insight into innovative decentralized wastewater technologies
TRANSCRIPT
Insight into Innovative Decentralized Wastewater Technologies
Barbara Siembida-LöschGordon Balch, Heather Broadbent
Centre for Alternative Wastewater Treatment, Fleming College, Lindsay,
2015 Annual OOWA Conference & Trade Show, Tuesday, March 24th, 2015, Niagara Falls, Ontario
Outline• Advanced Treatment Technologies
– residential, communal, and commercial systems
• Legal Framework and Performance
Validation Standards
• CAWT - Applied Research
- case study on phosphorus removal
• Future of Decentralized Treatment
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Advanced Treatment Systems
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SepticSmart 2010
or suspended
Advanced Treatment Systems
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Conventional Systems
Advanced Systems
Septic tank or advanced treatment unit
30-50%
50-70%
Soil ca. 90% ca. 10%
Legal Framework for Advanced Treatment Systems
• The Ontario Building Code, Part 8: Sewage Systems, regulates a number of different classes of onsite sewage systems up to 10,000 l/d (larger systems are regulated by the Ministry of the Environment)
• Class 4, typically applied to conventional onsite systems, is intended to minimize pathogens released into the environment– may also include secondary and tertiary
(advanced) treatment systems located between septic tank and leaching bed
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Approval of Advanced Treatment Systems
• Several advanced systems, listed under the Supplementary Standards SB-5 to the Building Code were evaluated by the Ministry of the Municipal Affairs and Housing (MMAH)
• The following performance criteria must be met:– testing and certification by the NSF
International (U.S.-based) standard– consideration of Ontario’s
environmental/climatic conditions– evidence of in-field performance
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Approval Performance Criteria
• As of January1, 2014, the treatment unit effluent criteria have changed
• These performance criteria now match up with the national CAN/BNQ 3680-600, “Onsite Residential Wastewater Treatment technologies”
• The SB-5 units must meet the CAN/BNQ 3680-600 before January 1, 2017!
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Secondary quality effl.Tertiary quality effluent
SB-5 Advanced Treatment Systems
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Advanced Treatment Systems
• Homeowners may want to consider the advanced systems when:
- properties have inadequate conditions for conventional systems (e.g., heavy clays, shallow soils, high water table, etc.) - limited space to accommodate the size of a conventional leaching bed - wanting to provide additional protection to groundwater by additional nitrate reduction (only some of the treatment units can reduce nitrate)
Enhanced Nitrogen Removal(stationary fixed film)
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Anoxic Aerobic Clarifier
Denitrification Nitrification+
BOD removal
Denitrification• 2.3 g BOD per g NO3-N• 3.02 g organic matter per g NO3-N• Heterotrophic bacteria for generation of carbon source• Significant portion of BOD generally consumed during nitrification,
leaving little for denitrification
High in BOD & NH4
Return unconsumed Carbon
Moving Bed BioReactor(MBBR)
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• Small foot print
• Very efficient
• Up to 5Xs biofilm
• Does require pumps and aeration
Treatment OptionsDomestic
Conventional Septic Systems Advanced Wastewater Treatment
• Microbial (suspended or fixed) ± aeration• Physical filtration ± aeration
Alternative Constructed Wetlands Engineered Bio Reactors (e.g., S-reducing Bacteria for
Arsenic) Sorptive media for Phosphorus removal Moving Bed Bio Reactors for Oxidized N Ozone UV Membrane Bioreactors others
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CAWT is active in the following sectors:• Mining• Agriculture• Aquaculture • Oil & gas • Pulp & paper • Food, etc.
Phosphorous adsorptive media for Stormwater runoff
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• Monitoring studies have identified issues pertaining to leaching of phosphorus from compost-containing bioretention installations
• A pilot study was conducted to assess the phosphorus removal performance of bioretention soil mix amended with Imbrium Systems Sorbtive®Media AI 28x48
• Sorbtive®Media is an engineered granular media containing aluminum oxide and iron oxide
Material and Methods
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Header Tank 3
Header Tank 2
Header Tank 1
Bioretention Cell 3
Bioretention Cell 2
Bioretention Cell 1
Ball valve
Sump pump with series of ball valves to control flow rate
Well water inflow
Outflow to Retention Pond
Side view
Bioretention Cell 4Header Tank 4
Header Tank 5 Bioretention Cell 5
Collection Tank
Artificial Stormwater Composition
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• 1000 L stormwater was spiked with KH2PO4
• Four target concentrations applied in order the lowest to the highest (0.2; 0.4; 0.6; 0.8 mg/L)
• Ionic compounds were added to simulate the typical matrix of stormwater
Target P-basis
concentrationAverage TDP
measured value
% of target
Average TP measured
value
% of target
(mg/L) (mg/L) (mg/L) 0.2 0.11 56 0.16 780.4 0.28 70 0.36 890.6 0.46 76 0.54 900.8 0.65 82 0.72 90
• Measured phosphorus concentrations were consistently lower than the target
• The deviations decreased as the target concentration increased
• Dissolved phosphorus concentrations were consistently lower than total
Bioretention Soil Mix Composition
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Cell Number
Soil Mix Composition (% by volume)
Sand Peat Moss Sorbtive®Media
Bioretention Cell 1 (control) 85% 15% 0%
Bioretention Cell 2 82% 15% 3%
Bioretention Cell 3 80% 15% 5%
Bioretention Cell 4 75% 15% 10%
Bioretention Cell 5 68% 15% 17%
Layers
• Bottom layer: 15 cm of ½-inch stone
• Middle layer: 3 cm of sand
• Top layer: 50 cm of soil mix
Phosphorus Removal Performance
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• The measured concentration difference between the effluent and header tank was multiplied by five to estimate phosphorus retained for a given week
• Calculated values were summed for all twenty weeks
Cumulative Retained Phosphorus Mass
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Cumulative mass of total dissolved phosphorus (TDP) retained in each bioretention cell
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Cumulative mass of total phosphorus (TP) retained in each bioretention cell
Phosphorus Removal Performance
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• The percent removal efficiency = (header tank concentration – effluent concentration)/(header tank concentration)
• Calculated percent values were averaged for five weeks
Percent Removal of Phosphorus
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Percent removal of total dissolved phosphorus (TDP) for each bioretention cell at each of four different target
phosphorus concentrations
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Percent removal of total phosphorus (TP) for each bioretention cell at each of four different target
phosphorus concentrations
Conclusions
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• Phosphorus removal using a sand/peat soil mix can be greatly enhanced through amendment with Sorbtive® Media.
• Sorbtive® Media amended bioretention cells demonstrated much greater removal of dissolved and total phosphorus.
• Removal efficiency of the amended cells reached upwards to 99% and at least 84% for the duration of the study.
• Effluent pH is relatively unaffected.
Thank you!
Future of Decentralized Treatment
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• Growth of cluster and other decentralized systems• Recycling treated effluents• Management program for onsite systems• May see greater need for advanced treatment
systems for Nitrate and Phosphorous in relationship to source water protection
• The global warming potential of septic tanks and other advanced technologies
Ionic CompoundQuantity of salt added per 990 L
(g)
Sodium Chloride (NaCl) 123.81Calcium Chloride (CaCl2 ) 24.50Sodium Sulfate (Na2SO4) 23.35Sodium Nitrate (NaNO3) 2.81Potassium Chloride (KCl) 2.59Magnesium Chloride Hexahydrate ( MgCl2.6H2O) 5.66
Quantity of salts added to 990 L of well water to create artificial stormwater
• Ionic compounds were added to simulate the typical matrix of stormwater
• The matrix remained standardized