2025 CCEA A-Level Environmental Technology 3930 模擬試題連答案詳解

The waste management hierarchy ranks methods from most to least preferred: prevention (not creating the waste in the first place) is the most preferred; reduction (reducing the amount of waste produced) is next; followed by reuse, recycle, energy recovery, and finally disposal as the least preferred.

[2] B1: prevention; B1: reduction/reduce, in that order.

Any one valid pairing: Pseudomonas putida — treats organic solvents; Pseudomonas aeruginosa — treats oil; Dehalococcoides ethenogenes — treats halogenated hydrocarbons.

[2] B1: correct named micro-organism; B1: correct matching pollutant type.

Any two of: copper; cadmium; strontium; rubidium; arsenic; antimony.

[2] B1 each for any two valid named metal contaminants (max 2).

Any two of: steam reforming of fossil gases; electrolysis of water; photocatalytic water splitting.

[2] B1 each for any two valid named methods (max 2).

Rate of heat flow = U value × area × temperature difference.

[2] B1: correct equation structure (three quantities multiplied together); B1: all three terms (U value, area, temperature difference) correctly named.

Tidal stream generator — e.g. SeaGen at Strangford Lough. Tidal barrage — e.g. Rance Estuary, France.

[2] B1: tidal stream generator with valid example; B1: tidal barrage with valid example.

I = environmental impact; P = population; A = affluence (level of consumption/wealth per person); T = damage caused by the technology used to support that consumption.

[2] B1: I, P and A all correctly identified; B1: T correctly identified as the damage/impact caused by technology (accept 1 mark for any three of the four correct if T is missed, examiner discretion within point-marking convention).

Any two of: economic viability; environmental impacts; dependence on fossil fuels; user safety.

[2] B1 each for any two of the four valid challenges (max 2).

Embodied energy is the total amount of energy required to extract raw materials, process them, and manufacture and transport a product or material, up to the point of use.

[1] B1: correct definition referencing total energy to extract/process/manufacture (and, ideally, transport) a product/material.

1. 'Dry tomb' design — the site is lined (e.g. with an impermeable liner) and capped once full, to isolate the waste and minimise the ingress of water; this slows the rate of decomposition and therefore the rate at which methane and leachate are produced, but does not eliminate the need to manage them over the long term.
2. Methane collection — modern sites install a network of pipes to collect methane gas as it is produced; this gas is either flared (burnt off safely) or captured and used to generate electricity/heat, preventing uncontrolled release of this potent greenhouse gas and reducing explosion risk.
3. Leachate collection and 'bioreactor' design — a drainage layer and liner collect leachate, which is then pumped out and treated before disposal; in a 'bioreactor' landfill, leachate is deliberately recirculated back into the waste to keep it moist, accelerating decomposition and increasing the rate (and therefore the efficiency of capture) of methane production for energy recovery, though this also requires robust liner and collection systems to prevent uncontrolled leachate migration into groundwater.

[6] 3 discussion points × 2 marks each ([1] point identified + [1] elaboration/explanation): dry tomb design (lined/capped, isolates waste, slows production); methane management (collection network, flared or used for energy, reduces GHG/explosion risk); leachate management/bioreactor design (drainage/liner, collected and treated, or recirculated to accelerate decomposition for enhanced methane recovery).

1. Mechanical pretreatment — the waste feedstock is shredded/homogenised, increasing its surface area and making it more accessible to microbial breakdown.
2. Hydrolysis — complex organic polymers (e.g. carbohydrates, proteins, fats) are broken down by bacteria into simpler, soluble molecules (e.g. sugars, amino acids, fatty acids).
3. Acidogenesis (and acetogenesis) — these simpler molecules are fermented by acidogenic bacteria into volatile fatty acids, alcohols, ammonia, carbon dioxide and hydrogen; acetogenic bacteria then convert these products further into acetic acid, carbon dioxide and hydrogen.
4. Methanogenesis — methanogenic bacteria (archaea) convert the acetic acid, carbon dioxide and hydrogen into methane and carbon dioxide, forming biogas, which can be collected and used as a fuel to generate heat and/or electricity.

[4] B1 each for correct description, in sequence: mechanical pretreatment (shredding/increasing surface area); hydrolysis (complex polymers broken into simpler soluble molecules); acidogenesis/acetogenesis (fermentation into acids/alcohols/gases, then to acetic acid); methanogenesis (conversion to methane and CO₂/biogas). Chemical equations not required.

Hydrogen gas is supplied to the anode of the fuel cell; at the anode, hydrogen is oxidised (loses electrons), splitting into protons (H⁺) and electrons: H₂ → 2H⁺ + 2e⁻; the electrons cannot pass through the polymer electrolyte membrane, so they are forced to flow through an external circuit, generating an electric current that can do useful work; the protons (H⁺) pass directly through the polymer electrolyte membrane to the cathode; at the cathode, oxygen (usually from air) is reduced, combining with the protons and the electrons (which have completed the external circuit) to form water: O₂ + 4H⁺ + 4e⁻ → 2H₂O; the overall reaction is 2H₂ + O₂ → 2H₂O, releasing electrical energy (and some heat), with water as the only by-product.

[5] B1: hydrogen supplied to anode and oxidised; B1: correct oxidation half-equation/description (H₂ → 2H⁺ + 2e⁻, or equivalent in words); B1: electrons flow through external circuit, generating current; B1: protons pass through the membrane to the cathode; B1: reduction at the cathode — oxygen combines with H⁺ and e⁻ to form water.

1. Production costs — producing hydrogen (e.g. by electrolysis of water) is energy-intensive and therefore costly, and unless the electricity used comes from a renewable/low-carbon source, the environmental benefit of using hydrogen as a 'clean' fuel is undermined by the emissions associated with its production.
2. Safe storage and transport — hydrogen is a highly flammable gas with a very low volumetric energy density (a given volume stores relatively little energy compared with fossil fuels), meaning it must be stored under high pressure or as a cryogenic liquid to be practical; both approaches are technically demanding and costly, and raise significant safety concerns (e.g. risk of leaks/explosion) during storage, transport and refuelling.

[4] 2 discussion points × 2 marks ([1] point identified + [1] elaboration): production costs (energy-intensive/expensive, source of electricity matters for true environmental benefit); safe storage/transport (flammable, low volumetric energy density, requires high-pressure/cryogenic storage, safety concerns).

1. Economic benefit — bioremediation is generally cheaper than traditional treatment methods (e.g. excavation and disposal to landfill, or thermal treatment), as it typically requires less specialised equipment, energy and transport, since the micro-organisms carry out the decontamination in place.
2. Environmental benefit — bioremediation causes much less physical disturbance to the site and its surrounding environment than excavation, and avoids the need to transport and dispose of large volumes of contaminated soil off-site (which reduces both the carbon footprint of transport and pressure on landfill capacity), while breaking pollutants down into harmless products rather than simply relocating them.

[4] 2 discussion points × 2 marks ([1] point identified + [1] elaboration): economic (cheaper, less equipment/energy/transport than traditional methods); environmental (less site disturbance, avoids transport/disposal of contaminated soil, pollutants broken down in situ).

1. Cost advantage — using plants such as alpine pennygrass and Indian mustard provides a low-cost, low-energy method of decontamination compared with traditional methods (e.g. excavation and off-site disposal, or chemical extraction), as it mainly requires the plants to be grown, then harvested and safely disposed of/processed to recover the metal.
2. Environmental advantage — the process causes minimal disturbance to the soil structure and surrounding ecosystem compared with excavation-based methods, and can help maintain or even improve overall soil quality (e.g. organic matter content) over the treatment period.
3. Limitation — phytoremediation using these plants is a comparatively slow process, potentially taking several growing seasons to reduce metal contamination to acceptable levels, which makes it unsuitable where land is needed for rapid redevelopment, and the depth of soil that can be treated is limited by the depth of the plants' root systems, restricting its use where contamination is deep or at very high concentrations.

[6] 3 discussion points × 2 marks each ([1] point identified + [1] elaboration): cost advantage (low cost/energy versus traditional methods); environmental advantage (minimal site disturbance, may improve soil quality); limitation (slow process/several growing seasons, and/or limited by root depth to shallow contamination).

Difference 1 — energy source: tidal stream generators (e.g. SeaGen, Strangford Lough) are underwater turbines that generate electricity directly from the kinetic energy of moving tidal currents, similar in principle to an underwater wind turbine; tidal barrages (e.g. the Rance Estuary, France) are dam-like structures built across an estuary that generate electricity from the potential energy created by the difference in water height between high and low tide, with water released through turbines as the tide changes.
Difference 2 — scale and impact: tidal barrages can generate much larger amounts of electricity from a single site than a tidal stream array, but require a far greater capital investment to construct and have a greater environmental impact on the estuary (e.g. altering natural tidal flow patterns and affecting sediment transport and wildlife habitats); tidal stream generators have a comparatively smaller individual output and environmental footprint, and do not require a barrage structure across the whole estuary.

[4] 2 pairs of [1] identification + [1] explanation: difference 1 — energy source (kinetic current energy for stream generators vs potential/height-difference energy for barrages), with a named example for each; difference 2 — scale/environmental impact (barrages generate more power but at greater cost and environmental impact than stream generators).

A smart system is a system that can sense changes in its environment or operating conditions (using sensors and data), and automatically respond to and adapt its behaviour to these changes, often using automated control and data processing, in order to optimise its performance. Example application: a smart electricity grid uses real-time data on electricity supply and demand to automatically balance the distribution of electricity from multiple sources — including variable renewable/microgeneration sources — reducing energy waste, improving reliability, and making it easier to integrate a higher proportion of renewable energy into the network.

[3] B1: correct definition of a smart system (senses and automatically responds/adapts to changing conditions); B1+B1: valid named example (e.g. smart grid, smart waste management, smart transport system) described with a clear link to environmental management/benefit.

1. Microgeneration and smart grid technology — buildings incorporate their own small-scale renewable energy generation (e.g. solar panels or small wind turbines), and smart grid technology manages the distribution and, where available, storage of this locally-generated electricity efficiently, reducing reliance on centralised, often fossil-fuel-based, power stations.
2. Integrated and flexible transport facilities — a good provision of public transport, together with safe cycling and walking infrastructure, integrated into the urban layout, reduces residents' dependence on private cars and the associated carbon emissions and congestion.
3. Sustainable urban drainage schemes and green spaces — features such as permeable paving, green roofs, and planted drainage channels manage surface water runoff sustainably, reducing flood risk, while green spaces help moderate the urban heat island effect and can support both biodiversity and local food production within the urban area.

[6] 3 discussion points × 2 marks each ([1] point identified + [1] elaboration): microgeneration/smart grid; integrated/flexible transport facilities; sustainable urban drainage/green spaces (heat island, biodiversity, food production) — any three valid characteristics from the specification credited similarly.

Insulation — reduces the rate of heat loss by conduction through the fabric of the building (walls, roof, floor) to the colder outside, by using materials with a low thermal conductivity/low U value.
Air tightness — reduces heat loss caused by uncontrolled draughts, i.e. the infiltration of cold air through gaps and cracks in the building fabric, which would otherwise require additional heating energy to compensate for the resulting heat loss.
Glazing — windows typically have a much higher U value (poorer insulation) than an insulated wall, so the type of glazing used (e.g. double or triple glazing, often with a low-emissivity coating and/or an inert gas fill between panes) significantly reduces heat loss through windows, while still allowing useful solar gain and daylight into the building.

[4] B1: insulation reduces conductive heat loss through the fabric; B1: air tightness reduces heat loss from draughts/uncontrolled air infiltration; B1: glazing (e.g. double/triple glazing) reduces heat loss through windows; B1: additional valid detail (e.g. windows have a comparatively high U value, or glazing still allows solar gain/daylight).

A network of refuelling stations equipped with high-pressure (or cryogenic) hydrogen storage and dispensing equipment would be required, similar in distribution to existing petrol stations; a hydrogen production and supply infrastructure (e.g. electrolysis plants connected to the grid, or delivery by specialised tanker) would be needed to keep these refuelling stations supplied; because hydrogen is highly flammable, dedicated safety infrastructure and staff training would be required at refuelling and storage sites to manage the associated risks.

[3] B1 each for any three valid points: refuelling station network with appropriate storage/dispensing equipment; hydrogen production/supply infrastructure to the refuelling network; safety infrastructure/training due to flammability of hydrogen.

Rate of heat flow = U value × area × temperature difference = 0.30 × 25 × 18 = 135 W.

[2] M1: correct substitution 0.30 × 25 × 18; A1: 135 W (units required).

(a) Saving per can = 1.9 − 0.14 = 1.76 MJ. Total saving for 1000 cans = 1.76 × 1000 = 1760 MJ.
(b) Embodied energy for 1000 virgin cans = 1.9 × 1000 = 1900 MJ. Percentage saving = (1760 ÷ 1900) × 100 = 92.6% ≈ 93% (nearest whole per cent).

(a) [2] M1: 1.9 − 0.14 (= 1.76) × 1000, or equivalent method; A1: 1760 MJ. (b) [1] B1 ft: 93% (accept 92–93%, ft from their (a)).

Indicative content: the cost and environmental impact of linking isolated rural dwellings to water, waste water, energy, communication and transport networks is far higher per dwelling than in dense urban areas, due to low population density spread over a large area; this favours the use of independent/local energy solutions using indigenous resources (e.g. biomass, agricultural waste treatment, small-scale wind power, small-scale district heating), reducing the need for costly, disruptive grid connection; small-scale wastewater treatment (e.g. septic tanks) is often more practical than connecting isolated dwellings to a mains sewage network; local food production and consumption in rural communities brings environmental benefits (reduced 'food miles'/transport emissions), economic benefits (local jobs and income) and social benefits (community cohesion); the impact of communication technologies (e.g. broadband) can improve rural residents' access to services, education and employment without generating the additional travel demand that would otherwise be needed to reach those services in person.

[6] Level 1 (1–2 marks): basic, undeveloped points about rural sustainability; limited specialist vocabulary; basic QWC. Level 2 (3–4 marks): competent discussion of some relevant issues (e.g. two of: service connection cost, independent energy, local food, communication technology) with reasonable explanation; competent QWC. Level 3 (5–6 marks): wide-ranging, well-explained discussion covering at least three distinct issues from the indicative content, with clear, accurate reasoning; accurate specialist vocabulary; clear organisation; accurate QWC.

Indicative content — four key challenges: economic viability (the cost of developing and adopting new transport technologies and the infrastructure to support them); environmental impacts (emissions and habitat/land-use impacts of both existing and new transport systems); dependence on fossil fuels (the need to reduce reliance on a finite, polluting energy source for transport); user safety (new technologies and infrastructure — e.g. hydrogen storage, increased cycling provision — must be demonstrated to be safe for users before widespread adoption).
Strategies to reduce transport demand, and their evaluation: improved/increased public transport provision gives people a viable alternative to private car use and can be very effective in reducing car dependency in dense urban areas, but is generally less viable/cost-effective in rural areas with low population density; promotion of walking and cycling for short journeys requires investment in safe, dedicated infrastructure to be effective and safe, and is most suited to shorter journeys and favourable climates/terrain; fuel and vehicle taxation makes high-emission transport more expensive, incentivising lower-emission choices, but can be criticised as regressive, disproportionately affecting lower-income road users; congestion charging in cities reduces unnecessary car journeys into congested areas and can fund public transport improvements, but similarly raises equity concerns for those who cannot avoid driving; air travel levies discourage frequent or unnecessary flying but may be ineffective for those who can absorb the extra cost, or may simply shift demand rather than genuinely reduce overall travel; use of technology such as videoconferencing can effectively reduce the need for business travel altogether, while apps that support efficient route planning can reduce (but not eliminate) congestion from journeys that still need to be made. A sound evaluative conclusion recognises that no single strategy is sufficient, and that a combination tailored to urban/rural context is likely to be most effective.

[8] Level 1 (1–3 marks): basic identification of one or two challenges and/or strategies, limited explanation or evaluation, limited specialist vocabulary, basic QWC. Level 2 (4–6 marks): competent coverage of most/all four challenges and at least two strategies, with some explanation, but evaluation of effectiveness may be limited or one-sided; competent QWC. Level 3 (7–8 marks): wide-ranging, accurate coverage of all four challenges, with a genuine evaluation (strengths and limitations) of at least two strategies to reduce transport demand, and a sound concluding judgement; accurate specialist vocabulary; clear organisation; accurate QWC.

Indicative content, organised around the three required bullet points:

I = PAT: the environmental impact (I) of human activity is presented as a function of population size (P), affluence/consumption per person (A), and the damage caused by the technology (T) used to support that consumption; as world population and affluence both tend to increase over time, overall environmental impact will also tend to increase unless this is offset by improvements in technology (T) that reduce the damage caused per unit of consumption, e.g. more resource-efficient or lower-emission technologies; this relationship illustrates that reducing environmental impact is not solely a matter of developing better technology — population growth and rising consumption/affluence must also be addressed, which requires policy intervention and individual behaviour change, not technology alone.

Ecological footprint, carbon footprint and One Planet Living: an ecological footprint measures the area of biologically productive land and water required to support an individual's or a nation's consumption, and to absorb the waste this generates; a carbon footprint is a related but narrower measure, focusing specifically on the greenhouse gas emissions associated with an individual's or organisation's activities; both provide a quantitative way to compare environmental impact between individuals, organisations, or nations, and can inform both government policy (e.g. national carbon budgets/targets) and individual choices; One Planet Living (OPL) is a framework of sustainability principles that aims to reduce ecological footprints to a genuinely sustainable level — one that could be supported indefinitely if adopted globally, given the biological capacity of only one planet Earth — and encourages coordinated change in areas such as energy use, transport, food, and waste, at both a government/community level (e.g. through planning policy for OPL-inspired developments) and an individual level (lifestyle choices).

Fossil fuel reliance and renewable/emerging technologies: continued reliance on fossil fuels contributes to the depletion of a finite resource, economic/geopolitical vulnerability associated with energy imports, and environmental damage including greenhouse gas emissions driving climate change; government policy can drive a transition away from fossil fuels through regulation, taxation (e.g. carbon pricing, fuel duty), and investment or subsidy in renewable and emerging technologies (e.g. wind, solar, tidal/wave power, hydrogen fuel cells, carbon capture and storage); such technologies offer lower-carbon alternative ways to meet energy demand, but each presents its own challenges (e.g. cost, intermittency/storage, infrastructure requirements, planning and site availability constraints) that must be managed through policy and continued technological development; individual behaviour change (e.g. reducing overall consumption, adopting microgeneration, choosing more sustainable transport) directly reduces the P and A components of the I=PAT relationship, complementing government policy and improvements in technology (T), rather than replacing the need for them.

A strong answer draws these three strands together in a concluding discussion, for example noting that building a genuinely sustainable future requires coordinated action across all three areas — technology alone cannot compensate for continually rising population and consumption, so government policy (to set the framework and incentives) and individual behaviour change (to act within it) are equally essential.

[15] Level 1 (1–5 marks): basic, fragmented coverage of the topic, likely addressing only one of the three required bullet points in any detail; limited use of specialist vocabulary; basic QWC with errors that may hinder meaning. Level 2 (6–10 marks): competent coverage of at least two of the three required bullet points, with reasonable explanation of most indicative points, though the answer may lack balance across all three bullets, or lack a clear synoptic link between technology, policy and individual behaviour; competent QWC. Level 3 (11–15 marks): wide-ranging, accurate and well-balanced coverage of all three required bullet points, correctly explaining I = PAT, ecological/carbon footprint and One Planet Living, and the challenges/alternatives to fossil fuel reliance; clear, sound synoptic discussion linking the roles of technology, government policy and individual behaviour, with a reasoned concluding judgement; accurate use of specialist scientific/technical vocabulary throughout; clear organisation; accurate QWC.