KPSC Departmental Exams - Environmental Eng/AEO 2017 — Paper 2 - Specific Paper

In digital image/signal processing, the standard set of statistical noise models includes Gaussian, Rayleigh, Gamma (Erlang), Exponential, Uniform and Impulse (salt-and-pepper) noise; 'black noise' is a colloquial acoustic term (near-silence with rare bursts), not one of these standard statistical noise distributions.

Using the common water-hardness classification (as CaCO3): under 50 mg/l is soft, 50-100 mg/l is moderately hard, 100-200 mg/l is hard, and above 200 mg/l is very hard, so 40-100 mg/l falls in the moderately hard range.

The first-order BOD exertion model gives the BOD exerted up to time t as BODt = L0(1 - e^-kt), where L0 is the ultimate BOD; rearranging shows L0 (BODu) is obtained from this same relationship.

Sedimentation tanks are designed based on the surface loading (overflow) rate, since settling depends on the area available for particles to settle out per unit flow, not on tank depth.

The Safe Drinking Water Act was originally enacted in 1974, not amended then, so it doesn't answer a question about an amendment year. Congress substantially amended the Act in 1986 and again in 1996; since 1986 isn't offered as a choice, 1996 (option B) is the correct amendment year among these options — the 1996 Amendments overhauled the Act with the Contaminant Candidate List and source-water assessment programs. The original marking of 1974 confused the enactment year with an amendment year.

Chronic ingestion of excess fluoride in drinking water damages tooth enamel, causing dental fluorosis (mottling and staining of teeth); at much higher levels it can also cause skeletal fluorosis.

A trickling filter is a fixed-film biological reactor where microorganisms growing on the filter media metabolize and remove the organic (biodegradable) matter present in domestic wastewater.

A skimming tank uses the density difference between water and oil/grease to let the lighter oil and grease float to the surface, where it is skimmed off before further treatment.

A facultative process is one where the microorganisms involved can survive and carry out treatment both in the presence and in the absence of dissolved oxygen, unlike strictly aerobic or strictly anaerobic processes.

Monod's equation for specific bacterial growth rate in the non-inhibitory range is μ = μmax·S/(S + Ks), where S is substrate concentration and Ks is the half-saturation constant.

The head loss through bar screens is commonly estimated using the Kirschmer equation, hL = β(W/b)^(4/3)·hv·sinθ, which accounts for bar shape, spacing, approach velocity head and the angle of the screen.

Aluminium sulphate (alum, Al2(SO4)3·xH2O) is the most widely used and economical coagulant in Indian drinking water treatment plants for destabilizing and settling suspended colloidal matter.

Under India's General Standards for Discharge of Environmental Pollutants (Environment Protection Rules), the permissible BOD5 limit for industrial wastewater disposed on land for irrigation is 100 mg/l.

Chlorination in water treatment is primarily done for disinfection — killing pathogenic (disease-causing) bacteria and other microorganisms to make the water safe for consumption.

Eutrophication near urban centres results from excess nutrients (mainly nitrogen and phosphorus from sewage and runoff) entering water bodies, which triggers excessive algal growth.

The Sodium Adsorption Ratio, used to assess the sodium-hazard/infiltration risk of irrigation water, is defined as SAR = Na / √[(Ca + Mg)/2], with concentrations expressed in meq/l.

ISO 14001 is a documented Environmental Management System standard that must be fully implemented and continually followed, is not a product standard, and is applicable to organizations of any type, size or geographic/cultural setting.

Under India's ambient noise standards (Noise Pollution Rules, framed under the Environment Protection Act), the permissible noise level in residential areas is 55 dB(A) during the day and 45 dB(A) at night.

Sound/noise intensity level in decibels is calculated using the logarithmic relation dB = 10·log10(I/I0), where I0 is the reference intensity corresponding to the threshold of hearing.

The US EPA established the National Ambient Air Quality Standards (NAAQS) in 1970 under the Clean Air Act to set limits for criteria air pollutants.

For small, dense particles settling under gravity in laminar (Stokes) flow, the terminal settling velocity is given by V = d²ρg/18η, derived from Stokes' law balancing gravity, buoyancy and viscous drag.

When the environmental (actual) lapse rate exceeds the dry adiabatic lapse rate, a rising air parcel stays warmer than its surroundings and keeps accelerating upward, a condition called the super-adiabatic (highly unstable) lapse rate.

Tube settlers increase the effective settling area within a sedimentation basin, improving the removal of suspended solids from wastewater before further treatment.

A multiple-port diffuser distributes effluent across the width/depth of the river through several openings, achieving much faster and more complete initial mixing than a single-point or bank outfall.

One-dimensional mixing-zone models assume that the wastewater becomes fully and uniformly mixed across the river's cross-section, simplifying the analysis to variation along the flow direction only.

Burning processed refuse (RDF) in power-plant boilers recovers useful heat from the waste, but because refuse-derived fuel is a less consistent, more corrosive fuel than coal, it also tends to raise operating and maintenance costs — so both effects occur together.

In the trench method of sanitary landfilling, a long narrow trench is excavated, the excavated soil is stockpiled alongside, and waste is placed in the trench and covered daily with this stockpiled soil.

In the early stage of composting, mesophilic microorganisms (thriving at moderate temperatures) dominate and drive most of the initial metabolic breakdown before the pile heats up and thermophiles take over.

The Gaussian plume dispersion model represents the spreading of pollutants downwind using dispersion coefficients derived from the mixing-length/eddy-diffusivity concept of atmospheric turbulence.

As composting progresses, temperatures rise into the thermophilic range, roughly 45°C to 70°C, where heat-loving microorganisms dominate and accelerate decomposition and pathogen destruction.

On the air-quality index scale commonly used in EIA studies (0-100 split into four bands of 25), the 51-75 range is classified as the 'moderate' pollution category.

Chloroform is a nephrotoxic and hepatotoxic solvent; its renal (kidney) toxicity typically manifests 24 to 48 hours after significant exposure, following its metabolism into reactive intermediates.

Fine respirable dust particles roughly in the 0.5 to 3 (up to about 5) micron range penetrate deep into the lung alveoli and, over prolonged exposure, cause fibrotic lung diseases collectively known as pneumoconiosis.

The ventilation coefficient, the product of average wind speed and mixing height, expresses the atmosphere's pollutant-dispersing capacity and is measured in units of m²/sec.

Lymphatic filariasis in humans is caused by thread-like filarial nematodes, chiefly Wuchereria bancrofti (responsible for most cases) and Brugia malayi, both transmitted by mosquito bites.

Under India's Bio-Medical Waste Management Rules, human anatomical waste is segregated into yellow-coloured bags/containers for incineration or deep burial.

Fabric (bag) filters achieve very high particulate collection efficiency but require large housings with many bags and correspondingly high capital/construction costs compared to some other control devices.

Under the water-quality classification scheme, Class A-II sources are those requiring conventional treatment equivalent to coagulation, sedimentation, filtration and disinfection before being used as public water supply.

Potassium permanganate is commonly dosed in water treatment to oxidize taste- and odour-causing compounds (and control iron/manganese) in both surface and ground water.

Adding ammonia after chlorination converts free chlorine residual into combined (chloramine) residual, which persists longer in distribution pipelines and produces fewer disinfection by-products such as trihalomethanes.

Phosphorus is usually the limiting nutrient for algal growth in freshwater lakes, so removing phosphorus from incoming sewage effectively slows down eutrophication.

Deep, high-rate trickling filters packed with modern synthetic media are commonly called 'biological towers' because of their tall, tower-like structure.

Full-scale field pumping tests are conducted on wells to determine aquifer characteristics and evaluate the safe yield (quantity) of water obtainable, typically from shallow wells.

A Parshall flume is an open-channel flow measuring device that develops a fixed relationship between upstream head 'h' and discharge 'Q' under free-flow conditions.

Strong-base anion exchange resins are used in boiler feed water treatment to remove dissolved (soluble) silica, which exists as a silicate anion and can otherwise deposit as hard scale on turbine blades.

Persistent foam in polluted streams historically resulted from non-biodegradable surfactants like alkyl benzene sulphonate (ABS) used in older detergent formulations, which resist microbial breakdown.

The US EPA's list of 13 priority pollutant metals includes antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, thallium and zinc — aluminium is not on this list.

Under India's Bio-Medical Waste (Management and Handling) Rules, 1998, Category 1 waste is defined as human anatomical waste (human tissues, organs, body parts).

On the Ringelmann smoke chart, which grades smoke opacity from 0 to 5 in steps of roughly 20%, chart No. 2 corresponds to about 40% black smoke density.

Respirable Suspended Particulate Matter (RSPM), as used in Indian air-quality monitoring, refers to particles up to 10 microns in diameter and is also designated PM10.

Plutonium-239, a major constituent of spent nuclear fuel, has a half-life of about 24,100 years, making its long-term radioactive decay and storage a major nuclear waste management concern.

Methemoglobinemia ('blue baby syndrome') results from excess nitrate in drinking water, which is reduced to nitrite in the infant gut and oxidizes haemoglobin's iron, impairing oxygen transport.

Leachate is the contaminated liquid formed when rainwater or moisture percolates through solid waste in a landfill, dissolving and carrying out pollutants from the decomposing garbage.

LEED (Leadership in Energy and Environmental Design) provides a rating and certification framework that guides the design and construction of green, resource-efficient and sustainable buildings.

Japan is widely regarded as a global leader in innovative recycling technologies and practices, driven by strict waste segregation laws and limited landfill space.

Air pollution control devices on incinerator stacks (such as fabric filters/ESPs) capture fine particulate and condensed pollutants from the flue gas as fly ash, distinct from the bottom ash left in the furnace.

EPR stands for Extended Producer/Product Responsibility, a policy approach that makes producers responsible for the environmental impacts of their products through their entire life cycle, including post-consumer disposal.

Thermal desorption treatment for dioxin-contaminated soil is typically carried out at around 550°C, high enough to volatilize the dioxins for subsequent capture and destruction without full incineration of the soil matrix.

The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal was adopted in 1989 and entered into force in 1992.

Under India's National Air Quality Index, the 'Good' category for PM10 (24-hour average) corresponds to the 0-50 µg/m³ range.

Per Indian CPCB water-quality tolerance limits for propagation of wildlife and fisheries, free ammonia (as N) should not exceed about 1.2 mg/l, since higher levels are toxic to aquatic life.

WHO guidance for harvested rainwater intended for drinking sets a benchmark of less than 10 CFU of E. coli per 100 ml to indicate acceptably low faecal contamination.

Under Rule 11 of the Solid Waste Management Rules, 2016, the Ministry of Agriculture's duties on compost are a bundled set: providing flexibility in the Fertilizer Control Order (FCO) for the manufacture and sale of city compost, promoting/propagating compost use on farmland, setting up or authorising laboratories to test compost quality, and issuing guidelines on the ratio of compost to chemical fertiliser use — this matches option A precisely. The market-development-assistance (subsidy) role for city compost described in option C is instead a distinct duty assigned to the Department of Fertilizers under the same rule, not the Ministry of Agriculture.

In a flash mixer, alum reacts to form flocs that entrap fine suspended solids, making them heavier so they settle out readily in the following sedimentation stage.

The Schedule to the Hazardous Wastes (Management and Handling) Rules, 1989 explicitly lists Waste Category No. 8 as 'wastes from dyes and dye-intermediates containing inorganic chemical compounds' and Waste Category No. 9 as 'wastes from dyes and dye-intermediates containing organic chemical compounds' (each with its own regulatory quantity threshold calculated as organic vs. inorganic chemicals). This confirms option B as the correct match for Category 9.

Under the National Lake Conservation Plan, lakes with a water-spread area of around 10 hectares or more are generally taken up for conservation and management interventions.

The Central Pollution Control Board's primary water quality criteria for outdoor bathing require total coliform levels (MPN/100 ml) of 500 or less, with lower values being desirable.

ISO 14001 (environmental management) and ISO 9000 (quality management) share the same generic management-system structure — plan, implement, check, review — despite covering different subject areas.

ISO 14031 is the international standard specifically dealing with Environmental Performance Evaluation, providing guidance on how organizations can assess their environmental performance.

Endocrine-disrupting chemicals discharged in wastewater interfere with hormone systems in aquatic organisms, a well-documented effect being intersex characteristics observed in exposed fish and molluscs such as roach and snails.

A Sequencing Batch Reactor treats sewage in a single tank by cycling through fill, aeration (reaction), settling and decanting phases, combining what would otherwise be separate primary settling, aeration and secondary clarification steps in a batch mode.

High-rate activated sludge BIOFOR-type systems use a co-current diffused aeration arrangement that improves oxygen transfer efficiency compared to conventional aeration layouts.

A well-run sewage treatment plant enables treated water reuse (for irrigation, industry, etc.), resulting in substantial savings on fresh water procurement costs.

Gasoline's hydrocarbons are conventionally tabulated with an overall carbon-number span of roughly C4 to C12 (boiling range about 30-210 degrees C), and paraffins spanning C4 to C12 are the standard reference range cited in environmental engineering texts — so option D (C4 to C12) is in fact a genuine gasoline paraffin fraction, not the odd one out. Option C (C4 to C13) extends one carbon number past gasoline's recognized upper limit and does not correspond to any standard gasoline paraffin fraction, making it the correct answer to 'not a component.' The original marking of D was therefore incorrect.

Halons (halogenated hydrocarbons such as Halon 1301) are extremely effective fire-suppressing agents because they chemically interrupt the combustion chain reaction, not just displace oxygen like inert gases.

Ventilation shafts/columns along sewer lines are typically spaced 150 to 300 metres apart to allow adequate release of sewer gases and prevent their accumulation.

Velocity = 10 ft / 4.2 s ≈ 2.38 ft/s, and cross-sectional area = 2.4 ft × 1.8 ft = 4.32 ft²; multiplying gives a flow rate of about 10.3 ft³/sec.

In the activated sludge process, incoming wastewater is aerated together with an admixture of previously aerated (return activated) sludge, which supplies the active microbial biomass needed for treatment.

If solids mass is held constant, reducing sludge moisture from 90% to 80% means the solids fraction doubles (from 10% to 20%), so the sludge volume is halved — a 50% decrease.

Lead inhibits ferrochelatase, the enzyme that inserts iron into protoporphyrin IX during the final step of heme synthesis, which is why lead poisoning disrupts haemoglobin production and causes anaemia.

A key purpose of an Environmental Management System like ISO 14001 is to give an organization an overall structured framework for managing and continually improving its environmental affairs.

Oxygen is the most abundant element in the Earth's crust by weight (about 46%), followed by silicon, aluminium and iron.

Under India's EIA Guidelines/Notification of 1994, Schedule I listed the projects requiring mandatory environmental clearance, the notification applied nationwide to all States and Union Territories, and the Ministry of Environment and Forests was responsible for its implementation.

Coniferous (largely boreal/taiga) forests cover the largest share of the world's total forested area of any single forest biome, more than tropical rainforests or deciduous forests.

India's EIA Notification of 2006 introduced the two-tier classification of development projects into Category A (cleared by the central Ministry) and Category B (cleared by State-level authorities).

Independent verification shows all four statements are individually true: Cr(VI) is well-documented as far more toxic than Cr(III); methylmercury is the mercury species responsible for essentially all human dietary bioaccumulation and neurotoxicity risk (the even-more-lethal dimethylmercury is a distinct, rarely encountered lab compound, not what 'methyl mercury' means in standard toxicology); arsenite As(III) is more toxic than arsenate As(V) because of its higher cell-membrane permeability and enzyme-binding reactivity; and cadmium is genuinely excluded from USEPA's six 'criteria pollutants' (CO, Pb, O3, NO2, PM, SO2) — lead, not cadmium, holds that status. Since no statement is actually false, this question is flawed at the source; option D is retained only because it matches the original key, not because it is demonstrably the incorrect statement.

Ozone (O3) is a classic secondary pollutant, formed in the atmosphere through photochemical reactions between primary pollutants like nitrogen oxides and volatile organic compounds, unlike SO2, CO2 and CO which are emitted directly.

Carbon monoxide is toxic because it binds to haemoglobin far more strongly than oxygen does, forming carboxyhaemoglobin and reducing the blood's oxygen-carrying capacity.

In Murli S. Deora v. Union of India (2001), the Supreme Court of India banned smoking in public places across the country.

Atmospheric CO2 concentration rose from roughly 280 ppm (pre-industrial, historically around 200-250 ppm in earlier estimates) to about 400 ppm today, an increase largely driven by fossil-fuel combustion since the Industrial Revolution.

Temporary (carbonate) hardness of water is caused by the dissolved bicarbonates/carbonates of calcium and magnesium, which precipitate out on boiling — distinguishing it from permanent hardness caused by sulphates and chlorides.

The USGS classifies water with less than 1,000 mg/l (and certainly under 500 mg/l) of total dissolved solids as fresh water, as opposed to slightly, moderately or very saline water.

A minimum dissolved oxygen level of about 4 to 5 ppm is generally prescribed as necessary to support healthy fish survival and reproduction in river streams.

For treating the large sewage volumes of a big city, a sedimentation tank followed by an activated sludge plant is generally recommended because it offers higher treatment capacity and efficiency in a compact footprint compared to trickling filters.

Turbidity is conventionally measured in units such as FTU (Formazin Turbidity Unit), JTU (Jackson Turbidity Unit) or NTU (Nephelometric Turbidity Unit); 'ATU' is not a recognized turbidity measurement unit.

Anaerobic digestion of sludge/wastewater, carried out in the absence of oxygen, breaks down organic matter and produces biogas rich in methane.

Coagulation and flocculation destabilize and clump together fine suspended particles, microorganisms and organic matter into larger flocs so they can be removed by subsequent settling and filtration.

A three-way automotive catalytic converter targets exactly three pollutant classes: it oxidizes carbon monoxide (CO) and unburned hydrocarbons to CO2/H2O while reducing nitrogen oxides (NOx) to N2 — hydrogen is never a targeted combustion pollutant. Among the given options, D (carbon monoxide and nitrogen dioxide) is the only pair drawn from the converter's actual target classes (CO and NOx), confirming D as correct over any option that substitutes hydrogen or carbon dioxide for one of the real targets.

Regulatory threshold limits commonly cap permissible sulphur dioxide concentration from industrial activity at around 5 ppm to limit its respiratory and environmental impact.

Tetraethyl lead was historically added to gasoline as an anti-knock compound to improve octane rating and prevent premature (knocking) combustion in engines, before being phased out due to lead pollution concerns.