Potable water

What is potable water?

Water that has been processed and is safe for human consumption but not necessarily pure (may contain dissolved substances).

What are the key properties of potable water?

- pH between 6.5 and 8.5

- little dissolved substances

- free of bacteria or harmful microbes

Where and how is potable water obtained in the UK?

From fresh water sources (e.g., reservoirs, rivers, lakes)

• Filtration (removes solids like sand and gravel) using a wire mesh screen or passing the water through filter beds to remove undissolved substances

• Sterilisation (kills microbes using chlorine, ozone, or UV light)

what is surface water

water that can collect in lakes, resevoirs etc

what is groundwater

water that collects in aquifiers ( porous rocks that store water underground) underground

How is potable water obtained from seawater?

Through desalination by distillation or reverse osmosis (removes salt but requires lots of energy).

how does desalination workk

distillation - Seawater is heated until it evaporates. Water vapour is cooled and condenses, leaving salt behind.

OR

reverse osmosis - a process that involves the use of membranes. When salt water is put through a semi-permeable membrane, only water molecules can pass through it. This happens as the membrane stops larger molecules and ions passing through

Why is desalination not widely used in the UK?

It requires a lot of energy, making it expensive and unsustainable. Instead it’s used in regions with a very hot climate