Key term
CCEA A-Level Environmental Technology 3930
Fossil Fuels
Global Action on Energy Conservation and Climate Change
Macrogeneration
Microgeneration
Energy From Wind
Topic overviewHorizontal and vertical axis wind turbinesKinetic energy, wind power and the Betz limitPower curves, rated output and energy lossesSwept area, blade length and turbine massAir density, hub height and turbine sitingPower control, yawing and survival speedChoosing a location for a commercial wind farm
Energy From the Sun
Topic overviewSolar radiation, tracking and concentrating solar powerFlat plate and evacuated tube collectorsSizing a domestic solar thermal systemPhotovoltaic cells and semiconductor wafersTypes of photovoltaic module comparedPlanning regulations and solar incentivesPassive solar design in new and existing buildings
Energy From Biomass
Energy Storage
Plastics for the Future
Topic overviewCrude oil as a fuel and a feedstockRefinery gases and the making of polymersPersistent plastic waste and the Great Pacific Garbage PatchToxic gases from incinerating plasticsBiodegradable, photodegradable and compostable plasticsTesting photodegradable plastic against polytheneBio-derived polyethylene and a sustainable plastics future
Renewable Energy Investigations
Sustainable Development
Waste Management
Waste to Energy Technologies
Land Contamination and Remediation
Topic overviewContaminated land, risk and traditional remediationBioremediation principles and bioreactor systemsMicro-organisms that degrade named pollutantsBioremediation benefits and genetically engineered microbesPhytoremediation of metals and other elementsPhytoextraction with Indian mustard and alpine pennycressBiohydrometallurgy and phytomining of ores
Hydrogen Fuel Cells
Transport System Challenges
Energy Performance of Buildings
Emerging Technologies
Sustainable Urban and Rural Communities
The Code for Sustainable Homes
Topic overviewPurpose, levels and assessment of the CodeEnergy, carbon dioxide and water categoriesMaterials, surface water run-off and waste categoriesPollution, health and wellbeing, management and ecology categoriesMeasuring the performance of an existing buildingPerformance profiles, improvements and evaluation
Waste to Energy Technologies
- 5 subtopics
- 15 things to know
- A2 1
What Waste to Energy Technologies covers
Waste to Energy Technologies is examined in Unit A2 1, Building and Managing a Sustainable Future, a written examination. It covers embodied energy, incineration with energy recovery, digester design: solids content, residence time and staging, stages of anaerobic digestion and biogas CHP and composting and catering waste.
Where it is assessed
A2 1
Building and Managing a Sustainable Future — a written examination.
Check the CCEA specification ↗The 5 subtopics
Each one has its own page.
- Embodied energyEmbodied energy and embodied carbon, cradle-to-gate and cradle-to-grave, aluminium's high embodied energy, why recycling saves more than burning, recycling calculations, transport distance, buildings and reducing embodied energy.Open →
- Incineration with energy recoveryThe moving-grate energy from waste plant, flue gas cleaning, bottom ash and its uses, volume reduction, advantages and disadvantages, the renewable share, CHP, an energy output calculation, and pyrolysis and gasification of waste.Open →
- Digester design: solids content, residence time and stagingLow-solids and high-solids digestion, suitable wastes, total solids and hydraulic residence time calculations, mesophilic and thermophilic residence times, and single-stage and multistage digesters.Open →
- Stages of anaerobic digestion and biogas CHPPretreatment and pasteurisation, hydrolysis, acidogenesis, acetogenesis and methanogenesis, why methanogens are sensitive, CHP from biogas, the parasitic load, and biogas energy and CHP output calculations.Open →
- Composting and catering wasteHow composting works, aeration and the carbon to nitrogen ratio, the thermophilic stage, windrow and in-vessel composting, catering waste and the animal diseases it can spread, where it must go, and composting against anaerobic digestion.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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Why does recycling a material save more energy than burning it in an energy from waste plant?
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What is an energy from waste plant?
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What does anaerobic digestion of waste produce?
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Why is waste mechanically pretreated before anaerobic digestion?
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What is composting?
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Outline how a moving-grate incinerator recovers energy from waste.
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What is meant by low-solids anaerobic digestion?
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Why must food waste containing animal by-products be pasteurised in an AD plant?
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What types of waste can be treated by composting?
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Define embodied energy.
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How are the flue gases from an energy from waste plant cleaned?
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What is meant by high-solids anaerobic digestion?
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What happens during hydrolysis in anaerobic digestion?
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Why must a compost heap be turned or aerated?
Take Waste to Energy Technologies further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Incineration vs Pyrolysis
Incineration: burning waste in excess air to release heat. Pyrolysis: heating waste without oxygen to give gas, oil and char.
Low-solids digestion vs High-solids digestion
Low-solids digestion: wet anaerobic treatment of pumpable slurry under about 15% dry matter. High-solids digestion: dry anaerobic treatment of stackable feedstock of about 20–40% dry matter.
Single-stage digester vs Multistage digester
Single-stage digester: one vessel in which every microbial step happens together. Multistage digester: separate vessels for acid formation and methane formation.
Questions from this topic
Each one with the model answer underneath.
- 1
Define embodied energy.
Model answer
Embodied energy is the total energy used to produce a product. The total covers extracting raw materials, processing, manufacturing and transporting them.
- 2
What is the difference between cradle-to-gate and cradle-to-grave embodied energy?
Model answer
Cradle-to-gate counts energy from extraction until the product leaves the factory. Cradle-to-grave also includes use, maintenance and final disposal.
- 3
In what units is the embodied energy of a material usually quoted?
Model answer
Embodied energy is usually quoted in megajoules per kilogram (MJ/kg). A product's total is found by multiplying by its mass.
- 4
Why does aluminium have a very high embodied energy?
Model answer
Aluminium ore must be mined, refined into alumina and then smelted by electrolysis. The electrolysis stage uses very large amounts of electricity.
- 5
How does recycling preserve embodied energy?
Model answer
Recycled material skips the extraction and primary processing stages. Much of the energy already invested in the material is kept in use.
- 6
Why does burning a material for energy recover less than recycling it saves?
Model answer
Incineration recovers only the material's calorific value. The energy used to extract, refine and manufacture the material is lost for good.
What is inside Levo
Six ways to work the same material.
Waste to Energy Technologies revision questions
- What does Waste to Energy Technologies cover in CCEA A-Level Environmental Technology?
- 5 subtopics: embodied energy, incineration with energy recovery, digester design: solids content, residence time and staging, stages of anaerobic digestion and biogas chp and composting and catering waste. Each one has its own page with questions and model answers.
- How is Waste to Energy Technologies organised?
- By the CCEA 3930 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Waste to Energy Technologies, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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