| #Q001 | design | treatment | recommended | Municipal Treatment Process Selection Considerations | drinking water | The selection of an appropriate treatment process for a specific water supply will depend on many factors, including the characteristics of the raw water supply, the concentration of the contaminant and the operational conditions of the specific treatment method. These factors should be taken into consideration to ensure that the treatment process selected is effective for the reduction of TEX in drinking water. | When selecting an appropriate municipal-scale treatment process. | high |
| #Q002 | design | treatment | recommended | GAC Process Design Considerations | drinking water | The selection of GAC for removing VOCs from drinking water supplies should factor in the following process design considerations: carbon usage rate, empty bed contact time (EBCT), type of adsorbent, pretreatment of the raw water, contactor configuration (e.g., beds in series or parallel operation) and method of GAC regeneration or replacement. | When selecting Granular Activated Carbon (GAC) for removing VOCs. | high |
| #Q003 | design | treatment | recommended | Consideration of Ozonation and AOP By-products | drinking water | The formation of by-products from the oxidation and/or advanced oxidation of VOCs or other inorganic compounds in the source water should be considered when using these processes. | When using Ozonation and Advanced Oxidation Processes (AOPs). | high |
| #Q004 | treatment | treatment | recommended | Avoidance of Additional Residential Treatment on Municipal Water | drinking water | Generally, it is not recommended that drinking water treatment devices be used to provide additional treatment to municipally treated water. | For homes receiving municipally treated water. | high |
| #Q005 | treatment | health | recommended | Use of Certified Residential Treatment Devices | drinking water | Health Canada does not recommend specific brands of drinking water treatment devices, but it strongly recommends that consumers use devices that have been certified by an accredited certification body as meeting the appropriate NSF International (NSF)/American National Standards Institute (ANSI) drinking water treatment unit standards. | When consumers use private residential drinking water treatment devices. | high |
| #Q006 | monitoring | operational | recommended | Periodic Testing of Residential Treatment Devices | drinking water | Periodic testing by an accredited laboratory should be conducted on both the water entering the treatment device and the water it produces to verify that the treatment device is effective. | When using point-of-entry treatment devices or custom constructed systems. | high |
| #Q007 | operational | operational | recommended | Verification of Component Longevity | drinking water | Consumers should verify the expected longevity of the components in their treatment device as per the manufacturer's recommendations. | When maintaining residential drinking water treatment devices. | high |
| #Q008 | design | operational | recommended | Reverse Osmosis Installation Location | drinking water | RO systems should only be installed at the point of use as the water they have treated may be corrosive to internal plumbing components. | When installing reverse osmosis (RO) systems in residential settings. | high |
| #Q009 | treatment | operational | guidance | Pretreatment for Reverse Osmosis Membranes | drinking water | A consumer may need to pretreat the influent water to reduce the fouling and extend the service life of the membrane. | When using residential reverse osmosis (RO) systems. | medium |
| #Q010 | operational | operational | guidance | GAC Operational Considerations | drinking water | Operational considerations may also include the need to ensure a proper backwash, maintain the bed depth and bed density after backwashing and control the flow rate. | When using GAC adsorption contactors | high |
| #Q011 | treatment | treatment | guidance | PTA Off-gas Treatment | drinking water | As PTA transfers VOCs from water to air, treatment of the stripping tower off-gas to reduce the contaminant concentrations prior to discharge into the atmosphere may be necessary | When using Packed Tower Aeration (PTA) | high |
| #Q012 | treatment | operational | guidance | Post-Aeration Corrosion Control | drinking water | Post treatment, such as the use of a corrosion inhibitor, may also be required to reduce corrosive properties of the water due to increased dissolved oxygen from the aeration process. | Post-treatment for air stripping processes | high |
| #Q013 | treatment | treatment | guidance | AOP By-product Management | drinking water | The formation of by-products may require additional treatment following AOPs and/or process optimization to minimize by-product formation. | When using Advanced Oxidation Processes (AOPs) | high |
| #Q014 | design | operational | mandatory | GAC Pretreatment for Clogging | drinking water | To prevent the bed from clogging, pretreatment of the water before it enters the GAC contactor is often required (Snoeyink, 1990; Speth, 1990; AWWA, 1991; Crittenden et al., 2005). | Before water enters a GAC contactor | high |
| #Q015 | operational | operational | guidance | Multi-bed GAC Operation Allowance | drinking water | In systems with multiple beds, the individual beds can be operated beyond the time of initial breakthrough, provided the blended effluents still meet the treatment objectives. | In GAC systems with multiple beds | high |
| #Q016 | design | treatment | guidance | Custom Residential Treatment System Construction | drinking water | Where certified point-of-entry treatment devices are not available for purchase, systems can be designed and constructed from certified materials. | Where certified point-of-entry treatment devices are not available for purchase | high |
| #Q017 | administrative | operational | mandatory | Certification Body Accreditation | drinking water | Certification organizations provide assurance that a product conforms to applicable standards and must be accredited by the Standards Council of Canada (SCC). | For organizations certifying drinking water devices and materials in Canada | high |
| #Q018 | operational | operational | mandatory | GAC Media Replacement | drinking water | Once the GAC is exhausted, it is removed from the contactor and replaced with fresh or regenerated GAC. | When GAC media is exhausted | high |
| #Q019 | operational | operational | mandatory | Residential Device Maintenance | drinking water | Devices can lose their removal capacity through usage and time and need to be maintained and/or replaced. | For private residential drinking water treatment devices | high |
| #Q020 | treatment | operational | guidance | PTA Fouling Prevention Methods | drinking water | Methods to prevent fouling of the column include pH suppression of the influent, using scale inhibitors or iron removal prior to the PTA application. | When operating Packed Tower Aeration (PTA) systems | high |
| #Q021 | treatment | operational | guidance | Fenton's Process pH Adjustment | drinking water | it should be noted that a pH adjustment may be needed after this treatment process [Fenton's reagent]. | When using AOP with Fenton's reagent | high |
| #Q022 | design | operational | mandatory | GAC Design Data Sources | drinking water | When designing a GAC system, relevant information and operational parameters are obtained from pilot plant experiments, rapid small-scale columns test (RSSCT) and vendor experience. | During the design phase of a GAC treatment system | high |
| #Q023 | design | health | recommended | Point-of-Entry System Preference | drinking water | Point-of-entry systems are preferred for the reduction of VOCs such as TEX, because they provide treated water for bathing and laundry as well as for cooking and drinking. This will reduce the potential for VOC exposure through inhalation. | For residential treatment of VOCs such as toluene, ethylbenzene, and xylenes. | high |
| #Q024 | design | treatment | mandatory | PAC Contact Time and Mixing Requirement | drinking water | Sufficient contact time is necessary, and the time required is a function of the characteristics and the concentration of the contaminant to be adsorbed (Najm et al., 1991). | When using Powdered Activated Carbon (PAC) for VOC removal at municipal treatment plants. | high |
| #Q025 | operational | operational | recommended | Combined Technology Operational Considerations | drinking water | The common operational problems inherent to PTA systems and GAC adsorption contactors are similar and should be considered when these combined technologies are employed. | When combining Packed Tower Aeration (PTA) and Granular Activated Carbon (GAC) technologies. | high |