Page 264 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

The City & Guilds Textbook: Plumbing Book 1

Air release valve

Inlet
Sand
Air and
Washout wash water
Gravel
inlet

Outlet

Drain

p Figure 5.11 Pressure filter

Sterilisation

Finally, water is treated with chlorine and ammonia before being allowed to
enter the water supply. This will kill off any bacteria missed by the water filters.
Fluoride is still added in some parts of the UK, but only in minute quantities.
Ultraviolet (UV) water treatment uses a simple concept where water passes
through a clear chamber where it is exposed to UV light. This UV light destroys
the majority of bacteria and viruses that are present in the water.

Control
panel Diluting water inlet

C
h Diluting water
l absorption tower
o
r
i
n
e

Water main
with injector
p Figure 5.12 Sterilisation by injection of chlorine

Aeration
Aeration is commonly used to treat groundwater by mixing water with air. This
removes dissolved metals and gases like CO through chemical reactions and
2
physical mixing.

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