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?

$PM2.5$ Signup and view all the answers