WAMITAB - Chartered Institution of Wastes Management Waste Treatment Processes Questions and Answers

Question 1

An Energy from Waste (EfW) facility processes municipal solid waste.
The process generates two main solid residues: Incinerator Bottom Ash (IBA) and Air Pollution Control residues (APCr).
How should these two waste streams be managed immediately after production?

Accepted Answer

IBA can be processed for recovery as a secondary aggregate, while APCr must be treated and disposed of as hazardous waste.

Answer

Both IBA and APCr are classified as hazardous and must be sent directly to a hazardous waste landfill.

Answer

Both IBA and APCr can be co-mingled and used as daily cover at a non-hazardous landfill.

Answer

APCr can be recycled directly into construction blocks, while IBA requires stabilisation before any use.

Question 2

Which of the following are the two primary outputs of a successful anaerobic digestion (AD) process when treating source-segregated food waste?

Accepted Answer

Biogas and digestate

Answer

Clean water and inert ash

Answer

Synthetic gas and bio-oil

Answer

High-quality compost and leachate

Question 3

In a Materials Recovery Facility (MRF), what is the primary function of an eddy current separator?

Accepted Answer

To separate non-ferrous metals like aluminium cans from other materials.

Answer

To sort different types of plastic polymers using optical sensors.

Answer

To remove ferrous metals like steel cans using a large magnet.

Answer

To flatten and bale cardboard and paper for transport.

Question 4

When treating catering waste containing meat in an In-Vessel Composting (IVC) facility, which critical control parameter must be met to comply with the Animal By-Products Regulations (ABPR)?

Accepted Answer

Achieving and maintaining a minimum temperature of 60-70°C for a specified period.

Answer

Maintaining a minimum moisture content of 80% for 48 hours.

Answer

Ensuring the pH level of the material remains below 5.0 throughout the process.

Answer

Shredding all incoming material to a particle size of less than 5mm.

Question 5

Which statement best describes the fundamental principle of pyrolysis as a thermal waste treatment process?

Accepted Answer

The thermal decomposition of waste in the complete or near-complete absence of oxygen.

Answer

The controlled combustion of waste with excess oxygen to maximise energy release as heat.

Answer

The partial oxidation of waste using a limited supply of oxygen to produce a syngas.

Answer

The use of a high-temperature plasma arc to vitrify waste into a solid, glass-like slag.

Question 6

A waste stream consists of filter cake contaminated with heavy metals, which fails the WAC leaching tests. Which treatment process is most suitable for immobilising these contaminants to allow for compliant disposal in a non-hazardous landfill?

Accepted Answer

Stabilisation/Solidification

Answer

Incineration

Answer

Anaerobic Digestion

Answer

Autoclaving