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Water treatment requirement in effect across B.C.
To the Editor,
Re: Referendum on loan for water treatment plant planned for fall, June 16.
With reference to your recent articles regarding the City of Nanaimo Water Treatment Plant, we wish to clarify the situation from the Vancouver Island Health Authority.
VIHA has required the City of Nanaimo to upgrade its water system to comply with a ‘4-3-2-1’ surface water treatment policy adopted from the Guidelines for Canadian Drinking Water Quality.
The 4-3-2-1 refers to:
u 4 log (99.99 per cent) inactivation of viruses;
u 3 log (99.9 per cent) removal or inactivation of giardia cysts and cryptosporidium oocysts;
u 2 refers to two treatment processes for all surface drinking water systems;
u 1 for less than one NTU of turbidity in finished water.
Water suppliers are required to provide potable water to all users of their system under the B.C. Drinking Water Protection Act and it is the mandate of Vancouver Island Health Authority to monitor compliance.
The 4-3-2-1 surface water treatment standard is a performance target for water suppliers to ensure they are meeting legislated requirements.
Chlorination alone is not effective at removal or inactivation of all pathogens (including giardia and cryptosporidium). VIHA’s 4-3-2-1 policy improves existing systems by adding additional treatment processes designed to substantially reduce risk to human health.
All existing water suppliers on Vancouver Island using a surface water source and serving populations greater than 500 people per day have been required to produce an implementation plan to meet this policy.
This policy has been applied to 22 existing water systems on Vancouver Island since 2007, including the City of Nanaimo. As well, this policy has been applied as a performance target for all new surface water systems, regardless of size since 1997. It is worth noting that many existing water systems already meet most of this standard.
Each health authority in B.C. is following a similar process and many dozens more water systems are involved provincewide.
It is important to note that British Columbia is one of the last jurisdictions in North America, and in fact among most developed countries, to adopt these objectives.
VIHA notified the City of Nanaimo of the new treatment standard in 2008 and has been working closely with staff there to achieve improvements that specifically meet the city’s needs.
Providing a second treatment process (filtration plant) will significantly reduce the associated risks of a potential waterborne illness for the city’s population and bring the city’s treatment processes in line with the Canadian Drinking Water Quality standards.