Mansell, Scott

Scott is the Principal Engineer in the Research and Innovation Department at Clean Water Services in Hillsboro, Oregon. After earning a PhD in environmental engineering from UC Berkeley in 2012, Scott spent 5 years in consulting at Geosyntec in California and Oregon before joining Clean Water Services in 2017. He leads three main areas of research at Clean Water Services. The first is the modeling group which builds a wide range of environmental models to support studies related to integrated planning, strategic planning, hydromodification, green infrastructure, and wetland restoration. The second is the trace organics program which focuses mainly on PFAS studies and other emerging contaminants. Finally, Scott leads the advanced sensing group which develops and tests new technologies for making continuous sensing more reliable and cost-effective, particularly in the sanitary sewer. Scott is a registered Professional Engineer in the state of Oregon.

Titles from this speaker

Effects of Removing Tertiary Alum Treatment on Tualatin River Water Quality

Abstract

The Tualatin River has had a phosphorus TMDL since 1988 that requires Clean Water Services (CWS) to add tertiary alum at its two advanced water resource recovery facilities (WRRFs) in the summer to meet stringent effluent limits for total phosphorus. Over several decades, management of the river has changed dramatically, especially flow management. U.S. EPA recently finalized new aluminum criteria in Oregon that challenges the use of alum in the tertiary process at current application rates to control phosphorus. CWS conducted a study in which tertiary alum addition at the WRRFs was ceased and the resulting effects on the river were monitored and modeled. While the total phosphorus concentrations in the effluent were higher than they are with alum use, the study demonstrated that the increase in total phosphorus concentration did not negatively impact water quality in the river.

Clean Water Services (CWS) demonstrated through experiments and modeling that river conditions have changed since the conditions in the 1988 TMDL that produced stringent effluent phosphorus limits for WRRFs, and river water quality can be maintained with higher effluent phosphorus concentrations. For three summers, CWS monitored the aluminum, pH, and chlorophyll-a response in the river which showed the ability to maintain water quality standards in the Tualatin River.

SpeakerCrown, Julia

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionNutrient Management: Growing Water Quality

Session locationRoom S504a - Level 5

TopicIntermediate Level, Nutrients, Watershed Management, Water Quality, and Groundwater

Author(s)

J. Crown

Author(s)J. J. Crown 1; S. Mansell 1 ; R. Baumgartner 1; P. Schauer 1; J. Crown 1;

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

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825158996

Volume / Issue

Content sourceWEFTEC

Word count12

Modeling of Eutrophication in the Tualatin River to Facilitate a TMDL Update

Abstract

A phosphorus TMDL has been in place for The Tualatin River in Oregon since 1988 that established strict effluent limits for phosphorus. To achieve the limit requires the use of alum to remove phosphorus from wastewater effluent. Since 1988, the river has changed dramatically in terms of operations, flows, and water quality. The EPA has recently proposed a new aluminum standard in Oregon that may necessitate curtailing the use of tertiary alum. A combined effort of modeling eutrophication in the river, data collection, and an experimental elimination of alum addition at the treatment plants was conducted in the summer of 2019. Results suggested that algal growth in the river is no longer phosphorus-limited, but is more sensitive to algal ‘seeding’ from upstream sources, including a treatment wetland. The treatment plants may be able to cease alum addition without harmfully affecting water quality in the river.

SpeakerMansell, Scott

Presentation time

09:30:00

09:50:00

Session time

08:30:00

10:10:00

SessionResiliency Runway: New Trends in Modeling

Session number526

TopicResilience, Disaster Planning and Recovery, Utility Management and Leadership, Watershed Management, Water Quality, and Groundwater

Author(s)

L. BarkerS. MansellS. MansellR. KapurB. BaumgartnerK.J. WilliamsonC. Cheney

Author(s)L. Barker1; S. Mansell1; S. Mansell1; R. Kapur1; B. Baumgartner2; K.J. Williamson1; C. Cheney1;

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

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157495

Volume / Issue

Content sourceWEFTEC

Word count13

Spatial and Temporal Measurements of SARS-CoV-2 in a Sewershed

Abstract

The SARS-CoV-2 virus can be shed in the feces of persons infected with COVID-19. As a result, sewer surveillance can be used to identify the presence of COVID-19 infections in a particular sewershed. Measurement of SARS-CoV-2 in influents to wastewater treatment plants (WWTPs) has been accomplished at hundreds of locations nationally and internationally. Such measurements provide information on the presence of COVID-19 infections, trends including rising and declining case numbers, and quantitative measures to allow comparisons of infection rates between communities. Less commonly, sewer surveillance has been used to measure SARS-CoV-2 within a sewershed (here termed micro-sewersheds) to attempt to determine presence and trends at the community and institutional scale.

Clean Water Services monitored 4 wastewater treatment plants (WWTPs) and 16 manholes in Washington County, Oregon, over a period of 15 months to determine whether SARS-CoV-2 concentrations corresponded with reported COVID-19 cases. SARS-CoV-2 concentrations at WWTPs appeared to be a leading indicator of reported cases. Neighborhoods with high LatinX and high poverty populations also had higher SARS-CoV-2 concentrations. Additionally, outbreaks at food processing plants corresponded with viral peaks in the associated manhole. Surprisingly, SARS-CoV-2 was rarely detected in hospital effluent despite the presence of known cases, and experiments revealed hospital disinfectants can destroy the RNA signal.

SpeakerMansell, Scott

Presentation time

13:50:00

14:10:00

Session time

13:30:00

15:00:00

SessionBuilding a Successful Wastewater-based Epidemiology (WBE) Program

Session number501

TopicFundamental Level, Laboratory Practices, Public Communication and Outreach, Utility Management and Leadership

Author(s)

Scott Mansell

Author(s)S. Mansell1; B.A. Layton1; T. Radniecki2; J. Cook1; A. George1;D. Kaya2;H. Ferguson1;A. Piemonti1; C. Kelly2;K. Williamson1;

Author affiliation(s)Clean Water Services, Hillsboro, OR1School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2021

DOI10.2175/193864718825158142

Volume / Issue

Content sourceWEFTEC

Word count10

The Road to Carbon Neutrality for Water Reclamation Utilities

Abstract

Clean Water Services (CWS) is a special service district that manages storm and wastewater within Washington County, Oregon. The district set a goal to reduce its carbon footprint through greenhouse gas (GHG) emission reductions and carbon sequestration provided by CWS’s many wetland, stream, and riparian restoration activities. Thus far the work has been done in two parts: 1) CWS operations GHG emission itemization and quantification, and 2) documentation of soil carbon sequestration potential in afforested wetlands and revegetated projects. The results showed that the highest GHG emissions from operations are due to indirect electricity use by the water resources recovery facilities estimated to represent 59% percent of CWS emissions. Soil carbon percentage in CWS revegetation projects were found to double within 5 years after planting, though this is dependent on soil type and revegetation type.

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

SpeakerPiemonti, Debora

Presentation time

15:30:00

15:50:00

Session time

15:30:00

17:00:00

SessionDecarbonization Case Studies

Session locationRoom S401d - Level 4

TopicIntermediate Level

Author(s)

Piemonti, A Debora

Author(s)A. Piemonti 1; G. DiGioia 1 ; F. Shackleford 2; J. Goetz III 1; D. Mansell 1; A. Piemonti 1;

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

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159023

Volume / Issue

Content sourceWEFTEC

Word count10

Description: Tracking Down and Addressing Sources of PFAS in Influent Flows Through Strategic...

Tracking Down and Addressing Sources of PFAS in Influent Flows Through Strategic Collection System Monitoring and Targeted Outreach

Abstract

Background
Poly- and Perfluoroalkyl Substances (PFAS) have been commonly used in many industrial applications, fire-fighting materials, and consumer products since the 1950s. These compounds have been associated with various negative human health effects. While manufacture of the most common types of PFAS, such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), has been phased out in the United States, in many cases other types have been substituted into products that sometimes have similar or worse toxicity [1]. Many types of PFAS exist in current domestic and industrial use, and many of the legacy PFAS types are still environmentally ubiquitous. The United States Environmental Protection Agency (EPA) released its strategic roadmap in October 2021 for addressing PFAS in the environment. Part of that strategy is expected to involve additional monitoring and source control for wastewater utilities. Many wastewater utilities are concerned that future regulations may threaten some resource recovery efforts such as beneficial reuse and land application of biosolids. Some states, such as Michigan, have already proactively issued limits to biosolids applications based on PFAS concentrations. Some wastewater utilities around the country have begun to sample their influent, effluent, and biosolids for PFAS. In general, this has provided useful data on the PFAS types in wastewater and their concentrations. However, results have been site-specific with both the types and concentrations of PFAS detected highly dependent on the sewershed properties. However, few wastewater utilities have done monitoring for PFAS in the sanitary collection system to determine the sources of different types of PFAS in the sewershed. While the EPA has provided guidance on the industrial types likely to have high PFAS in their discharges, in most cases the actual discharge concentrations are site-specific even from similar industry types. PFAS are also commonly found in domestic and commercial wastewater due to their widespread use in consumer products. Understanding the types and sources of PFAS present in their sewershed can help wastewater utilities better understand the threat posed by PFAS and help provide the tools to proactively mitigate the sources.
Objectives
Clean Water Services' (CWS's) objective was to determine the threat posed by PFAS and develop strategies to mitigate the threat proactively. This was done through strategic monitoring for PFAS at the treatment plants and within the collection system accompanied by targeted sampling and general outreach to industries, and the commercial, and domestic sectors, followed by development of PFAS minimization plans.
Methods
Between 2019 and 2022, samples were collected from the influent, effluent, and biosolids of CWS's treatment plants, from the soils where biosolids were applied, from specific industries, and from many sanitary sewer manholes. The concentration of 36 types of PFAS were quantified in each sample. Samples were collected approximately quarterly, though not all locations were sampled in each sample event as selected manhole locations in each sample event were determined based on the results from the previous samples to 'chase' high concentrations of specific PFAS 'upstream' to the source. Industries were initially selected for sampling based on EPA guidance. Additional industrial samples were focused on those industries that were identified as sources of PFAS in the initial industrial sampling and through the sanitary manhole sampling. CWS reached out to each industry prior to initial sampling to explain the reasons for sampling, and followed up with initial results. Additional samples were collected and additional outreach was conducted to industries identified as sources of high PFAS concentrations through ongoing industry sampling and strategic sanitary manhole sampling. CWS worked with the Pacific Northwest Pollution Prevention Resource Center (PPRC) to create outreach materials for commercial and domestic sources and to develop a PFAS minimization plan for CWS. CWS continued to work collaboratively with industries identified as sources high sources of PFAS as the concentrations decreased. Ordinances and policies were updated to be able to better regulate PFAS through source control. A dashboard was also created to provide easier access to PFAS data in the sewershed to stakeholders. Because CWS expects to continue monitoring PFAS and other contaminants of emerging concern into the future, in 2022 CWS began efforts to create a trace organics laboratory in order to analyze PFAS samples in-house.
Status
As of the writing of this abstract in Dec 2021, CWS is currently contracting with the PPRC for developing the outreach materials and PFAS minimization plan. While PFAS monitoring and outreach efforts have been ongoing since 2019 and are expected to continue well into the future, much has already been learned about the types of PFAS present, their removal in wastewater treatment, and their sources in the sewershed. Monitoring and targeted outreach has already succeeded in mitigating the two largest individual sources of high PFAS in the influent.
Findings
The concentration of PFAS in CWS influent was relatively low compared to nationwide data, although concentrations of individual PFAS were sometimes high, especially PFOA at the Durham treatment facility (Figure 1). Sampling in the sanitary sewer determined that a single industry was responsible for the elevated PFOA concentrations, and outreach to the industry coupled with additional monitoring resulted in the mitigation of the high PFOA concentrations in the influent. The most commonly detected forms of PFAS present were the 4-, 5-, and 6- carbon chain forms. These were nearly ubiquitous in liquid samples, but concentrations tended to be higher in manholes in industrial areas and at treatment plants where industries make up a large fraction of the wastewater flows, such as Rock Creek (Figure 1). CWS collaborated with largest industrial source to remove PFAS from their supply chain, and concentrations in the sanitary sewer downstream have subsequently decreased. Industries identified as having high concentrations of PFAS in their outfalls were mostly open to discussions with source control personnel, though many are concerned about future regulation. As found across the US, treatment processes were not effective at removing PFAS from influent. The shorter carbon chain compounds tended to be found in the effluent at similar concentrations as the influent, and the longer chain compounds tended to be found in the biosolids (Figure 2). However, concentrations in the soils where biosolids were applied were mostly below detection limits.
Significance
This study demonstrates that monitoring and outreach can be effective at reducing PFAS in wastewater. The results of this study provide a useful case study and template for other utilities seeking to understand the threat posed by PFAS and be able to locate and mitigate the sources without additional regulations or an adversarial relationship with industries.

Identifying and mitigating sources of PFAS to treatment plants in a cost-effective way is of paramount importance to meeting coming regulations. We collected 229 samples from industrial outfalls, influents, effluents, biosolids and strategic locations in the collection system, identified and quantified the types of PFAS coming to and leaving the plants, tracked down the major sources, and worked with them to reduce their PFAS discharges through outreach, education, and control plans.

SpeakerMansell, Scott

Presentation time

16:25:00

16:40:00

Session time

15:30:00

17:00:00

TopicIntermediate Level, PFAS, Research and Innovation

Author(s)

Mansell, Scott

Author(s)Scott Mansell1; Marney Jett1; Bob Baumgartner1; Joy E. Ramirez1; Steve L. Thompson1; Ken J. Williamson1

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