Regulations to ensure our water is of high quality Water providers must apply to provincial (or regional) authority to obtain permit to

provide water o In BC, apply to regional health authority o Permit based on parameters in Canadian Drinking Water Quality (CDWQ)

guidelines o Guidelines are not legally enforceable (Federal government does not have

jurisdiction ofver provincial water), but permits are legally enforceable

o CDWQ Guidelines for pathogens o Bacteria No numerical guideline required o Protozoa No numerical guideline required o Viruses No numerical guideline required

Why no guideline??? Too many pathogens to monitor!!!

Instead CDWQ guidelines sets limits for indicator parameters

o E coli: 0/100 mL

E coli is a fecal coliform that is present in the gut of ALL warm blooded animals, and therefore in fecal material

If E coli is present indicates source is contaminated with fecal material

o Total coliform (TC): 0/100mL Sum of fecal coliform (FC) and coliform that originates from

vegetation Approximately 60% of TC is FC Approximately 90% of FC is E.coli Total coliform often used since it is less $$ than E.Coli test

o Turbidity: 0.3/1.0/0.1 NTU

0.3 NTU for conventional sand filtration 1.0 NTU for slow sand filtration 0.1 NTU (i.e. detection limit) for membrane filtration Why different turbidity guidelines for different treatment

processes? o Based on what can be achieved by technology o Maximum detection limit for turbidity (approx 0.1 NTU)

An alternative approach is used by some jurisdictions (US and increasingly in

some Canadian jurisdictions). This alternative considers both limits for indicator organisms, as well as documented performance of existing filtration systems at removing pathogens

The alternative approach considers that filtration only provides part of the treatment to remove pathogens. The remainder is achieved by other means (e.g. disinfection). To achieve full treatment, use the 4-3-2-1-0 guideline

4 log removal for viruses 3 log removal for Giardia and Cryptosporidium 2 treatment barriers (e.g. filtration + disinfection) 1 NTU maximum 0 Total Coliform

What is a log removal (LR)

o LR = log finalConcOfPathogenInitialConcOfPathogen

90% removal is 1 LR 99% removal is 2 LR

Based on a survey of the operating performance of existing filtration

systems, if a system can achieve 1.0 NTU for slow sand filter or 0.3 NTU for conventional sand filters, filtration should be able to achieve 2 log removal for viruses and 2 log removal for Giardia and Cryptosporidium. For membrane filtration depends on the type of membrane. Therefore, can determine how much treatment, in addition to filtration, is required.

Example: For conventional sand filtration that achieves 0.3 NTU

You need to provide 4 LR for viruses, and filtration provides 2 LR, then you still need to provide an additional 2 LR (e.g. through disinfection).

You need to provide 3 LR for Giardia and Gryptosporidium, and filtration provides 2 LR, then you still need to provide an additional 1 LR (e.g. through disinfection).

Filtration and disinfection provides 2 barriers The treated water is < 1 NTU (which is achieved since NTU is 0.3) The treated water has a Total Coliform of 0