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Document ID ca-gcdwqgtd-2016-01-12-6 Title Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Ammonia URL https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-ammonia/page-8-guidelines-canadian-drinking-water-quality-guideline-technical-document-ammonia.html Jurisdiction /ca Subdomain(s) Drinking water, Water treatment Language en Status completed Analyzed at 2026-03-17 15:22:50.431240+00:00 Relevance Technical guidance on ammonia removal technologies for municipal water treatment.

41 Qualitative 37 Quantitative 34 Definitions

Q Qualitative Requirements (41)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Context	Conditions	Confidence
#Q001	operational	treatment	recommended	Optimization of Biological Nitrification	drinking water	As nitrite is an intermediate compound in the oxidation of ammonia to nitrate in biological filters, utilities should ensure that their system is optimized such that the biological process is complete and nitrite is not present in the treated water.	When using biological treatment (controlled nitrification)	high
#Q002	monitoring	operational	mandatory	Breakpoint Chlorination Monitoring	drinking water	The process requires frequent monitoring of ammonia concentrations and the various forms of chlorine (combined, total chlorine and free chlorine residual) to ensure that breakpoint chlorination is achieved at all times.	When using breakpoint chlorination	high
#Q003	operational	operational	mandatory	Breakpoint Curve Generation and Monitoring	drinking water	It is necessary to generate a breakpoint curve for every plant and to monitor the fluctuation of ammonia to ensure that breakpoint chlorination is always achieved.	When using breakpoint chlorination	high
#Q004	operational	operational	recommended	Experimental Determination of Breakpoint Ratio	drinking water	The breakpoint ratio should be determined experimentally for each water supply (Hill and Arweiler, 2006).	When determining breakpoint ratio	high
#Q005	operational	health	recommended	Maximum Use Limit for Chlorine Compounds	drinking water	Chlorine compounds certified to NSF International (NSF)/American National Standards Institute (ANSI) Standard 60 should respect the maximum use limit (MUL) stated in the standard.	When using NSF/ANSI Standard 60 certified chlorine compounds	high
#Q006	administrative	reporting	recommended	Consultation on MUL Exceedance	drinking water	As exceeding the MUL could invalidate the certification, consultation with the body that has certified the chlorine compound is recommended.	When the responsible authority allows a utility to exceed the MUL for breakpoint chlorination	high
#Q007	operational	health	mandatory	Disinfection Effectiveness	drinking water	However, efforts to limit the formation of disinfection by-products must not compromise the effectiveness of disinfection.	When limiting the formation of disinfection by-products	high
#Q008	operational	treatment	recommended	Permanent Nitrification Control Strategies	drinking water	Utilities should consider more permanent control strategies, such as changes in operation or engineering improvement (Kirmeyer et al., 1995; Hill and Arweiler, 2006).	For nitrification control in the distribution system	high
#Q009	operational	operational	mandatory	Ion Exchange Brine Waste Disposal	drinking water	Regeneration results in a brine waste stream that contains high ammonium concentrations and must be disposed of appropriately, thus increasing the cost of this process.	When regenerating ion exchange resins	high
#Q010	operational	operational	mandatory	Reverse Osmosis Reject Water Disposal	drinking water	The concentrate discharge must be considered and disposed of appropriately.	When using RO treatment	high
#Q011	monitoring	operational	recommended	pH Data Evaluation	drinking water	The pH data should be evaluated carefully, because pH may vary throughout the system depending on factors other than nitrification such as corrosion.	During nitrification monitoring in distribution systems	high
#Q012	operational	operational	mandatory	Chlorine to Ammonia Target Ratio Parameters	drinking water	However, the water quality parameters and utility-specific chlorine demand must be considered when selecting the target ratio (Skadsen and Cohen, 2006).	When selecting the target weight ratio of Cl2:NH3-N	high
#Q013	operational	health	recommended	Chloramine Guideline Compliance	drinking water	An optimization of Cl2:NH3-N ratio should ensure that Health Canada's guideline for chloramines is not exceeded (Health Canada, 1995).	When optimizing the Cl2:NH3-N ratio	high
#Q014	operational	treatment	recommended	Chloramine Demand and Decay Management	drinking water	Chlorine/chloramine demand should be satisfied as much as possible within the treatment plant, and chloramine decay should be minimized in the distribution system, as these reactions increase the free ammonia concentration in the distribution system and trigger nitrification (Baribeau, 2006; Wilczak, 2006b).	To maintain chloramine residual and prevent free ammonia release	high
#Q015	monitoring	operational	mandatory	Nitrification Parameters Monitoring Requirement	drinking water	The treatment plant, the distribution systems and storage facilities all require monitoring for specific parameters.	For potential causes and products of nitrification	high
#Q016	administrative	operational	mandatory	Nitrification Monitoring Program Evaluation	drinking water	A site-specific evaluation is necessary to establish a nitrification monitoring program.		high
#Q017	design	operational	recommended	Alert and Action Levels Identification	drinking water	The program should identify system-specific alert and action levels, which can be used to determine the appropriate level of nitrification response.	As part of the nitrification monitoring program	high
#Q018	monitoring	operational	recommended	Triggered Monitoring Frequency	drinking water	Changes in the trend of these nitrification parameters should trigger more frequent monitoring of other parameters, such as free ammonia.	Upon changes in trends of priority nitrification parameters (total chlorine residual, nitrite, nitrate)	high
#Q019	monitoring	operational	mandatory	Booster Chlorination Testing	drinking water	Free ammonia residual needs to be measured before chemical addition. If sufficient free ammonia is still present, only chlorine needs to be added.	During booster chlorination to recombine released free ammonia in the distribution system	high
#Q020	operational	health	recommended	Chlorite and Chlorate Guidelines Compliance	drinking water	Utilities wishing to use chlorite addition as a control strategy should ensure that the Guidelines for Canadian Drinking Water Quality for chlorite and chlorate (Health Canada, 2008b) are not exceeded.	When using chlorite addition as a nitrification control strategy	high
#Q021	operational	health	recommended	General Strategy Guideline Compliance	drinking water	Any strategy should also ensure that the relevant Guidelines for Canadian Drinking Water Quality (e.g., chloramines) are not exceeded.	When implementing a nitrification prevention or control strategy	high
#Q022	prohibition	health	recommended	Residential Treatment Device Limitation	drinking water	Generally, it is not recommended that drinking water treatment devices be used to provide additional treatment to municipally treated water.	When receiving municipally treated water	high
#Q023	monitoring	operational	recommended	Pre-Installation Water Testing	drinking water	Before a treatment device is installed, the water should be tested to determine general water chemistry and verify the presence and concentration of ammonia.	Before installing a private residential drinking water treatment device	high
#Q024	monitoring	operational	recommended	Periodic Efficacy Testing	drinking water	Periodic testing by an accredited laboratory should be conducted on both the water entering the treatment device and the finished water to verify that the treatment device is effective.	After installing a private residential drinking water treatment device	high
#Q025	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 treatment devices	high
#Q026	design	health	recommended	Use of Certified Treatment Devices	drinking water	Health Canada does not recommend specific brands of drinking water treatment devices, but 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 using private residential drinking water treatment devices	high
#Q027	operational	operational	recommended	Recommended Chlorine-to-Ammonia Weight Ratio Range	drinking water	A weight ratio of Cl2:NH3-N should generally be maintained between 4.5:1 and 5:1 in the plant effluent to enhance the formation of monochloramine and reduce the concentration of free ammonia entering into the distribution system (Harrington, 2003; Kirmeyer, 2004; Skadsen and Cohen, 2006).	In plant effluent to enhance monochloramine formation	high
#Q028	operational	operational	guidance	Source Water Ammonia Consideration for Chloramination Dosage	drinking water	For utilities practicing chloramination, it is important to take into consideration the ammonia concentration in the source water when establishing the ammonia dosage for chloramine formation (Skadsen and Cohen, 2006; Muylwyk, 2009; Shorney-Darby and Harms, 2010).	For utilities practicing chloramination	high
#Q029	operational	treatment	mandatory	Constant Oxygen Feed for Biological Treatment	drinking water	At ammonia concentrations exceeding this oxygen demand, the biological treatment process requires a constant oxygen feed (Lytle et al., 2007; White et al., 2009).	When ammonia concentrations exceed the stoichiometric oxygen demand (4.33 mg O2/mg NH4+ -N)	high
#Q030	treatment	treatment	guidance	Biological Treatment Post-Treatment	drinking water	The finished water typically requires polishing (e.g., granular activated carbon [GAC] filtration) and post-treatment, such as disinfection, to ensure that neither undesirable organisms nor growth products pass into the distribution system (Wilczak, 2006a).	When using biological treatment processes	high
#Q031	operational	operational	guidance	Ion Exchange Corrosion Control Measure	drinking water	In some cases, post-treatment corrosion control measures may need to be taken, to ensure that corrosion problems do not occur following treatment.	Following ion exchange treatment	high
#Q032	design	treatment	mandatory	Breakpoint Chlorination Contact Time	drinking water	A contact time of 30 minutes or longer is necessary for the reaction to go to completion (Kirmeyer et al., 2004; Hill and Arweiler, 2006).	When implementing breakpoint chlorination	high
#Q033	treatment	treatment	mandatory	Air Stripping pH Adjustment Requirement	drinking water	pH adjustment after the aeration is required for subsequent processes (U.S. EPA, 2000).	When using air stripping with pH elevation above 10	high
#Q034	operational	treatment	recommended	Nitrification Prevention Strategy Preference	drinking water	comprehensive strategies aimed at the prevention of nitrification episodes are recommended over strategies aimed at controlling nitrification as it occurs.	For distribution system management	high
#Q035	operational	operational	mandatory	Distribution System pH Optimization	drinking water	Establishing the proper pH level is essential for maintaining chloramine residual in the distribution system and limiting nitrification (Wilczak, 2006b).	For nitrification control in chloraminated systems	high
#Q036	operational	operational	recommended	Free Ammonia Optimization Concentration Goal	drinking water	A minimization of free ammonia entering the distribution system to concentrations below 0.1 mg NH3-N /L and preferably below 0.05 mg NH3-N/L is an important optimization goal to reduce the potential for nitrification (Kirmeyer et al., 2004).	For reduction of nitrification potential	high
#Q037	treatment	treatment	guidance	Breakpoint Chlorination Post-Treatment Consideration	drinking water	An advanced treatment, such as GAC adsorption, may be considered following breakpoint chlorination to remove resulting taste and odour compounds as well as chlorination by-products (Janda and Rudovský, 1994; Wilczak, 2006a).	Following breakpoint chlorination	high
#Q038	monitoring	operational	mandatory	Ammonia Dosing Free Chlorine Measurement	drinking water	The measurement of free chlorine immediately upstream of the point of ammonia addition is critical to the proper dosing of ammonia at the treatment plant.	During ammonia dosing for chloramine formation	high
#Q039	corrective_action	operational	guidance	Nitrification Episode Corrective Measures	drinking water	During severe nitrification episodes, reservoir cleaning, as well as drainage and disinfection, may be needed	During severe nitrification episodes	high
#Q040	operational	operational	mandatory	Ion Exchange Resin Regeneration	drinking water	Once the resin's capacity is reached, contaminant concentrations will increase in the finished water, and the resin must be regenerated.	When the ion exchange resin capacity is reached	high
#Q041	corrective_action	treatment	guidance	Nitrification Corrective Measures	drinking water	Corrective measures are similar to the preventive measures and include: distribution system pipe flushing; temporary/seasonal free chlorination (breakpoint chlorination); reservoir cycling to limit water age.	When responding to nitrification episodes in the distribution system	high

P Quantitative Requirements (37)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Limit Type	Limit Value	Context	Conditions	Confidence
#P001	operational	treatment	mandatory	stoichiometric oxygen (O2) demand	drinking water	requirement	4.33 mg O2/mg NH4+ -N	In order to have complete nitrification during biological treatment	When ammonia concentrations exceed this oxygen demand, constant oxygen feed is required	high
#P002	operational	treatment	recommended	chlorine-to-ammonia-nitrogen (Cl2:NH3-N) weight ratio	drinking water	OG	3:1 to 5:1 unitless	Reaction rate of monochloramine formation during breakpoint chlorination	Preferably in this range	high
#P003	operational	treatment	recommended	pH	drinking water	OG	7.0-8.0 unitless	Reaction rate of breakpoint chlorination	Ideally, the reaction takes place in this pH range	high
#P004	operational	treatment	mandatory	contact time	drinking water	requirement	>= 30 minutes	Breakpoint chlorination reaction to go to completion	Necessary for the reaction to go to completion	high
#P005	operational	operational	recommended	Cl2:NH3-N weight ratio	drinking water	OG	4.5:1 to 5:1 unitless	Ratio maintained in the plant effluent to enhance monochloramine formation	To reduce the concentration of free ammonia entering into the distribution system	high
#P006	chemical	operational	recommended	free ammonia	drinking water	OG	< 0.1 mg NH3-N/L	Minimizing free ammonia entering the distribution system	Optimization goal to reduce potential for nitrification	high
#P007	chemical	operational	recommended	free ammonia	drinking water	OG	< 0.05 mg NH3-N/L	Preferable level for minimizing free ammonia entering the distribution system	Optimization goal to reduce potential for nitrification	high
#P008	chemical	operational	guidance	free ammonia	drinking water	OG	> 0.1 mg NH4+-N/L	At storage facilities, indicator of nitrification requiring further investigation	Used as an alert level	high
#P009	chemical	operational	guidance	chloramine residuals	drinking water	OG	> 2.0 mg/L	Leaving the treatment plant	Appears effective in preventing nitrification by limiting growth of ammonia-oxidizing bacteria	high
#P010	chemical	treatment	mandatory	Chlorine dose for breakpoint chlorination	drinking water	requirement	8-10 times higher than ammonia concentration (weight basis)	Breakpoint chlorination process requirements	To achieve a free chlorine residual	high
#P011	operational	treatment	guidance	Actual Cl2:NH3-N weight ratio for breakpoint chlorination	drinking water	OG	8:1 to 10:1 unitless	Variation from theoretical ratio in practice	Depends on pH, temperature and presence of reducing agents	high
#P012	physical	operational	guidance	Optimum temperature for nitrifiers	drinking water	OG	20-30 °C	Growth conditions for ammonia-oxidizing bacteria in distribution systems		high
#P013	chemical	operational	guidance	Optimum pH for nitrifiers	drinking water	OG	7.5-8.0 unitless	Growth conditions for nitrifying bacteria		high
#P014	chemical	operational	guidance	Ammonia-nitrogen concentration promoting growth	drinking water	OG	0.25 mg/L	Growth rate of nitrifying organisms in plant and distribution system		high
#P015	chemical	operational	guidance	High chloramine residual limit	drinking water	OG	<= 8 mg/L	Nitrification control in distribution systems	Residuals up to this level may not control nitrification once underway	high
#P016	chemical	treatment	mandatory	pH for air stripping	drinking water	requirement	> 10 unitless	Separation of non-ionized ammonia from water using air stripping in a packed tower	Achieved by raising the pH of the water above 10 and increasing temperature	high
#P017	chemical	health	guidance	Total ammonia concentration threshold for nitrite risk	drinking water	OG	> 1 mg-N/L	Potential increase of nitrite in the distribution system due to nitrification	Theoretically occurs in any system in which the total ammonia concentration entering the distribution system is above this level	high
#P018	physical	operational	guidance	Temperature threshold for nitrification occurrence	drinking water	OG	5 °C	Regrowth and nitrification in distribution systems with long detention times	Can occur at temperatures as low as this value	high
#P019	chemical	operational	guidance	pH range for nitrification occurrence	drinking water	OG	6.6-9.8 unitless	Nitrification growth conditions in the distribution system	Nitrification can occur within this pH range	high
#P020	operational	treatment	guidance	Stoichiometric oxygen (O2) demand for ammonia oxidation to nitrite	drinking water	requirement	3.22 g O2/g NH4+-N	Biological oxidation of ammonia to nitrite	Theoretical requirement	high
#P021	operational	treatment	guidance	Stoichiometric oxygen (O2) demand for nitrite oxidation to nitrate	drinking water	requirement	1.11 g O2/g NO2--N	Biological oxidation of nitrite to nitrate	Theoretical requirement	high
#P022	operational	treatment	guidance	Total theoretical oxygen (O2) demand for ammonia oxidation in distribution	drinking water	requirement	4.33 g O2/g NH4+-N	Biological oxidation of ammonia to nitrate	Total theoretical O2 requirement	high
#P023	chemical	treatment	guidance	Theoretical chlorine-to-ammonia-nitrogen (Cl2:NH3-N) weight ratio	drinking water	requirement	7.6:1 unitless	Breakpoint chlorination stoichiometry	Free ammonia is oxidized to nitrogen and chlorine is reduced to chloride at this ratio	high
#P024	operational	treatment	guidance	Hydraulic loading rate threshold	drinking water	requirement	<= 5 m/h	Manganese dioxide coated sand filters for ammonia removal	Ammonia breakthrough and nitrite observed when rates exceeded this value	high
#P025	design	treatment	mandatory	Empty bed contact time (EBCT)	drinking water	requirement	15 minutes	Biological activated carbon filter for ammonia oxidation	Full-scale application reported by Muramoto et al. (1995)	high
#P026	operational	treatment	mandatory	LPRO Feed Pressure	drinking water	requirement	3-6 bar	Low-pressure reverse osmosis (LPRO) membrane operation	For ammonia rejection in the range of 90% to 95%	high
#P027	operational	treatment	mandatory	RO Feed Pressure	drinking water	requirement	130 psi	Polyamide thin film composite RO membrane operation	At a system recovery of 82% to achieve >96% reduction	high
#P028	operational	treatment	mandatory	Dissolved oxygen concentration	drinking water	requirement	3 mg/L	Biological filters used in combination with RO	Maintenance concentration while seeding filters	high
#P029	operational	treatment	mandatory	Biological filter loading rate	drinking water	requirement	9.8 m/h	Ammonia biological filters in combined RO system	Equivalent to 4 gpm/ft2	high
#P030	operational	treatment	guidance	Breakthrough concentration for ammonium ion exchange	drinking water	requirement	0.5 mg NH4+/L	Ion exchange treatment using clinoptilolite or synthetic resins	Predefined level for regeneration or resin capacity monitoring	high
#P031	operational	treatment	guidance	Air-to-water ratio	drinking water	requirement	50 ratio	Sand filters coated with manganese dioxide for ammonia oxidation in pre-aerated groundwater	Used in studies by Janda and Rudovský to achieve specific ammonia reduction levels	high
#P032	operational	treatment	guidance	New filter colonization period	drinking water	requirement	< 3 months	Time required for new biologically active filters to obtain complete nitrification	Achieved by constantly running aerated raw water to promote bacterial regrowth	high
#P033	design	treatment	guidance	GAC filter empty bed contact time (EBCT)	drinking water	OG	20-30 minutes	Range investigated for controlled nitrification in GAC filters	Filters in service for several years, fed with pre-filtered/ozonated water	high
#P034	operational	treatment	guidance	GAC filter hydraulic loading rate	drinking water	OG	3.9-5.0 m/h	Range investigated for controlled nitrification in GAC filters	Study by Andersson et al. (2001)	high
#P035	physical	treatment	guidance	Nitrification temperature threshold in GAC filters	drinking water	OG	>= 16 °C	Temperature required to achieve 90-98% ammonia removal in GAC filters	Removal drops to 30% below 4°C	high
#P036	design	treatment	guidance	Ion exchange technology suitability capacity threshold	drinking water	requirement	<= 80000 m3/day	Maximum recommended capacity for ion exchange suitability	Technology becomes inconvenient above this capacity due to large footprint required	high
#P037	operational	treatment	guidance	Gravity flow sand filter hydraulic loading rate	drinking water	OG	4.9 m/h	Operational rate for gravity flow sand filters in full-scale plant achieving complete nitrification	Equivalent to 2 gpm per square foot	high

D Definitions (34)

Req ID	Name	Context	Confidence
#D001	AOB	ammonia-oxidizing bacteria	high
#D002	NOB	nitrite-oxidizing bacteria	high
#D003	GAC	granular activated carbon	high
#D004	EBCT	empty bed contact time	high
#D005	Breakpoint chlorination	Breakpoint chlorination is described as a process in which chlorine demand is satisfied, combined chlorine compounds are destroyed, ammonia is oxidized to form nitrogen gas and free chlorine residual is achieved when additional chlorine is added.	high
#D006	Cl2:NH3-N	chlorine-to-ammonia-nitrogen	high
#D007	NSF	NSF International	high
#D008	ANSI	American National Standards Institute	high
#D009	MUL	maximum use limit	high
#D010	RO	reverse osmosis	high
#D011	NF	nanofiltration	high
#D012	LPRO	low-pressure reverse osmosis	high
#D013	BWRO	brackish water reverse osmosis	high
#D014	SWRO	saline water reverse osmosis	high
#D015	HPC	heterotrophic plate count	high
#D016	DPD	N,N-diethyl-p-phenylendiamine	high
#D017	NOM	natural organic matter	high
#D018	NDMA	N-Nitrosodimethylamine	high
#D019	SCC	Standards Council of Canada	high
#D020	Biological treatment processes	Biological treatment processes are based on the ability of microorganisms (non-pathogenic bacteria) to catalyse the biochemical oxidation or reduction of drinking water contaminants and produce biologically stable water	high
#D021	Ion exchange	Ion exchange is a physicochemical process that employs an exchange of ions (cations or anions) in the water to be treated with ions sorbed at the solid phase of the natural or synthetic resins.	high
#D022	nitrifiers	ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB)	high
#D023	nitrification	a two-step process that oxidizes ammonia either in natural water or in water that has been disinfected by chloramine.	high
#D024	MGD	million gallons per day	high
#D025	gpm	gallons per minute	high
#D026	psi	pounds per square inch	high
#D027	BV	bed volumes	high
#D028	chloramine demand	reactions with natural organic matter (NOM) and inorganic constituents	high
#D029	chloramine decay	a combination of hydrolysis and acid-catalysed disproportionation reactions	high
#D030	solids retention time	a biomass hold-up in the filter	high
#D031	Trichloramine	nitrogen trichloride	high
#D032	Electrochemical removal	a process [that] employs an adsorption of ions on the surface of two oppositely charged electrodes	high
#D033	Submerged membrane bioreactors	hollow fibre membrane modules directly immersed inside the activated sludge reactors	high
#D034	alert level	a free ammonia concentration greater than 0.1 mg NH4+-N/L at storage facilities can be used as an indicator of nitrification requiring further investigation	medium