| #Q001 | treatment | operational | guidance | Pretreatment for GAC Contactors | drinking water | To prevent clogging of the bed, pretreatment of the water prior to the GAC contactor is often required (Snoeyink, 1990; Speth, 1990; Crittenden et al., 2005). | When using granular activated carbon (GAC) adsorption contactors. | high |
| #Q002 | treatment | treatment | guidance | PTA Off-gas Treatment | drinking water | As the PTA transfers VOCs from water to air, treatment of the stripping tower off-gas to decrease the contaminant concentrations prior to discharge into the atmosphere may be necessary (Crittenden et al., 1988; Adams and Clark, 1991). | When using packed tower aeration (PTA). | high |
| #Q003 | treatment | operational | guidance | PTA Post-treatment Corrosion Inhibition | 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. | Following the use of packed tower aeration (PTA). | high |
| #Q004 | operational | operational | recommended | AOP Operational Issues Consideration | drinking water | Specific operational issues should be considered when using each of the above-described AOP technologies. | When using advanced oxidation processes (AOPs). | high |
| #Q005 | operational | health | recommended | AOP By-products Consideration | drinking water | The formation of by-products from the oxidation and/or advanced oxidation of tetrachloroethylene or other inorganic or organic compounds in the source water should be considered when using these processes. | When using oxidation and/or advanced oxidation processes. | high |
| #Q006 | treatment | treatment | guidance | Additional Treatment for AOP By-products | drinking water | The presence of by-products may require additional treatment following AOPs and/or process optimization to minimize by-product formation. | Following the use of advanced oxidation processes (AOPs) that result in by-product formation. | high |
| #Q007 | operational | health | recommended | Fenton Oxidation By-products Consideration | drinking water | The formation of by-products such as TCA should be considered when using AOPs such as Fenton oxidation (Yoshida et al., 2000). | When using AOPs such as Fenton oxidation. | high |
| #Q008 | prohibition | unknown | recommended | Prohibition of Additional Treatment for Municipally Treated Water | drinking water | Generally, it is not recommended that drinking water treatment devices be used to provide additional treatment to municipally treated water. | When utilizing municipally treated water. | high |
| #Q009 | monitoring | operational | recommended | Residential Treatment Device Testing | 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 residential drinking water treatment devices. | high |
| #Q010 | operational | operational | mandatory | Residential Treatment Device Maintenance | drinking water | Devices can lose their removal capacity through usage and time and need to be maintained and/or replaced. | When using residential drinking water treatment devices. | high |
| #Q011 | administrative | operational | recommended | Component Longevity Verification | drinking water | Consumers should verify the expected longevity of the components in their treatment device as per the manufacturer's recommendations. | When using residential drinking water treatment devices. | high |
| #Q012 | design | health | recommended | Use of Certified 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 select drinking water treatment devices. | high |
| #Q013 | administrative | unknown | 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 |
| #Q014 | design | operational | recommended | Reverse Osmosis System Installation | drinking water | Reverse osmosis 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 residential reverse osmosis systems. | high |
| #Q015 | operational | operational | mandatory | GAC Operational Maintenance | drinking water | Operating considerations include the needs 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 |
| #Q016 | operational | operational | mandatory | UV System Operational Management | drinking water | The common operating issues related to the use of UV radiation are UV lamp replacement, regular removal of the suspended particles that coat the quartz tubes housing the UV lamps and ensuring low levels of colour and turbidity of the water. | When using UV radiation as part of an AOP. | high |
| #Q017 | design | treatment | guidance | Custom POE System Design | drinking water | Where certified point-of-entry treatment devices are not available for purchase, systems can be designed and constructed from certified materials. | When certified point-of-entry (POE) systems are unavailable for purchase. | high |
| #Q018 | treatment | operational | guidance | PTA Fouling Prevention Methods | drinking water | Methods to prevent the fouling of the column include pH suppression of the influent, use of scale inhibitors or iron removal prior to the PTA application (U.S. EPA, 1984; Dyksen, 2005). | When using packed tower aeration (PTA) systems. | high |
| #Q019 | operational | operational | guidance | Multi-bed GAC Operation | drinking water | In systems with multiple beds, the individual beds can be operated beyond the time of initial breakthrough, provided the contaminant concentration in the blended effluents still meets the treatment objectives. | In GAC systems utilizing multiple beds. | high |
| #Q020 | operational | treatment | mandatory | GAC Exhausted Media Replacement | drinking water | Once the GAC is exhausted, it is removed from the contactor and replaced with fresh or regenerated GAC. | When the granular activated carbon media is exhausted or treatment objectives can no longer be met through blending. | high |
| #Q021 | operational | treatment | mandatory | PAC Contact Time Requirement | drinking water | Sufficient contact time, a function of the characteristics and the concentration of the contaminant to be adsorbed, is necessary (Najm et al., 1991). | When applying powdered activated carbon (PAC) for VOC removal. | high |