Menniti, Adrienne

Clean Water Services ODIN Pilot Case Study

Print publication date Oct 2023

DOI10.2175/193864718825159117

Volume / Issue

Content sourceWEFTEC

Word count12

Abstract

Water Research Foundation Project 5121 is titled Development of Innovative Predictive Control Strategies for Nutrient Removal. The project is focused on developing and full-scale testing of a hybrid (machine learning + mechanistic model) nutrient management controller at four different WRRFs. The project team has named the controller ODIN: Operational Decision-making Information Network. The primary objectives of the ODIN pilot for CWS are to: Predict the expected diurnally varying plant influent orthophosphate loading over the following 24 hours. Recommend an alum dosing set point to maintain a requested primary effluent orthophosphate load. A secondary goal is the additional information provided on parameters like influent ammonia. For the CWS application, the ODIN systems appears to be a promising opportunity to improve plant operation using digital twin technology.

A hybrid (machine learning + mechanistic modelling) controller called ODIN has been developed through WRF5121 and is currently being tested at the Clean Water Services Durham WRRF. The system recommends for primary alum addition setpoints based on forecasted phosphorus loads and target bioreactor ortho-phosphate mass loading targets. The ODIN system appears to be a promising opportunity to improve plant operation using digital twin technology. This paper summarizes the status of the CWS pilot.

Presentation time

15:35:00

15:50:00

Session time

15:30:00

17:00:00

SessionCase Studies of Machine Learning in Full-Scale Nutrient Management Part II

Session locationRoom S505b - Level 5

TopicAdvanced Level, Facility Operations and Maintenance, Intelligent Water, Nutrients

Author(s)

Author(s)A. Menniti 1; A. Menniti 1 ; B. Johnson 2; K. Lesnik 3; C. Yang 4;

Author affiliation(s)Clean Water Services 1; Clean Water Services 1 ; Jacobs 2; Jacobs 3; 4;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Dance of the Machines at AlexRenew WRRF: Piloting Experience of Machine Learning Hybrid Nutrient Controller

Print publication date Oct 2023

DOI10.2175/193864718825159116

Volume / Issue

Content sourceWEFTEC

Word count8

Description: Dance of the Machines at AlexRenew WRRF: Piloting Experience of Machine Learning...

Abstract

A full-scale pilot of a hybrid (machine learning + mechanistic modelling) based nutrient controller is being implemented at Alexandria Renew Enterprises (AlexRenew), VA as part of The Water Research Foundation project 5121. The hybrid nutrient controller developed for this project has been named ODIN (Operational Decision-making Information Network). At AlexRenew, ODIN is used to recommend equalization discharge and return pumping setpoints with the goal of minimizing overall energy and chemical usage at the facility while maintaining a very low effluent total nitrogen. Recent historical and simulated nutrient removal performance is presented along with the metrics selected to evaluate the control period with ODIN suggestions being considered.

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

SpeakerOristian, Monica

Presentation time

16:25:00

16:40:00

Session time

15:30:00

17:00:00

SessionCase Studies of Machine Learning in Full-Scale Nutrient Management Part II

Session locationRoom S505b - Level 5

TopicAdvanced Level, Facility Operations and Maintenance, Intelligent Water, Nutrients

Author(s)

Oristian, Monica

Author(s)M. Oristian 1; M. Oristian 1 ; B. Johnson ; C. Yang 3; J. Registe 5; H Stewart 6; K. Lesnik 7; A. Menniti 8;

Author affiliation(s)Alexandira Renew Enterprises (AlexRenew) 1; Alexandira Renew Enterprises (AlexRenew) 1 ; Jacobs ; Jacobs 3; Jacobs 5; Jacobs 6; Jacobs 7; Clean Water Services 8;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Data Management Planning: Creating the Foundations of Digital Maturity

Print publication date Oct 2023

DOI10.2175/193864718825159118

Volume / Issue

Content sourceWEFTEC

Word count16

Abstract

INTRODUCTION Clean Water Services (CWS) is a water resources management utility that serves more than 600,000 customers in Washington County, Oregon. As with many utilities, CWS generates a large amount of data from a range of sources but struggles to integrate those data sources. The current data systems create inefficiencies in accomplishing routine data-driven decisioning making tasks. To address these challenges, CWS initiated a data management planning project in March 2024 with the goal to improve data access for evaluation and decision making. The project was created to outline a vision and implementation plan for a resilient and secure data management system. This project also sets the foundation for the sustainable adoption of advancements such as artificial intelligence and digital twins.

The project is taking a phased approach. Phase 1 defined the current digital limitations and future data needs for works groups from treatment and conveyance operations and engineering. The most prevalent digital limitations were difficulty in data visualization, lack of data quality transparency and disorganized file management. Phase 1 identified several key initiatives to move those work groups to an improved future state. With Phase 2, the program is starting to build the foundations of digital maturity by establishing a centralized data storage system and data governance frameworks. It will also create a program management system to prioritize initiatives from Phase 1 and expand or adapt initiatives into the future.

PHASE 1 The objective of Phase 1 was to evaluate staff challenges around data usage, data storage, and data security - then to develop a vision and plan to unify the large volumes of utility data from a variety of sources. Phase 1 concentrated on identifying and documenting the current and future requirements of stakeholders in operations and engineering. The first step was to gain a better understanding of the existing workflows and data assets. Staff feedback was gathered through a series of in-person meetings and workshops. Workshops to gather workflows and challenges covered the following topic areas:

• Managing instrumentation
• Pump station data collection and use
• Capital project delivery
• Regulatory reporting
• Treatment process decision making
• Treatment facility asset management
• Biosolids and reuse
• Operator data entry and operations data use
• Collection system capital planning
• Treatment facility capital planning
• Conveyance system operations

The most prevalent issues identified included difficulty in data visualization, lack of data quality transparency and disorganized file management.

A visioning workshop was used to align stakeholders in a collective vision. The workshop allowed CWS staff to discuss their ideal state and prioritize opportunities to help reach that state. Based on CWS stakeholder feedback, Hazen proposed several initiatives to address the various data management challenges identified. Stakeholders voted to rank these opportunities during the visioning workshop, allowing CWS to collaboratively prioritize opportunities in the context of common challenges.

Hazen used a Value and Effort framework (Figure 1) to systematically assess the business value of each initiative against the level of effort required. Projects were sorted by effort using T-Shirt sizing estimation (S, M, L, XL), and by value using an assigned priority from 1-4 based on which quadrant they fell into (quick wins, phased projects, fill-in-tasks or time sinks). Using this framework, a roadmap of high priority, high impact projects was developed. Tables 1-4 summarize the high priority projects sorted into four categories: data analytics, data management, document management, governance/IT planning.

PHASE 2 The following initiatives will be addressed in Phase 2, which kicks off in January 2026:
(1) Initial development of a central data repository.
(2) Establishment of data governance standards to maintain the quality and traceability of data.
(3) Development of a program management system to prioritize the initiatives identified in Phase 1. The goal is to develop a structured system to track progress, measure value and adjust initiatives and priorities over time as needs and resources change.
(4) Selection of the future visualization, analytics and regulatory reporting software for treatment data. The HachWIMS platform is the current software used for all three purposes. It is central to operational process control for wastewater treatment and handles several major regulatory reporting tasks. The software evaluation will include definition of the software requirements, review of alternative vendor offerings and comparison of vendor versus custom-developed options.

Along with this implementation comes a need for focused change management support. Based on the Prosci ADKAR approach (Awareness, Desire, Knowledge, Ability, and Reinforcement), we will incorporate elements of leadership engagement, organizational strategy, and prioritized focus areas.

CONCULSION CWS is developing the foundational elements of digital maturity and using change management principles to make the program a success. This presentation will summarize the approach to developing a road map for digital transformation, discuss implementation of the Phase 2 initiatives, and provide an overview of the strategies used to facilitate user communication and adoption.

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

Presentation time

08:30:00

08:45:00

Session time

8:30:00

10:00:00

SessionDigital Maturity and Data Management for Utilities: The Foundation for Data Utilization

Session locationErnest N. Morial Convention Center

TopicUtility Management and Leadership

Author(s)

Menniti, Adrienne, Shaw, John, Arrigotti, Greg, Stanford, Benjamin, Rein, Jeremy, Turner, Malia

Author(s)A. Menniti1, J. Shaw1, G. Arrigotti1, B. Stanford2, J. Rein2, M. Turner2

Author affiliation(s)Clean Water Services, 1Clean Water Services, 1Hazen and Sawyer, 2Hazen and Sawyer, 2Hazen and Sawyer, 2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Print publication date Sep 2026

DOI10.2175/193864718825160522

Volume / Issue

Content sourceWEFTEC

Word count10

Designing for Humans

Abstract

The Water Research Foundation Project 5121 is titled Development of Innovative Predictive Control Strategies for Nutrient Removal is focused on developing and full-scale testing of a hybrid (machine learning + mechanistic model) nutrient management controller at four different WRRFs. The project team has named the controller ODIN: Operational Decision-making Information Network. The philosophy behind the ODIN User Interface is to make this tool easy to use for operations staff. To accomplish this objective, we’ve focused on two goals with the user interface design: 1. Keep the user priorities and mind set in mind at every step of the user interface design. 2. As engineers, we need to remember to keep the interface easily accessible and simple. Any new way of doing things must make the life of the operator better in some way. Without that, even the best ideas will likely fail at widespread adoption

A hybrid (machine learning + mechanistic modelling) controller developed through WRF5121 and named ODIN has been developed and is currently being tested at four different WRRFs. The philosophy behind the ODIN User Interface is to make this tool easy to use for operations staff. Every step of the user interface development process has kept user priorities and needs at the forefront. This paper reviews the ODIN approach to user interface development.

Presentation time

13:35:00

13:50:00

Session time

13:30:00

15:00:00

SessionApplications of Machine Learning in Full-Scale Nutrient Management Part I

Session locationRoom S504c - Level 5

TopicFacility Operations and Maintenance, Intelligent Water, Intermediate Level, Nutrients

Author(s)

Author(s)A. Menniti 1; B. Johnson 2 ; A. Menniti 1;

Author affiliation(s)Clean Water Services 1; Jacobs 2 ; Clean Water Services 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Evaluating Measurement Approach and Variability of the Apparent Fermentation Rate

Print publication date Oct 2023

DOI10.2175/193864718825159078

Volume / Issue

Content sourceWEFTEC

Word count4

Abstract

In an effort to understand options to improve EBPR stability, research into the sidestream EBPR process configurations has increased. Understanding the carbon generation rate of S2EBPR is key to determining if the process may improve EBPR performance. CWS has investigated methods to describe this apparent fermentation rate and evaluated AFR implications for fullscale performance. The results indicate that differences in measurement methodology can cause the resulting AFR to vary greatly.

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

SpeakerSchauer, Peter

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionBiomass Fermentation for Carbon Efficient Biological Phosphorus Removal

Session locationRoom S404c - Level 4

TopicFacility Operations and Maintenance, Intermediate Level, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Schauer, Peter

Author(s)P. Schauer 1; P. Schauer 1 ; A. Menniti 1;

Author affiliation(s)Clean Water Services 1; Clean Water Services 1 ; Clean Water Services 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Genetic Analysis in Treatment Process Monitoring

Print publication date Oct 2023

DOI10.2175/193864718825158989

Volume / Issue

Content sourceWEFTEC

Word count11

Abstract

Interest in the use of genetic and genomic data for biological wastewater treatment process monitoring has risen rapidly, evidenced by the recent Water Research Foundation (WRF) request for proposals on the topic (WRF 5291). This presentation will serve as a mini 101 course on genetics and genomics for wastewater professionals, offering accessible information on relevant background, potential applications, types of tools, limitations, biomarker assay design, and study design considerations. 'Genetic tools' refers to technologies based on DNA and other nucleic acids. There are two main types, known as targeted or untargeted methods. Targeted methods typically use PCR (polymerase chain reaction) to identify a specific gene or organism of interest. Targeted genetic tools commonly used in wastewater process monitoring applications include quantitative or digital PCR (qPCR or dPCR). Nontargeted methods employ DNA sequencing, which refers to laboratory and computational methods which determine the order of the DNA building blocks; essentially spelling out the genetic code. A commonly used nontargeted method is metagenomic sequencing. (The 'metagenome' refers to all of the DNA present in a sample; see Figure 1). Nontargeted methods yield information on the composition of the microbial community and its functional potential but are not absolutely quantitative. Each type of method has its own set of advantages and limitations (Table 1). Targeted methods are highly sensitive and specific, and can provide highly accurate quantitative data, but are limited in the amount of information they can provide — typically only a single gene or organism out of thousands of relevant potential targets. Care must be exercised in choosing an appropriate target for monitoring, as well as in interpreting the results. Nontargeted methods, in contrast, provide a wealth of information; however, advanced expertise and substantial computing power is required to parse hundreds of gigabytes of data into actionable conclusions. Additionally, application of the wrong genetic technique or interpretation of genetic data without proper data context can greatly complicate or confound conclusions. Genetic tools are an attractive option for wastewater treatment process monitoring because they provide a look 'under the hood' at what is essentially a black box when it comes to biological treatment processes, particularly biological nutrient removal (BNR). These tools can offer information on the health and functioning of the microbiome, as well as insights into complex metabolic systems which can in turn inform process control. However, the field is still emerging, and many research questions remain regarding which targets are appropriate and informative; whether it's possible to develop 'universal' targets that could be widely used; and how the data should be interpreted. Clean Water Services is leading one such research effort, focused on developing biomarkers for biological phosphorus removal (BPR) process stability (WRF 5273). This presentation will describe the procedure used to develop and test these biomarkers as a case study in the application of both targeted and untargeted genetic technologies (Figure 2). Briefly, metagenomic and metatranscriptomic sequencing was performed to thoroughly characterize the aeration basin microbiomes. From these data, key genes were identified which are differentially expressed during stable versus unstable BPR conditions. These genes were used to design biomarkers which are measured with reverse transcription droplet digital PCR (RT-ddPCR). The biomarker assays were tested virtually (in silico) and validated in the laboratory prior to pilot deployment. Lastly, we will touch on the importance of robust study design when employing genetic tools. Too often, a utility will sequence a low number of samples (n<10) and draw broad conclusions from those results. Unfortunately, this can lead to spurious conclusions and a fundamental misunderstanding of the system. We will offer guidance on robust study design for genetic analyses, and suggestions for interpretation of results. This presentation will describe the different types of genetic tools available, summarize their advantages and disadvantages for biological nutrient removal applications and give an overview of the process used to develop and test biomarker targets for WRF project 5273. The goal is to improve communication between molecular biologists and process engineers to improve collaboration on the beneficial application of genetic tools to improve BNR understanding and operation.

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

Presentation time

15:30:00

16:00:00

Session time

15:30:00

17:00:00

SessionBringing Bugs into Focus: Microbial and Genetic Tools for Optimizing WRRF Performance

Session locationMcCormick Place, Chicago, Illinois, USA

TopicResearch

Author(s)

Layton, Blythe, Golda, Rachel, Coats, Erik, Menniti, Adrienne, Schauer, Peter

Author(s)B. Layton1, R. Golda1, E. Coats, A. Menniti1, P. Schauer

Author affiliation(s)Clean Water Services1, DC Water and Sewer Authority2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Genome-centric Insights into Full-scale EBPR Captured During a Biomonitoring Campaign

Print publication date Sep 2025

DOI10.2175/193864718825160139

Volume / Issue

Content sourceWEFTEC

Word count7

Description: Genome-centric Insights into Full-scale EBPR Captured During a Biomonitoring...

Abstract

Phosphorus removal from wastewater remains a core component of modern wastewater treatment strategies critical for protecting aquatic ecosystems and capturing valuable nutrients. Enhanced biological phosphorus removal (EBPR) is attractive since it reduces the need for chemical precipitating agents and facilitates phosphorus recovery. However, instability can limit the reliable application of EBPR for meeting stringent effluent phosphorus limits. As part of an ongoing biomonitoring campaign, samples were collected before and during an EBPR process stability episode and sequenced for paired metagenomes and metatranscriptomes. Analysis revealed that shifts in carbon and phosphorus loads coupled with changes in the population sizes of non-fermenting polyphosphate accumulating organisms (PAOs; Candidatus Accumulibacter spp.), as identified in the metagenomic data, were associated with poor P-uptake. Metatranscriptomic data from these PAO populations revealed they were indeed substrate limited, as hypothesized from process data, with key genes related to carbon storage appearing down regulated during the instability event with respect to the stable control despite having a greater cell load during the instability period. Accordingly, several gene families related to carbon uptake, VFA metabolism, and PHA synthesis were found to be sensitive to the underlying carbon-limited conditions of the process instability. Our findings illustrate how combined metagenomic and metatranscriptomic sequencing can facilitate interpretation of process data and aid in evaluating the root cause of instability. These data also indicate potential gene targets suitable for developing EBPR performance markers as part of longer term or more frequent biomonitoring efforts.

As part of an ongoing biomonitoring campaign, samples were collected before and during an EBPR process stability episode and sequenced for paired metagenomes and metatranscriptomes. Analysis revealed that shifts in carbon and phosphorus loads coupled with changes in the population sizes and gene transcription of PAOs were associated with poor P-uptake. Our findings illustrate how sequence data can facilitate interpretation of process data and aid in evaluating the root cause of instability.

SpeakerLindner, Blake

Presentation time

14:00:00

14:30:00

Session time

13:30:00

15:00:00

SessionConnecting Molecular Biology Sensors to EBPR Performance

Session locationRoom S502 - Level 5

TopicAdvanced Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Lindner, Blake

Author(s)B. Lindner 1; B. Layton 2 ; B. Lindner 1; B. Layton 2; R. Golda 2; K. Lesnik 3; K. Konstantinidis 4; A. Menniti 2; P. Schauer 2;

Author affiliation(s)School of Civil and Environmental Engineering, Georgia Institute of Technology 1; Clean Water Services 2 ; School of Civil and Environmental Engineering, Georgia Institute of Technology 1; Clean Water Services 2; Clean Water Services 2; Maia Analytica 3; School of Civil and Environmental Engineering, Georgia Institute of Technology 4; Clean Water Services 2; Clean Water Services 2;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Heating Primary Sludge for Increased Fermenter Volatile Fatty Acid Production

Print publication date Oct 2023

DOI10.2175/193864718825159085

Volume / Issue

Content sourceWEFTEC

Word count11

Abstract

The Durham Advanced Treatment Facility in Tigard, OR operates a fermentation complex that utilizes a Unified Fermentation and Thickening (UFAT) process to ferment primary sludge. Volatile fatty acid (VFA) produced through fermentation are used to support biological phosphorus removal (BPR). During cold weather months, solids retention time (SRT) limitations result in reduced VFA production, leaving BPR somewhat unstable especially in late spring when the plant effluent total phosphorus limit becomes more stringent. A sludge heating system was installed upstream from the fermentation complex to heat primary sludge, overcoming SRT limitations of the current system to increase cold weather VFA production. This improves BPR stability in the late spring and changes future fermenter design criteria, reducing the required footprint for future fermentation system expansion.

A. MennitiA. MennitiR. GoldaJ. Abrook

Presentation time

10:50:00

11:10:00

Session time

10:30:00

11:10:00

SessionAddressing Low Influent Carbon for EBPR

Session number517

TopicMunicipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Author(s)A. Menniti1; A. Menniti1; R. Golda2; J. Abrook2;

Author affiliation(s)Clean Water Services, OR1; Clean Water Services, OR, OR2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Insights from Full-scale Primary Sludge Fermentation for Carbon Management and Nutrient Removal

Print publication date Oct 2020

DOI10.2175/193864718825157520

Volume / Issue

Content sourceWEFTEC

Word count11

Description: Insights from Full-scale Primary Sludge Fermentation for Carbon Management and...

Abstract

Background and Objectives
Nitrogen and phosphorus removal from municipal wastewater require sufficient organic carbon in the form of readily biodegradable carbon (rbCOD) and volatile fatty acids (VFA), which are often limited in influent. Primary sludge (PS) fermentation has been applied for decades in a variety of configurations (Table 1) to produce rbCOD and VFA while also providing sludge reduction benefits1. Despite their widespread application, there is a lack of unified guidance for PS fermenter design, operation, and monitoring and limited information on tradeoffs of different elutriation mechanisms (e.g. solids vs dilute feed). While fermenters are ultimately intended to increase nutrient removal performance, unoptimized fermenters may act as internal sources of additional nitrogen and phosphorus that outweigh the benefits of increased carbon availability. This work will synthesize findings from full-scale PS fermenters (Table 2) to
1) Compare fermentation performance and key performance indicators of different types of PS fermenters and elutriation mechanisms
2) Provide guidance for monitoring PS fermenters to maximize understanding of carbon and nutrient contributions to the mainstream An example case study is provided for Eagles Point Water Resource Recovery Facility and similar analyses will be performed for the facilities in Table 2.

Eagles Point Case Study
#Eagles Point Water Resource Recovery Facility in Cottage Grove, Minnesota is operated by Metropolitan Council Environmental Services (Met Council). This facility, which utilizes biological phosphorus removal in an A2O configuration, has an average design flow of 10 MGD and a 1 mg/L total phosphorus (TP) effluent permit limit. Eagles Point has operated a PS fermenter (~90,000 gal gravity thickener with recirculating elutriation pump) since 2004. As part of a recent transition to low DO operation in the mainstream, staff collected weekly NH4, PO4, and filtered COD samples from the gravity thickener overflow (fermentate). During this period, influent BOD:TP ratios averaged 36, meeting recommended levels without the PS fermenter addition. The PS flow to the thickener and thickened sludge pumping were stable this sample collection period at 0.22 &PLUSMN; 0.03 MGD and 23 &PLUSMN; 2 gpd, respectively. Fermenter sludge blanket levels ranged from 1.5ft to over 9ft during this period with an HRT of ~0.4 d.

In recent years, staff noted that mainstream P removal performance did not seem to correlate with fermenter operation, in that effluent P concentrations did not increase during maintenance periods when the fermenter was offline. Data collected during the low DO transition provides additional context for these observations. On a mass basis, fermentate contributed 22 ± 5 lbs/day PO4-P to the anaerobic zone, while influent wastewater accounted for 166 &PLUSMN; 7 lbs/day. As expected, there was a strong positive correlation between fermentate filtered COD and fermentate PO4 at a consistent ~32:1 COD to P ratio (Figure 1). Assuming a VFA to sCOD ratio of 0.6:1 in PS fermentate2, the VFA to P ratio (19:1) in the produced fermentate is theoretically sufficient to uptake more P in the mainstream anaerobic zone than is recycled from the fermentate itself. However, fermentate P concentrations were positively correlated with effluent P (Figure 1). While effluent P was maintained at low levels regardless of the fermenter contribution, this result suggests a minimal or even net negative effect of the PS fermenter on mainstream P removal.

An additional consideration is temperature, which can have competing effects on fermenter performance and nutrient removal. Fermenter temperature was not measured, but influent wastewater temperature was positively correlated with both fermentate COD and effluent P. Higher ambient and water temperatures improve fermentation, resulting in increased COD outputs1, but also tend to favor microbes that compete with phosphate accumulating organisms (PAO) for rbCOD, leading to worse P removal3,4. Surprisingly, no relationship was found between fermentate COD and sludge blanket levels, suggesting that temperature was the main driver of fermenter productivity rather than SRT (Figure 2). Further sampling to be performed this year will provide a more complete accounting of carbon contributions from the fermenter. This case study highlights the value in routine nutrient monitoring of fermentate and demonstrates a gravity thickener PS fermenter that provided minimal or net negative effects to mainstream nutrient removal performance.

Significance for audience
PS fermenters are widely adopted and provide an 'internal' source of carbon for nutrient removal facilities. However, as demonstrated at Eagles Point, PS fermenters may introduce nutrient loadings back to the mainstream that are not neutralized by increased carbon availability. As facilities continue to meet lower effluent nutrient limits, accounting for internal nutrient recycles in addition to internal carbon recycles is critical. This presentation will use multiple case studies to evaluate the value proposition of PS fermenters, tradeoffs of PS fermenter configurations, and recommendations for monitoring strategies. We will also facilitate knowledge sharing of PS fermenter operation and monitoring through open discussion with participants.

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

Presentation time

10:30:00

10:45:00

Session time

10:30:00

12:00:00

SessionFull-Scale Primary Sludge Fermentation

Session locationMcCormick Place, Chicago, Illinois, USA

TopicLiquid Stream Treatment - Nutrient Removal and Recovery

Author(s)

Farmer, McKenna, Pifer, Leah, Liberzon, Jon, deBarbadillo, Christine, Prater, Trevor, Hogan, Kelsey, Pinkerton, Lee, Menniti, Adrienne, Schauer, Peter, Downing, Leon

Author(s)M. Farmer1, L. Pifer1, J. Liberzon1, C. deBarbadillo1, T. Prater2, K. Hogan2, L. Pinkerton2, A. Menniti3, P. Schauer3, L. Downing1

Author affiliation(s)Black & Veatch1, Metropolitan Council Environmental Services2, Clean Water Services3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Living Capital Planning Tools

Print publication date Oct 2025

DOI10.2175/193864718825160079

Volume / Issue

Content sourceWEFTEC

Word count13

Abstract

INTRODUCTION Clean Water Services (CWS) operates four WRRFs that are expanded and improved through a ~$40 million yearly capital budget. The goal of the CWS capital planning approach is to have a level capital outlay year to year. Capital expenditures are reprioritized yearly to achieve this goal and to ensure that processes are expanded only as they reach capacity. Typical master planning approaches are updated only about every five years. A 'living' capital plan allows CWS to adapt to changes in critical assumptions that drive planning timelines and proactively manage capital expenditures. This paper presents the CWS approach to creating and managing a living capital plan and summarizes the benefits. OVERVIEW The first integrated capital planning tool was developed for the Durham WRRF in 2020 with Carollo and Jacobs, the consultants for the most recent Durham master plan project (Figure 1). As part of the ongoing West Basin master plan, work is underway with Carollo to develop the tool for the three interconnected West Basin facilities, which include Rock Creek, Hillsboro and Forest Grove (Figure 1). The initial pieces of the tool are developed in collaboration with consultants but the final product is owned and managed by CWS. The goal of the living capital planning tool is that it's updated every year and should improve and evolve over time. OUTCOMES FLOW AND LOAD PROJECTIONS Flow and load projections are developed from base assumptions in the flow and load spreadsheet. The process of building the spreadsheet provided CWS with a comprehensive understanding of all the critical assumptions used to generate the projections, making it easier to evaluate those assumptions over time. Alternate planning scenarios were also created based on differing growth assumptions for the Durham WRRF, and flow diversion alternatives for the West Basin WRRFs. Historic flows and loads are evaluated annually and compared to projections. Tracking observations against planning numbers makes it evident when revisions are necessary (Figures 2 and 3). While the intention is not to revise the projections every year, the spreadsheet tool and yearly evaluation process is meant to make the effort for revising projections more efficient when needed. PROCESS PERFORMANCE AND DESIGN CRITERIA Design criteria, which set the capacity of the unit processes (e.g. solids loading rate), and process performance criteria, which are assumptions based on operational observations (e.g. percent removal, solids capture, sludge volume index) are also evaluated yearly. The data validation and process capacity spreadsheets gather process performance assumptions and design criteria from the master plan and compare them to historical observations. This comparison determines when unit processes are approaching capacity triggers and identifies when unit processes should be optimized due to declining performance. One example of a process performance parameter (capture in the primary solids thickening process, Figure 4) that drove the capital planning timeline for secondary treatment (Figure 5) is illustrated here. Lower solids thickening capture sends additional solids loads to the secondary process, decreasing its treatment capacity. Just this single assumption changed the secondary capacity trigger year by 4 years (Figure 5). With projects at four WRRFs to phase, improving this 4-year discrepancy in secondary capacity allows capital outlay to be phased more effectively. MASS BALANCE SPREADSHEET VERUS PROCESS SIMULATOR CWS uses both a process simulator and a spreadsheet mass balance model to create solids projections for its West Basin WRRFs. The mass balance spreadsheet can be used to quickly evaluate scenarios that require a lower level of sensitivity and to identify scenarios that could have a major impact to timelines. This simpler, quicker approach is beneficial with the three interconnected West Basin treatment facilities as running a process simulator with all three WRRFs connected is complex and prohibitively slow. However, the process simulator generates more detailed predictions within each individual facility that are beneficial for informing comprehensive planning evaluations. Table 1 compares CWS experiences using these tools. CWS aims to extend both approaches to its East Basin capital planning system to take advantage of their complementary strengths. LESSONS LEARNED The living capital planning approach means that planning is not confined to periodic, consultant-lead master planning efforts. Tracking of flows and loads and other critical assumptions yearly against master planning values has provided valuable insights into when capacity and capital planning shifts are needed. It also daylights areas of conservatism or risk as capacity triggers are reached. Even if a utility is not running models or doing the projections themselves, tracking assumptions against reality is beneficial and achievable for any utility. Other benefits: Having ownership over the data and tools gives CWS the independence to quickly evaluate new scenarios (e.g. impact of a new large industrial user or shifts in population growth). Daylighting and tracking assumptions also aids in documenting the information that drives capital planning decisions. The integrated tool makes capital planning information more accessible to a wider range of CWS stakeholders from executive managers to operators.

This presentation presents the Clean Water Services approach to creating and managing a living capital plan and summarizes the benefits. The goal of our approach is to daylight areas of conservatism and risk as capacity triggers are reached and to routinely review unit process performance and plant influent flows and loads to catch and address deviations as they arise.

TopicEnergy Production, Conservation, and Management, Facility Operations and Maintenance, Intelligent Water, Intermediate Level, Nutrients

Presentation time

16:30:00

16:50:00

Session time

15:30:00

17:00:00

SessionLeveraging Automation and Analytics for Better Situational Awareness and Optimization: Part II

Session number224

Session locationRoom 350

Author(s)

Menniti, Adrienne, Sosa-Hernandez, Ornella, Barker, Leila, Schauer, Peter

Author(s)A. Menniti1, O. Sosa-Hernandez1, L.K. Barker1, P. Schauer1

Author affiliation(s)1Clean Water Services, OR

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Online Instrumentation for Dewatering Centrifuge Optimization

Print publication date Oct 2024

DOI10.2175/193864718825159537

Volume / Issue

Content sourceWEFTEC

Word count5

Abstract

Dewatering is a major resource recovery facility operating cost. Therefore, dewatering optimization could provide a significant cost saving opportunity. At CWS, the historical approach for dewatering centrifuge operation is to set targets for dewatered cake dryness and solids capture. This approach encouraged increased polymer use with limited incentive to critically evaluate operational set points. Because of the costs associated with dewatering, CWS has moved toward cost-based dewatering centrifuge operation using a suite of analyzers from Valmet that allows cost-based dewatering optimization information to be available in real time. The first of four new dewatering centrifuges installed at the Durham and Rock Creek facilities was commissioned in May 2019. Valmet instruments measuring centrifuge feed total solids (Valmet TS analyzer), dewatered cake total solids (Valmet DS analyzer) and centrate total suspended solids (Valmet LS analyzer) were also commissioned in May 2019 with a pilot agreement to allow their performance to be evaluated for 60 days before investing fully. Based on trial period performance, CWS has chosen to retain the Valmet instrumentation to support dewatering centrifuge operation and will install instrumentation on the remaining new dewatering centrifuges.

M. GatesM. GatesA. MennitiA. MennitiM. Idehara

Presentation time

11:10:00

11:30:00

Session time

10:30:00

11:30:00

SessionOvercoming Dewatering Difficulties

Session number520

TopicBiosolids and Residuals, Facility Operations and Maintenance

Author(s)

Author(s)M. Gates1; M. Gates1; A. Menniti2; A. Menniti2; M. Idehara1;

Author affiliation(s)Clean Water Services, OR, OR1; Clean Water Services, OR2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Online Phosphorus Stability Analyzer: Quantifying The Risk Of BPR Upset

Print publication date Oct 2020

DOI10.2175/193864718825157544

Volume / Issue

Content sourceWEFTEC

Word count7

Abstract

INTRODUCTION
Biological phosphorus removal (BPR) has been a cornerstone of the Clean Water Services (CWS) effluent phosphorus permit compliance strategy for decades. The BPR process has historically been observed to operate stably over long periods of time, only to become upset during critical times of the phosphorus permit compliance season. For CWS, an upset condition is defined as the secondary effluent orthophosphate (OP) daily average concentration > 0.1 mg/L P. To reliably meet a stringent effluent phosphorus permit with limited chemical use, it is useful to have an early warning metric for detection of upsets in the secondary effluent. We have demonstrated the effectiveness of an online orthophosphate analyzer coined the 'Stability Analyzer' to better understand BPR Stability (Menniti et al, 2016, Bushee et al, 2018). The analyzer has been operating on aeration basin one (AB1) at the Durham Wastewater Resource Recovery Facility (WRRF) since 2017. Its location was intentionally determined at about halfway through the aerobic zone, which we define as the stability point, where generally all phosphorus uptake has occurred by this point during stable operation. The purpose of this paper is to quantify the risk of an upset event using historical stability analyzer data. A new aeration basin (AB5) recently came online at the Durham facility. This paper will also demonstrate the process of strategically locating a stability analyzer on AB5, which has a different physical geometry to AB1 (Figure 1, Table 1).
UPSET RISK QUANTIFICATION RESULTS
Through empirical observation, we found that BPR operates stably when the Stability Analyzer reads 'zero,' which we define as a daily average concentration < 0.2 mg/L P, and that the BPR process is moving toward an upset event when the analyzer becomes non-zero (Figure 2). Not all instances of non-zero daily average Stability Analyzer measurements result in upset events. Therefore, we have quantified the risk of upset using historical data. Through data analysis from summers 2018-2020, we have quantified the risk of near-future upset events. All analysis is based on daily average analyzer concentrations and excludes time periods when alum was applied to the secondary clarifiers, isolating periods of phosphorus removal solely by biological means. We observe two types of conditions where the Stability Analyzer offers early warning of upset events: A. The daily average Stability Analyzer OP concentration has read zero for at least three days followed by an increase into non-zero daily average territory (Figure 3A, 3B). B. The daily average Stability Analyzer OP concentration is already non-zero and the daily average concentration increases the next day (Figure 4). There are 18 instances of Condition A and 139 instances of Condition B. Of the 18 Condition A instances, 9 resulted in a secondary effluent upset event within the next 2 to 6 days. This equates to a 50% risk of upset. Within these 9 scenarios, the average early warning of upset is 2.8 days. Of the 139 Condition B instances, 107 resulted in a secondary effluent upset event within 3 days. This equates to a 77% risk of upset. To divert an upset, the operations analysts can re-direct VFA flow from fermentate, and if necessary, add alum in the primary and/or secondary clarifiers. The Stability Analyzer has informed process decision making on a day to day basis and has proven useful in predicting BPR stability.
FINDING THE STABILITY POINT
After success with the Stability Analyzer on AB1, CWS wanted to demonstrate that the process could be replicated for basins with different geometries. AB5 is configured with a larger anaerobic and anoxic volume than AB1 (Figure 1, Table 1). In order to find the stability point in AB1, basin OP profiling efforts began in 2013 on all four identical aeration basins at the Durham WRRF (Figure 5). The profiles measure OP concentrations in multiple locations throughout the aerobic zone, with the goal of locating the stability point (Menniti et al, 2016). The stability point for AB1 was found 58% down the aerobic zone, referred to as Cell 7B (Figure 5). However, the stability analyzer was installed in the middle of Cell 7B, 52% down the aerobic zone, rather than where the sampling point was located due to inaccessibility for an analyzer to be placed. The profiling procedure was repeated for AB5 during its first summer of operation (2021) to determine the stability point, therefore informing stability analyzer installation location (Figure 6). The sampling points focused on for AB5 were accessible and appropriate locations for installing an analyzer. It is imperative to collect the profile samples at the same time of day due to diurnal patterns observed in carbon and phosphorus loading (Figure 7). Throughout summer 2021, AB5 was profiled once a week between 9-9:30am for 3.5 months, through stable times and during upset events. Determining the stability point and therefore the location for a stability analyzer is informed by where uptake is complete during time periods when no secondary effluent upset is observed. The OP Basin Profiling efforts on AB5 suggest the ideal location for predicting stability is at Cell 6C, where 45% of the aerated volume is completed (Figure 6). Figure 8 includes the profile results from the anaerobic and anoxic zones in addition to the aerobic zone. These profiles demonstrate that there is limited correlation between anaerobic zone release and corresponding strong aerobic zone uptake. In fact, the anaerobic release is highest during a secondary effluent upset event. We will be installing the stability analyzer on AB5 in January 2022.
CONCLUSIONS
The Stability Analyzer on AB1 provides an indication of BPR stability, and has enabled us to calculate for risk of secondary effluent upset given two prominent conditions, which have been empirically observed to provide early warning of upset events. Operations analysts have used the stability analyzer data in combination with other bioassay data to determine the need to re-distribute fermentate flow and decide on alum dosing approaches to divert a major upset event during stringent phosphorus permit limits. Despite the difference in anaerobic and anoxic volumes, we conclude that the stability points for the two basins with different geometries to be about halfway through the aerobic zone, with AB1 stability analyzer located at 52% and the AB5 stability point found at 45% down the aerobic zone of the basins.
<bF>UTURE WORK
We are currently performing OP Basin Profiling on two step feed basins at our Rock Creek WRRF. The results of this effort will be included in the full paper. Operational experience with the AB5 stability analyzer will also be included from its first 9 months in service, specifically focusing on summer operation when upsets are likely to occur while under strict phosphorus permit limits.

CWS has demonstrated the effectiveness of an on-line orthophosphate analyzer installed halfway through the aerobic zone to predict impending BPR instability. The Stability Analyzer provides an indirect measure of phosphorus uptake and offers 3 days early warning for BPR upsets. This paper quantifies the risk of upset events using 5 years of historical Stability Analyzer data and describes the process of strategically locating the stability point on an operating aeration basin.

Presentation time

10:30:00

10:55:00

Session time

10:30:00

12:00:00

TopicAdvanced Level, Intelligent Water, Nutrients, Research and Innovation

Author(s)

Author(s)Adrienne Menniti1; Peter Schauer1; Skylar Watnick1;

Author affiliation(s)Clean Water Services, Tigard, OR1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Predicting Biological Phosphorous Removal Performance through Measuring Intracellular Carbon Storage Levels

Print publication date Oct 2022

DOI10.2175/193864718825158551

Volume / Issue

Content sourceWEFTEC

Word count11

Description: Predicting Biological Phosphorous Removal Performance through Measuring...

Abstract

INTRODUCTION Over the last decade, Clean Water Services (CWS) has been studying biological phosphorus removal (BPR) at full-scale to gain insight into potential process control parameters to inform process stability and predict upsets. In the search for stability indicators CWS focused on residual phosphorus uptake (RPU) testing [2], online stability analyzers [3], functional gene expression [4], and measuring carbon storage compounds – specifically PHA (polyhydroxyalkanoates). PHA is known to drive phosphorus uptake [5]. CWS therefore hypothesized that RPU and intracellular PHA content are directly correlated. While RPU is a clear indicator of BPR health, the procedure is labor intensive and only performed weekly. If PHA is a meaningful indicator of BPR health, its ease of measure could provide daily information on BPR health. Initial investigations indicated a strong Monod-like relationship between phosphorus uptake rate and biomass PHA content [2]. However, subsequent full-scale testing pairing only RPU with PHA present in the last aerobic zone (same source of biomass for the RPU test) revealed a poor relationship when evaluated over a long period of time [6]. CWS examined multiple PHA profiles collected on several basins throughout the 2024 dry weather phosphorus permit season. The results demonstrated that, while the expected Monod-type relationship is consistently observed on a given day, the relationship is highly variable both in time and across basins [Figure 1] [7]. OBJECTIVES Given previous results, the following objectives were laid out for testing during the summer of 2025. •Objective 1: Determine if the PHA concentration at the end of the anaerobic zone acts as an improved indicator of BPR performance when correlated with RPU. •Objective 2: Determine if anaerobic PHA, when examined in the context of a wider range of BPR relevant parameters, can expand our understanding of BPR stability and health. •Objective 3: Measure the PAO and GAO relative abundance in the basins to examine if biomass abundance can explain PHA variability. METHODOLOGY PHA grab samples were taken weekly at the end anaerobic zone for eight basins across two CWS facilities, Durham and Rock Creek. PHA samples were measured in-house [8]. RPU was measured weekly on biomass sampled from the last aerobic zone. DNA samples were shipped to the University of Idaho for quantitative polymerase chain reaction (qPCR) testing and subsequent GAO and PAO quantification (16S rDNA and ppk for PAOs). Several relevant predictor variables were evaluated for correlation with anaerobic zone PHA (see Figures 5 and 6 for a complete list). Correlation statistics with PHA were interpreted with Pearson or Spearman tests with alpha values of 0.05. FINDINGS / STATUS Objective 1: Using anaerobic PHA as a replacement indicator for RPU had mixed results [Figure 2,3]. While Durham basins 2, 4, and 5 showed a significant linear correlation, other basins – particularly those with periods of poor BPR stability – did not. Longer anaerobic detention time is known to improve BPR performance [9]. Further investigation found that the average anaerobic PHA concentration was at least 150% greater in Durham basin 5 than any other basin [Figure 4]. Related, the anaerobic detention time for Durham basin 5 is roughly twice that of any other basin [Figure 4]. Long term operation of Durham basin 5 has clearly demonstrated that an aeration basin designed with current best industry knowledge for BPR is more stable and experiences fewer process upsets [data not shown]. Objective 2: The correlation analysis [Figure 5] found that at Durham, basin 5 had a significant relationship between the end anaerobic zone PHA and over half of the potential predictor variables tested. The other Durham basins had a few significant correlations amongst them, but no universal variable. Looking at the Rock Creek analysis [Figure 6], there were only seven instances of potential correlation – none of which were significant across all basins. Objective 3: Microbial measurements revealed higher GAO levels at Rock Creek than Durham [Figure 7,8], but the differences did not translate into predictable impacts on PHA or basin performance on initial review. PRELIMINARY CONCLUSIONS The relationship between end anaerobic PHA and RPU is better than that found previously for end aerobic PHA. However, the relationship is not universal, even across identical basins at Durham, and is non-existent for any Rock Creek basin. Moreover, end anaerobic PHA is not predictive of secondary effluent phosphorus removal performance. PHA also did not show any consistent trends across basins when searching for correlations with any other predictive parameters. A greater number of potential relationships were identified for Durham Basin 5, with the differentiating factor appearing to be linked to the higher anaerobic detention time. This finding of increased anaerobic detention time reaffirms the industry's understanding of appropriate basin design for improved BPR performance [9]. Based on these results, we do not believe that anaerobic PHA concentration is a reliable replacement for RPU as a stability indicator. It is also not a strong indicator of BPR health. This presentation will summarize CWS findings around the utility of PHA as a BPR health indicator. Further analysis of the relationship between PHA and PAO/GAO population abundance will also be presented.

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

Presentation time

16:00:00

16:15:00

Session time

15:30:00

17:00:00

SessionAdvancing Phosphorus Removal: What We Still Have to Learn

Session locationErnest N. Morial Convention Center

TopicFacility Operations and Maintenance, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Menniti, Adrienne, Passe, Theresa, Coats, Erik

Author(s)A. Menniti1, T. Passe1, E. Coats2

Author affiliation(s)Clean Water Services, 1Clean Water Services, 1University of Idaho, 2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

State Point in Action: Evaluating Assumptions and Making Operational Decisions

Print publication date Sep 2026

DOI10.2175/193864718825160434

Volume / Issue

Content sourceWEFTEC

Word count12

Abstract

INTRODUCTION The process engineering group of Clean Water Services (CWS) is working side by side with Operations to develop and validate tools that can help in making day-to-day decisions to operate the treatment facilities, and to plan for future conditions. This work requires an understanding of the level of risk compounded in process assumptions. State Point Analysis (SPA) is a simple but well-loved tool that is used across the industry to evaluate secondary clarification capacity. CWS has historically used SPA to establish secondary expansion timelines, and more recently, to routinely evaluate clarifier operation. With active validation of assumptions and consistency of use, this tool has been useful for Operations to create protocols and assess risks, despite its simplicity and limitations. CWS's process engineers work to make sure the tool can actually indicate risk under conditions that are changing such as flows, settling characteristics, nitrification requirements and underflow pumping capacity.

OVERVIEW The Rock Creek Water Resources Recovery Facility (WRRF) is one of four CWS treatment facilities. It is a 37 MGD plant operating six secondary trains rated for 125 MGD peak day flow, with an option to divert to high-rate clarification. In recent years, managing the clarifiers has become critical as flows increased and settling worsened. Filamentous outbreaks occur more often in winter and spring than 5+ years ago, and a high mixed liquor suspended solids (MLSS) inventory (~3000 mg/L) is maintained year-round to ensure nitrification to meet effluent ammonia limits. Return activated sludge (RAS) flow requirements have increased to prevent blanket rise under current process conditions. Compared to design assumptions, the current conditions have higher influent flows, higher MLSS inventories and, at times, poorer settling. The RAS system was designed for a RAS ratio of 30%, but operations now require a RAS ratio of 60% for typical operation. This deviation between operational need and design assumptions has caused the RAS pumping system to be operated without redundancy. This creates an operational risk that must be actively managed while the RAS system capacity is expanded. Asset failure during these periods of risk would reduce secondary treatment capacity, impacting downstream units and compliance. It is even more critical for Operations to have a tool to test changes to flow distribution and basin configurations before challenging events, to establish operating procedures and contingency plans.

STATE POINT TOOL DESCRIPTION AND USES The SPA used by CWS is a typical graphic representation of a solids balance around the clarifier developed by (Daigger, 1995). It plots the solids flux to the clarifier against the solids concentration. The flux curve is constructed using a relationship of Sludge Volume Index (SVI) to Vesilind parameters that have been measured in-house by conducting settling column tests at the Rock Creek WRRF. To expand the SPA tool's functionalities, an MLSS calculator was added to test aeration basin configurations and solids inventory impacts. Figure 1 shows the spreadsheet interface. Operators can simulate MLSS dilution by changing aeration basin configurations, and visualize clarification impacts in the SPA tool. SPA tool uses at CWS's facilities:
• Annual review of secondary expansion timelines: o Assess clarification performance for future plant capacity evaluations using projected MLSS inventory and peak flows. o Evaluate changes in Vesilind parameters or SVI and their effect on timelines.
• Day-to-day operations:
o Adjust flow distribution when SVI or MLSS differ between basins or RAS pumping is limited.
o Prepare for high flows, which can rise very quickly with large rain events, by simulating flow distributions and basin configurations (e.g., step-feed, contact stabilization) to manage solids and mitigate risk of lack of RAS pump redundancy.

VALIDATION OF VESILIND PARAMETERS The usability of SPA depends on representation of full-scale settling through the solids flux curve, which is impacted by measurements of SVI and settling column Vesilind parameters. SVIs are easy to measure daily but may be less accurate than settling column tests, which are more difficult to conduct routinely. The relationship between these can also change over time. More than 30 settling columns tests have been conducted in 2024 and 2025 to obtain a new empirical relationship of Vesilind parameters to SVI. As shown in Figure 2, this is compared to a 2014 relationship that was used for all previous planning and operational analysis. The 2014 relationship is not conservative and does not indicate appropriate levels of risk under more recent operational conditions (Figure 3). The risk of using these relationships to build the solids flux curve is daylighted in Figure 4, where different events of clarification/thickening failure are represented in SPA.

TAKEAWAYS
• Because of their simplicity, tools such as SPA are readily available for operators to simulate clarification scenarios and develop procedures, while being a learning resource for newer generations.
• The limitations of SPA and risk factors can be understood with consistency of use and ability to compare results to full-scale operation.
• Recurring validation of key assumptions (i.e. Vesilind parameters) is recommended to be confident in the tool's ability to predict issues.

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

Presentation time

13:30:00

14:00:00

Session time

13:30:00

15:00:00

SessionOptimizing Secondary Clarifier Performance using SPA, data driven modeling and intensification approaches

Session locationErnest N. Morial Convention Center

TopicFacility Operations and Maintenance, Municipal Wastewater Treatment Design

Author(s)

Menniti, Adrienne, Sosa-Hernandez, Ornella, Lorntson, Erik

Author(s)A. Menniti1, O. Sosa-Hernandez1, E. Lorntson1

Author affiliation(s)Clean Water Services, 1Clean Water Services, 1Clean Water Services, 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

Use of Bio-electrochemical Sensors to Inform Enhanced Biological Phosphorus Removal Operation Under RAS Fermentation and A2O Conditions

Print publication date Sep 2026

DOI10.2175/193864718825160503

Volume / Issue

Content sourceWEFTEC

Word count11

Description: Use of Bio-electrochemical Sensors to Inform Enhanced Biological Phosphorus Removal...

Abstract

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

This paper summarizes the performance bio-electrochemical sensors deployed at the Clean Water Services Durham WRRF with the following goals to support EBPR operation: 1. Guide RAS-fermentation operation to determine the optimal setpoints to create stable EBPR. 2. Compare anaerobic zone performance during A2O operation between two aeration basins where one basin has an anaerobic zone that is twice as large as the other. 3. Inform plant operations of process influent carbon loadings.

Presentation time

13:30:00

14:00:00

Session time

13:30:00

15:00:00

SessionConnecting Molecular Biology Sensors to EBPR Performance

Session locationRoom S502 - Level 5

TopicAdvanced Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Author(s)A. Menniti 1; J. Ambler 2 ; J. Mejia Franco 3; R. Cusick 4; A. Menniti 1;

Author affiliation(s)Chemical Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, QC, Canada 1; SENTRY Water Technologies 2 ; SENTRY Water Technologies 3; University of Illinois at Urbana-Champaign 4; Clean Water Services 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

WRF 5121 Final Report Overview: Long-Term Evaluation of Hybrid Digital Twins at Three Full-Scale WRRFs

Print publication date Oct 2023

DOI10.2175/193864718825159084

Volume / Issue

Content sourceWEFTEC

Word count18

Abstract

INTRODUCTION The Water Research Foundation (WRF) project 5121, Development of Innovative Predictive Control Strategies for Nutrient Removal, aims at developing full-scale hybrid nutrient management controllers (named here as Hybrid Optimizer, HO) by employing a hybrid approach that combines both machine learning and mechanistic models. Three full-scale pilots are deployed and evaluated for this project to demonstrate long-term controller abilities. The concept, design and preliminary results have been shared previously [1-7], which triggered wide interest and heated discussion. Over the past year, refinements were made to improve performance and evaluation approaches were standardized. Currently, all three pilots are fully deployed and operational. This paper provides an overview of three case studies. The control for three pilots is advisory only with no direct control functions due to cybersecurity concerns. Instead, operators receive daily email notifications outlining recommended operations and/or access a web-based user interface (UI), guiding their actions. The full-scale pilots are: 1. Clean Water Services Durham WRRF (CWS): Primary clarifier alum addition setpoints once a day, aiming to stabilize orthophosphate load to the downstream biological treatment system. 2. Agua Nueva WRF (AN): Dissolved oxygen setpoints twice daily for the bioreactor systems, aiming to minimize overall aeration energy consumption. 3.AlexRenew WRF (AR): HO recommends three equalization setpoints once a day to equalize the influent loadings to the bioreactor to minimize energy, chemicals, and blower staging. METHODOLOGY As shown in Figure 1, Hybrid Optimizer consists of seven major components. Descriptions of each component can be found in [1-3]. In this paper, the performance of Soft Sensor, Influent Forecaster and emulator/optimizer is mainly presented and discussed. Four different types of standard graphs are used to evaluate the performance of the HO. (1)Control Chart. Directly conveys the validity of the model, based on which warnings and alarms are derived. It integrates the measured and the modelled values into a dimensionless metric (t_score) and allows its comparison with predefined bounds. (2)Process Plot. The process plot presents the measured and the modelled values. (3)Unscaled Error Plot. The Error plot presents the residuals between the modelled and the measured. (4)XY Plot. The XY Plot presents the Modelled v. s. the Measured and the prediction intervals. (not shown here for brevity) RESULTS AND DISCUSSION The components and timelines of the three pilots are listed in Table 1. The Graphic User Interface (GUI) for two pilots are in progress. Evaluation results are available for all three, however this abstract presents only partial results. The soft sensor can be considered a full digital twin of the modelled components. Thus, it provides dynamic 15-minute frequency data on all wastewater components in the model scope. For CWS the primary influent and effluent ortho-phosphate data was used to support primary alum addition recommendations, without an actual sensor. For AN the focus was ammonia. The soft sensor demonstrates alignment with measured data (Figure 2).

*In the Control Chart, the t score falls within the warning and alarm bounds (set at 95% and 99% confidence intervals), which indicates soft sensor performance. The t-score is the normalized metric of a given set of measurements.

*The Process and Residual Plots are more intuitive for process engineers to evaluate. The modelled and measured values align closely, and their parallel trends indicate good soft sensor performance. Figure 3 shows the AN performance for primary influent and effluent ammonia. The top graph shows a good match between the composite samples. However, the primary effluent in the middle and bottom graphs shows a poor match. It was found that high influent sulfide was biasing the measurements high. The bottom graph showing the dynamic concentration variation, other than the bias, shows a good variability match. Flow forecasting is critical to predictive control. The Forecaster uses the available weather forecast and other variables to estimate plant influent flow. Figure 4 compares influent flow (forecasted vs actual) as well as the forecasted versus actual rainfall. A close examination shows that much of the influent forecast error can be attributed to the error in the precipitation forecast. The AR optimizer (Figure 5) aims to equalize ammonia load, which helps stabilize the aeration demand and optimization of aeration and chemicals. The flow and loading prediction from the HO allows the optimizer to recommend three equalization setpoints for the next 24 hours. In the top graph, the green line is the target daily average loading, red and blue show the load with and without the recommendations. CONCLUSIONS This abstract presents abbreviated results of the long-term performance of HO during three full-scale pilot studies. The HO appears to be a promising opportunity to improve plant operation using digital twin technology by giving both optimized operational recommendations and increased insight into the facility's status. The ongoing assessment of the HO performance is anticipated to yield further valuable practical experiences and insights, including the benefits and costs of such applications.

This paper was presented at the WEFTEC 2024 conference in New Orleans, LA October 5-9.

SpeakerYang, Cheng

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionLeveraging Automation and Analytics for Better Situational Awareness and Optimization: Part I

Session number205

Session locationRoom 350

TopicEnergy Production, Conservation, and Management, Facility Operations and Maintenance, Intelligent Water, Intermediate Level, Nutrients

Author(s)

Yang, Cheng, Johnson, Bruce, Lesnik, Keaton, Registe, Joshua, Rieger, Leiv, Stewart, Heather, Miletic, Ivan, Menniti, Adrienne, Oristian, Monica, Pienta, Drew, Mason, Tim

Author(s)C. Yang1, B.R. Johnson1, K. Lesnik2, J. Registe3, L.P. Rieger4, H.A. Stewart5, I. Miletic6, A. Menniti7, M.K. Oristian8, D.J. Pienta9, T. Mason10

Author affiliation(s)1Jacobs, CO, 2Maia Analytica, OR, 3Jacobs Engineering, NJ, 4Jacobs, NL, 5Jacobs, PA, 6inCTRL Solutions Inc., ON, 7Clean Water Services, OR, 8Alexandria Renew Enterprise, VA, 9Jacobs, 10Jacobs Eng, AZ

SourceProceedings of the Water Environment Federation

Document typeConference Paper