Sustainable Passive Wastewater Treatment

Troy D. Vassos, PhD FEC PEng Technical Director Integrated Sustainability (Calgary/Vancouver)

AOWMA 22ND ANNUAL CONVENTION & TRADE SHOW “SUSTAINABLE PASSIVE WASTEWATER TREATMENT ” SEMINAR Outline

Wastewater Characteristics Treatment Mechanisms Lagoon & Wetland Treatment Sustainability Considerations Lagoon Upgrade Examples Wastewater Characteristics and Treatment Domestic Wastewater

URINE 30% 10%5% 35% 20% KITCHEN DISH BATH TOILET LAUNDRY SINK WASHER SHOWER 5% FAECES MISC BLACK WASTE GREY WATER WATER WATER Treatment

BLACKWATER TREATMENT DISPOSAL or REUSE Toilets & Urinals

Organic Solids Kitchen Sink Fats Oils & Grease Compost BIOSOLIDS Bacteria Soluble Organics Digest REUSE Nutrients (N & P) Laundry Toxic Organic & Inorganic DISCHARGE Pathogens Disinfect DISCHARGE Bath & Shower Screenings, Sand & Grit LANDFILL

GREYWATER Treatment Levels & Objectives

• Primary – remove coarse solids & FOG • Secondary – remove soluble BOD & TSS • Tertiary – remove N & P – remove turbidity (filtration) • Disinfection – remove microoganisms Treatment Summary

1. Lower temperature → more time 2. Complex organics → more time 3. Long solids retention is better than short 4. Mechanical treatment simply mimics and accelerates natural processes 5. Mechanical high capital and O&M cost 6. Passive Treatment – more land Bacteria & Wastewater Treatment Aerobic Bacteria

Two general types of aerobic bacteria 1. Heterotrophic Bacteria Consume Organics – Needs oxygen in proportion to the amount of organics consumed – Rapid consumption & growth Aerobic Bacteria

2. Autotrophic Bacteria

– uses CO2 as a carbon source

– Nitrification: oxidize ammonia NH4 to form nitrite (NO2) and nitrate (NO3) – Not a significant process in lagoons due to limited bacteria in suspension – Lagoon nitrogen reduction generally due to algae growth Anoxic Bacteria

• Anoxic: No oxygen, but other electron

acceptors present (NO2, NO3, SO4 etc.) • Heterotrophic facultative bacteria digest and remove readily biodegradable soluble organics (electron donors) under

anoxic conditions forming sludge, CO2 and nitrogen gas (N2) Anaerobic Bacteria

• Anaerobic: No O2, NO2, NO3, SO4 etc. present • Heterotrophic anaerobic bacteria ferment and consume biodegradable soluble and particulate organic constituents forming

sludge, CH4, CO2 and odour compounds • Very slow growing • Key condition for biological phosphorus removal Treatment Elements

BOD REMOVAL TSS REMOVAL NH4 → NO3

AEROBIC

RETURN BACTERIA

WASTE BACTERIA Treatment Elements

NITROGEN REMOVAL BOD REMOVAL TSS REMOVAL NO3 → N2 NH4 → NO3

RECIRCULATION LOOP

ANOXIC AEROBIC

RETURN BACTERIA

WASTE BACTERIA Treatment Elements

PHOSPHORUS NITROGEN REMOVAL REMOVAL BOD REMOVAL TSS REMOVAL PHOSPHORUS NO3 → N2 NH4 → NO3 RELEASE RECIRCULATION LOOP

ANAEROBIC ANOXIC AEROBIC

RETURN BACTERIA BACTERIA WITHOUT NO3 WASTE BACTERIA Lagoon Treatment Treatment Elements

BOD REMOVAL TSS REMOVAL NH4 → NO3

AEROBIC

RETURN BACTERIA

WASTE BACTERIA Treatment Elements

BOD REMOVAL TSS REMOVAL

AEROBIC

WASTE BACTERIA Treatment Elements

BOD REMOVAL TSS REMOVAL TSS REMOVAL DUCKWEED HARVESTING N & P REMOVAL

AEROBIC

WASTE BACTERIA Facultative Lagoons

NH P AEROBIC WASTEWATER 4 ALGAE O2 10 NH3 (FAST) C NH4 P BACTERIA ANOXIC CO pH m 2.0 2 – (FACULTATIVE) SLUDGE 5 1.5 ANAEROBIC NH4 (SLOW) Facultative Lagoon

NH P AEROBIC WASTEWATER 4 ALGAE O2 10 NH3 (FAST) C NH4 P BACTERIA ANOXIC CO pH m 2.0 2 – (FACULTATIVE) SLUDGE 5 1.5 ANAEROBIC NH4 (SLOW) Lagoon Advantages

• Achieves good treatment under cold climate conditions • Withstands high flow and organic loading fluctuations • Lower capital and operating cost than mechanical systems – Lower energy and Labour – Lower operator skill and attention – Easy to maintain Lagoon Disadvantages

• Algae blooms affect TSS & BOD • Seasonal nitrogen removal (algae growth) • Limited phosphorus removal • Seasonal turnover and odours • Exfiltration concerns • Sludge accumulation & desludging • Land requirements Algae Water Quality Impact Algae Control Considerations

NH4 P WASTEWATER ALGAE O2 C NH4 P

CO2 Algae Control Considerations

NH4 P WASTEWATER ALGAE O2 C NH4 P BACTERIA CO2 Algae Control Considerations

NOT GENERALLY PRACTICAL

NH4 P WASTEWATER ALGAE O2 C NH4 P

CO2 Algae Control Considerations

NH4 P WASTEWATER ALGAE O2 C NH4 P

CO2 Algae Control Considerations

NH P WASTEWATER 4 ALGAE O2 C NH4 P O2 BACTERIAO2 BACTERIA O2 O2 BACTERIA BACTERIA O AEROBIC

2 m 5.0 (FAST)

O2 – 3.0 3.0 O2 Size Comparison – 3,800 m3/d (1 MGD)

LAGOON SYSTEM LAND (m2) FACULTATIVE 667,000 PARTIAL-MIX AERATED 200,000 COMPLETE-MIXED AERATED 20,000 Wetland Treatment Constructed Wetlands

N & P REMOVAL BY HARVESTING BACTERIA BOD REMOVAL AMMONIA NITRIFICATION Effluent Quality Requirements Wastewater Effluent Systems Regulations

• Four “Prescribed Deleterious Substances” 1. 5-day Carbonaceous Biochemical Oxygen Demand (CBOD5) < 25 mg/L (avg) 2. Total Suspended Solids (TSS) < 25 mg/L (avg) 3. Total Residual Chlorine < 0.02 mg/L (avg) 4. Un-Ionized Ammonia (NH3) < 1.25 mg-N/L(max) @ 15 OC +/- 1 OC • Quarterly reports for average annual flows of 2,500 – 17,500 m3/d & HRT > 5 days WSER and Lagoons

• WSER impacts small remote communities who rely on lagoon treatment • Upgrading required to mitigate: – Algae growth effects on WSER TSS & BOD effluent criteria – Effluent total & unionized ammonia

– Fish toxicity (high pH → high NH3 ) Improved BOD & TSS Removal

• BOD REMOVAL – Increase Retention Time (Size & Depth) – Increase Oxygen (Mechanical Aeration) – Increase Bacteria (Attached Growth Media) – Primary Filtration (vs Anaerobic Lagoon) • TSS REMOVAL – Inhibit Algae Growth – Mechanical Separation – Constructed Wetlands (Biofilter) Algae & Ammonia

• Problem: Inhibiting algae growth reduces nitrogen and ammonia removal • Seasonal nitrogen removal useful for only intermittent discharges • Post-treatment ammonia nitrification is required for continuous discharges Ammonia Removal Options

• INTERMITTENT DISCHARGE LAGOON – Algae Uptake & Seasonal Discharge – Wetland Post Treatment (Nitrification) – Attached-Growth Post Treatment – Attached-Growth In-situ Technology • CONTINUOUS DISCHARGE LAGOON – Wetland Post Treatment (Nitrification) – Attached-Growth Post Treatment – Attached-Growth In-situ Technology Additional Upgrade Measures

• Increase oxygen supply and efficiency • Increase depth • Add partitions to optimize HRT • Add media (Fixed film) to increase bacteria • Reduce BOD loading (primary filtration) • Add mechanical treatment components • Phosphorus precipitation & separation Additional Upgrade Measures

Economics Social

Optimal Conventional Spot Model Environment Alternative Sustainability Model

Social

Alternative Environment Model Economics Alternative Sustainability Model

Social

Key Environment Constraint Economics Regulations Cumberland Lagoon Upgrade Village of Cumberland

Cumberland

Vancouver

Victoria Village of Cumberland

• Coal mining town incorporated in 1898 • Old combined (storm & sanitary) sewer • Discharge Permit issued in 1967 • Provided 48 years to reduce flows • Authorized works (1967) mechanical screens, aerated/facultative lagoon, phosphorus removal & disinfection • 2-Cell Aerated & facultative lagoons • $2M - 85% Separation = no flow reduction Village of Cumberland

• Discharge to man-made drainage canal leading to fish bearing stream with extremely low summer flows • 2018 ADWF = 800 m3/d PWWF > 20,000 m3/d • Permit Effluent Criteria

– CBOD5 & TSS < 30 mg/L (max) – Total-P < 1.0 mg-P/L – Fecal Coliforms < 200 MPN/100 mL (median) • Design ADWF = 1,800 m3/d Pop = 3,800 Village of Cumberland

SCREENS

MAPLE LAKE “CREEK” Full-Flow Mechanical

Option 1 – “Lagoon Upgrade” using mechanical enhancements to remove phosphorus, disinfect, discharge to adjacent wetland area to restore natural “wet” conditions and provide for natural polishing treatment. Option 2 – “Excess Wet-Weather Lagoon Treatment” - Membrane Bioreactor (MBR) treatment for 2 x ADWF, wet weather flows directed to existing lagoons. Option 3 – “Full Flow Mechanical” - Moving Bed Biofilm Reactor (MBBR) to treat and disinfect full wet weather flow, with additional tertiary filtration for 2 x ADWF. The lagoons would then be decommissioned. Lagoon Upgrade

INLET AERATED FACULTATIVE PERACETIC SOLIDS CHANNEL LARGE SMALL ACID SEPARATION SCREENING LAGOON LAGOON DISINFECTION

BYPASS > 3,600 m3/d

NATURAL WETLANDS < 3,600 m3/d

MLC SOLIDS DISCHARGE MANAGEMENT > 3,600 m3/d Excess Wet-Weather Lagoon Treatment

INLET PERACETIC CHANNEL FINE SCREEN MBR ACID SCREENING DISINFECTION

< 3,600 m3/d MLC DISCHARGE

AERATED FACULTATIVE SOLIDS SMALL LARGE MANAGEMENT LAGOON LAGOON

> 3,600 m3/d Full-Flow Mechanical

INLET SOLIDS PERACETIC CHANNEL FINE SCREEN MBBR FILTRATION SEPARATION ACID SCREENING DISINFECTION < 3,600 m3/d

MLC DISCHARGE c c

SOLIDS SOLIDS MANAGEMENT MANAGEMENT

> 3,600 m3/d

> 14,500 m3/d Community Sustainability Assessment

• Community stakeholder sustainability assessment resulted in the Lagoon- Upgrade option achieving the highest score Natural Wetlands Treatment

Treatment achieved by the lagoons and natural wetland combined is superior to most mechanical tertiary treatment processes Phase 1 – Wetlands Tertiary

INLET AERATED FACULTATIVE PERACETIC SOLIDS CHANNEL LARGE SMALL ACID SEPARATION SCREENING LAGOON LAGOON DISINFECTION

BYPASS > 3,600 m3/d

NATURAL WETLANDS < 3,600 m3/d

MLC SOLIDS DISCHARGE MANAGEMENT > 3,600 m3/d Village of Cumberland Future - Tertiary Filtration - Reuse

INLET AERATED FACULTATIVE PERACETIC SOLIDS CHANNEL FINE SCREEN LARGE SMALL FILTRATION ACID SEPARATION SCREENING LAGOON LAGOON DISINFECTION

BYPASS > 3,600 m3/d BYPASS > 3,600 m3/d

MLC DISCHARGE

SOLIDS MANAGEMENT Village of Cumberland Funding Received – August 2019

• High performance lagoon upgrade $9.7M • Investing in Canada Infrastructure Program (ICIP-EQ) Environmental Quality Stream Award of $7,113,010 • Government of Canada ($3,880,000) • Province of British Columbia ($3,233,010) Kamloops Lagoon-Based BNR Process Kamloops Lagoon Upgrade

• Population growth 80,000 – 125,000 • Mechanical plant $73M estimate • Total-P objective of 1.0 mg-P/L • 20-year life • UV Disinfection • Lagoon-BNR Savings of $33M • Also saves $200,000/yr in chemicals What’s BNR? Conventional Activated Sludge Anoxic + Aerobic Zones Anaerobic + Anoxic + Aerobic Zones BNR Process

NH4 NO3 NO N 3 2 Poly-P PO 4 Rich Bacteria Anaerobic Zone P-Release

VFA NO2 VFA VFA NO3

PO4 PO CARBON O2 (PHB) 4 PO 4 PO4 POLY-P

PO4 PO4 ANAEROBIC CELL PO4 BIO-P BACTERIA Anoxic Zone P-Removal

O PO4 2 PO4 PO4

CARBONPHB PHB PO CELL DIVISION 4 POLY- POLY- P P PO 4 PO4 ANOXIC CELL P-UPTAKE Anoxic Zone Denitrification

NO NO3 3 N2 O2 VFA N2 N2 NO 3 CELL DIVISION

N VFA VFA 2 VFA NO3 ANOXIC CELL DENITRIFICATION Aerobic Zone Nitrification

NH NH 4 O O 4 N0 CO2 O2 2 2 3 O O2 O2 2 N03 O NH4 2 CELL DIVISION CO2 O2 O2 N03 O CO CO2 2 O 2 2 N03 NH4 O2 O2 AEROBIC CELL NITRIFICATION Aerobic Zone P-Uptake

O2 PO O2 PO O 4 4 O2 2 O2 O2 PO4

O2 O2

CELL DIVISION O2 POLY-P POLYPOLY-P- P PO4 PO O2 O2 4 AEROBIC CELL P-UPTAKE Kamloops BNR Adaptation Conventional Activated Sludge

ANAEROBIC

AEROBIC ANOXIC Conventional Activated Sludge Maximum N Removal

SECONDARY CLARIFIERS Maximum N Removal

WASTE ACTIVATED SLUDGE

SECONDARY CLARIFIERS Kamloops BNR Lagoon

Left – BNR Lagoon conversion. Middle – membrane covered anaerobic lagoon (biogas). Example Design Checks & Expected Performance Aerated Fraction

BNR plants are generally designed to ensure that the aerated fraction does not drop below 60%.

Aerated Fraction 4,000 m3 = 33,000 / 47,000 m3 = 70 % 33,000 m3 10,000 m3 Maximum N Removal

25,000 m3/d 25,000 m3/d 95,000 m3/d

RAS = 62,000 m3/d

− 95,000 + 62,000 %NO −N removed = = 86% 3 25,000 + 95,000 + 62,000 95,000 + 62,000 Total Recycle Ratio = = 6.3 25,000

Alkalinity destroyed by nitrification = 219 mg/L Alkalinity recovered = 96 mg/L as CaCO3 Thank you!

Troy D. Vassos, PhD FEC PEng [email protected] Cell: +01-604-657-6559