Transcript CONTROLLING WATER POLLUTION
Sewage and Organic Wastes
TREN 3P14: Sustainable Integrated Waste Management
David T. Brown
Water Pollutants
• • • • •
toxics nutrients suspended matter
•
pathogens thermal pollution dissolved gases
•
anthropogenic
origin
(e.g. industrial effluent, municipal sewage, tourism operations)
•
natural origin (e.g. silt, mineral nutrients, wild animal wastes)
Significant concern in the tourism industry
• • • • • Water quality Water quantity Aesthetic concerns Disease and pathogens Local equity issues
Controlling Water Pollution
•
Upstream:
before the problem occurs
•
Downstream:
after the problem occurs
Upstream Methods of Controlling Water Pollution
•
process modification in industry: elimination of pollutants and toxics
• •
avoidance of direct discharge into:
–
water bodies
–
storm sewers
–
sanitary sewers identification of storm drains (e.g. Yellow Fish Road project)
Upstream Methods of Controlling Water Pollution
•
decoupling of storm and sanitary sewers
• •
runoff control:
–
increasing absorptive surfaces
– –
avoiding erosion maintaining streambank and shoreline vegetation
legislation and regulation: guidelines
and laws establishing limits on discharge
S E W A G E Neolithic revolution
•
small towns and settlements -> human waste control generally non problematic
S E W A G E
“In days of old When knights were bold And toilets weren’t invented They’d leave their loads Upon the roads And walk away contented.”
S E W A G E Post - Neolithic revolution:
Large towns and cities ->
human waste control became a problem
high-density living required
•
technologies for handling human wastes in urban areas:
chamber pots and open gutters
•
pit privies / trench latrines/ outhouses
•
septic systems and variants
•
centralized sewage collection and treatment systems
Downstream Methods of Managing Sewage: Small scale
• Temporary / short term: – packing it out – single-use holes – pit privies – trench latrines Meyer, Kathleen. 1989. How to shit in the woods : an environmentally sound approach to a lost art. Ten Speed Press, Berkeley, Calif.
Downstream Methods of Managing Sewage: Small scale
• Long-term – outhouses – settling ponds – septic tanks – septic fields – composting toilets van der Ryn, Sim. 1978 (republished and revised 1999). The Toilet Papers: Recycling Waste and Conserving Water. Chelsea Green Publishing, Vermont. Online edition available at www.brocku.ca/tren/courses/tren3p14/2006/ToiletPapers.pdf
Tourism operations:
Tourism operations:
Tourism operations:
Land-based wastewater treatment: Surface spray
Land-based wastewater treatment: Overland flow
Land-based wastewater treatment: Subsurface infiltration
Downstream Methods of Sewage Treatment: Large Scale
Downstream Methods of Sewage Treatment
•
domestic sewage treatment:
–
preliminary: screening and removal of large contaminants
–
primary: straining and settling of solids
–
secondary: removal of biodegradable organic matter and nutrients
–
tertiary: removal of residual dissolved nutrients and pollutants
Downstream Methods of Sewage Treatment
•
effluent treatment processes:
– – –
mechanical: chemical: biological:
filtering, gravity separation flocculation, coagulation microbes or macrophytes
–
disinfection:
aerobic or anaerobic chlorination, ozonation, etc.
(pathogen control)
Downstream Methods of Sewage Treatment
•
‘physical plant’/ ‘engineered’ approach
(usually centralized, large scale)
•
‘constructed wetland’ approach
decentralized, large or small scale) (centralized or
Primary Sewage Treatment
BAR SCREEN GRIT CHAMBER SETTLING TANK CHLORINATION TANK
outflow Raw sewage
SLUDGE DIGESTER
Sludge
SLUDGE DRYING BED
Secondary Sewage Treatment
BAR SCREEN GRIT CHAMBER SETTLING TANK AERATION TANK SETTLING TANK 2
outflow Raw sewage
SLUDGE DIGESTER
Methane Air pump
SLUDGE DRYING BED CHLORINATION TANK
Activated sludge
Constructed Wetland
Constructed Wetland
EXPERIMENTAL CELLS S.W.A.M.P. (SEWAGE WASTE AMENDMENT MARSH PROJECT)
Niagara on the Lake, Ontario
Constructed Wetland
EXPERIMENTAL CELLS
Constructed Wetland
macrophytes
Cattails and Water Hyacinth
Large scale constructed wetland
Saha Pat Industrial Park, Laem Chabang, Thailand
Settling tank
Saha Pat Industrial Park, Laem Chabang, Thailand
Sludge dewatering and drying
Saha Pat Industrial Park, Laem Chabang, Thailand
Aeration pond
Saha Pat Industrial Park, Laem Chabang, Thailand
Outflow into constructed wetland
Saha Pat Industrial Park, Laem Chabang, Thailand
Large scale constructed wetland
Saha Pat Industrial Park, Laem Chabang, Thailand
Water and Legislation
• •
multijurisdictional:
federal, provincial, and municipal areas of responsibility
multifaceted:
laws and regulations deal with
–
conservation and management of water resources; protection of aquatic life
– –
pollution and liquid discharge drinking water standards
Federal Water Legislation
(in areas of federal jurisdiction)
Canadian Environmental Protection Act (CEPA) :
regulates the release of specified toxic substances, the concentration of nutrients in products (e.g. nitrates, phosphates); national regulations for pulp and paper mill effluents
Fisheries Act:
forbids the depositing of deleterious substances in any waters frequented by fish; regulates aquatic toxicity testing; regulates pulp and paper mill effluents and requires monitoring of effects on fish habitat
Provincial Water Legislation
Ontario Water Resources Act :
Section 30(1) prohibits the discharge of any material into any water body, shoreline, or bank that may impair the quality of the water
Environmental Protection Act (EPA) :
Subsection 14 : prohibits discharge of any contaminant into the natural environment that causes or is likely to cause an adverse effect
• •
Water Quality Guidelines, Policies, and Objectives:
cover water quality for many types of water uses and aquatic environments (e.g. water storage structures, sewage plant discharge, drinking water quality objectives and treatment requirements, etc.) legally enforceable when incorporated into a Certificate of Approval or a Control Order
•
Banned and Phased-Out Chemicals:
primary and secondary lists of substances to be banned, phased out, or reduced in use due to their persistence in water or aquatic systems
•
Drinking Water:
Municipalities are responsible for conforming to provincial water quality and treatment guidelines for drinking water from surface and ground sources
MISA (Municipal, Industrial Strategy for Abatement)
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program aimed at the virtual elimination of persistent toxic contaminants from all discharges into Ontario waterways
•
dealt with direct dischargers (into surface waters, e.g. sewage treatment plants, certain industries) and indirect dischargers (into municipal sewer systems).
Objectives:
•
identify and measure toxic substances in discharges
•
increase emphasis on control technlogy
•
pollution prevention and reduction in multi-media transfer of pollutants
•
strengthen abatement and enforcement mechanisms -> eventual virtual elimination of persistent toxic substances
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Municipal-Industrial Strategy for Abatement Advisory Committee was eliminated by Harris government, and MISA program severely weakened.
•
Avenues for both public input and multi stakeholder input to government decision making were removed.
Starting in 1995, the Harris Government weakened or revoked nearly every environmental protection law in Ontario and numerous regulations under these laws.
•
Every aspect of environmental protection was affected, including controls on air pollution, water pollution, pesticides, waste disposal and recycling, urban sprawl, energy use and climate change, natural heritage and biodiversity protection, mining, and forestry.
DETAILS:
•
Canadian Environmental Law Association (http://www.cela.ca/) : Environmental Deregulation in Ontario - 1996-2000 http://62.44.8.131/coreprograms/detail.shtml?x=1780
Municipal Water Legislation
Discharges to Sewers:
Municipal sewer use by-laws regulate substances which can be discharged to sanitary, combined, or storm sewers. Based on MOE Model Sewer Use Bylaw.
In absence of municipal by-laws, the Ontario Clean Water Agency regulated these parameters.
Harris Government Bill 107 promoted privatization of municipal water and sewer
infrastructure without voter assent.
Budgets for monitoring and regulation were slashed.
Walkerton
•
E. Coli contamination of municipal water supply from cattle manure results in hundreds of illnesses and seven deaths, including two-year old child
•
Tragedy deemed preventable
•
Incompetent management by Koebel brothers (managers of water supply), lack of adequate water testing, excessive budget cutbacks and deregulation all identified as factors in tragedy
Further Details:
• The Walkerton Tragedy: http://www.canoe.ca/EcoliTragedy/ • Walkerton Flash presentation: http://www.canoe.ca/EcoliTragedy/Walkerton.swf
• Walkerton Inquiry report: http://www.attorneygeneral.jus.gov.on.ca/english/about/pubs/walkerton/part1/
• •
2002: Tory government introduced
Safe Drinking Water Act Sustainable Water and Sewage Systems Act
to guard against another water tragedy like Walkerton
http://www.ene.gov.on.ca/envision/water/sdwa/index.htm
• Act authorized the government to implement key recommendations in Walkerton inquiry report
• Acts criticized as inadequate, as source contamination concerns not addressed • Tories defeated in 2003 • Liberal government elected 2003 • Introduced Clean Water Act (Dec 2005)
Clean Water Act
(received Royal Assent on October 19, 2006)
• • The Act ensures that communities are able to identify potential risks to their supply of drinking water, and take action to reduce or eliminate these risks. Municipalities, conservation authorities, landowners, farmers, industry, community groups and the public all work together to meet common goals.
• http://www.e-laws.gov.on.ca/DBLaws/Source/Statutes/English/2006
Other related Ontario government initiatives: • Watershed-based source protection planning • Revision of Permits To Take Water • Nutrient Management • Groundwater Studies