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Treatment Options for Wastewaters Collected from On-Site Systems
Gordon Balch Centre for Alternative Wastewater Treatment, Fleming
College, Lindsay,
Ontario Association of Sewage Industry Services (OASIS)Friday October 24th, 2014, Lindsay, Ontario
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Disposal Challenges• Regulatory oversight / requirements
increasing– post Walkerton– Ont. Environ Protection Act, Ont. Clean Water Act,
etc.
• Complexity of wastewater increasing– Pharmaceuticals and personal care products
• Increasing number of wastewater sources– Petroleum, agra-farms, aquaculture, etc.
• Treatment Costs Increasing
only 2.5% of global
water is drinkable
of this nearly ¾ is
locked away in ice and
snow
only a small fraction
if readily available for
human use
Global Perspective
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1st everything (1,385 km diameter)
2nd groundwater, fresh surface water (272.8 km diameter)
3rd fresh water in lakes and rivers (56.2 km diameter)
Source: Scientific American
Global Water Supply
Water use growing twice as fast as population growth
world’s 6 billion people are drawing from 54% of all water resources (rivers, lakes, aquifers)
Water Use Trends
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North AmericaWastewater Infrastructure Deficit
• Wastewater infrastructure deficit in 2 Provinces and 8 US states is $10 billion
• $90 billion needed in next 10 y (2007) to replace and upgrade Canada wide
Great Lakes Commission – 2007 report
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Aging municipal infrastructure
When Bigger Isn’t Better: Decentralized Wastewater Treatment Systems (Environ. Commission 2009)
• Small or rural communities in Ontario faced with: – Increasing population– Climate change– Stricter environmental regulations
• A call for decentralized systems
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Waste Generation from DWWTs
• 1980 USA census – 3.8 trillion L per year to vadose zone (US EPA 1987)
• 25-30% of households in USA are served by septic systems (Bremer & Harter 2012)
• 22% of Canadians utilize on-site systems (Richardson & Fulton 2009)
Septic system leachate represents the largest unregulated source of wastewater
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Increasing complexity of wastewaters
• Consumption of pharmaceuticals $16 million in Canada (2000)– double digit growth (nearly doubling 2000-2005) Morgan
2004 & 2005• Estrogen example (2007) Richardson & Fulton 2009
– dispensed 1,700 kg of synthetic estrogen compounds• 760 kg diverted to wastewater (½ to WWTPs; ½ to on-
site)– excreted 960 kg endogenous estrogen compounds
• ½ to WWTPs; ½ to on-site– WWTPs (75% degraded) ; on-site (zero degradation)– Mass of estrogens released via on-site equivalent to
release from WWTPs
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Impediment to Decentralized Systems
• DWWT have historically been poorly understood and managed
• Regulatory agencies need scientifically sound third party validation
• Need new more advanced systems to treat a greater complexity of wastewater matrices
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What Wastewater Disposal Options Exist?
• Options depend on source of wastewater and regulatory requirements
• Most treatment options are best suited for liquids with final disposal via absorption into ground
• Solids have fewer options at this time
• Primary focus of talk on treatment of liquids (all options to treat liquids need some form of solids separation)
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Liquid disposal options• Decentralized systems typically dispose of the
primary treated wastewater to soil absorption systems rather than release to surface waters
• There are several options for disposal to soils, including:– Sandfilters (open, buried, recirculating)– Spray and drip irrigation– Mounded systems– Evaporation systems
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Alternative Treatment Systems
Number of treatment options is increasing to accommodate• Complexity of waste stream• Volume of waste generation• Replacement of older technology found
to be inadequate• Mitigate environmental impacts
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Future Trends in Treatment
• New twist on old methods– Constructed
wetlands,– lagoon systems
• Biofilm Technologies– Fixed films
• Advanced Systems– ozonation
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Constructed Wetlands
Many different configuration
Designed for different wastes
Passive, low maintenance
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Hybridized Constructed Wetlands
• Growing trend towards combining different types of CWs
• Can treat complex wastewater• Large wastewater volumes
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Continuous Stirred Tank Reactor
Blue Frog™ (base unit) is an efficient mixer and passive aerator that provides up to 7 mm gallons per day flows and has the ability to layer the treated water
• helps to better mix lagoon systems
• Aids in sludge digestion
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Continuous Stirred Tank Reactor
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Hog Farm Location: Western Oklahoma
Farrowing operation with 6,600 sows Total of 14 feet of sludge was remediated in-situ over a one
year period
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BioCord Floating Islands (fixed film)
Absorbed by plants and biofilm
Nitrogen Gas to atmosphere
Phosphorus removal however is limited to what plants can accumulate during growth
Phosphorus
Nitrogen
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Waterloo Biofilter
There are different configuration depending on the wastewater constituents and desired treatment level
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Fixed Film Bioreactor- rotating contact reactor -
• Biofilm grown on several discs stacked in a row• Only half of disc rotates through effluent
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Fixed Film Bioreactor- rotating contact reactor -
Rotation ensure oxygenation for bacteria
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Moving Bed Biofilm Reactor
• High BOD, NH4+, NO2/NO3, potential to add a P removal media that is
regenerative• Relatively small foot print• Chamber 1: BOD Chamber 2: organic solids & N oxidation
Chamber 3: NO3 removal
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Advanced On-Site Treatment
• Ozone
• Pressure differentials
• Poly-filter
• Granulated activated carbon filter
• Nutrients (N & P)
• TSS
• BOD
• Pathogens
• PPCPs
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Results: Selected PPCPs (ppt)
Levonargestrel
Progesterone
Medroxyprogesterone
Aspartame
Diclofenac
Carbamazepine
Trimethoprim
Sulfamethoxazole
0 100 200 300 400 500 600 700 800 900 1000
Influent Effluent
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
Concentration (ng L-1) Mean ± SD
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Summary
• Need is great• Expect greater demand for on-site
treatment• More research needed to increase
options for solids• Greater effort needed for verification
of emerging environmental technologies
Questions
“You cannot get through a single day without having an impact on the world around you. What you do makes a difference, and you have to decide what kind of difference you want to make.” — Jane Goodall
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