Biology Reference
In-Depth Information
through specific UK regulation, such as the Water Supply Regulations, 2010
and the Private Water Supplies Regulation, 2009. 7 The DWI sets forth an
enforcement policy as the independent regulator of drinking water. The
policy indicates that the company's objectives and priorities for the UK for
the 2010-2015 period are as follows:
• Watersuppliersdeliversafeandcleanwater.
• Thepublichasconfidenceinthedrinkingwater.
• Legislationfordrinkingwaterisfitforthepurposeandimplemented
according to the public's interest. 8
The DWI's enforcement policy also indicates that when companies do not
comply with the law and their responsibilities, the DWI is able to use a
variety of civil and criminal options. In the UK, water undergoes a num-
ber of different stages of process for treatment. These stages include the
following:
1. Screening and microstrainers: fine solids and fragments are removed as
water passes through a series of coarse, fine steel and plastic mesh.
2. Aeration: using either “water-fall” or “air diffusion” aerators to reduce
carbon dioxide, dissolve ion and other organic compounds. 9
3. Chemical coagulation: use of chemicals such as aluminum or iron salts
to induce small particulates in the water to agglomerate into larger par-
ticulates called “floc”.
4. Clarification: removal of “floc” through use of either a horizontal flow
of sedimentation tanks or by using millions of air bubbles to float the
particles to the top, allowing them to be removed from the surface. 6
5. Filtration: passing water through a series of porous beds.
6. Activated carbon adsorption: use of a granular or powdered form of
activated carbon in adsorption vessels to remove any trace taste, color or
organic compounds and toxins. 6
7. Disinfection: one of the final stages of the process—use of strong oxi-
dizing chemicals such as chlorine to remove or inactivate pathogenic
organisms such as bacteria, viruses or pathogens. 6 Increasingly many
water companies are looking to use UV light and ozonation to disinfect
their water supplies.
A review of the UK drinking water industry in 2011 was released by the
DWI in July, 2012. The review demonstrates that the quality of public water
is improving and that compliance to EU standards is now achieved within
99.96% of public supplies. However, private supplies have not achieved as
high levels—with 7.2% failing to meet the standards in 2011. 10 Structural
change within the water industry has occurred over the last few years for
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