Guideline for release of ammonia in wastewater effluents: guide
Guide
- Interpretation
- Application
- Standards
- Factors to Cconsider
- Additional Information
- Environment Canada Contact Iinformation
- Appendix A - Acute Ammonia Toxicity
Whereas ammonia dissolved in water is a substance specified on the List of Toxic Substances in Schedule 1 of the Canadian Environmental Protection Act, 1999;
Whereas the Minister of the Environment published a Proposed Notice requiring the preparation and implementation of pollution prevention plans for ammonia dissolved in water, inorganic chloramines and chlorinated wastewater effluents in the Canada Gazette, Part I, on June 7, 2003;
Whereas persons were given the opportunity to file comments with respect to the proposed Notice for a comment period of 60 days;
Whereas the Minister has considered all comments received;
Whereas this Guideline is issued as an instrument respecting preventive and control actions in relation to ammonia dissolved in water found in wastewater effluents in application of section 92 of the Act;
And whereas the Minister of the Environment has published a Notice requiring the preparation and implementation of pollution prevention plans for inorganic chloramines and chlorinated wastewater effluents;
Therefore, the Minister of the Environment, pursuant to subsection 54(1) of the Canadian Environmental Protection Act, 1999, has decided to issue a Guideline as a means to reduce the impact of releases of ammonia dissolved in water to surface water, and pursuant to subsection 54(4) directs that it be published in the Canada Gazette, Part I.
Stéphane Dion
Minister of the Environment
1. Interpretation
"Act" means the Canadian Environmental Protection Act, 1999
"acutely lethal concentration of ammonia" means a level of ammonia in an effluent at 100% concentration that kills more than 50% of the rainbow trout subjected to it over a 96-hour period when tested in accordance with the acute lethality test set out in Reference Method EPS 1/RM/13. For the purpose of this Guideline, this is represented by a concentration of ammonia that is on or above the curve when plotted versus the effluent pH as shown in Figure 1 of Appendix A. Owners must measure the pH and concentration of ammonia in the effluent and use the curve (Figure 1).
"ammonia" means total ammonia expressed as nitrogen. Total ammonia means the sum of the unionized ammonia (NH3) and ionized ammonia (NH4+) species which exist in equilibrium in water. Analytical methods measure and typically report on ammonia nitrogen as opposed to total ammonia.
"chronic toxicity" means the ability of a substance or mixture of substances to cause harmful effects over an extended period, usually upon repeated or continuous exposure sometimes lasting for the entire life of the exposed organism. For the purpose of this Guideline, chronic toxicity results in reduced reproductive capacity and reduced growth of young in fish and benthic invertebrate populations.
"effluent" means untreated or treated wastewater that is released from the outfall(s) of a wastewater system, excluding combined sewer overflows from the wastewater system.
"fresh water" means water that generally contains less than 1000 milligrams per litre of dissolved solids.
"representative sampling" means the weekly measurement of ammonia and pH in the effluent under normal operating conditions of the wastewater treatment facility.
"surface water" means a lake, pond, marsh, creek, spring, stream, river, estuary or marine body of water, or other surface watercourse.
"wastewater" means a mixture of liquid wastes primarily composed of domestic sewage, that can also include other liquid wastes from industrial, commercial and institutional sources.
"wastewater system" means any works for the collection or treatment and release of wastewater or any part of such works.
2. Application
This Guideline applies to any person who owns a wastewater system at the time of publication of this Guideline that has an effluent discharge flow to surface water that is greater than or equal to 5 000 m3 per day, based on an annual average.
3. Standards
The available scientific literature indicates that the environmental risks associated with ammonia are related to both its acute and chronic toxicity to freshwater organisms. The 2001 Priority Substances List (PSL) Assessment Report that led to the addition of "Ammonia dissolved in water" to the List of Toxic Substances in Schedule 1 of the CEPA 1999 and the CCMECanadian Water Quality Guidelines for the Protection of Aquatic Life, provide an overview of the factors known to affect the toxicity of ammonia. Any person who meets the criteria in section 2 of this guideline should take measures to meet the following standards.
Acute toxicity:
The concentration of ammonia deposited to surface water frequented by fish should not be acutely lethal. Refer to Appendix A which describes the procedure for determining whether the effluent is acutely lethal to fish due to ammonia.
- An objective for ammonia releases to surface water is to achieve and maintain a concentration of ammonia in the effluent that is not acutely lethal to fish due to ammonia.
Chronic toxicity:
The chronic toxicity of ammonia to fish and benthic invertebrate populations is likely to result in reduced reproductive capacity and reduced growth of young. The zone of impact of non-treated or inadequately treated effluents varies greatly with discharge conditions, mixing capacity of the receiving water, temperature and pH. Potentially toxic conditions resulting from municipal wastewater-related ammonia typically start in May and continue into October in receiving waters that are routinely basic in pH, relatively warm in temperature, and have a low flow. Further guidance to ascertain how site-specific conditions may impact on the chronic toxicity of ammonia can be found in the PSL Assessment Report. Refer to section 5 of this Guideline for links to information on the PSL Assessment Report.
- An objective for ammonia releases to surface water is to achieve and maintain a concentration of ammonia in the effluent that will ensure the protection of freshwater life. Wastewater systems should not release ammonia in quantities or concentrations resulting in a concentration of unionized ammonia greater than 0.019 mg/L in the aquatic environment.
Further information on the chronic toxicity of ammonia can be found in the CCMECanadian Water Quality Guidelines for the Protection of Aquatic Life for ammonia. Canadian water quality guidelines are intended to provide protection of freshwater and marine life from anthropogenic stressors such as chemical inputs or changes to physical components.
4. Factors to Consider
Any person who owns a wastewater system as defined in section 2 above should consider the following factors while developing plans and actions to meet the standards outlined in section 3:
- Following detailed scientific assessments, ammonia dissolved in water was found to be toxic in accordance with the criteria set out in section 64 of the Act. As such, it was added to the List of Toxic Substances in Schedule 1 of the Act. In addition, the deposit of a deleterious substance of any type in water frequented by fish is prohibited by the Fisheries Act, under subsection 36(3), unless there is a regulation under subsection 36(5) of the Fisheries Act or under another federal law authorizing the deposit. With respect to the release of ammonia through municipal wastewater effluents, there is no federal regulation at the time of publication of this Guideline. Refer to section 5 of this Guideline for links to information on the Fisheries Act, and the compliance and enforcement policies of the Fisheries Actand the Act.
- The Canadian Council of Ministers of the Environment (CCME) agreed in November 2003 to develop a Canada-wide Strategy for the management of municipal wastewater effluents, which will address specific parameters and governance. The Strategy will be based on the following three cornerstones:
- harmonization of the regulatory framework,
- coordinated science and research,
- an environmental risk management model.
- To ensure that the overall risk to the environment or human health is reduced, owners of wastewater systems should consider actions that reduce or eliminate risks posed by other substances that may be found in municipal wastewater effluent, in particular the following substances which are specified in Schedule 1 of the Act:
- nonylphenol and its ethoxylates
- effluents from textile mills that use wet processing
- mercury
- lead
- hexavalent chromium compounds
- inorganic cadmium compounds
- inorganic arsenic compounds
- inorganic chloramines
- chlorinated wastewater effluents
- Nitrogen in ammonia, along with phosphorus, is a nutrient responsible for stimulating plant and algal growth in the aquatic environment. However, excessive amounts of ammonia and phosphorus can cause over-fertilization or eutrophication, resulting in excessive growth of algae. Eutrophication reduces available dissolved oxygen, can have toxic effects on aquatic organisms, harm spawning grounds, alter habitat, lead to a decline in certain species, and impair the aesthetic enjoyment of water. Municipal wastewater is the largest point source of nitrogen and phosphorus released to the Canadian environment although non-point sources may also be significant. The occurrence of eutrophication depends on a number of site- specific factors, and is not generally a problem associated with every municipal wastewater discharge. Excessive loadings of nitrogen and phosphorus are usually best managed on a watershed basis, where loadings from all sources can be identified and the appropriate ones reduced to minimize eutrophication.
- A process audit should be conducted and may be useful in identifying the sources and quantities of ammonia discharged to the wastewater collection system from industrial, commercial, and institutional facilities. These facilities may be amenable to pollution prevention or control options that minimize the introduction of ammonia into the wastewater system. Refer to section 5 of this Guideline for links to technical guidance on system and process audits.
- Many wastewater treatment facilities are not operated with ammonia reduction as a primary objective. Optimization of the wastewater treatment facility may reduce the concentration of ammonia released to surface water and, where chlorination is practiced, the creation of inorganic chloramines without impairing the attainment of other treatment objectives. A process audit of the wastewater treatment facility should be conducted specifically looking for means to reduce the release of ammonia to surface water. Refer to section 5 of this Guideline for links to technical guidance for process audits.
5. Additional Information
To obtain a copy of the Priority Substances List Assessment Report "Ammonia in the Aquatic Environment", refer to the Existing Substances Evaluation web site or contact the Inquiry Centre, 70 Crémazie, 7th Floor, Gatineau, Québec, K1A OH3, 1-800-668-6767.
To obtain a copy of the report "Treatment Processes for the Removal of Ammonia from Municipal Wastewater" (Environment Canada, 2003, ISBN 0-662-33551-1) contact Environment Canada's Inquiry Centre at 1-800-668-6767.
To obtain a copy of the following documents: "Wastewater Source Control - A Best Practice By The National Guide to Sustainable Municipal Infrastructure (March 2003)", "Wastewater Treatment Plant Optimization (November 2003)", and "Optimization of Lagoon Operation (March 2004)", refer to the National Research Council - National Guide to Sustainable Municipal Infrastructure's website or contact them at 1-866-330-3350.
To obtain information regarding the CCME Canada-wide Strategy for the management of municipal wastewater effluents, visit the CCME website.
To obtain further information regarding the Canadian Environmental Quality Guidelines, refer to the CCME website or contact CCME by phone at 204-948-2090.
To obtain a copy of the following document "Guidance Manual for Sewage Treatment Plant Process Audits", refer to the Great Lakes Sustainability Fund website or contact: Manager, Great Lakes Sustainability Fund, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6, 905-336-6273.
To obtain a copy of the Fisheries Act. For more information on the compliance and enforcement policies of the Fisheries Actand the Act, visit the Environmental Law Enforcement website.
Additional information on pollution prevention is available from the Pollution Prevention website, the Canadian Pollution Prevention Information Clearinghouse, and Environment Canada's regional offices.
Electronic copies of this Guideline are available from the CEPA Registry website or can be requested by contacting one of the Regional Offices listed in section 6.
For residents of Newfoundland and Labrador
Environmental Protection Branch - Atlantic Region
Environment Canada
6 Bruce Street
Mount Pearl, NL A1N 4T3
Tel: (709) 772-5491
Fax: (709) 772-5097
For residents of Prince Edward Island
Environmental Protection Branch - Atlantic Region
Environment Canada
97 Queen Street, Room 202
Charlottetown, PEC1A 4A9
Tel: (902) 566-7043
Fax: (902) 566-7279
For residents of Nova Scotia
Environmental Protection Branch - Atlantic Region
Environment Canada
Queen Square, 45 Alderney Drive, 16th Floor
Dartmouth, NS B2Y 2N6
Tel: (902) 426-8926
Fax: (902) 426-3897
For residents of New Brunswick
Environmental Protection Branch - Atlantic Region
Environment Canada
77 Westmorland, Suite 450
Fredericton, NB E3B 6Z3
Tel: (506) 452-3286
Fax: (506) 452-3003
For residents of Quebec
Environmental Protection Branch - Quebec Region
Environment Canada
105 McGill Street, 4th Floor
Montreal, QC H2Y 2E7
Tel: (514) 283-4670
Fax: (514) 283-4423
For residents of Ontario
Environmental Protection Branch - Ontario Region
Environment Canada
4905 Dufferin Street
Downsview, ON M3H 5T4
Tel: (416) 739-5888
Fax: (416) 739-4342
For residents of Manitoba
Environmental Protection Branch - Prairie and Northern Region
Environment Canada
123 Main Street
Winnipeg, MB R3C 4W2
Tel: (204) 983-4811
Fax: (204) 983-0960
For residents of Saskatchewan
Environmental Protection Branch - Prairie and Northern Region
Environment Canada
300 - 2365 Albert Street
Regina, SK S4P 4K1
Tel: (306) 780-6390
Fax: (306) 780-6466
For residents of Alberta
Environmental Protection Branch - Prairie and Northern Region
Environment Canada
4999 - 98th Avenue
Edmonton, AB T6B 2X3
Tel: (780) 951-8860
Fax: (780) 495-4099
For residents of the Northwest Territories and Nunavut
Environmental Protection Branch - Prairie and Northern Region
Environment Canada
301 - 5204 50th Avenue
Yellowknife, NWTX1A 1E2
Tel: (867) 669-4725
Fax: (867) 873-8185
For residents of British Columbia
Environmental Protection Branch - Pacific and Yukon Region
Environment Canada
201 - 401 Burrard Street
Vancouver, BC V6C 3S5
Tel: (604) 666-2799
Fax: (604) 666-9107
For residents of Yukon
Environmental Protection Branch - Pacific and Yukon Region
Environment Canada
91782 Alaska Hwy.
Whitehorse, YT Y1A 5B7
Tel: (867) 667-3401
Fax: (867) 667-7962
Environment Canada Headquarters
Environmental Technology Advancement Directorate
Environmental Protection Service
Place Vincent Massey
351 St. Joseph Boulevard
Hull, QC K1A 0H3
Tel: (819) 953-8074
Fax: (819) 953-7253
Appendix A - Acute Ammonia Toxicity
This appendix describes the method for determining whether or not an effluent contains an acutely lethal concentration of ammonia based on the curve of Figure 1.
Step 1. Take a weekly sample of the effluent released to surface water and analyze the sample for ammonia concentration and pH.
Step 2. Plot the ammonia concentration vs. pH on Figure 1 below.
Step 3. If the data point falls below the curve in the shaded area, your effluent does not contain an acutely lethal concentration of ammonia. If the data point falls on or above the curve, the effluent contains an acutely lethal concentration of ammonia.
Maximum allowable ammonia concentration (y) at the measured pH of the effluent can be calculated using the following equation:
y = 306132466.34 x (2.7183(-2.0437 x pH))
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