20-0114 v3.X Chlorination / Dechlorination

Question

Our project is a shopping centre with 40+ different tenancies, as well as end-of trip facilities for staff and public. One component of the project includes on-site wastewater treatment.
After a prolonged period of negotiation with the Authorities Having Jurisdiction (locally called the Environment Protection Authority Victoria and the Victorian State Department of Health), it has been determined that the project must chlorinate our treated water. The purpose of chlorination is to maintain a small residual disinfectant in the pipe network within the project, to appease the AHJ that our water is safe for use. This is especially the case because our building is very public, with an anticipated visitation of over 3 million every year.
We understand that previous projects that are required by their local municipality to use chlorine disinfection must meet the requirements of I05-E3 Chlorine Disinfection, including appealing the requirement, minimising the use of chlorine and adding point of use dechlorination filters.
Whilst we are able to appeal the requirement and only dose the chlorine to the minimum requirement, for our context we do not recommend dechlorination at point of use, for a few reasons:
1. Dechlorination at point of use (a typical system is pictured in the attached) would mean literally hundreds of dechlorination units around the building.
2. In practice, all water leaving our wastewater treatment plant needs to be dosed with chlorine, and then would be dechlorinated only a few metres away.
3. Point of use dechlorination systems rely on activated carbon to absorb chlorine and organic compounds in the water. These cartridges are a consumable and will be consumed rapidly under these circumstances, resulting in a significant additional maintenance demand as well as creating a waste stream.
We fully understand the intent of excluding chlorine from Living Buildings, and support such an aim.
Our request is to not install dechlorination systems and instead continue to advocate to the AHJs to be able to remove chlorination from our treatment train, with the hope that at some point in future will be able to stop chlorinating the water.
Thank you.

Answer

The project may chlorinate its treated wastewater as required by the authority having jurisdiction, in accordance with the existing Chlorine Disinfection Exception, as modified below. The Institute supports the team's proposal to advocate to the AHJ for development of non-toxic treatment methods that provide protection of public health.

I05-E3 7/2009        Chlorine Disinfection
Chlorine disinfection for water uses on projects is allowed if required by the authority having jurisdiction. The chlorine added should be the minimum amount allowed by the code. In addition, the project must include and document point-of-use dechlorination with a 0.5 micron carbon block filter or other approved dechlorination method for all potable end uses.

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