Who should Consider Point-Of-Entry Treatment?An affirmative answer to any one of the following questions suggests that point-of-entry water treatment may be a desirable option for a small community:
- Does the small number of homes served by the water system, or another factor, make centralized water treatment prohibitively expensive?
- Is the majority of the water distributed by the system used for purposes other than domestic water supply (e.g. agricultural irrigation)?
- Is there low confidence in the integrity of the distribution system (i.e. risk of contamination from within the distribution system due to aged pipes)?
- Are there any contaminants present in the water that require treatment for health reasons that are not easily addressed with conventional centralized treatment equipment (heavy metals, arsenic, uranium, sodium, nitrates, etc.)
- Do the community residents have a strong aversion to traditional centralized water treatment due to perceived esthetic (taste/odor) issues?
- Does the source water contain an elevated level of organics that would be expected to result in the formation of harmful disinfection by-products such as trihalomethanes if chlorine was used as a primary disinfectant?
The primary advantages of POE treatment are economic. For small communities, POE treatment is often cheaper, faster to install, simpler to maintain and operate, and easier to get community support to implement. As communities grow in size, the balance shifts and centralized treatment typically becomes more attractive. Point-of-entry water treatment is most often considered by relatively small communities with less than 40 connections (homes). As a general rule, the smaller the community, the more attractive POE will be from an economic perspective. However, there are rare instances where POE treatment can be an attractive choice for much larger communities. There are a limited number of larger communities in Canada consisting of more than 200 homes that have either installed or strongly considered POE treatment. The communities in B.C. that have been implemented POE treatment to meet their obligations under the Act and Regulations generally have 15 or fewer connections.
One of the most common reasons that POE treatment is so popular with small water systems is the negative perception of centralized treatment involving chlorination. Despite the fact that the chlorination of water is one of the greatest public health advances in human history, it has a very negative perception due to the change in taste and smell it creates, and concerns that it may be toxic. These are all very valid considerations. However, it should be conveyed to community members that chlorine is very easy to remove once it has disinfected the water and made it safe to consume. There is a very wide array of low cost filters that can remove the chlorine ranging from "Brita" style pitcher filters to whole house activated carbon filters. If POE is under consideration as a treatment option solely because of community opposition to chlorination on the basis of these perceptions, it is strongly recommended that community members be educated in the options to remove chlorine from their water. In many cases, some simple education of this fact can go a long way. Performing centralized treatment and then allowing concerned homeowners to remove the chlorine once it reaches their home is perfectly acceptable, and may be much more cost effective.