Shen, Emma

Dr. Shen is a process engineer based in Jacobs Toronto Office, with more than 10 years of experience in municipal wastewater treatment design, process modelling and performance assessment, with special focus on optimizing energy efficiency, recovery and minimizing GHG emissions from wastewater treatment, solids handling and biosolids management. She is currently Jacobs Global Principle for Wastewater Energy Optimization and Sector Decarbonization, and vice-chair of the WEF GHG sub-committee. Emma currently serves on the Scientific Review Team for the BEAM annual update.

Titles from this speaker

Description: Balancing Carbon for Energy Recovery and Nutrient Removal for the World's Largest...

Balancing Carbon for Energy Recovery and Nutrient Removal for the World's Largest MBR Facility

Abstract

The 800 ML/d Tuas Water Reclamation Plant (WRP) will be the largest membrane bioreactor facility in the world, featuring many advanced treatment technologies and an integrated NEWater facility that produces high-grade water for reuse. The Tuas WRP will be co-located with an Integrated Waste Management Facility (IWMF) which will generate electricity to meet the demand for the co-located facility, making it energy self-sufficient. A key component to energy efficiency is the management of carbon through the treatment process, as it has major impacts on the energy production (through conversion to biogas in the anaerobic digestion process), energy consumption (especially from oxygen demand in the MBR process), and the dependency of carbon to drive biological nutrient removal. Extensive process modelling was completed to inform the design, specifically, incorporating flexibilities to allow for optimizing the degree of carbon re-direction via A-stage primary treatment while achieving effluent goals for NEWater and outfall discharge

SpeakerShen, Emma

Presentation time

13:00:00

13:30:00

Session time

11:00:00

12:00:00

SessionGoing KETO: Stories of Carbon Re-Direction in the Age of Advanced Nutrient Removal

Session number9B

TopicEnergy Production, Conservation, and Management, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

E. ShenT. ConstantineC. NewberyY. Wei HinM. WongL. Yee WenA. Ang

Author(s)E. Shen1; T. Constantine1; C. Newbery1; Y. Wei Hin2; M. Wong2; L. Yee Wen2; A. Ang2;

Author affiliation(s)Jacobs1; Singapore's National Water Agency2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157906

Volume / Issue

Content sourceWEFTEC

Word count15

Description: Development of an Integrated Resource Recovery Strategy for the 630 ML/d Duffin...

Development of an Integrated Resource Recovery Strategy for the 630 ML/d Duffin Creek Water Pollution Control Plant

Abstract

The Duffin Creek Water Pollution Control Plant (WPCP) is a conventional activated sludge secondary treatment facility located in Pickering, Ontario that treats municipal wastewater from the Regional Municipality of Durham and York (the Regions). The plant has an average day design capacity of 630 megaliters per day (ML/d). The liquid treatment process consists of headworks, primary and secondary treatment, phosphorus removal via dual-point chemical addition, and chlorine disinfection. Waste activated sludge (WAS) is co-thickened with raw sludge in the primary clarifiers. Solids handling processes include anaerobic digestion (for a portion of the sludge generated), dewatering, and incineration. The plant also receives hauled septage, liquid raw sludge and digested biosolids from wastewater treatment plants in both Regions. Several internal energy sources generated at the plant are being used to offset energy consumption. Heat from the incineration process is recovered to generate steam, which is used to drive turbines to power the fluidizing air blowers, with excess steam to supplement plant heating. Biogas generated from the digestion process is captured to fuel hot water boilers and supplement digester and building heating. Capital upgrades to the incinerators are underway, which will allow heat recovered from incineration to meet plant-wide process and building heating demand, freeing up biogas for alternative utilization. In addition, ongoing upgrades to the digesters will divert imported sludge (largely digested) away from the primary digesters, therefore improving digestion performance and increasing biogas generation. The current solids treatment and energy recovery operations are illustrated in Figure 1. In alignment with Regional goals to advance sustainability and reduce greenhouse gas (GHG) emissions, the Regions initiated an Integrated Resource Recovery (IRR) Study at the Duffin Creek WPCP in 2019. The purpose of this study is to identify feasible opportunities that can be integrated into the plant, including energy efficiency/recovery, material use reduction/recovery, and water conservation/recycling opportunities. This paper presents the review and development of energy use reduction and recovery opportunities associated with solids treatment at the Duffin Creek WPCP.

Emma Shen is a process engineer based in Jacobs’ Toronto office, with 10 years of experience in municipal wastewater and water treatment plant performance assessment and process upgrades evaluation, process modelling, energy optimization, and chemical system and disinfection optimization. She is Jacobs’ Global Technology Lead for Wastewater Energy Optimization and Sector Decarbonization. Emma holds a PhD degree in Civli Engineering from University of Toronto, Ontario, Canada, and a bachelor degree in Environmental Engineering from Tsinghua University, Beijing, China. She was the 1st place recipient for the 2014 American Water Works Association Academic Achievement Award for her doctoral dissertation. In her spare time, Emma loves travel, reading, podcast, Lego, and puzzles.

SpeakerShen, Emma

Presentation time

14:00:00

14:15:00

Session time

13:30:00

14:30:00

SessionBiogas: Market-based Decisions for Resource Recovery

Session number507

TopicBiosolids and Residuals, Energy Production, Conservation, and Management, Policy and Regulation

Author(s)

Emma Shen

Author(s)E. Shen1; P. Burrowes1; A.D. Willoughby1; T.A. Constantine1; D. Ross1;

Author affiliation(s)Jacobs, Toronto, ON, CA1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2021

DOI10.2175/193864718825158137

Volume / Issue

Content sourceWEFTEC

Word count18

Description: Global Lessons for Benchmarking and Reducing Fugitive Methane Emissions from Sludge...

Global Lessons for Benchmarking and Reducing Fugitive Methane Emissions from Sludge Treatment and Biogas Handling

Abstract

Introduction Sludge generated from wastewater treatment typically goes through a series of handling processes such as thickening, stabilization and dewatering, before its final use or disposal. Anaerobic digestion is widely applied in medium to large water resource recovery facilities (WRRFs) for sludge stabilization. In anaerobic sludge treatment, fugitive methane emissions can occur from digesters (due to aging infrastructure), downstream storage, from associated pressure relief valves and pipework, and also due to methane slip through combined heat and power (CHP) engines and biogas upgrading. For example, work in Denmark over the past few years has quantified methane emissions at 69 biogas facilities and shows methane emissions account for up to 7.5 percent of the gas production at WRRFs (Fredenslund, A.M et al., 2021; Scheutz & Fredebslund, 2019). Large leakage of methane may negate the positive climate impact from biogas energy recovery and contribute significantly to the facility's operational carbon footprint. A portion of the methane generated is dissolved in the digestate, which can also be released during the downstream dewatering or sidestream treatment processes. In addition, long-term sludge drying (e.g., in lagoons) is commonly applied in many countries, such as Australia, due to its ease of operation and low operational costs. Methane generated from sludge drying lagoons is typically not captured and can be a significant greenhouse gas (GHG) emission source. In the US, a country-wide standard methodology for quantifying GHG emissions from the wastewater sector does not exist. Among the available reporting protocols, methodologies for quantifying fugitive methane emissions from sludge treatment and biogas handling are limited to combustion of biomass and biogas, which essentially assumes zero methane emissions from anaerobic digestion and biosolids dewatering processes. The latest Biosolids Emissions Assessment Model (BEAM 2022) has recommended a minimum of 1 percent of methane in biogas as fugitive emission and allows a user-input value if site-specific data are available. The lack of consistent methodology and lack of facility level measurement result in significant risk to facilities in the estimation of their fugitive methane emissions through the sludge treatment and biogas handling processes. This paper presents an overview of challenges and issues in quantifying fugitive methane emissions from sludge treatment and biogas handling, impacts on GHG inventory and practical tips for reducing methane emissions based on global experience to date across a growing number of case studies. Benchmarking Fugitive Methane Emissions Methodologies and Key Considerations In the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, a three-tier method is described for quantification of methane emissions from WRRFs. Tier 1 provides global activity and emission factors; Tier 2 provides for local in-country activity factors and/or emission factors and Tier 3 methods require facility level monitoring. Accurately quantifying fugitive methane emissions requires Tier 3 facility level measurement using methods such as differential absorption lidar (DIAL), tracer gas dispersion (TDM) and inverse dispersion modelling (IDM), which may be combined with point source leak detection or other process unit methods to determine location of leaks. This practice remains emerging with significant work ongoing in Europe to provide facility level quantification and mitigation at WRRFs. Elsewhere, Tier 2 methods are common. The UK Carbon Accounting Workbook is used by Utilities to report on operational emissions and includes country-specific (Tier 2) theoretical emission factors associated with the most common sludge and biosolids processes in the UK, with emissions based on mass of methane per unit of tonnes dry solids of raw sewage sludge (UKWIR, 2020). In the Australian National Greenhouse and Energy Reporting (NGER) framework, methane process emissions are indirectly estimated using sampled influent and/or effluent streams and application of assumed biogas generation and percentage biogas utilization to calculate the net tonnes of CO2 equivalent released to the atmosphere. This approach considers facility level data but does not require direct measurement of the GHG, hence still considered Tier 2. Emissions from biogas flaring is based on best practice flow rate measurements of the flared biogas and its methane concentration. Different facilities may have a range of approaches to sampling process streams for operational, planning or reporting requirements. Sampling locations, frequencies and methodologies can result in inaccuracies in estimating the fugitive methane emissions. The recently published IWA book 'Quantification and Modelling of Fugitive Greenhouse Gas Emissions from Urban Water Systems' includes additional information on fugitive methane emissions from a range of wastewater treatment, sludge and biogas handling processes, estimated through facility level monitoring (IWA, 2022). Table 1 provides a summary of key methane emissions from global case studies including both those which directly monitor methane emissions and those which use various alternative GHG accounting methodologies, generally aligned with Tier 2 level approaches. A more complete table will be provided in the full paper. In the absence of global full scale monitoring data to estimate fugitive methane emissions, existing methodology estimates may be beneficial for benchmarking emissions from sludge treatment and biogas handling processes however, Tier 3 level facility monitoring is required to accurately estimate methane emissions and to validate any mitigation efforts. Monitoring and Reducing Fugitive Methane Emissions Whilst published literature studies of methane mitigation are limited, practical examples of programs for monitoring and mitigation across European countries 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. Table 2 summarizes some of the key sources and (limited) mitigation approaches from work to date; further details to be provided in the full paper. In future planning, it is critical that decisions regarding anaerobic versus aerobic sludge digestion consider fugitive emissions from existing and proposed assets. Conclusions Fugitive methane emissions from sludge treatment and biogas handling processes are a significant source of GHG emissions which must be monitored and mitigated by utilities taking action to reduce their carbon footprint. These emissions are particularly critical for WRRFs with anaerobic digestion and open anaerobic systems such as sludge drying ponds. There is lack of consistent methodology 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 for the WRRFs. As shown by ongoing work in Europe, facility level measurement is critical in quantifying the fugitive methane emissions. This paper will provide practical recommendations to WRRF operators to guide best practices for methane monitoring and mitigation throughout the facility life cycle.

This paper was presented at the WEF/IWA Residuals and Biosolids Conference, May 16-19, 2023.

SpeakerShen, Emma

Session time

11:45:00

SessionSession 11: Circular Water Economy

Session number11

Session locationCharlotte Convention Center, Charlotte, North Carolina, USA

TopicSustainability and Resource Recovery

Author(s)

E. Shen

Author(s)E. Shen1, A. Romero2, A. Vellacott3, A. Lake4,

Author affiliation(s)Jacobs1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2023

DOI10.2175/193864718825158791

Volume / Issue

Content sourceResiduals and Biosolids

Word count16

Subject keywordsCWECircular Water Economy

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