N4-Advanced Oxidation Disinfection

Many industrial facilities are presently chlorinating their intake water to control biofouling.  This practise has also been successfully applied to control potentially problematic zebra mussel infestations.  Even though chlorination is a proven and cost effective strategy for biofouling control, investigations have revealed that it is having an adverse impact on the environment. The major concerns being focused on the formation of chlorinated organic byproducts that have the potential to impact on the environment and general health of the planet.

Due to results from these investigations, the MOEE has stated that its goal is to try to find effective and environmentally friendly alternatives to chlorination.

To help achieve this goal, the use of Advanced Oxidation Processes (AOPs) may be a solution.  Research performed in this area indicate potential treatment strategies using combinations such as:

  • ultraviolet light and ozone
  • ultraviolet light and peroxide
  • ozone and peroxide (Peroxone Process)

The important point here is that an oxidizing residual be maintained in the water system, downstream of the chemical injection point. With regards to the peroxone process, the formation of the hydroxyl free radical has been found to be very potent and is able to maintain an effective downstream residual concentration. However, this downstream residual is not as effective and long lasting as for free and combined available residual chlorine.

The purpose of this paper is to find out if there is any:

  • interest from industry in investigating this as a potential alternative use product line (eg. additional applications for hydrogen peroxide, ozone, and UV).
  • potential for receiving funding from interested parties for performing preliminary investigations.

The objective of this project will be to investigate the potential treatment strategies through laboratory trials to test the feasibility of applying one or more of the AOP technologies.  More specifically, the resultant AOP residual durations along with biofouling control ability will be compared with sodium hypochlorite.

The objectives of this preliminary work will be to:

  • Perform research review on Advanced Oxidation Processes (AOPs).
  • Develop testing protocols so that AOP strategies can be directly compared with the effectiveness of sodium hypochlorite.  For the effectiveness evaluation, a suitable AOP residual monitoring protocol will be developed.
  • Compare AOP strategies with chlorination by varying dosage rates and measuring mortality rates.  The goal is to determine dosage levels to achieve 100% mortality of the zebra mussels.

This project should provide additional information regarding potentially useful water treatment strategies, as alternatives to chlorination.
If these alternative treatment strategies can be successfully applied to industry (and possibly municipal drinking water plants), it will potentially lessen the potential for environmental impact, as well as enhance the possible applications of the above products.  However, it is recommended that a list of potential reaction by-products be measured to confirm their presence or absence in the treated water.

If the laboratory trials are successful the next step will be to scale up the equipment and to study the different strategies in an industrial and/or municipal environment.

In addition to the above general scope, the identified strategies may be applied to other treatment strategies, such as for the removal of volatile organic compounds (eg. trichloromethane, tetrachloromethane, trichloroethane, etc.) and the reduction of other water and/or air chemical parameters of concern.