Lake, Amanda

Lake, Amanda

Amanda Lake is a speaker at WEFTEC 2026.

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About Lake, Amanda

Amanda Lake is a speaker at WEFTEC 2026.

Lake, Amanda

Amanda Lake is a speaker at WEFTEC 2026.

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Description: Cross-Validation of Liquid-Phase and Offgas N2O Emission Measurements at Full-Scale...

Cross-Validation of Liquid-Phase and Offgas N2O Emission Measurements at Full-Scale Wastewater Treatment Plants

Abstract

Danish utilities will soon face regulation based on nitrous oxide (N[sub]2[/sub]O) emissions from biological wastewater treatment. The Danish EPA-funded N[sub]2[/sub]O Mobile project demonstrated a comprehensive, multi-sensor approach for measuring and validating N[sub]2[/sub]O emissions across multiple wastewater treatment plants. Using liquid N[sub]2[/sub]O and offgas sensors operating simultaneously at up to eight positions-either within one or across several bioprocess tanks-the project developed a mobile setup for complete detection of N[sub]2[/sub]O emissions. Through extensive measurement campaigns, the project enabled detailed emission profiling at both tank and plant levels. The results form the basis for a standardized method to extrapolate N[sub]2[/sub]O emissions from single-point measurements to total plant emissions, supporting future regulatory implementation. This is important for other utilities as it provides a practical blueprint for measuring N[sub]2[/sub]O emissions reliably [b]Results and discussion[/b]: Two full-scale WWTPs were monitored; Aalborg Vest (3 treatment trains, 6 tanks, 265.000 PE) and Lynetten (10 treatment trains, 20 tanks, 1.000.000 PE). The WWTPs have fully mixed aeration tanks and are full BNR bioprocesses with fine bubble diffused air and intermitted aeration. N[sub]2[/sub]O emissions were monitored at single tanks and across entire WWTPs using 8 offgas hoods (UpWater, 8 min intervals) and 8 liquid phase N[sub]2[/sub]O sensors (Unisense Environment, 1 min intervals), installed in pairs at 8 process locations. Each pair, placed in proximity, collected data that was pre-processed and transferred to a cloud server for centralized processing in Hubgrade (Veolia). Emission calculations and time series matching were conducted with Python. At both WWTPs, comprehensive 5-month cross-validation study was undertaken between liquid-phase N[sub]2[/sub]O sensors and offgas-based emission measurements with all-in-one tank ([b]Figure 1[/b]). In both WWTPs all monitoring positions showed comparable N[sub]2[/sub]O liquid (mgN/L) and offgas (ppm) concentrations, demonstrating fully mixed raceways. Comparison of each liquid N[sub]2[/sub]O/offgas pair, utilizing hood airflow, demonstrated strong correlations for both Aalborg slope 0.95, R[sup]2[/sup] = 0.98) and Lynetten (slope 1.10, R[sup]2[/sup] = 0.99), as established through published monitoring and mass transfer models (Foley et al., Schulthess, R. & Gujer) and advanced hood systems (Gruber et al.) ([b]Figure 2[/b]). Additionally, when tank airflow was normalized per m[sup]2[/sup] of aerated surface for the same pairs, similarly linear correlations were observed at both wastewater treatment plants (slopes 0.94 & 1.12, R[sup]2[/sup]=0.98 & 0.97). Due to low emissions at Aalborg Vest, comparisons were over a high ammonium load period. Comparing emissions calculated from hood measured airflow (1m2) to those based on tank-wide airflow reveals much weaker correlations, as shown in [b]Figure 2[/b] for both WWTPs (lower left and upper right quadrants), mainly due to differences in airflow across the tank surface. For both liquid N[sub]2[/sub]O and gas phase monitoring technologies used, depending solely on airflow measurements at one or a few hoods can lead to considerable uncertainty in total N[sub]2[/sub]O emission estimates, even within a single zone or bioprocess tank. By calculating or installing distributed airflow meters at tank or zone level, overall emission reporting accuracy can be greatly improved, eliminating errors caused by uneven or localized airflow. Results from multi-tank monitoring in 8 of 20 process tanks at Lynetten show that true mean emissions were 31.54 kgN/day (SD = 6.06 kgN/day, mean of all liquid N[sub]2[/sub]O sensor measurements, [b]Figure 3 & Table 1[/b]). To statistically test monitoring requirement for a ~15% accuracy, progressively increasing the number of measured tanks 1 to 8 tanks (17–100% of the total), the relative uncertainty decreased from originally 22% demonstrating that approx. 30% coverage is required to obtain estimates within 10–15% of the true plant mean. This finding aligns with earlier multi-tank assessments covering 100% at Aalborg Vest, where daily emissions rates ranged from 0.45 to 0.93 kgN/day and an average emission rate of 0.71±0.19 kgN/day ([b]Table 2[/b]). Highlighting this variability, statistically testing the number of tanks needed to get within 10-15% of the Aalborg Vest mean value shows that at least 50% of the bioprocess volume should be monitored. [b]Conclusions[/b]:This report summarizes a multi-site assessment of two N[sub]2[/sub]O measurement methods for emission quantification. Long-term validation showed that liquid-phase N[sub]2[/sub]O sensor and offgas emission measurements produce comparable results, confirming the reliability of mass-transfer models for liquid-based calculations. Accurate bioprocess emission estimates require airflow data from all tanks or zones, as relying on local readings may lead to significant errors; local tank or zone level airflow improve reporting accuracy. Measurements across multiple treatment trains reveal that monitoring at least 30-50% of bioprocesses helps reduce uncertainty caused by uneven loading. The study identifies best practices for extrapolating single-point measurements to whole-plant emissions, offering validated guidelines to support accurate total emissions reporting in wastewater treatment plants

This paper was presented at WEFTEC 2026 in New Orleans, Louisiana.

Presentation time

08:30:00

09:00:00

Session time

8:30:00

10:00:00

SessionDecarbonizing Water: Best Practice Measurement N2O

Session locationErnest N. Morial Convention Center

TopicFacility Operations and Maintenance

Author(s)

Andersen, Mikkel, Mxller, Martin, Debel, Laura, Mattesen, Eva, Gruber, Wenzel, Lake, Amanda

Author(s)M. Andersen1, M. Møller1, L. Debel2, E. Mattesen2, W. Gruber3, A. Lake4

Author affiliation(s)Unisense Environment AS, 1Unisense Environment AS, 1Veolia, 2Veolia / Kruger A/S (Hubgrade), 2UpWater AG, 3Jacobs Engineering Headquarters Office, 4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160282

Volume / Issue

Content sourceWEFTEC

Word count14

Developing utility guidance for monitoring nitrous oxide at WRRFs

Abstract

[b]Introduction[/b] While monitoring nitrous oxide at WRRFs is a key priority for Utilities globally, limited guidance exists for how to do this in order to obtain sufficient data and insights for quantification and mitigation. This project sought to develop good practice guidance for N[sub]2[/sub]O monitoring, providing practical steps for utilities who are considering or already implementing N[sub]2[/sub]O monitoring, including recommendations for site selection, location of sensors, data management and developing mitigation insights. [b]Methodology[/b] Through a consensus based approach with industry and academic experts and with support from the International Water Association, the project team defined the key steps of designing and implementing measurement campaigns and subsequent data management and use. The practical experiences of the authors alongside literature review were used to develop the good practice guidelines. [b]Findings[/b] Mechanisms for N[sub]2[/sub]O emissions, primarily in aerated treatment zones of an activated sludge reactor, are shown in Figure 1.1. Whilst completely mixed secondary treatment exhibits more uniform N[sub]2[/sub]O production across reactor volumes, for WRRFs with plug flow characteristics and variable load and/or aeration intensity, N[sub]2[/sub]O production varies within and between zones. Figure 1.2 shows monitoring techniques which are currently applied for site wide and process unit level N[sub]2[/sub]O measurement. N[sub]2[/sub]O production is a risk wherever biological nitrogen transformation is being undertaken. Evidence shows the majority of this is likely from secondary treatment, and sidestream treatment. Biosolids processing and final effluent discharge are further recognised sources of N[sub]2[/sub]O (Galfalk et al. 2025). In practice, utilities are limited in terms of the number of measurement locations and resources which can be sustained; focus on secondary treatment tanks is recommended given they are responsible for the majority of WRRF N[sub]2[/sub]O emissions and are able to be measured with available technologies and typical utility resources. Table 1.1 provides a comparison of the two key methods for open tank monitoring – liquid phase and gas phase measurement with multi-hood systems. Accurate tank and ideally zone air flow data is required for both methods. Long-term continuous monitoring spanning at least 12 months is required due to seasonal (e.g. Andersen et al. 2022; Seshan et al. 2024). A short-term campaign may entirely miss or misrepresent N[sub]2[/sub]O risks at a WRRF. Figure 1.3 shows suggested measurement locations in typical WRRF configurations (recommended as dark green and optional in light green symbols). Figure 1.4 shows a suggested process for site selection and measuring locations for N[sub]2[/sub]O monitoring. Process evaluation to determine 'most representative' lanes for monitoring should be undertaken– load or aeration performance variation between lanes leads to variation in N[sub]2[/sub]O production and emission. A suggested approach for N[sub]2[/sub]O and wider process data processing pipeline and common assessment techniques shown in Figure 1.5. Data sets of long term monitoring will likely include data gaps or incomplete data; these should be identified clearly with various imputation techniques able to be applied with a focus on training and engagement to sustain high quality process data. When monitoring of N[sub]2[/sub]O shows production and potential drivers of N[sub]2[/sub]O, evaluation of site potential for mitigation can be undertaken. This should consider a hierarchy for mitigation as shown in Figure 1.6 (adapted from original figure by authors, first published IChemE, 2024). Process optimisation offers great potential for cost effective N[sub]2[/sub]O mitigation from demonstrated though limited full scale mitigation studies (WEFTEC, 2025) and co-benefits of improved process control. Close attention to effluent quality and compliance and energy efficiency must remain. A key consideration is whether a WRRF can implement operational changes– these may include control of dosed chemicals (e.g. for alkalinity control or carbon source), aeration control, increasing sludge age and mixed liquor management. More novel mitigation approaches are subject to ongoing trials and in some cases full scale installation, including nitrous oxide destruction, ammonia recovery in lieu of side stream treatment and engineering microbial ecosystems (WEFTEC, 2025). [b]Key Outcomes and Significance [/b] The guide provides practical guidance for utilities to monitor N[sub]2[/sub]O – supporting design and execution of monitoring campaigns which offer the potential to collect best possible data and mitigation insights and addressing the key topic of 'sufficiency' in design and implementation of N[sub]2[/sub]O measurement. While collective sharing of monitoring outcomes will lead to more in depth and comparable data globally, this remains challenged by volume of data, security concerns and the need for detailed site-specific process information for meaningful interpretation. This work must be pursued to enable the use of context-specific N[sub]2[/sub]O emission and wider WRRF data to inform improved emission factors and collective learning that supports mitigation across asset types and operational conditions.

This paper was presented at WEFTEC 2026 in New Orleans, Louisiana.

Presentation time

09:30:00

10:00:00

Session time

8:30:00

10:00:00

SessionDecarbonizing Water: Best Practice Measurement N2O

Session locationErnest N. Morial Convention Center

TopicFacility Operations and Maintenance

Author(s)

Lake, Amanda, Andersen, Mikkel, Brotto, Ariane, Clifford, Eoghan, Haimi, Henri, Holohan, Conall, Rodrigues, Bernardete, Schmidtke, Jurgen, Sieranen, Milla, Vellacott, Aprilia

Author(s)A. Lake1, M. Andersen2, A. Brotto3, E. Clifford3, H. Haimi4, C. Holohan5, B. Rodrigues3, J. Schmidtke6, M. Sieranen4, A. Vellacott1

Author affiliation(s)Jacobs Engineering Headquarters Office, 1Unisense Environment AS, 2University of Galway, Ireland, 3Aalto University, 4Radboud University, 5University of Galway, 3Stuttgart, 6Aalto University, 4Jacobs Engineering Headquarters Office, 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160443

Volume / Issue

Content sourceWEFTEC

Word count10

Getting to Grips With Grit: Opportunities For Circular Economy in Scotland

Abstract

Grit recovery in wastewater treatment offers an opportunity to realise additional value from wastewater residuals and an important opportunity to introduce Circular Economy in bioresources and residuals recovery - recognising global finite resources of mineral sands and the social, economic, environmental and carbon costs of extraction. The benefits of reusing grit are of increasing interest in Europe, in particular given increasing disposal costs, tightening regulation on organics to landfills and carbon impact of the current predominant landfill disposal route. This paper provides a case study from Scotland, United Kingdom where reuse options for grit from wastewater treatment are evaluated. It reviews current practice in beneficial grit reuse and presents outcomes for potential reuse opportunities and considerations, presenting case study cost and carbon impacts and regulatory framework considerations. Recommendations and opportunities for recognising the grit value chain are provided for the case study in context of the emerging Circular Economy.

SpeakerLake, Amanda

Presentation time

13:40:00

14:00:00

Session time

13:00:00

14:00:00

SessionHead(works) of the Class: Case Studies and Advancements in Grit Removal

Session number603

TopicFacility Operations and Maintenance, Global Perspectives, Municipal Wastewater Treatment Design

Author(s)

A. LakeA. LakeT. KennedyC. Stamper

Author(s)A. Lake1; A. Lake1; T. Kennedy2; C. Stamper3;

Author affiliation(s)Jacobs1; Scottish Water2; Zero Waste Scotland3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157560

Volume / Issue

Content sourceWEFTEC

Word count12

Lessons Learned from Nitrous Oxide Monitoring at 15 WRRFs

Abstract

Objectives
No standard methodologies exist for N2O measurement at water resource recovery facilities (WRRFs) and multiple approaches are being taken by utilities. Sharing experiences, approaches and findings is critical in order to support progressive N2O measurement and mitigation. The objective of this study is to analyse and compare insights from N2O measurement campaigns at 15 WRRFs which have been ongoing since 2022/2023 and to summarise key lessons learned.

Methodology
Nitrous oxide monitoring campaigns were designed for 14 WRRFs (a total of 15 campaigns with full scale and pilot facility monitored at one site; refer Table 1). Methodology considerations which will be discussed in the paper include methodology applied in design of the campaign, specification of measuring methods, the number and location of N2O measurements and methodologies for data analysis and visualisation to obtain meaningful insights into N2O production and opportunities for mitigation.

Findings
Key findings from the 15 campaigns to date with examples will be presented in the paper as ten key learnings with key examples from the WRRF campaigns.
(1) The seasonality of N2O emissions is clearly observed at some facilities but in plug flow systems it is most useful if all tapered aeration zones are monitored as the system nitrification point is known to shift. Figures 1 and 2 show this summer and winter variation in N2O concentrations in location along reactor as well as the difference in magnitude between summer and what appears to be a peak winter period. This highlights the importance of multi-zone N2O measurement.

(2) Short term emissions calculations can yield very different conclusions because of this seasonality. Four discrete periods and EFs were calculated for the WRRF in Figure 2 from available data of sufficient volume/quality.

(3) Nitrous oxide is typically correlated with diurnal ammonia concentration (and load) profiles in settled sewage. Figure 3 shows a moderate correlation of winter time zone 2 N2O (nitrifying ASP, 19MGD) with in-zone ammonia (R = 0.67), previous zone 1 ammonia (R = 0.55) and in-zone dissolved oxygen (DO. R = 0.72) which is often below 1.0mg/L. Sufficient DO and improved DO control may support reduced N2O at this WRRF.

(4) More complex data analysis can offer additional insights and mitigation tools. An innovative data model development and application as described in Figure 4 has been developed and applied at 2 WRRFs (nitrifying ASP, 166MGD and nitrifying ASP + MABR, 2MGD). This includes use of measured and simulated model inputs. It identifies key operational parameters that have the highest importance on the measured N2O peaks within the given dataset which may allow meaningful mitigation interventions and future online effluent energy and N2O optimisation.

(5) To quantify N2O mass emissions, accurate air flow data is key — including accuracy of installed mass flow meters and assumptions about individual aeration zone distribution, particularly where flow data is lacking. Calibration of air flow meters is recommended as significant over or underestimates of N2O can otherwise result (Figure 5).

(6) Additional measurement sensors may be required to draw useful N2O insights — for example when monitoring carbonaceous facilities which may unintentionally nitrify in which N is not measured or to understand in-zone nitrogen species variation with N2O. In lane profiling is an innovative approach which may support production and emission understanding in plug flow systems (Figure 6; pilot concept this is a completely mixed reactor).

(7) Quantification at some WRRF typologies is challenging — these include coarse air bubble systems such as biological aerated filters (BAFs) (Figure 7) and trickling filters. For MABRs both liquid phase and off-gas measurement (both in lumen and from bulk reactor during MABR scouring and in any downstream aerated tanks) is key to provide whole-system N2O quantification.

(8) Site-level N2O campaigns may also support WRRFs and utilities. Whilst also offering a short term snap shot only, site-wide N2O quantification is useful for typologies which cannot be measured with in-process sensors and to allow an estimate of site-wide emissions across all bioreactors/lanes as well as prioritisation across multiple WRRFs in the event of limited resources (Figure 8).

(9) Sidestream treatment processes can be extremely high N2O sources due to their designed operational conditions which have been shown to pose risks for N2O. These include high ammonia loadings, intentional nitrite production, reliance on external carbon dosing and high process rates and conditions. EF of 8% N2O_N/TNin was calculated during initial 3 month campaign at a liquor treatment plant (Figure 9) which is now considering N stripping and N2O destruction options in funded mitigation work.

(10) Regular calibration of liquid phase sensors at recommended 2 monthly or +-/ 3 degrees Celsius is important for quality data. Calibration records provide an important audit trail, as utilities move towards facility level quantification and reporting of N2O.

Conclusions and significance
Ten key lessons learned from 15 WRRF ongoing N2O measurement campaigns illustrate the challenges and opportunities for utilities to collaborate for shared learning, development of standard measurement approaches and most effective mitigation.

This paper was presented at WEFTEC 2025, held September 27-October 1, 2025 in Chicago, Illinois.

Presentation time

15:40:00

15:50:00

Session time

15:30:00

17:00:00

SessionDecarbonizing Water: International Efforts to Measure and Reduce Process N2O Emissions

Session locationMcCormick Place, Chicago, Illinois, USA

TopicClimate Change Adaptation and Resilience

Author(s)

Lake, Amanda, Tsotsos, Manthos, Brookes, Adam, Mansell, Lisa, Taylor, Tom, O'Connor, Jane, Kimble, Alec, Holmen Andersen, Mikkel

Author(s)A. Lake1, M. Tsotsos2, A. Brookes3, L. Mansell4, T. Taylor5, J. O'Connor6, A. Kimble7, M. Holmen Andersen8

Author affiliation(s)Jacobs Engineering Headquarters Office1, Jacobs UK Ltd2, Anglian Water Services3, United Utilities 4, Yorkshire Water Services5, South West Water6, Bi-Zen7, Unisense Environment A/S8

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2025

DOI10.2175/193864718825160037

Volume / Issue

Content sourceWEFTEC

Word count10

Nitrous Oxide: No Laughing Matter - Case Studies from Europe

Abstract

Whilst water utility greenhouse gas emissions may typically comprise only one percent of country level emissions, increasing decarbonisation of electricity supplies is pivoting focus to direct process emissions of nitrous oxide and methane from water resources recovery facilities. Nitrous oxide emissions present considerable challenges for utilities’ paths to net zero – in particular monitoring and mitigating these emissions. Production pathways for nitrous oxide from nitrifying and denitrifying processes are yet to be fully understood and approaches to mitigation remain the subject of ongoing academic and industry research. This project summarises the progress of selected utilities in Europe – using case studies from Denmark, the United Kingdom, and Netherlands where progressive utilities are showing ambition and progress in understanding and reducing their nitrous oxide emissions.

In Europe, increasing decarbonisation of electricity supplies is pivoting focus to direct process emissions of nitrous oxide and methane from water resources recovery facilities. Nitrous oxide emissions present considerable challenges for utilities’ paths to net zero – in particular monitoring and mitigating these emissions. Production pathways for nitrous oxide from nitrifying and denitrifying processes are yet to be fully understood and approaches to mitigation remain the subject of ongoing academic and industry research. This project summarises the progress using case studies from Denmark, the United Kingdom, and Netherlands where progressive utilities are showing ambition and progress.

SpeakerLake, Amanda

Presentation time

16:30:00

16:45:00

Session time

16:00:00

17:30:00

SessionKnowledge Development Forum: Decarbonization of the Water/Wastewater Sector

Session number114

TopicGlobal Perspectives, Research and Innovation, Sustainability and Climate Change, Utility Management and Leadership

Author(s)

Amanda Lake

Author(s)A. Lake1;A. Brotto1;J. Porro2;M. Andersen3;J. Sandino1;

Author affiliation(s)Jacobs, USA1Cobalt Water Global, USA2Unisense Environment, DE3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2021

DOI10.2175/193864718825158176

Volume / Issue

Content sourceWEFTEC

Word count11

Quantifying Fugitive GHG Emissions At Metro Vancouver’s Lulu Island WWTP

Abstract

[b]Introduction[/b] Metro Vancouver's Climate 2050 Strategic Framework established regional targets of achieving 45 percent reduction in greenhouse gas (GHG) emissions by 2030 and becoming carbon neutral by 2050. In 2025, a two-stage multi-method monitoring project was launched at Metro Vancouver's Lulu Island WWTP (LIWWTP) to identify and quantify fugitive methane (CH₄) and nitrous oxide (N₂O) emissions. Results will inform a Fugitive Emission Management Plan for the plant, develop tangible measures to reduce emissions, and guide strategies at Metro Vancouver's other WWTPs. Efforts to monitor and ultimately reduce fugitive CH4 emissions will lead to additional revenue and cost savings. LIWWTP is a secondary treatment plant with a design average dry weather flow capacity of 89 ML/d. Major treatment processes include primary and secondary treatment, disinfection, sludge thickening, anaerobic digestion and dewatering. Biogas is used in boilers to meet on-site heating demand. Excess biogas is upgraded to produce renewable natural gas for grid injection. Secondary treatment is designed for BOD removal only using trickling filters (TF) followed by solids contact tanks (SCT). N2O emissions are expected to be minimal, while multiple sources of fugitive CH4 emissions are likely. [b]Approach and Methodology[/b] Standard protocols for quantifying GHG emissions do not exist for wastewater facilities. Some measurement methods allow both CH4 and N2O, while others only measure one. Some technologies are great at spotting leaks but poor at quantifying emissions, while other technologies may be ideal for short-term campaigns but not financially or technically viable for year-round continuous monitoring. A multi-method approach is adopted, allowing for source-level and area/site-level quantification, as well as seasonal campaigns and long-term, continuous monitoring. The project uses commercially available technologies and innovative solutions (Figure 1) through academic partner University of Calgary (UoC). The project is being carried out in two stages: [b]Stage 1 (April - May 2025):[/b] This stage used initial monitoring to determine the most important locations and appropriate technologies for longer-term monitoring in Stage 2. Efforts included near-continuous site-level monitoring using a QLM light detection and ranging (LiDAR) camera, and a one-week campaign based on dispersion modelling by the UoC. [b]Stage 2 (August 2025 – March 2026):[/b] Multiple methods are being deployed, including the QLM LiDAR camera, seasonal site-level campaigns using tracer correction (Aerodyne) and dispersion modelling (UoC), process unit level CH4 leak detection and quantification by Montrose Environmental using optical gas imaging camera and Hi-Flow Sampler integrated with Tunable Diode Laser Absorption Spectroscopy, and process unit assessment from various odour control units (OCUs) using gas canister sampling and/or flux chamber on bark filers (Jacobs/UoC/ALS). Other innovative site-level methods to be tested include low-cost metal oxide sensors, Open-Path Tunable Diode Laser (TDL) camera and satellite imaging for CH4 quantification (UoC). [b]Stage 1 Results[/b] Estimated site emissions during the monitoring period based on QLM's system were 20,000 kg CH4. Most emissions were from three sources: 66% from the biogas upgrade system water scrubber pressure safety valve (Figure 2); 14% from a combination of near-range air vent (exhaust from biogas upgrade system water scrubber) and more distant emissions from TF3 (Figure 3); and 7% from ground-based biofilter 3 which receives air from TF4 and TF pump station 2 (Figure 4). UoC concentration mapping identified CH4 hotspots around ground-level biofilters and around the Biogas Upgrade System (Figure 5 example). N2O was not measured above ambient levels – this was expected as the plant is not operated for nitrification. CH4 losses based on biogas production was estimated to be between 4 and 7 percent. This is higher than the default value currently used by Metro Vancouver (which is based on the OWWA/WEAO GHG Inventory Tool), but within the typical range identified in the IPCC protocol (0-10%). QLM-based estimates from a 4-day sampling period in April 2025 are nearly twice those from UoC data. However, the two methods are not directly comparable; UoC measurement data are extrapolated from ground-level readings during site operating hours only, while QLM data are extrapolated from near-continuous monitoring. [b]Key Outcomes and Next Steps[/b] Both Stage 1 methods identify OCUs and the biogas upgrading system as key CH4 sources. The near-continuous monitoring and dispersion modelling approaches aligned fairly well, and Stage 2 work will be able to further develop these comparisons. The first and second phase of Stage 2 field campaign were completed in late August 2025 and early December 2025, respectively. One more seasonal campaign is scheduled for March 2026. In addition, two continuous methods (QLM LiDAR and low-csot sensors) will be deployed for site-wide CH4 measurements. Full results from Stages 1 and 2 will be presented at the conference. Results will be used to create a monitoring-based plant emissions inventory, provide a comparison to IPCC guideline-based calculations, develop recommendations on GHG emission reduction actions, and to inform process-based emission monitoring and reduction at other Metro Vancouver WWTPs.

This paper was presented at WEFTEC 2026 in New Orleans, Louisiana.

Presentation time

09:30:00

10:00:00

Session time

8:30:00

10:00:00

SessionDecarbonizing Water: Fugitive Methane

Session locationErnest N. Morial Convention Center

TopicAir Quality and Odor Management, Biosolids and Residuals, Facility Operations and Maintenance

Author(s)

Shen, Emma, Lake, Amanda, Davis, Taryn, Das, Rony, Carmichael, Jeff, Mehrdad, Seyed Mostafa, Du, Ke

Author(s)E. Shen1, A. Lake1, T. Davis1, R. Das2, J. Carmichael3, S. Mehrdad4, K. Du7

Author affiliation(s)Jacobs, 1Jacobs Engineering Headquarters Office, 1Jacobs, 1Associated Engineering (B.C.) Ltd., 2Metro Vancouver, 3University of Calgary, 4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160367

Volume / Issue

Content sourceWEFTEC

Word count11

Tacking Fugitive Methane Emissions at WRRFs - Global Lessons

Abstract

Fugitive methane emissions from sludge treatment and biogas handling processes are a significant source of GHG emissions, particularly critical for WRRFs with anaerobic digestion. Sewer methane production can also contribute to significant GHG emissions for the entire wastewater systems. There is lack of consistent methodologies for quantifying and monitoring these emissions in North America, which could lead to over- or (more likely) underestimation of their contributions to the overall GHG footprint. Ongoing work in Europe show the criticality of direct methane emissions monitoring, and operational approaches to mitigate methane emissions through regular survey, proactive leak detection and repair and independent certification. This session will present an overview of the sources of fugitive methane emissions in collection systems and at WRRFs, available methodologies in monitoring and quantifying fugitive methane emissions (including challenges and issues), and practical tips for reducing methane emissions based on global case studies.

This paper was presented at WEFTEC 2023 in Chicago, IL.

SpeakerLake, Amanda

Presentation time

13:30:00

15:00:00

Session time

13:30:00

15:00:00

SessionGlobal Approaches to Tackling Fugitive Methane Emissions

Session locationRoom S402a - Level 4

TopicIntermediate Level, Sustainability and Climate Change, Water Reuse and Reclamation

Author(s)

Lake, Amanda

Author(s)A. Lake 1; C. Scheutz 2 ; B. Beelen 3; E. Shen 4; P. Nielsen 5; A. Vellacot 6; A. Fredenslund 7; K. Kraemer 8;

Author affiliation(s)Jacobs 1; Technical University of Denmark 2 ; GHD 3; Jacobs 4; VCS Denmark 5; Jacobs 6; Technical University of Denmark 7; GHD 8;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825158977

Volume / Issue

Content sourceWEFTEC

Word count10

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