WAMITAB - Chartered Institution of Wastes Management Recycling and Resource Recovery Questions and Answers — Questions and Answers
Question 1: A Materials Recovery Facility (MRF) needs to separate aluminium cans from a mixed stream of dry recyclables that has already had ferrous metals removed. Which piece of equipment is specifically designed for this purpose?
- Trommel Screen
- Near-Infrared (NIR) Sorter
- Eddy Current Separator (Correct answer)
- Air Classifier
Correct answer: Eddy Current Separator
An Eddy Current Separator uses a powerful rotating magnetic field to induce an electric current (an eddy current) in non-ferrous metals like aluminium. This creates a secondary magnetic field that repels the metal, causing it to be ejected from the main waste stream. Trommels separate by size, NIR sorters separate plastics by polymer type, and air classifiers separate by density.
Question 2: The PAS 110 specification is a critical quality standard in the UK resource recovery sector. To what waste treatment process and its primary output does it apply?
- The recycling of waste aggregates into secondary construction materials.
- Production of Refuse Derived Fuel (RDF) for energy recovery.
- In-Vessel Composting and the resulting compost-like output.
- Anaerobic Digestion and the resulting whole digestate. (Correct answer)
Correct answer: Anaerobic Digestion and the resulting whole digestate.
Publicly Available Specification (PAS) 110 sets the quality criteria for digestate produced by anaerobic digestion (AD). Meeting this standard means the digestate is considered a product, not a waste, allowing it to be used as a biofertiliser without waste management controls. The equivalent standard for compost is PAS 100.
Question 3: Which of the following is considered a major contaminant in a paper and card recycling stream that significantly reduces the quality and value of the final recycled product?
- Grease and food residue from a pizza box (Correct answer)
- Metal staples from office documents
- A plastic window from a billing envelope
- Corrugated cardboard packaging tape
Correct answer: Grease and food residue from a pizza box
Grease and food residue cannot be effectively separated from paper fibres during the re-pulping process, where the material is mixed with water. The oils contaminate the slurry and bond to the fibres, causing defects and quality issues in the new paper product, potentially leading to the entire batch being rejected. While other items are contaminants, modern MRF processes are better equipped to remove them.
Question 4: An Energy from Waste (EfW) facility produces two primary solid residues from the combustion process: Incinerator Bottom Ash (IBA) and Air Pollution Control residues (APCr). Which statement correctly distinguishes between them?
- IBA is a hazardous residue sent to specialist landfill, while APCr is a non-hazardous material used as an aggregate.
- IBA is the non-combustible material from the furnace grate, often recycled as aggregate, while APCr is the hazardous fly ash captured from the flue gas. (Correct answer)
- Both IBA and APCr are non-hazardous and are typically used together in construction projects.
- IBA is the fine particulate matter captured by filters, while APCr is the coarse residue from the bottom of the furnace.
Correct answer: IBA is the non-combustible material from the furnace grate, often recycled as aggregate, while APCr is the hazardous fly ash captured from the flue gas.
Incinerator Bottom Ash (IBA) is the bulky, non-combustible residue left after combustion, which, after treatment, is often used as a secondary aggregate. Air Pollution Control residues (APCr), or fly ash, consist of the fine particles and chemical residues captured by the flue gas treatment system. APCr is classified as hazardous waste due to the concentration of pollutants and requires specialist disposal.
Question 5: In the context of household recycling collections, what is a primary advantage of a 'kerbside sort' system compared to a 'co-mingled' system?
- Collection rounds are significantly faster and require less specialised vehicles.
- It generally results in higher quality recycled materials with lower contamination rates. (Correct answer)
- It requires less public education and participation to be effective.
- It allows for a much wider range of materials to be collected from households.
Correct answer: It generally results in higher quality recycled materials with lower contamination rates.
In a kerbside sort system, materials are separated by the resident and/or the collection crew at the point of collection. This minimises cross-contamination (e.g., broken glass mixed with paper), resulting in cleaner material streams that have a higher value and are more desirable to reprocessors. Co-mingled systems rely on a Materials Recovery Facility (MRF) for separation, which often leads to higher contamination levels.
Question 6: A recycling facility processes various polymers. Which of the following plastic types is one of the most widely recycled in the UK, with a strong end-market, and is commonly used for beverage bottles and food trays?
- Polyvinyl Chloride (PVC)
- Polyethylene Terephthalate (PET) (Correct answer)
- Polystyrene (PS)
- Polypropylene (PP)
Correct answer: Polyethylene Terephthalate (PET)
Polyethylene Terephthalate (PET), identified by the resin code #1, is one of the most commonly and successfully recycled plastics in the UK. It is used extensively for soft drinks bottles, water bottles, and certain food packaging. There is a well-established and strong market for recycled PET (rPET), which is used to make new bottles, polyester fibres for clothing, and other packaging.
WAMITAB - Chartered Institution of Wastes Management Recycling and Resource Recovery Questions and Answers
A Materials Recovery Facility (MRF) needs to separate aluminium cans from a mixed stream of dry recyclables that has already had ferrous metals removed.
Which piece of equipment is specifically designed for this purpose?