Evaluation of Passive Treatment Technologies for the Treatment of - PowerPoint PPT Presentation

Evaluation of Passive Treatment Technologies for the Treatment of Septic Tank Septage Under Temperate Climate Conditions Christine Gan, Geof Hall Pascale Champagne, Professor Department of Civil Engineering Queen’s University Kingston, Ontario, Canada June 23-25, 2016

Waste Stabilization Ponds (WSPs) in North America • Low operational cost • No electrical energy required • Easy to implement and maintain • High reductions of solids, BOD, pathogens, nutrients • Possibility of effluent reuse (irrigation, agriculture) 2

Need for WSP attenuation Rural Growth (Canada) 1. Increases in rural 7,0 growth 6,5 Population (millions) 2. More stringent 6,0 discharge guidelines: 5,5 Wastewater Systems 5,0 Effluent Regulations by 4,5 the Government of 4,0 Canada 1920 1940 1960 1980 2000 2020 Year http://www.statcan.gc.ca/ More waste, less leniency! 3

Storring Septic • Licensed wastewater treatment facility in Tamworth, ON • Passive, evaporative stabilization ponds • Environmentally-friendly operation 4

Improve treatment efficiency and robustness Test three, low-energy technologies to insulate ponds: 1) BioDome system 2) BioCord system 3) Zebra Mussels ( Dreissena polymorpha ) 5

Biofilm technologies (fixed film submerged media) BioDome system BioCord system Optimal conditions for • Optimal conditions for • proliferation, activity proliferation, activity Increased aeration/surface • Increased aeration/surface area • area, min. sunlight Fibers meant for attached growth • Increased cold-weather performance • naturalized, low-cost systems • easily customizable • able to be retrofit into any lagoon system • 6

Zebra Mussels • Known filtration capabilities (particulate removal) • Suspended solids removal up to 1L/day per mussel (Effler et al., 1996) • Ability to reduce other wastewater parameters not definitively known • Invasive species • Collected from Beaver Lake 7

Overall Project Objectives • Deploy best technology for full-scale testing and use • Ability to handle greater amounts of septage by increasing efficiency of wastewater parameter reductions • Ability to recover from shock (i.e. due to unknown 3 rd -party materials in influent, system shutdown, etc.) • Effective treatment with smallest energy and maintenance requirements • Safely accept excess septage with minimum carbon footprint • Recommendation matrix for optimal efficiency • Optimal aeration cycling, retention times, discharge periods for cold and warm weather 8

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Site and Experimental Setup Summer/fall 2015 (full operational cycle) TSS • Ammonia/ammonium • Nitrite, nitrate • COD • Orthophosphate • pH/temp • HRT/loading rates • Dissolved oxygen (DO) • Water temperature • - Sampling ~2-3x/week - On/off cycling of aeration and retention times 16

Summer/fall 2015 testing (full operational season) Temperature/Precipitation Data 40 60 Compare overall May 22 – Oct 8 th , 2015 • treatment efficiencies 35 50 of each technology Precipitation (mm) Temperature (°C) 30 over the course of a 40 typical WSP 25 operational season 20 30 Varied aeration cycles • 15 20 for differing objectives 10 and treatment targets 10 5 Addition of control • tank (air stones only) 0 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Day Max Min Average Precipitation Overall average temperature = 17.7 o C 17

Testing/air cycling schedule Day 1 (start of flow) = May 22 Loading rates HRT Air Cycling (kg CODm -3 d -1 ) Week Rationale (days) (on/off) Consistent aeration • 1-7 3-7 ~1 – 1.21 Allow biofilm to acclimatize and • 24h/0h reach steady-state Develop heterogeneous microbial • 4-7 7-10 ~0.57 – 0.77 population Beginning to cycle aeration 8-13 4d/3d • Long aerobic/anaerobic conditions • 6-7 ~0.15 – 0.80 Inducing nitrification/denitrification, • 14 0h/24h possible P uptake 15, 16 7-10 ~0.15 — 0.55 4h/4h Shorter on/off air cycles • Looking for best regime (low energy, 17, 18 12h/12h • high reductions) 3-7 ~0.57 – 0.87 19, 20 24h/24h 18

Testing/air cycling schedule Day 1 (start of flow) = May 22 Loading rates HRT Air Cycling (kg CODm -3 d -1 ) Week Rationale (days) (on/off) Consistent aeration • 1-7 3-7 ~1 – 1.21 Allow biofilm to acclimatize and • 24h/0h reach steady-state Develop heterogeneous microbial • 4-7 7-10 ~0.57 – 0.77 population 19

Testing/air cycling schedule Day 1 (start of flow) = May 22 Loading rates HRT Air Cycling (kg CODm -3 d -1 ) Week Rationale (days) (on/off) Beginning to cycle aeration 8-13 4d/3d • Long aerobic/anaerobic conditions • 6-7 ~0.15 – 0.80 Inducing nitrification/denitrification, • 14 0h/24h possible P uptake 20

Testing/air cycling schedule Day 1 (start of flow) = May 22 Loading rates HRT Air Cycling (kg CODm -3 d -1 ) Week Rationale (days) (on/off) *Zebra mussel tank decommissioned 15, 16 7-10 ~0.15 — 0.55 4h/4h Shorter on/off air cycles • Looking for best regime (low energy, 17, 18 12h/12h • high reductions) 3-7 ~0.57 – 0.87 19, 20 24h/24h 21

Results – Total ammonia (ammonia/ammonium) (pH range: 7-8.1) Aeration 4d/4d 24h/0h 12h/12h 24h/24h 4h/4h off 350 120 Average volume of septage added/week Total ammonia concentration (mg/L) 300 100 250 (thousand litres) 80 200 60 150 40 100 20 50 0 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Time (days) Influent BioDome BioCord Zebra Mussels Control Volume 22

Results – Ammonia/ammonium 23

Total Nitrogen Compositions Influent 4h/ 12h/ 24h/ 24h/0h 4d/4d 4h 12h 24h BioCord BioDome 4h/ 12h/ 24h/ 4h/ 12h/ 24h/ 24h/0h 24h/0h 4d/4d 4d/4d 4h 12h 24h 4h 12h 24h 24

Total Nitrogen Compositions Influent 4h/ 12h/ 24h/ 24h/0h 4d/4d 4h 12h 24h Zebra Mussels Control 12h/ 24h/ 4h/ 24h/0h 4d/4d 24h/0h 4d/4d 4h 12h 24h 25

Mean percent reductions of total nitrogen (from influent) Timeframe Aeration cycling BioDome BioCord Zebra Mussel Control (Weeks) (on/off) (%) (%) (%) (%) 1-7 24h ON 23 ± 5 36 ± 10 14 ± 10 23 ± 11 8-13 4d/3d 42 ± 6 †55 ± 6 43 ± 7 14 ± 7 14 24h OFF 16 ± 8 40 ± 6 5 ± 10 18 ± 2 15/16 4h/4h 33 ± 21 42 ± 11 21 ± 18 No 17/18 12h/12h 58 ± 6 78 ± 4 35 ± 7 data 19/20 24h/24h 12 ± 5 55 ± 6 7 ± 5 Overall average percent 31 ± 4 47 ± 5 17 ± 5 20 ± 5 reductions • Blue highlighted cells = percent reductions from influent are significantly higher (p<0.05) than the control 26 *Statistics performed using Kruskal-Wallis post-hoc analysis

Results – Ortho-P 4h/4h 24h/0h 24h/24h 4h/4h 12h/12h 30 Average volume of septage added/week Ortho-P concentration (mg/L) 100 25 80 20 (thousand litres) 60 15 40 10 20 5 0 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Time (days) Influent BioDome BioCord Zebra Mussels Control Volume PAOs – phosphorus-accumulating organisms (aerobic) • enriched by alternating aerobic/anaerobic • Anaerobic phases—release P; aerobic—uptake P • No significant reductions for any treatment/air cycling (vs. control) • Overall, all treatments showed significantly lower P levels than influent (overall), with • lowest concentrations seen during weeks of 12/12h cycling 27

Results – Chemical Oxygen Demand (COD), Total suspended solids (TSS) COD reductions TSS reductions 4h/4h 4h/4h Average volume of septage added/week (thousand 24h/ 12h/ 12h/ 24h/ 4d/4d 24h/0h Average volume of septage added/week 4d/4d 24h/0h 24h 12h 12h 24h 800 120 350 TSS concentration (mg/L) COD concentration (mg/L) 100 700 300 100 (thousand litres) 600 80 250 80 litres) 500 200 60 400 60 150 300 40 40 200 100 20 20 100 50 0 0 0 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Time (days) Time (days) BioCord showed significant reductions (vs. BioCord showed significant reductions • • control) during all air cycling regimes (vs. control) during all air cycling regimes BioDome: only period 2 (24h off) BioDome: only period 1 (24h on) • • ZMs: only period 2 (24h off) ZMs: only period 2 (3d/4d) • • Highest reductions overall seen during Highest reductions overall seen during • • 12/12h, followed by 24h on 24h on, followed closely by 12/12h 28

Dissolved Oxygen levels 24h/0h 4d/4d 24h/24h 4h/4h 12h/12h 10 9 DO Concentration (mg/L) 8 7 6 5 4 3 2 1 0 0 20 40 60 80 100 120 140 Time (days) BioDome BioCord Zebra Mussels Control 29

Full-scale testing and implementation at Storring Septic – Current operational regime 30

Full-scale testing and implementation Split-pond operation Regular septage 31

Full-scale testing and implementation Split-pond operation 3 rd -party/excess materials 32

In the case of pond shock . . . Regular septage 33

Full-scale implementation – alternative scenario All septage All septage 34