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Document ID ca-gcdwqgtd-2015-04-24-7 Title Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Selenium URL https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-selenium/guidelines-canadian-drinking-water-quality-guideline-technical-document-selenium-page-8.html Jurisdiction /ca Subdomain(s) Drinking water, Water treatment process Language en Status completed Analyzed at 2026-03-18 16:16:53.488323+00:00 Relevance Technical guidance on selenium removal technologies and treatment efficiencies.

29 Qualitative 6 Quantitative 18 Definitions

Q Qualitative Requirements (29)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Context	Conditions	Confidence
#Q001	design	treatment	recommended	Ion Exchange Pilot Studies	drinking water	Pilot studies should be conducted in order to verify the effectiveness of ion exchange technology for site-specific water quality.	When considering ion exchange technology for selenium removal.	high
#Q002	design	health	recommended	Ion Exchange Resin Selection	drinking water	To minimize nitrosamine formation, attention should be paid when selecting strong-base ion exchange resins (Kimoto et al., 1980; Najm and Trussell, 2001).	When selecting strong-base ion exchange resins.	high
#Q003	treatment	operational	mandatory	RO Feed Water Pretreatment	drinking water	A pretreatment of the feed water is required to prevent scaling and fouling of the RO membranes.	When using reverse osmosis (RO) membrane systems.	high
#Q004	treatment	treatment	mandatory	RO Product Water Post-treatment	drinking water	The product water typically requires post-treatment, consisting of pH and alkalinity adjustments.	When using reverse osmosis (RO) membrane systems.	high
#Q005	treatment	treatment	mandatory	RO Post-treatment Corrosion Control	drinking water	In most cases, post-treatment corrosion control measures need to be undertaken.	Following reverse osmosis (RO) treatment.	high
#Q006	design	operational	mandatory	Activated Alumina Chemical Handling Consideration	drinking water	Utilities need to consider the chemical handling and disposal requirements prior to selecting this treatment technology (U.S. EPA, 1989, 1998).	Prior to selecting activated alumina treatment technology.	high
#Q007	design	treatment	mandatory	Electrodialysis Pilot Testing	drinking water	Utilities planning to utilize electrodialysis for the reduction of selenium, total dissolved solids and other trace metals would require pilot plant testing of the feed water in order to verify the effectiveness of selenium removal.	Utilities planning to utilize electrodialysis.	high
#Q008	treatment	treatment	recommended	Ferric Oxide Media pH Adjustment	drinking water	At pH values greater than 8.0 to 8.5, pH adjustment is recommended to ensure adsorption capacity is maintained.	When using ferric oxide media at pH values greater than 8.0 to 8.5.	high
#Q009	treatment	operational	recommended	Avoidance of Additional 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 drinking water.	For municipally treated drinking water at the residential scale.	high
#Q010	monitoring	treatment	recommended	Well Water Pre-installation Testing	drinking water	Before a treatment device is installed, the well water should be tested to determine general water chemistry and to verify the concentration of selenium.	Before installing a residential treatment device on a private well.	high
#Q011	monitoring	treatment	recommended	Testing for Competing Ions	drinking water	The testing should also include assessing the presence and concentration of competing ions (e.g., sulphate, nitrate, chloride) and organic matter in the water, which could interfere with selenium removal.	Before installing a residential treatment device on a private well.	high
#Q012	treatment	operational	mandatory	Device Maintenance and Replacement	drinking water	Devices can lose removal capacity through usage and time and need to be maintained and/or replaced.	Over the operational lifespan of residential drinking water treatment devices.	high
#Q013	operational	operational	recommended	Consumer 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 using residential drinking water treatment devices.	high
#Q014	design	health	recommended	Use of Certified 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/ANSI drinking water treatment unit standards.	When selecting residential drinking water treatment devices.	high
#Q015	administrative	operational	mandatory	Accreditation of Certification Organizations	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 certification organizations verifying NSF/ANSI standards in Canada.	high
#Q016	treatment	operational	guidance	Residential RO Feed Water Pretreatment	drinking water	A consumer may need to pretreat the influent water to reduce fouling and extend the service life of the membrane.	When using reverse osmosis (RO) drinking water treatment systems at residential scale.	high
#Q017	operational	operational	mandatory	Ion Exchange Resin Regeneration	drinking water	Once the resin has reached its capacity (i.e., when all the resin sites are occupied by the contaminant ion), the resin must be regenerated to reverse the process.	Once ion exchange resin capacity is reached.	high
#Q018	operational	operational	mandatory	Activated Alumina Bed Regeneration	drinking water	When adsorption sites on the activated alumina surface become filled, the bed must be regenerated.	When adsorption sites on activated alumina are filled.	high
#Q019	operational	operational	mandatory	Activated Alumina Operational Considerations	drinking water	When employing activated alumina technology, operational issues that must be considered include the degradation of activated alumina through the regeneration process and the fouling of the activated alumina bed, resulting in an increase in headloss across the media bed.	When employing activated alumina technology.	high
#Q020	operational	reporting	mandatory	RO Concentrate Disposal	drinking water	the concentrate discharge must be disposed of appropriately.	Disposal of reject water/brine from RO systems.	high
#Q021	design	health	mandatory	NSF/ANSI Standard 61 Selenium Leaching Limit	drinking water	When materials are certified to the standard, the concentration of selenium must not exceed the single product allowable concentration of 0.005 mg/L (NSF/ANSI, 2011a).	For materials certified to NSF/ANSI Standard 61.	high
#Q022	design	treatment	mandatory	NSF/ANSI Residential Device Performance Requirement	drinking water	Drinking water treatment devices certified to NSF/ANSI Standards 53, 58 and 62 specifically for selenium removal, must be capable of reducing the concentration of selenium in water from an influent (challenge) concentration of 0.1 mg/L (added as 0.05 mg/L for Se(IV) and 0.05 mg/L for Se(VI)) to a maximum final (effluent) concentration of 0.05 mg/L (NSF/ANSI, 2009a,b, 2011b).	When devices are certified specifically for selenium removal under NSF/ANSI 53, 58, or 62.	high
#Q023	design	treatment	mandatory	NSF/ANSI 62 TDS Surrogate Performance Requirement	drinking water	Treatment devices certified to NSF/ANSI Standard 62 using TDS as a surrogate, must achieve a minimum TDS reduction of 99.0% from an influent (challenge) concentration of 1000 mg/L(NSF/ANSI, 2009b).	When devices are certified using TDS as a surrogate under NSF/ANSI 62.	high
#Q024	prohibition	treatment	mandatory	Small System BAT Restriction	drinking water	Conventional coagulation/filtration and lime softening processes are not defined as BATs for small systems unless these treatment processes are currently in place (U.S. EPA, 1991c).	For small water systems evaluating Best Available Technologies (BATs) for selenium removal.	high
#Q025	design	treatment	guideline	Residential RO Point-of-Use Limitation	drinking water	RO systems certified to NSF/ANSI Standard 58 (Reverse Osmosis Drinking Water Treatment Systems) are intended for point-of-use installation only.	When using residential RO systems certified to Standard 58.	high
#Q026	design	treatment	guideline	Residential Distillation Point-of-Use Limitation	drinking water	Distillation systems certified to NSF/ANSI Standard 62 (Drinking Water Distillation Systems) are also intended for point-of-use installation only.	When using residential distillation systems certified to Standard 62.	high
#Q027	design	treatment	recommended	Ion Exchange Se(IV) Speciation Consideration	drinking water	The ion exchange behaviour of the monovalent biselenite form (HSeO3−) and divalent form (SeO32−) should be considered, as the monovalent anion is less preferred than the divalent anion (Maneval et al., 1985).	When considering the ion exchange removal of Se(IV).	high
#Q028	operational	operational	mandatory	Manganese Greensand Bed Regeneration	drinking water	When the manganese greensand bed is exhausted, the bed is regenerated to restore its oxidizing capacity.	When using manganese greensand filtration and the bed is exhausted.	high
#Q029	operational	operational	mandatory	Activated Alumina Surveillance and Maintenance	drinking water	The technology requires adequate surveillance and maintenance, including the use of concentrated acids (sulphuric acid or hydrochloric acid) and base (sodium hydroxide) for regeneration of activated alumina.	When employing activated alumina technology.	high

P Quantitative Requirements (6)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Limit Type	Limit Value	Context	Conditions	Confidence
#P001	chemical	treatment	mandatory	Selenium influent challenge concentration	drinking water	requirement	0.1 mg/L	Drinking water treatment devices certified to NSF/ANSI Standards 53, 58 and 62 specifically for selenium removal	added as 0.05 mg/L for Se(IV) and 0.05 mg/L for Se(VI)	high
#P002	chemical	treatment	mandatory	Selenium maximum final effluent concentration	drinking water	MAC	<= 0.05 mg/L	Drinking water treatment devices certified to NSF/ANSI Standards 53, 58 and 62 specifically for selenium removal	must be capable of reducing the concentration of selenium in water to a maximum final (effluent) concentration	high
#P003	physical	treatment	mandatory	Total dissolved solids (TDS) minimum reduction	drinking water	requirement	>= 99.0 %	Treatment devices certified to NSF/ANSI Standard 62 using TDS as a surrogate		high
#P004	physical	treatment	mandatory	Total dissolved solids (TDS) influent challenge concentration	drinking water	requirement	1000 mg/L	Treatment devices certified to NSF/ANSI Standard 62 using TDS as a surrogate		high
#P005	chemical	health	mandatory	Selenium single product allowable concentration	drinking water	MAC	<= 0.005 mg/L	NSF/ANSI Standard 61 (Drinking Water System Components--Health Effects) limits the leaching of selenium into drinking water	When materials are certified to the standard	high
#P006	chemical	treatment	guidance	Selenium treatment goal	drinking water	treatment_goal	0.01 mg/L	Benchmark effluent concentration used to evaluate the effectiveness and breakthrough capacity of various municipal treatment technologies.	Applied as the target effluent limit for performance testing of technologies like Ion Exchange, Activated Alumina, and Manganese Greensand Filtration.	high

D Definitions (18)

Req ID	Name	Context	Confidence
#D001	BATs	best available technologies	high
#D002	SBA	strong base anion	high
#D003	Chromatographic peaking	Chromatographic peaking is a process in which less preferred ions will be concentrated in the column and will, at some time, exit the column in concentrations exceeding their influent concentrations.	medium
#D004	EBCT	empty bed contact time	high
#D005	Mgd	million gallons per day	high
#D006	breakthrough capacity	the amount of selenium adsorbed per litre of activated alumina before the effluent selenium concentration exceeded the treatment goal of 0.01 mg/L.	high
#D007	GFH	Granular ferric hydroxide	high
#D008	RO	reverse osmosis	high
#D009	SCC	Standards Council of Canada	high
#D010	TDS	total dissolved solids	high
#D011	Co-precipitation	involves sorption/inclusion of contaminants to an actively precipitating substrate, resulting in the formation of mixed solid-phase.	high
#D012	Ion exchange	a physicochemical process in which there is an exchange of ions in the raw water with ions within the solid phase of a resin.	high
#D013	contaminant breakthrough	finished water concentrations that increase	high
#D014	Activated alumina	a physicochemical process by which ions in the feed water are sorbed to the oxidized activated alumina surface.	high
#D015	Secondary adsorption	occurs as a joint adsorption of anions with multivalent cations or as a joint adsorption of cations with multivalent anions	high
#D016	Electrodialysis	an electrochemical separation process in which charged species from water are transported through semipermeable membranes under the influence of an electric potential.	high
#D017	Greensand	glauconite, a green, iron-rich mineral that has ion exchange properties.	high
#D018	Biological treatment	uses microorganisms to reduce, oxidize or eliminate groundwater contaminants, either as the sole treatment technique or combined with other conventional physicochemical processes	high