Water in the UK (Water Companies, Regulators and Stakeholders)
Always there, clean, safe and abundant; water, the
essence of life. We need it every day, but we often forget
that safe drinking water starts way before it gets to our
tap, before the pipes that lead to our home, even before
the complicated process of treatment and disinfection
that makes raw water drinkable. It starts at the source. Our source water can come from
surface water, such as rivers, lakes and streams or groundwater; the aquifers that lie
beneath the Earth. Public water suppliers tap into these sources to provide us with our
Flocculation is the process in which colloids aggregate or come together to form larger
particles called flocs by the addition of a chemical called flocculant.
Typical flocculants include Alum (Hydrated Aluminium Sulphate) and Ferrix (Commercial Iron
Salts) because they work well with high turbidity fluid mixtures. Almost all colloids have
negatively charged surfaces which means that positive ions or charged particles in the
water will attract to the colloid surface forming a first layer. A diffuse layer made up of a mix
of positive and negative ions will then surround the first, forming what is called a double
layer area. This double layer area provides a repulsive force that prevents two colloids from
sticking to each other. Once the flocculant is added, it adheres to the surfaces of the
particles, compressing the double layer and allowing the colloids to stick to each other and
form flocs. These flocs are now heavy enough to settle to the bottom by gravity