KPSC Departmental Exams - Environmental Eng/AEO 2021 — Paper 2 - Specific Paper

CFC-114 is 1,2-dichlorotetrafluoroethane, structurally CF2Cl-CF2Cl, matching option A.

The Air (Prevention and Control of Pollution) Act was enacted in India in 1981, following commitments made at the 1972 Stockholm Conference.

Excess nitrate in drinking water is converted to nitrite in an infant's digestive system, which impairs the blood's oxygen-carrying capacity and causes methemoglobinemia (blue baby syndrome).

Ozone layer (column) thickness is conventionally measured in Dobson units (DU), where 1 DU equals 0.01 mm of ozone at standard temperature and pressure.

Under Bio-Medical Waste Management Rules, human anatomical waste such as a disposed placenta is segregated into yellow-coloured bags/bins.

Older fax machines and photocopiers used selenium-coated imaging drums, and selenium released during their operation or disposal is considered a hazardous pollutant.

Calgon (sodium hexametaphosphate) sequesters calcium and magnesium ions in solution, making it effective for removing the permanent (non-carbonate) hardness of water.

Sewer hydraulics design manuals conventionally adopt a porosity value of about 0.013 for settled sediment deposits in sewer pipes.

As per IS 2490-1974, the tolerance limit for COD in industrial effluent discharged into inland surface waters is 250 mg/l.

Dr. Henry Antoine Des Voeux is credited with coining the term "smog" (smoke + fog) in 1905 to describe London's layered polluted air.

The Central Pollution Control Board identifies fine particulate matter of 2.5 micrometre diameter (PM2.5) as most harmful to human health, since particles this small penetrate deep into the lungs and bloodstream.

Sewage is indeed a primary source of oxygen-demanding waste and pathogens (making R true), but this fact alone does not specifically explain the general rise in BOD and COD levels across almost all water bodies, so R is true without being the correct explanation of A.

A "green muffler" refers to greenbelts/tree buffers planted around industries and roads specifically to absorb and attenuate noise pollution.

Typical library/soft-whisper ambient sound levels are around 30 dBA, not 50 dBA, making this the incorrectly paired option among the choices given.

The Upflow Anaerobic Sludge Blanket (UASB) reactor is a high-rate anaerobic system capable of handling high COD loading rates from industrial effluent more economically than aerobic alternatives.

Indian pollution control norms set the maximum permissible limit for hexavalent chromium in industrial effluent discharged into public sewers at 2 mg/l (ppm).

Photocatalysis, an advanced oxidation process using catalysts like TiO2 under UV light, is highly effective at breaking down persistent, priority pollutants such as pharmaceutical residues.

Surfactants, phenols, pesticides, and endocrine disruptors are all classified as refractory organics that resist breakdown by conventional wastewater treatment processes.

Discrete settling removes grit and sand, flocculant settling removes chemically coagulated wastes, zone settling removes biological floc (as in secondary clarifiers), and compression settling thickens sludge — giving the pairing (a-iv, b-i, c-iii, d-ii).

The Minamata Convention specifically addresses mercury and the Stockholm Convention addresses persistent organic pollutants, so both (a) and (b) are correctly matched; the Basel Convention governs transboundary movement of hazardous waste in general rather than lead specifically, making (c) incorrect.

Since settling efficiency in a gravitational chamber scales with the square of the particle-diameter ratio, a 48 micrometre particle compared to the 60 micrometre size needed for 100% removal gives (48/60)^2 = 64% collection efficiency.

High-temperature combustion in a boiler oxidizes atmospheric nitrogen to form thermal NO, the primary nitrogen oxide released in flue gas before further atmospheric oxidation to NO2.

Per the (pre-2012) BIS drinking water standard, the maximum desirable limit for lead was 0.05 mg/l.

Because COD measures both biodegradable and non-biodegradable oxidizable matter while BOD measures only the biodegradable fraction, BOD is always less than or equal to COD, so the BOD/COD ratio is always less than 1.

Windrow composting and in-vessel composting both require oxygen for aerobic microbial decomposition, whereas Bokashi composting is an anaerobic fermentation process using effective microorganisms.

BOD is calculated as dissolved oxygen depletion divided by the dilution fraction used; here, 8 mg/l divided by a 2% (0.02) dilution gives a BOD of 400 mg/l.

As per BIS drinking water standards, the permissible limit for nitrate is 45 mg/l.

Adding coagulants promotes flocculation of fine suspended particles into larger, faster-settling flocs, thereby enhancing sedimentation tank performance.

The Nalgonda technique — developed and standardized by NEERI (National Environmental Engineering Research Institute), India — uses lime and alum flocculation specifically to remove excess fluoride from drinking water, not chloride; this is a well-documented, standard fact in Indian water-treatment literature. Since (a) zeolite softening, (b) Katadyn silver disinfection, and (d) aeration for dissolved-gas removal are all correctly paired, while (c) misstates the Nalgonda technique's purpose, the correct combination is (a), (b) and (d), confirming option B.

The Water (Prevention and Control of Pollution) Act, 1974 was enacted to prevent and control water pollution and to maintain/restore the wholesomeness of water bodies, covering all the listed provisions.

Carbon monoxide is a toxic byproduct of incomplete combustion and is classified as an air pollutant, unlike nitrogen and oxygen, which are natural atmospheric constituents.

Dissolved oxygen saturation in fresh water at typical ambient temperatures (20-25°C) is about 8-9.2 mg/l at 1 atmosphere, per standard DO-temperature saturation tables used in water quality engineering. Unpolluted natural water stays close to this saturation value, so its DO level is correctly stated as being of the order of 10 mg/l, not 1 mg/l — a value that would instead indicate significant oxygen depletion from pollution.

When total hardness exceeds total alkalinity, carbonate (temporary) hardness is limited by and equal to the total alkalinity, with the remainder classified as non-carbonate hardness.

Oxidation ditches, an extended-aeration activated sludge variant with long retention times, typically achieve the highest BOD removal efficiency among the listed options.

Bureau of Indian Standards method IS:3025 (Part 44) explicitly permits incubating the BOD sample at either 20°C for 5 days or 27°C for 3 days as equivalent alternatives, since the higher incubation temperature accelerates the same first-order oxidation reaction enough to reach a comparable fraction of ultimate BOD in less time. This makes 3 days at 27°C the standard, code-specified equivalent of the classic 5-day, 20°C BOD test, confirming option A.

Effective nitrogen control for urea-based wastewater requires first hydrolyzing urea to ammonia, followed by lime dosing/mixing, then air stripping of ammonia, and finally nitrification-denitrification of any residual nitrogen.

Wastewater treatment methods are conventionally classified as physical/mechanical, chemical, or biological; sedimentation removes suspended solids purely through gravity settling with no chemical reaction, making it a physical (mechanical) unit operation. Chlorination, by contrast, works by a chemical oxidation/disinfection reaction with the pollutant, so it belongs to chemical treatment, not mechanical — confirming sedimentation (option D) as the correct answer.

Historical CPCB ambient air quality standards for residential areas specified SPM at 200, SO2 at 80, NOx at 80, and CO at 2000 micrograms per cubic metre.

The ozone layer (ozonosphere) is concentrated mainly within the stratosphere and extends into the lower mesosphere, where ozone concentration falls off sharply.

Night soil and garbage are the readily biodegradable organic fractions of solid waste, whereas rubbish and debris are largely inert; summing night soil (35 t) and garbage (40 t) gives 75 t of organic solids.

Dry mass equals total mass minus moisture content: 52 kg x (1 - 0.70) = 15.6 kg.

Subtitle C of the U.S. Resource Conservation and Recovery Act (RCRA) establishes the regulatory framework for managing hazardous waste from generation to disposal.

Sound pressure levels expressed in decibels are conventionally referenced to a standard threshold pressure of 20 micropascals (uPa).

Combining two incoherent noise sources uses logarithmic (energy) addition: 10*log10(10^9 + 10^9.4) is approximately 95.5 dB.

Hospitals typically generate an average of about 0.5 to 4 kg of biomedical waste per bed per day, depending on facility type and services offered.

Workers handling bio-medical waste are recommended to receive both Hepatitis B (HBsAg) and Tetanus vaccinations, given their occupational exposure to bloodborne pathogens and sharps injuries.

PET (polyethylene terephthalate) is the most widely accepted plastic type at recycling centres due to its high recyclability and market demand, unlike PVC.

Eutrophication refers to the excessive enrichment of a water body with nutrients (mainly nitrogen and phosphorus), driving excessive algal/plant growth and subsequent oxygen depletion.

Cleaner production assessment focuses on pollution prevention, ecological sustainability, and health/safety protection within processes, rather than evaluating the products and services themselves.

The overlay method in EIA superimposes multiple thematic maps of a study area to visually identify and assess cumulative spatial environmental impacts.

The ISO 14000 family comprises a defined set of five core standards covering various aspects of environmental management systems.

Biogas, produced by anaerobic digestion of organic matter, is primarily a mixture of methane and carbon dioxide with traces of hydrogen sulphide.

Corals are highly temperature-sensitive organisms, and even small rises in sea surface temperature due to global warming trigger coral bleaching and mass die-offs.

Minamata disease is caused by eating fish contaminated with methylmercury from industrial mercury discharge, first identified in Minamata Bay, Japan.

Coal mining is considered one of the most hazardous occupations due to risks such as gas explosions, roof collapses, and pneumoconiosis (black lung disease).

A combined sewage system carries domestic sewage together with storm water runoff, with or without industrial wastewater, through a single conduit.

Surface loading (surface overflow rate) of a sedimentation tank is defined as the flow rate divided by the tank's plan/surface area, Q/(B.L).

In trickling filters used for wastewater treatment, coarser media placed at the bottom aids drainage and ventilation, while finer media at the top increases surface area for biofilm growth.

An intercepting trap seals the house drainage system from the municipal sewer, preventing foul sewer gases from entering the building's plumbing.

Schedule 1 of the Hazardous Wastes (Management and Handling) Rules, 1989 lists 122 categories of waste generated from 36 types of industrial processes.

Under India's Bio-Medical Waste Management Rules, disposable items like tubing/catheters/blood bags and liquid wastes are assigned to the red category, while sharps are placed in the white/translucent category, matching pairing (a), (b) and (d).

Carbon monoxide forms specifically when carbon fuel is oxidized without enough oxygen to go all the way to CO2 — exactly the condition created by a poorly maintained or inefficiently tuned engine, whose fuel-rich, incomplete combustion is a primary, direct source of tailpipe CO. Smog, in contrast, is not itself emitted by the vehicle; it is a secondary photochemical product formed later in the atmosphere from sunlight acting on NOx and hydrocarbons, so it cannot be the direct output of a faulty engine, confirming carbon monoxide (option C) as correct.

A comprehensive Environmental Impact Statement addresses deforestation and compensatory afforestation, risk analysis and disaster management, and air, water and groundwater pollution together.

Energy (calorific) value is a compositional/chemical property obtained via proximate analysis, and is not part of the routine physical characterization (moisture, density, particle size) of solid waste.

Nitrogen dioxide (NO2) is largely formed through atmospheric oxidation of primary emissions like NO, making it a secondary pollutant.

Applying Stokes' settling law to the given tank dimensions, flow rate, and particle specific gravity yields a critical settling particle diameter of about 0.60 mm.

The required bleaching powder dosage is found by dividing the total chlorine demand (dosage x flow) by the powder's 40% available chlorine content, giving about 20 kg/day.

A BOD/COD ratio below about 0.6 generally indicates a substantial fraction of non-biodegradable or refractory organic matter, making biological treatment less suitable.

The activated sludge process is an aerobic, suspended-growth biological treatment system in which microorganisms are kept in suspension through continuous aeration and mixing.

Conserving solids mass across the moisture change (100 x 0.05 = V x 0.20) gives a final sludge volume of 25 cub-m after moisture content drops from 95% to 80%.

Standard-rate trickling filters are typically designed for organic loading rates in the range of 0.08 to 0.30 kg BOD per cubic metre per day.

Raw dairy industry effluent typically carries an average BOD of around 1000 mg/l, owing to its high organic content from milk solids, whey and fats.

Lagooning treatment of paper industry effluent typically achieves around 80% BOD removal through extended natural biological degradation.

A cane sugar mill's mill-house section typically generates an average liquid effluent of about 1730 litres per day per tonne of cane processed.

Using standard stack-height design formulas for the given particulate emission rate yields a theoretical stack height of approximately 15.4 m.

Section 19 of the Air (Prevention and Control of Pollution) Act, 1981 empowers state governments to declare air pollution control areas.

Liquefied Petroleum Gas (LPG) is primarily a mixture of butane and propane.

Alum (aluminium sulphate) acts as a coagulant that destabilizes and aggregates suspended colloidal impurities in water, allowing them to be removed by sedimentation.

Smog is formed by the combination of atmospheric gases (pollutants) together with water vapour and dust/smoke particles.

Composting food processing waste in a milled (shredded) form increases surface area for microbial action, making it a practical and eco-friendly disposal method compared to incineration.

Both statements correctly describe the greenhouse effect: incoming shortwave solar radiation is re-emitted by the Earth as longwave heat radiation, which greenhouse gases and water vapour then trap, warming the atmosphere.

The Montreal Protocol (1987) is an international treaty specifically aimed at phasing out substances responsible for depleting the stratospheric ozone layer.

Oxidation ponds achieve high removal efficiencies of about 90% for BOD and about 99% for pathogenic coliform bacteria through prolonged natural biological treatment and sunlight-driven disinfection.

The Water (Prevention and Control of Pollution) Cess Act, 1977 levies and collects a cess on water consumed by specified categories of industries to help fund pollution control efforts.

Press mud is generated when lime-treated (clarified) sugarcane juice sludge is filtered during sugar processing, yielding this filter-cake byproduct.

Statement I correctly defines breakpoint chlorination as chlorine dosing carried far enough to destroy both organisms and other oxidizable impurities. Statement II is false: ozone is a strong oxidizing gas that is toxic to the respiratory system even at low concentrations (occupational exposure limits are on the order of 0.1 ppm), and excess ozone in water treatment is a recognized hazard associated with off-gassing risk and byproduct formation such as bromate — it is not harmless. Since only statement I holds, option A is correct.

Under the Swachh Bharat air-quality monitoring initiative, India measures ambient air quality using eight parameters: CO, O3, PM2.5, NH3, PM10, Pb, NO2 and SO2.

The Ministry of Environment and Forest established the National Waste Management Council in January 1990 to guide the country's waste management policy.

Environmental (xeno-)oestrogens are pollutants that mimic natural estrogen by binding to and activating the estrogen receptor; polychlorinated biphenyls (PCBs) are a classic, well-documented example of this, with several PCB congeners shown in reporter-gene and receptor-binding assays to produce weak-to-moderate estrogenic activity, which is why PCBs are named alongside DDT and Bisphenol-A in the foundational "environmental estrogen" literature (e.g., Colborn et al.). Dioxin (TCDD), by contrast, acts through the aryl hydrocarbon receptor and is well characterized in toxicology as anti-estrogenic — it suppresses rather than mimics estrogen signaling in most tissues studied — so it does not fit the definition. The correct answer is therefore PCB (option B), not Dioxin.

India's solid waste management siting norms require landfills to maintain a minimum buffer distance of about 500 m from human settlements.

The Noise Exposure Forecast (NEF) is a metric specifically used to quantify and forecast aircraft/air-traffic noise exposure around airports.

Category A projects under the EIA notification have significant potential adverse environmental impacts and require a full/detailed EIA along with Environmental Clearance from the central government.

ISO 14010 lays down the general principles of environmental auditing within the ISO 14000 series of environmental management standards.

Owen's dust counter is an instrument used to measure and count the concentration of airborne particulate matter.

Strontium-90 is chemically analogous to calcium, so plants and animals take it up and deposit it in bone and milk just as they would calcium, and its 28.8-year half-life lets it persist and accumulate through successive links of the food chain — this is the textbook example of a bioaccumulative fission product. Iodine-132 cannot compete for this role because its half-life is only about 2.3 hours, decaying away long before it could biomagnify through a food chain (its longer-lived isotope Iodine-131, half-life 8 days, is the one of concern for thyroid uptake, and even that is far shorter-lived than Sr-90). Thorium-232 and Radium-226, while long-lived, are not chemically mimicked by any essential nutrient and so are not readily taken up and concentrated by living tissue in the same way. This confirms Strontium-90 (option A) as correct.

Article 51-A(g) of the Indian Constitution, under the Fundamental Duties, obligates every citizen to protect and improve the natural environment.

Photosynthesis consumes atmospheric CO2 rather than releasing it, unlike combustion of fossil fuels, volcanic eruptions, and respiration/decay, which are all sources of CO2.

Only about 1% of the world's total water supply is easily accessible fresh water for human use, since most freshwater remains locked in glaciers, ice caps, or deep groundwater.

The maximum permissible limit for fluoride in drinking water, in the absence of an alternate source, is 1.5 mg/l as per BIS/WHO standards.

The Water (Prevention and Control of Pollution) Act, 1974 was India's first major environmental protection legislation, preceding the Air Act (1981) and the Environment (Protection) Act (1986).