Kraemer, Jeremy

Jeremy Kraemer is a Wastewater Technical Director with GHD in their Waterloo, Ontario office. His focus over the last 5 years has been mitigating GHG emissions through improved GHG accounting, measuring methane and nitrous oxide and moving forward on embodied carbon. Jeremy is a member of WEF's GHG Focus Group and the National Advisory Committee of Canadian Water Network's net zero water roadmap project. He is a registered professional engineer in Ontario and obtained his Ph.D. from the University of Toronto.

Titles from this speaker

Description: Advancing Our Understanding of Sewer Methane: Modelling Sewer Generated Methane...

Advancing Our Understanding of Sewer Methane: Modelling Sewer Generated Methane Using SeweX

Abstract

This technical session will provide a forum for knowledge exchange in our understanding and modeling of sewer generated methane that has occurred within the last 1-2 years. Speakers will discuss lab/pilot research, advanced modeling, and full-scale measurement campaigns that are improving our understanding of the key contributing factors to methane generation in sewers, how to quantify it, and where our industry should continue to put our future research efforts.

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

Presentation time

13:30:00

15:00:00

Session time

13:30:00

15:00:00

SessionAdvancing Our Understanding of Sewer Methane

Session locationErnest N. Morial Convention Center

TopicCollection Systems

Author(s)

Beelen, Benjamin, Kraemer, Jeremy

Author(s)B. Beelen1, J. Kraemer1

Author affiliation(s)GHD Limited, 1GHD Limited, 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160339

Volume / Issue

Content sourceWEFTEC

Word count13

Description: Decarbonization Strategy Best Practices Derived from a Water Utility Experience...

Decarbonization Strategy Best Practices Derived from a Water Utility Experience Survey

Abstract

Water utilities are experiencing climate change impacts such as flooding, energy disruptions, and extreme temperatures, alongside existing challenges of serving growing populations, aging infrastructure, and meeting evolving regulations under budget constraints. Despite these challenges, the water sector holds potential to both reduce greenhouse gas (GHG) emissions and build resiliency to climate impacts. Water utilities are increasingly adopting decarbonization strategies, but face challenges due to limited guidance, technical uncertainties, and resource constraints. To characterize current practices, barriers, and opportunities in decarbonization strategy development and implementation, we surveyed 28 water utilities across six countries. The survey explored key components of decarbonization strategies, including GHG emission inventorying, monitoring of fugitive emissions (notably nitrous oxide [N[sub]2[/sub]O] and methane [CH[sub]4[/sub>), mitigation methods, climate adaptation and resiliency, and the challenges and opportunities utilities experienced in implementing these strategies.

Key survey insights include:
• Figure 1 summarizes the key components that utilities included in their decarbonization strategies. Seventy-nine percent of the utilities have adopted climate action plans, most of which were created in the past five years, indicating rapid sectoral progress.
• Figure 2 shows the GHG emission sources utilities included in their GHG emission inventories. Over 90% of the utilities maintain emission inventories, with most including scope 1 and 2 sources.
• Table 1 shows the GHG emissions utilities are measuring, and the measurement locations. Fifty-seven percent of the utilities measure N[sub]2[/sub]O, CH[sub]4[/sub], and/or CO[sub]2[/sub].
• Figures 3, 4, and 5, show the mitigation methods utilities are implementing to reduce emissions from energy-use, N[sub]2[/sub]O, and CH[sub]4[/sub], respectively. All of the utilities are reducing energy-related emissions, 80% are addressing N[sub]2[/sub]O, and 90% are addressing CH[sub]4[/sub].
• Figure 6 summarizes the challenges utilities experienced in creating and implementing decarbonization strategies.

Most challenges were related to technical and financial constraints, whereas leadership and strategic priorities were the main drivers of GHG reduction activities. The survey found that while most utilities have made significant advances in reporting and reducing energy-related emissions, many struggle with monitoring and mitigation process emissions of N[sub]2[/sub]O and CH[sub]4[/sub], which are often the largest contributors to wastewater sector emissions. The lack of a structured, step-by-step approach can result in focusing on less significant emission sources, resulting in slower progress and higher costs, underscoring the need for a practical framework they can follow. Drawing from these findings, and experiences using these findings to develop a strategy for a Municipality in Ontario (whose strategy was presented at WEFTEC 2025), the authors developed the Water Utility Net-Zero Strategy Best Practice Framework. This framework is a systematic, four-phase guide designed to help utilities create, assess and continuously improve their decarbonization strategies. Shown in Figure 7, the framework provides guidance on the following phases:

• [b]Phase 1: Evaluate[/b] the utility's existing goals and commitments, services, climate risks, and GHG emission impact through annual GHG emission inventories that include Scope 1, 2, and 3 emissions.
• [b]Phase 2: Plan[/b] cost-effective and feasible GHG mitigation projects and prioritize each using utility-defined criteria. Develop a roadmap outlining implementation methods, timelines, and expected reductions.
• [b]Phase 3: Implement[/b] the roadmap, refining mitigation methods during design. Monitor progress annually though updated GHG inventories, comparing actual reductions to projected targets.
• [b]Phase 4: Rework and Refine[/b] the strategy to reflect new industry knowledge, evolving technology, and experiences (i.e., implementing mitigations, or measuring GHGs) and challenges encountered in meeting reduction goals. To supplement the framework, the authors created a Best Practice Checklist Tool, enabling utilities to self-evaluate the maturity of their strategy compared against each step of the framework, and identify actionable improvements. Screen captures from this tool are shown in Figures 8 and 9. This work is among the first to consolidate global experiences into actionable guidance for water utilities worldwide. The findings provide an overview of the current state of water utility decarbonization strategy advancements informed by global experiences and synthesizes this knowledge into practical guidance and tools. The framework and checklist tool are designed for broad applicability, enabling utilities of vary sizes, capacities, and that reside in varying jurisdictions, to systematically advance their GHG reduction commitments, while mitigating risks through informed, strategic decision-making.

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

Presentation time

10:30:00

10:45:00

Session time

10:30:00

12:00:00

SessionInnovative Approaches to Resource Recovery and Carbon Reduction in Wastewater

Session locationErnest N. Morial Convention Center

TopicBiosolids and Residuals, Circular Water Economy, Energy Production, Conservation, and Management, Resilience, Safety, and Disaster Planning

Author(s)

sabzwari, Aby, Kraemer, Jeremy

Author(s)A. sabzwari1, J. Kraemer1

Author affiliation(s)GHD Group Pty Ltd., 1GHD Group Pty Ltd., 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160386

Volume / Issue

Content sourceWEFTEC

Word count12

Description: Developing a Cost-Effective Resilient Decarbonization Strategy: Lessons for...

Developing a Cost-Effective Resilient Decarbonization Strategy: Lessons for Decision-Makers

Abstract

Introduction
Wastewater utilities are working towards a circular economy by reducing energy consumption and other greenhouse gas (GHG) emissions. To support these goals utilities may create a long-term decarbonization strategy. However, the complexity of wastewater infrastructure and treatment processes necessitates a tailored, case-by-case approach to guide decision-making. York Region in Ontario, Canada has developed a cost-effective resilient wastewater decarbonization strategy and its experience provides valuable insights to other utility decision-makers on the challenges, approaches, and lessons learned in this important endeavor.

Boundary Definition
Deciding which emissions are within the boundary of the strategy is an important step. Table 1 summarizes the emissions that York Region included, organized by scope. This choice was informed by a global scan, other local municipalities, regulatory agency reporting requirements, and previous studies. For example, York Region included sewer generated methane in its inventory owing to having a previous assessment to build on.

Baseline Conditions and Business-as-Usual Projection
Baseline emissions were quantified for historical years using the OWWA/WEAO GHG Inventory Tool for Water Utilities supplemented by additional quantifications such as for sewer-generated methane. Using the baseline conditions and existing systems as a guide, the project team developed a business-as-usual (BAU) projection that assumes existing practices are continued accounting for additional flow. The BAU conditions starting at the baseline year of 2014 to 2050 are presented in Figure 1, suggesting emissions could nearly double.

Mitigation Activities Long-listing and Refinement
The project team brainstormed a long list of potential mitigation projects based on a global scan and team knowledge. The overall approach to filter the long list is illustrated in Figure 2. The project team then refined this long list into a short-list of feasible-by-2050 activities and programs. This feasibility assessment considered: technology availability and anticipated development before 2050, alignment with stakeholders, alignment with the existing wastewater master plan and alignment with co-owned facilities.

The feasible options were then categorized as a mitigation activity or a supporting activity. Mitigation activities are those where a cost and GHG reduction could be quantified such as changes to fugitive emissions or reducing the consumption of electricity. Supporting activities are those that cannot be numerically quantified but provide support to achieving GHG reductions, such as measuring emission factors, increasing staff capacity through training, and developing different purchasing policies. For each mitigation activity, capital and O&M costs were estimated and GHG emissions over the project service life were estimated. From these values the cost of abatement was calculated by dividing the net present value lifecycle cost by the total tons of carbon dioxide equivalent (CO2e) mitigated (i.e. $/t-CO2e). Mitigation projects exceeding $1,000 CAD/t-CO2e were deemed not cost-effective. Of the 17 projects that were considered cost-effective, a multi-criteria analysis (MCA) was used to rank them using the criteria listed in Table 2.

Results and Outcomes
A marginal abatement cost (MAC) curve was generated from the 17 feasible and cost-effective mitigation projects. This MAC curve is shown in Figure 3 while the same projects sorted by MCA rank is shown in Figure 4. These two plots highlight that despite some projects having a negative abatement cost, these projects are not necessarily optimal when considering the criteria in Table 2. These plots indicate the cost-effective mitigations would reduce the 2050 BAU emissions by approximately 45 percent.

Getting to zero GHG emissions was found to be not feasible at the present time even if all cost-effective mitigation projects were implemented. Figure 5 shows the projected emissions of the BAU case, and the decarbonization projections with and without constraints. Owing to York Region's planned doubling of the service population by 2050, the decarbonization pathway would keep the total emissions at roughly the same magnitude as historical emissions. As an alternative that can better communicate decarbonization progress even with population growth, the GHG emissions can be normalized per volume of wastewater treated. In this view, the benefit of decarbonization action is clearly seen and offers another communication tool that utilities can use with their stakeholders.

Significance
Although York Region found that decarbonizing to zero GHG emissions is not yet cost-effective to achieve, there are many mitigations available that do achieve significant reductions supporting a more sustainable and circular wastewater infrastructure. This presentation will further identify the lessons for utility decision-makers when pursuing a comprehensive decarbonization strategy that is feasible and cost-effective. In addition, the presentation will explain how adapting and improving resilience to climate change was also incorporated into the project.

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

Presentation time

11:00:00

11:30:00

Session time

10:30:00

12:00:00

SessionPathways for Decarbonization and Circular Water Economy

Session locationMcCormick Place, Chicago, Illinois, USA

TopicEffective Utility Management

Author(s)

Kraemer, Jeremy, Chen, Shengdi, Szeptycki, David, Kraemer, Jeremy, Bogoslowski, Tanya, Beelen, Benjamin, Sabzwari, Aby

Author(s)J. Kraemer1, S. Chen2, D. Szeptycki2, J. Kraemer1, T. Bogoslowski1, B. Beelen1, A. Sabzwari1

Author affiliation(s)GHD Group Pty Ltd.1, Regional Municipality of York2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2025

DOI10.2175/193864718825160098

Volume / Issue

Content sourceWEFTEC

Word count10

Dynamic Process Modelling for Aeration Blower Design at the Humber Treatment Plant

Abstract

The City of Toronto initiated a design and construction project in 2022 to replace the existing secondary treatment aeration blowers at the Humber Treatment Plant. A comprehensive review of historical flow and plant operating data was conducted to derive a design-year hourly diurnal flow and load profile (8,760 discrete data points) for input into a commercial wastewater process simulation tool. The output oxygen demands were used to generate process airflows considering varying wastewater temperatures, standard oxygen transfer efficiency based on net airflow per diffuser and diffuser depth, and dynamic alpha based on aeration basin oxygen uptake rates at each time step in the flow and load profile. Statistical and seasonal analyses were applied to the resulting airflow data sets to determine performance guarantee points at varying inlet air conditions for blower equipment preselection

The City of Toronto initiated a capital project in 2022 to replace the existing secondary treatment aeration blowers at the Humber Treatment Plant. A comprehensive approach was implemented to develop the process design basis for the new aeration blowers using dynamic wastewater treatment process modelling to derive process airflows for a one-year hourly diurnal flow and load profile. Resulting airflows were used to determine performance guarantee points at varying inlet air conditions.

SpeakerRizzuti, Daniel

Presentation time

08:30:00

09:00:00

Session time

08:30:00

10:00:00

SessionThe Big Bad Blower: Huffing and Puffing Air Through Your Aeration Basins

Session locationRoom S401d - Level 4

TopicEnergy Production, Conservation, and Management, Facility Operations and Maintenance, Intermediate Level, Municipal Wastewater Treatment Design

Author(s)

Rizzuti, Daniel

Author(s)D. Rizzuti 1; J. Kraemer 2 ; Pretorius 3; T. Young 4; T. Gretarsson 5; D. Pease 6; T. Shen 7; E. Eini 8; V. Szonda 6; D. Rizzuti 1;

Author affiliation(s)GHD Ltd., Waterloo, ON 1; GHD Ltd., Waterloo, ON 2 ; GHD 3; GHD 4; GHD 5; City of Toronto, ON 6; City of Toronto, ON 7; City of Toronto, ON 8; City of Toronto, ON 6; GHD 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159068

Volume / Issue

Content sourceWEFTEC

Word count13

Description: Full-Scale Testing of Intentional Operational Changes to Influence Nitrous Oxide...

Full-Scale Testing of Intentional Operational Changes to Influence Nitrous Oxide Emissions

Abstract

Halton Region collects and treats wastewater from over 600,000 people in Ontario, Canada. In early 2024, the Region installed online dissolved nitrous oxide (N₂O) sensors at their two largest wastewater treatment plants (WWTPs), Skyway and Mid-Halton, and initiated a two-year project to measure and mitigate N₂O. N2O is a potent greenhouse gas (GHG) and the Region's largest emission from wastewater treatment. The objectives of the project include: (1) Measure N2O emission factors for Mid-Halton and Skyway; (2) Identify operating parameters influencing N2O, and (3) identifying low-cost operational optimization N2O mitigation techniques. Results of objectives 1 and 2 were presented at WEFTEC 2025. This presentation focuses on the full-scale mitigation testing (Objective 3) conducted at the Mid-Halton WWTP. Skyway WWTP is testing optimizations not directly related to N2O and therefore not reported here. Table 1 summarizes the operational optimization strategies tested at full-scale at Mid-Halton WWTP with potential to reduce N2O emissions. These strategies were developed and refined with the plant operations staff, as they considered current operational practices and limitations that exist both in operations (i.e. maintaining effluent quality) and physical equipment and control systems. The testing was constrained by the requirement to work within the plant's existing systems; there were no changes to SCADA programming and no capital improvements. As of writing, three of four tests are complete and the fourth will finish imminently (Feb. 2026). Tables 2, 3 and 4 summarize the process changes for each test and the schedule. Some tests included additional field sampling and data collection such as bioreactor dissolved oxygen (DO) profiling. The Region's Technical Services supported operations staff with customized field data collection sheets and standard procedures. Other than some additional grab sampling, the testing was constrained to using the existing data sources and frequency. For example, there was no online ammonia sensor available, only the typical composite sampling for ammonia available 2-3 times per week. Data and information sources included SCADA data for online instrumentation and flowmeters (including N₂O sensors), laboratory data from the Region's laboratory information management system, a plant operations spreadsheet with daily summary operating parameters maintained by plant staff, digital operator logbook, and N₂O sensor maintenance log. An important activity was weekly check-in meetings between plant operations, the Region's Technical Services, and consultant. These meetings provided immediate information about what was happening at the plant, allow fast decisions on adjusting test plans, and give plant staff an open forum for discussing how to run the plant and what changes would be acceptable within their experiences. Increasing the RAS rate from 45% to 75% during test periods 3 and 10 (Figures 1 to 3) saw slight N₂O reductions, however in test period 5 N₂O increased despite the higher RAS likely due to high DO risk. Running the secondary swing zones under anoxic conditions resulted in higher N₂O emissions, not lower (Figures 4 and 5). Although operations staff were able to step feed sufficient carbon to achieve low DO, there was little denitrification and higher nitrite leading to higher N2O. There were also limitations in airflow control – the law of unintended consequences found it was difficult to predict ahead of time all the follow-on effects of operational changes. Optimizing aeration is a common approach in the literature for mitigating N2O. The difficulty at Mid-Halton, however, was the constraints on both the physical airflow distribution (only one airflow controller for the whole train and limits on how the manual dropleg valves could be adjusted) and limits on how SCADA controls could be tweaked. Testing included using one DO probe for control (instead of normal averaging two probes) and adjustments to DO setpoints. Lowering the DO did not provide significant N₂O reductions (Figures 6 and 7). Because airflow cannot be controlled independently at the front and back of the tank, DO remained high in the back, leading to elevated N₂O. Slight reductions were observed when DO setpoints were lowered to 1.6–1.8 mg/L (from the normal 2.0–2.5 mg/L); however, the improvement was marginal, N₂O remained elevated due to high DO risk, and further lowering the setpoint was not recommended operationally. The higher MLSS / higher SRT testing will be finished imminently. Preliminary results (Figure 8) suggest that other factors, such as high DO, overshadowed SRT-driven changes in N₂O. Results of all tests will be fully described in the full paper. Halton Region's N2O project has demonstrated the need for considering site-specific operational practices and limitations. These results indicate it can be challenging to determine the exact cause of N₂O reductions during full-scale operations, as N₂O is highly influenced by multiple parameters. Halton Region's experience demonstrates, however, that to improve things sometimes we need to figure out how to make them worse. Understanding the conditions when N2O emissions have been higher has been a useful exercise. The Region plans to consider the outcomes of the intentional mitigation tests and how their typical operations may be modified for a more sustainable and optimized treatment process.

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

Presentation time

16:00:00

16:30:00

Session time

15:30:00

17:00:00

SessionDecarbonizing Water: Facility Optimization and N2O

Session locationErnest N. Morial Convention Center

TopicFacility Operations and Maintenance

Author(s)

Kraemer, Jeremy, Pharand, Lizanne, Duong, John, sabzwari, Aby, Porro, Jose

Author(s)J. Kraemer1, L. Pharand2, J. Duong2, A. sabzwari1, J. Porro2

Author affiliation(s)GHD Group Pty Ltd., 1GHD Group Pty Ltd., 1Cobalt Water Global, 2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160431

Volume / Issue

Content sourceWEFTEC

Word count12

Halton Region's Operations-Focused Nitrous Oxide Monitoring and Mitigation

Abstract

Halton Region in Ontario, Canada, collects and treats wastewater from over 600,000 people. The Region's WRRF operations staff have learned that N2O emissions can be an indicator of stress to the biology causing treatment inefficiencies. By adjusting process conditions to remove stressors, staff hope to both optimize treatment and prevent N2O emissions. The Region initiated a two-year project to pursue 'low hanging fruit' N2O mitigation strategies through operational optimization they believe are achievable based on current global experience. The objectives include: (1) Measuring WRRF N2O emission factors; (2) Identifying the operating parameters influencing N2O emissions and identifying low-cost operational optimization mitigation techniques; (3) Verifying the effectiveness of operational changes to reduce N2O emissions.

The Region installed online dissolved N2O sensors at two of its largest facilities. Figure 1 illustrates the locations of dissolved oxygen and N2O sensors. Once N2O emissions are measured within different areas of the plant, actions can be taken to reduce these emissions.

Table 1 summarizes the measured N2O emission factors from the first eight months of monitoring. Interestingly, the emission factors differ dramatically between Halton's two WRRFs and differ from the typical default which reaffirmed their decision to measure N2O.

Operations staff used a standard procedure and field data collection sheet at both plants to conduct quarterly bioreactor nitrogen profiling. The nitrogen concentration results for Mid-Halton WWTP in

#Figure 2 show the highest nitrification rates were at positions 4 and 5 which corresponded to the highest measured N2O concentrations.

#N2O concentrations varied continuously on an hourly, daily, and seasonal basis (Figure 3). High data sampling frequency from the N2O sensors, to capture short-term variation in emissions, presents data collection, handling and manipulation challenges. In addition, five different sources of data from each facility must be compiled together: SCADA data for online instrumentation and flowmeters including N2O sensors, laboratory data from the Region's laboratory information management system, a plant operations spreadsheet with daily summary operating data which is maintained manually by staff, the plant's digital operator logbook, and the N2O sensor maintenance log.

#Operations staff have observed the solids retention time can significantly influence N2O production. Figure 4 illustrates a period in March 2024 when the mixed liquor concentration at Mid-Halton was being increased in tank #12 in preparation to bring tank #11 back online which had been out of service for several months for repairs. During the initial rise from March 9 to 14 the N2O concentration decreased by about 50%. Then Tank #11 was brought online March 14 which divided Tank #12's mass inventory and the ammonia load was spread across two tanks resulting in lower mixed liquor concentrations and a further 50% decrease in N2O concentration. By the end of March, the N2O concentration was about 85% lower than at the beginning of the month, which clearly demonstrated how operational changes can influence N2O generation.

At Skyway, the Region dewaters biosolids using a centrifuge about 6 hours per day for 5 or 6 days per week. The centrate is stored and then returned to the headworks the same day typically over a four-hour period from 4 to 8pm. This slug load of ammonia reaches the aeration tanks in the late evening around midnight when influent loads are low. The impact of this time-varying ammonia loading is observable in the N2O concentrations of Figure 5. Each day when there is dewatering there is a corresponding spike in N2O generation around midnight, while on the weekend when there is no dewatering there is no midnight N2O spike.

Many of the Region's WRRFs experience seasonal alkalinity deficiency during warmer drier months of the year which results in low effluent pH. The Region observed an inverse relationship between N2O and pH at both plants: higher N2O is seen when effluent pH is lower (Figure 6). This relationship is stronger at Skyway which does not control pH in secondary treatment, while the relationship is not as strong at Mid-Halton where magnesium hydroxide is added as alkalinity supplement (although the dosing is limited to manage operating costs).

Dissolved oxygen (DO) that is too low or too high is the most common N2O risk and optimizing aeration is the most common mitigation strategy. Due to difficulty with aeration turndown and control, both Skyway and Mid-Halton have quite high DO concentrations, routinely >4 mg/L, whereas a DO of 1-2.2 mg/L would be recommended by the Cobalt Water Global N2ORisk AI/ML Decision Support System (Figure 7) being used on this project. The Region observed that changes in N2O concentrations are often aligned with DO changes (Figure 8).

Halton Region's operations team has found value from N2O measurement. The need to collect many data sources on regular basis and review changes in plant operation has been valuable for understanding how its facilities are performing. Operations staff have been keenly interested in the new data and have taken initiative to mitigate N2O emissions, for example at Skyway they are working to manage dewatering centrate returns over a longer duration. The project team is selecting several operational changes that will be field tested during 2025 to assess low-cost N2O mitigation.

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

Presentation time

13:30:00

13:45:00

Session time

13:30:00

15:00:00

SessionDecarbonizing Water: N2O Modeling - From Low DO to HPO

Session locationMcCormick Place, Chicago, Illinois, USA

TopicOptimization of Municipal Facility Operations

Author(s)

Kraemer, Jeremy, Pharand, Lizanne, Duong, John, Sabzwari, Aby, Beelen, Benjamin, Porro, Jose

Author(s)J. Kraemer1, L. Pharand2, J. Duong2, A. Sabzwari1, B. Beelen1, J. Porro4

Author affiliation(s)GHD Group Pty Ltd.1, Regional Municipality of Halton, Oakville2, Metro Water Recovery3, Cobalt Water Global4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2025

DOI10.2175/193864718825159974

Volume / Issue

Content sourceWEFTEC

Word count9

MBRs Are More Cost-effective Than Ever Before

Abstract

A cost model was developed to compare the capital and 20-year lifecycle cost of MBR vs. CAS treatment technology for a greenfield WRRF. Concept designs and cost estimates were developed for six treatment performance scenarios at two design flow capacities: 20 ML/d and 200 ML/d. Compared with a prior version of this model developed in 2012, MBR has become more cost effective compared to CAS in general, most notably for less stringent treatment requirements, while the cost savings of MBR for more stringent treatment requirements has improved, but more modestly. A primary driver of this is the advancements in membrane design, primarily the reduction in air scour energy for membrane cleaning due to new diffuser technology, greater membrane packing density reducing membrane equipment costs and further reducing air scour requirements, decreased membrane cleaning requirements and longer membrane life, and increased use of gravity permeation from membranes under average day operation.

SpeakerYoung, Thor

Presentation time

16:30:00

16:50:00

Session time

15:30:00

17:00:00

SessionAlternative Approaches to Intensify Secondary Treatment

Session locationRoom S404a - Level 4

TopicIntermediate Level, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Young, Thor

Author(s)T. Young 1; J. Kraemer 2 ; D. Rizzuti 3; S. Malatches 4; J. Lim 5; C. Thiemig 5; T. Young 1;

Author affiliation(s)GHD Inc 1; GHD Inc, Waterloo, ON 2 ; GHD Inc, Waterloo, ON 3; GHD Inc, Toronto, ON 4; Veolia Water Technologies & Solutions, Oakville, ON 5; Veolia Water Technologies & Solutions, Oakville, ON 5; GHD Inc, Bowie, MD 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159019

Volume / Issue

Content sourceWEFTEC

Word count8

Practical Guidance for Biogas Leak Detection at Wastewater Facilities

Abstract

Anaerobic digesters and the biogas they produce have allowed wastewater resource recovery facilities (WRRFs) to transform into power plants. Through the refinement and collection of biogas, renewable natural gas (RNG) can be produced, which is able to be injected into local gas distribution grids or used on-site to offset grid natural gas usage. However, these advancements in waste-to-energy infrastructure provide new challenges for WRRFs. Just like any other type of pressurized gas system, these systems can leak. Biogas/RNG leaks are a direct loss of product, present a health and safety hazard for workers and additionally is a potent greenhouse gas. It is therefore important for plant managers to reduce or eliminate these leaks where possible. To assist in this challenge, the wastewater industry has begun to use tools established in the oil and gas industry, such as optical gas imaging cameras (OGI cameras) that use infrared radiation to visualize methane in air, and portable methane analyzers that use lasers to accurately measure across a range of methane concentrations (these tools are shown in Figure 1). Although these and many other types of methane measurement devices are being tested at wastewater facilities, what is missing is an overarching approach to how to appropriately conduct biogas leak surveys. This presentation will discuss a practical framework for conducting biogas leak finding campaigns at WRRFs as well as case studies utilizing this framework in the hopes of contributing towards our sector's eventual development of best practices. A framework was developed to assist WRRFs in creating effective and efficient leak detection programs following a plan-do-check-act structure for continuous improvement (Figure 1). In general, the planning stage should create a leak finding plan that considers the risk of equipment leaking biogas (age of equipment, leak history, pressure of system, etc.) as well as equipment prioritization. Some facilities may have hundreds to thousands of individual locations that could leak, and it is not typically practical to assess them all in detail, which is why prioritizing equipment/areas is vital. The next step is to do the leak finding study using appropriate tools such as OGI cameras and portable methane analyzers. Once the data is collected, a detailed review of the information must be conducted to compare actual leaks/equipment conditions to the original plan. Finally, observed leaks are actioned, which can include issuing work orders for maintenance repair, longer-term capital repair or improvement, or do nothing (i.e. the leak is too impractical to address, or system operates as designed e.g. methane-laden condensate from biogas drip traps). FIGURE 1: FRAMEWORK FOR CONTINUOUS IMPROVEMENT OF LEAK DETECTION City of Toronto Case Study The City of Toronto's Humber Treatment Plant undertook a fugitive methane leak finding survey following the described framework. Key locations determined in the initial risk assessment were a floating roof digester, pressure relief valves on digesters, digester roofs, gas compressor equipment, and biogas-mixing piping. An OGI camera and portable methane analyzer were selected as suitable tools for the evaluation (Figure 2). The OGI camera used in this study was a FLIR Gx320 (shown in use in Figure 3). The camera visualizes methane and other hydrocarbons such as butane and propane, as black/dark smoke on the device's display (Figure 4). The camera was particularly effective in complex environments, such as around biogas piping, where visual confirmation amidst dense equipment was critical. FIGURE 2: DEVICES USED FIGURE 3: OGI CAMERA IN USE FIGURE 4: OGI CAMERA OUTPUT EXAMPLE WITH METHANE INDICATION CIRCLED IN RED The other device used was a SEM5000, which uses Tunable Diode Laser Absorption Spectroscopy to quantify methane concentrations. The device recorded methane concentrations in parts per million (ppm) at one-second intervals, pairing each reading with time and location data via an integrated GPS module. Several types of information were developed from the observation data, including videos, a map of methane concentrations (Figure 5), and a list of leaks that could be resolved through maintenance activities. A key finding was that almost all biogas piping and gas compressor piping were in good condition, and only a few leaks required addressing. The City of Toronto is currently considering future leak detection assessments at a frequency to be informed by this study. FIGURE 5: VISUALIZED PORTABLE METHANE ANALYZER DATA

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: Fugitive Methane

Session locationErnest N. Morial Convention Center

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

Author(s)

Beelen, Benjamin, sabzwari, Aby, Joseph, Kevin, Kraemer, Jeremy, Szonda, Vanessa

Author(s)B. Beelen1, A. sabzwari1, K. Joseph1, J. Kraemer1, V. Szonda2

Author affiliation(s)GHD Group Pty Ltd., 1GHD Group Pty Ltd., 1GHD Group Pty Ltd., 1GHD Group Pty Ltd., 1City of Toronto, 2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2026

DOI10.2175/193864718825160447

Volume / Issue

Content sourceWEFTEC

Word count10

Description: Real-world Reliability and O&M of High-speed Turbo and Integrally-geared...

Real-world Reliability and O&M of High-speed Turbo and Integrally-geared Blowers

Abstract

Aeration blowers consume around half of all electricity used at a water resource recovery facility (WRRF). Choosing the most efficient blowers can save money, electricity, and greenhouse gas emissions. High-speed turbo blowers and single-stage integrally-geared (SSIG) blowers offer some of the highest efficiencies for process aeration, but operations and maintenance (O&M) staff may not have experience with these technologies. This paper documents comparative O&M experiences between turbo and SSIG blowers compiled from interviews with thirteen (13) North American water utilities with medium to large size blower installations as well as the authors’ own experience and past projects. In addition, turbo blower reliability and failure data and maintenance contract information were solicited from turbo blower manufacturers and summarized. This information was used to support one water utility’s blower technology decision and the authors hope this information will be useful to other utilities as well.

This paper compares O&M experiences with turbo blowers and single-stage integrally-geared blowers from interviews with 13 North American water utilities with medium to large blower installations and the authors' experience and projects. Turbo blower reliability data and maintenance contract information from manufacturers is summarized. This information was used to support one utility's blower technology decision and the hope is this information will be useful to other utilities as well.

SpeakerKraemer, Jeremy

Presentation time

09:30:00

10:00:00

Session time

08:30:00

10:00:00

SessionThe Big Bad Blower: Huffing and Puffing Air Through Your Aeration Basins

Session locationRoom S401d - Level 4

TopicEnergy Production, Conservation, and Management, Facility Operations and Maintenance, Intermediate Level, Municipal Wastewater Treatment Design

Author(s)

Kraemer, Jeremy

Author(s)J. Kraemer 1; J. Kraemer 1 ; T. Jenkins 2; T. Young 3; C. Pretorius 4;

Author affiliation(s)GHD 1; GHD 1 ; JenTech Inc 2; GHD 3; GHD 4;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159070

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

Description: Technical Brief 1: Pursuing Low-Cost Operational Changes to Mitigate Nitrous Oxide...

Technical Brief 1: Pursuing Low-Cost Operational Changes to Mitigate Nitrous Oxide at Two Halton Region WRRFs

Abstract

INTRODUCTION Nitrous oxide (N2O) is a potent greenhouse gas (GHG) with a global warming potential of nearly 300 times that of carbon dioxide. It is a major contributor to Scope 1 direct process emissions from wastewater treatment plants. In Ontario, Canada, the provincial electrical grid is already decarbonized, with a grid intensity <40 g-CO2-e/kWh, compared to the global average around 480 g-CO2-e/kWh (Ritchie and Rosado, 2020). Owing to low GHG emissions from electricity consumption, the Regional Municipality of Halton (Halton Region or Region) has estimated that N2O from treatment contributes a majority portion of Scope 1 GHG emissions at their wastewater treatment plants (WWTP). The Region's plant operations staff understand that N2O emissions may be an indicator of 'unhappiness' of the biomass and sub-optimal environmental conditions for treatment. Optimizing these conditions and removing stressors can reduce N2O emissions which is why operational optimization can be an effective mitigation approach. However, N2O generation mechanisms are complex due to multiple production and consumption pathways covering high dissolved oxygen (DO), low DO, and anoxic conditions (Figure 1; readers are referred to Ye et al. (2022) for a comprehensive explanation of N2O generation). Owing to variability of N2O production across space (i.e. different areas of a bioreactor) and time (daily, seasonally, yearly), Halton Region determined N2O needs to be measured to know what is happening. Therefore, the Region has undertaken a 2-year project with the goal of pursuing 'low hanging fruit' N2O mitigation strategies through operational optimization which is achievable based on current global experience. The objectives of the work include: (1) Measuring N2O emission factors (EFs) for Mid-Halton and Skyway WWTPs; (2) Identifying the operating parameters influencing N2O emissions & identifying low-cost operational optimization mitigation techniques; (3) Verifying the effectiveness of operational changes to reduce N2O emissions. METHODS In early 2024 Halton Region installed online dissolved nitrous oxide sensors (Unisense Environment, Aarhus, Denmark) at their two largest WWTPs, Skyway and Mid-Halton, with sensor data recorded starting early February 2024. The Skyway WWTP is rated 140 ML/d average day flow, with liquid treatment comprised of primary clarification, nitrifying activated sludge configured as long single pass tanks operated fully aerobic, dual-point ferric addition for phosphorus removal, deep bed tertiary sand filters, and sludge treatment comprised of thickening, anaerobic digestion, and dewatering. The Mid-Halton WWTP is rated 125 ML/d average day flow, with liquid treatment comprised of primary clarification, nitrifying activated sludge configured as 5-pass serpentine tanks operated with a year-round anoxic zone plus a seasonal anoxic swing zone, ferric addition for phosphorus removal, and sludge treatment comprised of thickening, anaerobic digestion, and dewatering. Figure 2 illustrates the bioreactors of both plants along with locations of dissolved oxygen and N2O sensors. Halton Region will conduct quarterly nitrogen profiling along the length of the bioreactors containing N2O sensors to understand where nitrogen conversion and N2O generation risk is highest. The Region created a standard operating procedure (SOP) and field data collection sheet for operations staff. The first bioreactor profiling was conducted at both plants on July 8, 2024 and the second one on October 28, 2024. Three sources of data are used: online SCADA data, lab data from the Region's laboratory information management system (LIMS), and a plant operations spreadsheet with daily summary data and operating information. A 'data lake' is generated by aggregating all data sources together through data merging and processing and calculating derived data (e.g. N2O mass emission rate, ammonia turn-over rate). Data analytics were performed including correlation 'heat maps' and other data synthesis. Artificial intelligence (AI) and machine learning (ML) methods are being applied through Cobalt Water Global's N2ORisk DSS which helps understand risk conditions for N2O, and is creating site- and location-specific ML models that will be used as soft-sensors later in the project when mitigations are tested. RESULTS Figures 3 and 4 illustrate the first 3 months of dissolved N2O concentrations measured at sensor location #1 at the Skyway and Mid-Halton WWTPs. As of writing this abstract, the second batch of data (months 4 through 8) are being analyzed. Four operational factors anticipated to relate to N2O generation are discussed. Dissolved Oxygen Both plants have high DO concentrations, routinely >4 mg/L, whereas the Cobalt Water N2O DSS recommends DO of 1-2.2 mg/L (Figure 5). There are periods of time when N2O generation is well aligned with DO changes (Figure 6). Optimizing aeration is the most common N2O mitigation technique owing to energy savings often being a co-benefit. Several European plants such as Eindhoven (Netherlands) have realized N2O reduction through DO adjustment (Porro et al., 2017) and this operational change is applicable to both Mid-Halton and Skyway WWTPs. Ammonia Turn-Over Rate Ammonia turn-over rate influences N2O generation at Mid-Halton and Skyway WWTPs. Figure 4 illustrates the Mid-Halton bioreactor MLSS compared to N2O concentration. The drop in both concentrations around March 14, 2024 was related to bringing the neighboring bioreactor online after a maintenance period. Operations staff built up the mass inventory prior to that time. With another bioreactor online the ammonia concentration and loading rate dropped resulting in less N2O. Bioreactor profiling was useful for understanding the nitrogen turnover rate along the length of the bioreactors, illustrated in Figure 7 for Mid-Halton and Figure 8 for Skyway. Although there is uncertainty in the nitrogen values at Mid-Halton (total nitrogen balance drops and then rises again), the highest ammonia turn-over rate was at positions 3, 4, and 5 at Mid-Halton (Figure 7) while it was positions 1 and 2 at Skyway (Figure 8). N2O production at a given sampling location was correlated with ammonia conversion in the upstream location (Figure 9). Skyway's profile was unexpected, and on investigation it was determined the ferric dosing prior to aerated grit tanks was resulting in extremely high primary clarifier performance with 80% TSS and 68% BOD removals. This extreme performance resulted in low organic loading to the Skyway bioreactors allowing immediate nitrification at the front of the tanks. These observations suggest a potential operational change to increase the MLSS so the biomass-specific ammonia turn-over rate will decrease. This mitigation was observed to reduce N2O emissions by 74% at the AvedÃ¸re WRRF (Andersen et al., 2022). Similarly, increasing the return activated sludge rate to dilute nitrogen concentrations and shorten hydraulic retention to push activity further down the train may also be useful. Diurnal Centrate Loadings At Skyway, the Region dewaters biosolids using a centrifuge about 6 hours per day for 5 or 6 days per week. The centrate is stored and then returned to the headworks over a four-hour period around 4-8pm. This slug load of ammonia reaches the aeration tanks in the late evening around midnight. The impact of this time-varying ammonia loading is observable in the N2O concentrations of Figure 10. Each day when there is dewatering there is a corresponding spike in N2O generation around midnight, while on the weekend when there is no dewatering there is no midnight N2O spike. At Skyway, extending the duration of centrate return would decrease the slug load ammonia. Rodriquez-Caballero et al. (2015) lowered N2O in a full-scale SBR with this technique. This approach is not applicable at Mid-Halton since dewatering centrate is already fully equalized and returned over a 24-hour period. pH There was also an observed correlation between N2O and pH at both plants (Table 1). This relationship could also be observed in the data (Figure 11). DISCUSSION/CONCLUSIONS Based on the first 3 months of data, Halton Region has observed N2O generation at the Skyway and Mid-Halton WWTPs is correlated as expected with DO levels, ammonia loadings, mass inventory levels, and pH. It is already clear there will be several operational changes that can be tested during year 2 to assess low-cost N2O mitigation. Interestingly, the N2O emission factors are quite different between the two WWTPs and differ from the IPCC default (Table 2). These results confirm the site-specific nature of N2O emissions and reaffirms the need for WRRFs to measure N2O to know their actual emission rate. At time of writing data from June to September is being analyzed. The conference presentation will include all data available and the Region will have decided which operational changes to test.

This paper was presented at the WEF Residuals & Biosolids and Innovations in Treatment Technology Joint Conference, May 6-9, 2025.

SpeakerKraemer, Jeremy

Presentation time

14:15:00

14:20:00

Session time

13:30:00

15:00:00

SessionHow DO Setpoints and Control Impacts Performance and Emissions

Session numberITT Session 04

Session locationBaltimore Convention Center, Baltimore, Maryland, USA

TopicAdvanced Biological Nutrient Removal (ABNR), Aeration Control, Full-scale Optimization, Greenhouse Gases, Microbial communities, Modeling, Nitrogen, Nitrous oxide, Simultaneous Nitrification-Denitrification (SND)

Author(s)

Kraemer, Jeremy, Duong, John, Baker, Chandra, Oberoi, Sanjeev, Pharand, Lizanne, Porro, Jose, Andersen, Mikkel, Ye, Liu, de Haas, David, Bhayani, Bhavin, Beelen, Benjamin, Sabzwari, Aby

Author(s)J. Kraemer1, J. Duong C. Baker2, S. Oberoi2, L. Pharand2, J. Porro3, M. Andersen L. Ye4, D. de Haas1, B. Bhayani1, B. Beelen1, A. Sabzwari1

Author affiliation(s)GHD, 1The Regional Municipality of Halton, 2Halton Regional Laboratory, 2Cobalt Water Global, Inc., 3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2025

DOI10.2175/193864718825159750

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count17