Lake, Amanda

Amanda Lake was a speaker at the WEFTEC 2025 conference held in Chicago, IL from September 27-October 1.

Titles from this speaker

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

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