Unit 331 / 5 Water for single-occupancy dwellings – treatment

Multiple Choice

Why is it important to treat water before it is used in buildings?

• To improve taste only

• To ensure safety and suitability for use

• To make it look clearer

• To reduce water pressure

Multiple Choice

Which of the following is a reason why the disinfection stage in water treatment should only be discarded after frequent testing and risk assessment?

• To save costs on chemicals

• To ensure the water supply is pathogen-free on a consistent basis

• To speed up the water treatment process

• To reduce the need for surveys

Multiple Choice

What are some potential risks associated with the use of activated carbon filters in water treatment systems?

• They can increase water hardness

• They may aid the development of micro-organisms

• They remove beneficial minerals

• They make water taste bitter

Multiple Choice

Which of the following disinfection methods is most commonly used for smaller, single-dwelling water supplies?

• Chlorine disinfection

• Boiling

• Ultraviolet irradiation

• Activated carbon filtration

Multiple Choice

Which method is preferred for disinfecting private water supplies in small, single domestic dwellings?

• Ultraviolet irradiation

• Chlorination

• Boiling

• Filtration

Multiple Choice

What is the main function of a type AB air gap with weir overflow on a cistern?

• To prevent backflow contamination

• To increase water pressure

• To filter water

• To store rainwater

Multiple Select

Which of the following processes are part of the multiple-barrier system for water treatment?

• Initial pre-treatment by settling

• Pre-filtration through a coarse media

• Sand filtration

• All of the above

Multiple Select

Which of the following statements about slow sand filters are correct?

• They are suited to small water supplies.

• They use coarse sand with a depth of over 2 meters.

• They remove micro-organisms and turbidity.

• They require micro-straining or coarse filtration before use.

Multiple Choice

What is the main difference between slow sand filters and rapid sand filters in terms of sand size and tank shape?

• Slow sand filters use coarser sand and rectangular tanks, rapid sand filters use finer sand and circular tanks.

• Slow sand filters use finer sand and circular tanks, rapid sand filters use coarser sand and rectangular tanks.

• Both use the same sand size and tank shape.

• Slow sand filters use activated carbon, rapid sand filters do not.

Multiple Choice

Which material is commonly used to make the cylinder of a pressure sand filter?

• Specially coated steel

• Copper

• Plastic

• Aluminum

Multiple Select

Which of the following statements about sedimentation tanks is/are correct?

• Sedimentation tanks slow down water velocity to allow solids to settle.

• The inlet and outlet should be on the same side of the tank.

• Covering the tank helps prevent contamination.

• Simple sedimentation can reduce turbidity.