Conference Agenda

Use of these collaborative delivery models is on the rise as Owners realize the potential advantages of quality-based selection, schedule acceleration and performance-based risk transfer of some of their most complex projects. While these models provide benefits, they are not right for every project or every client, and strong execution of any model is key to success.

This presentation will leverage Water Collaborative Delivery Association (WCDA) training materials designed to educate Owners and Practitioners about collaborative delivery models, get beyond the high-level portrayal of the models, and dig into the nitty-gritty of project execution.

The presentation will compare and contrast to following for these two models:

- Fundamental risk allocation differences

- Project progression from selection of a Contractor/Design-Builder to authorization of construction

- How a Guaranteed Maximum Price Proposal is developed and negotiated

- Guaranteed Maximum Price Proposal (GMP) contents – what does it include?

- How Open Book Pricing works in practice

- Utilization of a Risk Register to create risk transparency

- Definition of the Off-ramp and when it is utilized

- Contract Fundamentals

- High level overview of state statues

A more detailed understanding of how these models are executed will help to refine an Owners’ and Practitioners’ understanding of whether these models are appropriate ‘tools in the procurement toolbox’ for a particular organization.

The Portland Bureau of Environmental Services (BES) Columbia Boulevard Wastewater Treatment Plant (CBWT) practices CEPT during wet weather events that increases settling performance in the plant’s wet weather clarifiers (WWCLs). Wet-weather flows dilute the alkalinity of the plant influent such that ferric chloride (FeCl₃) addition results in a decreased effluent pH. During the summer of 2020, the NPDES permit was updated to require continuous monitoring of pH limits between a daily minimum of 6.0 and a daily maximum of 9.0. With continuous monitoring in lieu of grab samples, BES has observed pH violations when CEPT is practiced which is believed to be due to the coagulant, ferric chloride. The objective of this project is to determine an alternative CEPT chemical or the addition of post-coagulation pH adjustment to prevent future permit violations for pH.

An investigation occurred to trial different polyaluminum chloride (PACl) based coagulants to limit pH decrease. The investigation included vendor outreach for coagulant candidates, jar testing, full-scale pilot testing during both dry and wet weather events trialing multiple coagulants, as well testing the use of post-coagulant chemical addition for pH adjustment and buffering. This presentation will present and reflect upon the results showing that PACl coagulants are effective, but products differ significantly in cost effectiveness. It will also discuss the challenges during the project including pandemic associated variables such as unstable costs, unreliable chemical availability, and labor shortages.

A potential secondary use of the CEPT system is to pre-treat wastewater to reduce loading to the secondary treatment system. BES is also testing the performance of dry weather clarifier (DWCL) CEPT to determine the effectiveness of aeration basin loading to provide a solution for growth projections with limited space for expansion. Results from a 2022 full-scale pilot and lessons learned will be presented.

Attendees will gain an understanding of the technical engineering involved in evaluating alternatives to prevent the pH excursions, as well as the creative problem-solving and collaborative effort between all parties that led to an updated CEPT process that benefited both the wet and dry weather treatment processes.

After five years of related construction activity, King County’s Georgetown Wet Weather Treatment Station (GWWTS) began treating combined sewage in December 2022 that would have otherwise been released into the Duwamish River in Seattle. The station was designed to control combined sewer overflows at the South Michigan and Brandon Street outfalls by limiting untreated discharges to an average of no more than one per year, per outfall. The GWWTS has a capacity for a peak inflow of 133 mgd. The station includes a 1.1 MG equalization basin and two 35-mgd treatment trains that use ballasted sedimentation and ultraviolet disinfection to meet discharge permit requirements. Additionally, the GWWTS includes a regulator, screening and handling, influent pump station, chemical storage and distribution, odor control and solids storage systems. During the wet weather season, the station is ready to quickly startup and treat intermittent and variable events on short notice. Startup and shutdown sequences between events consist of a recycle stream, solids discharge, water management, and tank flushing. During dry weather, the station can recycle treated water to allow for operator training, maintenance, and inspection.
The presentation will review the station’s features and discuss operational testing that was performed before commissioning. After testing individual systems in isolation, additional testing was conducted to ensure full integration and that the station operated as intended. During the first part of operational testing, the station was hydraulically tested using City water. In the second part, dry weather flow from the conveyance system was mixed with potable water to simulate the combined sewage the station would treat during a wet weather event. Rather than being discharged, treated water was recirculated, but otherwise the station operated as it would during a wet weather event. With coordination and support from the manufacturers, the performance of the ballasted sedimentation and UV disinfection systems was tested by sampling influent and effluent flows, with a third-party lab analyzing the samples.

King County commissioned an alternatives analysis to increase wastewater conveyance capacity between North Mercer Pump Station, on Mercer Island, and Sweyolocken Pump Station, in Bellevue. Alternatives identified a range of alignments and construction techniques for over 4 miles of pipeline and the preferred alternative was selected based on scoring of the alternatives using a triple bottom line approach. One key section of the preferred alternative is the Enatai Siphon, an inverted siphon from Enatai Beach Park, on the Lake Washington shoreline, to the Sweyolocken Pump Station. This 3,000 foot, 32-inch diameter High Density Polyethylene pipeline required installation by horizontal directional drilling (HDD) under the hillside of the Enatai neighborhood at depths of up to 160 feet. The Enatai Siphon will accommodate high flows, with lower flows continuing to use an existing sewer lakeline that is routed along the shoreline of Lake Washington and Mercer Slough.

Design of the HDD provided solutions for physical obstacles, geotechnical challenges and identified methods for pullback of the pipe from Lake Washington. As well as HDD elements, the design also determined optimal system hydraulics, essential for sizing and minimizing build-up of sediment. Methods of maintenance were also evaluated to enable periodic cleaning with suitable access for cleaning incorporated in the site and structure design. And the design incorporated methods to minimize the impacts of working in and adjacent to critical areas.

With critical areas including shoreline and wetlands adjacent to the entry and exit locations, significant permitting coordination was required to successfully obtain the federal, state and local permits. In addition, with the Enatai Siphon entry structure in the Enatai Beach Park, on WSDOT property and immediately adjacent to the Interstate 90 bridge extensive coordination with required with WSDOT for utility franchise and air lease.

Construction of the work was completed in early 2023 and the presentation will include images of the casing installation, HDD and pullback, and structure installation.

Seattle Public Utilities (SPU) is responsible for 1,900 miles of pipelines providing wastewater and drainage conveyance to 1.5 million customers. As part of their proactive assessment and prioritization process, SPU identified a critical drainage pipe that served a large upstream basin that crosses Interstate 5 (I-5) through heart of downtown Seattle. Inspection of this 58”x36” arched shaped flat bottom corrugated metal drainage pipe indicated that the pipe was deteriorating. The pipe has numerous vertical alignment changes and a horizontal curve, which limited the feasible rehabilitation technologies.

SPU performed an Options Analysis and determined that a spray-on fully structural liner that minimized loss of hydraulic capacity was the most feasible solution. Being the first time utilizing this rehabilitation technology, SPU’s team conducted a thorough evaluation of the use of geopolymers, wrote new specifications for the product, evaluated the hydraulic capacity limitations, and developed a bid package for the work. In addition, the velocities in the drainage pipe necessitated an evaluation of abrasion-resistance of the product, leading to a requirement for the contractor to apply a sacrificial wearing course. And because of the large drainage basin, even a trace amount of rainfall resulted in flows that would be problematic to bypass.

This paper will present how SPU determined that a geopolymer spray applied liner was the best solution, the site-specific design challenges of the project, the complex bypassing and evaluation of risk management versus expected costs, the presentation of the construction activities, and lessons learned. Construction was successfully completed ahead of schedule.

The water industry is composed of a diverse mix of people and businesses with unique perspectives of how to use innovation and inclusion to solve water challenges. The Racial and Social Justice Subcommittee of PNCWA will host a panel with small women- and minority-owned business owners, utilities/clients, and larger (prime) firms in the water industry to talk about what it is like being a Minority, Women and Disadvantaged Business Enterprise (MWDBE), the strengths they bring to the water industry, and what challenges they face. This discussion will also provide an opportunity for both large and small firms to have a dialogue about ways to address challenges faced when working together.

This discussion is intended to provide insight into the MWDBE experience, share ideas for better engaging MWDBE firms and leveraging their strengths, and give recognition to the value these critical entities provide from both a technical and a diversity, equity, and inclusion lens.

The panel will have up to 5 speakers, including two MWDBE speakers (e.g., Osborn Consulting, Leeway Engineering), one utility/client speaker (e.g., City of Portland), and one person representing larger firms (e.g., Jacobs). The panel will be facilitated by the RSJ Subcommittee. The intent for this panel is to provide multiple viewpoints into the benefits all firms in the water industry can achieve from inclusivity and open communication, and to highlight how these benefits transcend the professional world and touch our communities.

Building relationships with underserved communities is a hot topic for many utilities. Though relationship building is an important first step, putting relationship building at the core of our efforts can inadvertently cause harm by consuming a community’s capacity without addressing their needs. This presentation focuses on putting community capacity and needs at the heart of our engagement. The first half will focus on applying a capacity-driven model for engaging with communities of color. How can we meet people where they are, augment their capacity, then stand back and let them lead when they are ready? The second half of the presentation will focus on integrating community benefits into project implementation. How do we look beyond the current subcontracting community to create economic benefit for those who need it most?

At the end of the day, relationship building is an important first step but it comes with a responsibility to turn those relationships into positive change for those we want to serve. Only then will we truly be integrating equity into our engagement and our work.

The Water Infrastructure Finance and Innovation Act (WIFIA) program is a government bank operated by EPA headquarters that provides supplemental, flexible, low-cost credit assistance to public and private borrowers for all types of wastewater, drinking water, and stormwater projects. The WIFIA program offers long-term loans that can be combined with State Revolving Fund assistance, municipal bonds, and federal and state grants to help communities deliver more critical water infrastructure projects for a lower cost with less impact on rate payers.

In this session, we will provide an overview of the WIFIA program and describe WIFIA’s water infrastructure-related eligibilities and priorities. Additionally, we will discuss the benefits and flexibilities of WIFIA financing, including customized repayment schedules, coordination with other types of debt, the option to fund multiple projects through a single loan, and the ability to finance a combination of staggered projects, like those in a capital improvement plan, under a “master agreement”. Finally, we will demonstrate, through case studies presented with current borrowers/utilities, how WIFIA loans are providing financial benefits to borrowers across the country, including over $5 billion in savings.

The Bellevue Utilities Capital Investment Plan is a seven-year $317M capital plan for the water, sewer, and stormwater utilities that is updated every two years. In the past four years, Bellevue Utilities has made great strides in developing a successful collaborative budget process that is structured with input from the Utilities Leadership Team, Engineering Division, Operations and Maintenance Division, the Finance Group, the community. This collaborative process has been significantly boosted with process improvements in project identification and scoping, project cost estimating, project prioritization, staff resource analysis, and community engagement In addition, asset management risk information has been used to budget for asset-based rehabilitation programs such as pipe rehabilitation and water main replacement programs.

Prior CIP budgets were successfully developed internally by engineering management; however, retirements and departures of management responsible for developing the CIP. and the challenge of finding supporting documentation, provided new opportunities for successor positions to develop the CIP. A collaborative budget framework was developed approximately 8-months prior to the Preliminary Budget deadline. The framework included the process improvements and the collaborative engagement of Utilities staff in distinct phases of the budgeting process, specifically Operations and Maintenance and Engineering staff in the project identification and prioritization, and the Engineering Project Management Group in the cost estimating elements of the budget. Over two budget cycles, the process improvements have become foundational and standardized in the budget process. The benefits of a collaborative budget process include the support and buy-in from staff at all levels of the organization; in addition, the transparency in the budget development process helps the entire utility and provides a sense of teamwork and collaboration across the Utilities Department. Although the collaborative budget process is a once every other year investment of time and energy from many staff and Bellevue Utilities Leadership Team, it results in a significantly improved capital plan that increases the department’s ability to support a high level of service to Bellevue Utilities Customers.

Per- and Poly-Fluoroalkyl Substances (PFAS) are a large family of organic compounds, including more than 4,500 synthetic fluorinated organic chemicals used in commercial, consumer and industrial products since the 1940s. Conventional sewage treatment methods do not efficiently remove PFAS which are resilient to degradation and tend to sequester to the treated solids produced and the resultant biosolids. In its most recent (2021) review of pollutants in biosolids, the US EPA identified eight PFAS in biosolids, and is undergoing a problem formulation process which will serve as the basis for determining whether regulation of PFOA and PFOS in biosolids is appropriate. If EPA determines that a regulation is appropriate (currently expected in 2024), biosolids producers will be required to meet certain standards. This potential outcome of EPA’s review underscores the importance of understanding technical solutions available to treat PFAS in biosolids if required based on EPA’s review process.

To assist utilities and biosolids producers understand options available to mitigate potential PFAS contamination in biosolids, Jacobs has tested several biosolids products including dried biosolids, pyrolyzed dried biosolids and composts, all produced with non-industrially impacted biosolids to assess the concentration of PFAS compounds in the finished products and the ability of these processes to reduce and or remove PFAS compounds. Samples of input and output solids, bulking agents and finished products were analyzed for 24 PFAS compounds utilizing Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS). Data will be presented on three dried biosolids facilities, two pyrolyzed dried products including output solids, gas and oil, and six compost products.

This presentation will provide information regarding the measured concentrations of PFAS in wastewater solids, dried biosolids, pyrolyzed biosolids and biosolids based compost products. PFAS precursor analyte presence and concentrations in the input solids as well as the wastewater treatment process used to generate these products will also be presented. This information will be useful for those considering methods to reduce or eliminate PFAS in their own wastewater solids or other input wastewater solids at existing or planned biosolids management operations to ensure the lowest feasible PFAS concentrations in end products can be achieved.

Federal and state regulatory agencies—and the public—have growing concerns about public health and environmental wellbeing associated with per- and polyfluoroalkyl substances (PFAS). As of this writing, the United States does not yet have federally enforceable PFAS standards for drinking water, wastewater, or biosolids. This has left states to develop their own regulations to address PFAS contamination, creating a diverse regulatory patchwork across the country. State regulations on PFAS in drinking water are becoming common, but now a few states are also enacting regulations on PFAS in surface water and biosolids as well. For example, Michigan has developed screening levels for PFAS in biosolids, and Maine has effectively banned biosolids land application due to concerns about PFAS.

The EPA plans to complete a risk assessment for two PFAS [perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS)] in biosolids for land application by Winter 2024. PFOS is commonly detected in biosolids at a concentration around 10 ppb, even without any industrial sources. A biosolids PFOS limit below that level could widely restrict land application, having a large impact on our industry. This risk assessment requires knowing many parameters for PFAS toxicity, occurrence, fate, and transport. This presentation will walk through the risk assessment process, what parameters are known, and which are not, along with proven methods utilities can use to keep stakeholders and customers informed.

Elected officials, stakeholders and the public are interested in actions utilities are taking to protect public health and the environment. Having a response plan in place to monitor, assess and respond to emerging regulations can “calm the waters” while the regulatory process unfolds. One topic of interest is how to treat PFOS. Ongoing research on PFAS-destroying technologies includes investigations into incineration, pyrolysis, gasification, supercritical water oxidation (SCWO), hydrothermal liquefaction, and hydrothermal alkaline treatment. This presentation will compare the latest known PFAS destruction efficiencies, market readiness, and other considerations that impact the feasibility of these technologies for widespread use. A regulatory update on proposed legislation in the Pacific Northwest will also be provided.

As wastewater treatment facilities are being rebranded as water resource recovery facilities, carbon is being viewed in a new light. Traditionally, the removal of carbon, expressed as biochemical oxygen demand (BOD) or chemical oxygen demand (COD), is the primary objective in wastewater treatment. However, with recent nutrient removal requirements and energy recovery incentives, carbon is now viewed not as a waste, but as food for the biological nutrient removal process and a source of renewable energy by capturing and re-using the digester gas. The increased attention on carbon benefits is now putting a spotlight on how it is managed across the entire treatment facility process. Understanding the nuances of carbon management is a critical issue for many municipalities, as more treatment facilities in the Puget Sound area are required to provide nitrogen removal, while others have both effluent nitrogen and phosphorus limits. To gain insight on how carbon can be used, it is critical to know the factors that affect carbon management. This presentation will provide a discussion of these factors including presence and types of primary treatment, biological nutrient removal requirements, energy recovery potential and methods, fermentation use, and external carbon sources. In the first case study, a treatment plant currently without primary treatment and digestion is being retrofitted to include primary treatment and digestion. While carbon re-use was not originally the main driver for the plant expansion, carbon management has become an important topic during the planning and design process. The implications of adding primary treatment and potential future fermentation are presented. In the second study, the carbon values of different digester gas uses are compared to the offsets of external carbon addition with sludge fermentation. This study allows a comparison of both costs and greenhouse gas emissions based on the different carbon management schemes. The findings from these examples can be applied to many municipalities in the Northwest as they are faced with the need to meet more stringent nutrient limits and to become more energy-neutral.

This presentation provides an overview of Pima County RWRD Biosolids and Biogas Management Program’s two sustainability projects: beneficial biogas utilization and controlled struvite formation. The Pima County RWRD serves the City of Tucson Arizona and the surrounding communities. The PCRWRD serves 900,000+ wastewater customers within a service area of approximately 700 square miles. It owns and operates 3,400 miles of sewer pipes, 66,000 manholes, 29 active lift stations, and two major regional Water Reclamation Facilities and several small sub-regional WRFs.

PCRWRD’s has been proactively planning for biosolids and biogas beneficial utilization. Land application continues to be the preferred option for its Class B biosolids due to lower cost, simpler to operate, satisfies current regulations, and is consistent with current market conditions. For biogas utilization, different options have been considered, such as CHP for onsite plant use, CNG for fleet use, recovery of carbon dioxide, district heating system, use of excess thermal energy to generate ice for local skating rink, among others.

In the past, biogas was captured and used for onsite cogeneration. An Energy Study for the WRF concluded that a higher value of the one million cubic feet per day of biogas was to purify the biogas to natural gas quality and sell the product in the renewable gas market. Sale of renewable natural gas is scheduled for early 2021.

Dilution of dewatered sludge centrate, and/or chemical addition to the digesters had long been practiced to suppress struvite formation. Planning studies evaluated the pathways of struvite formation and recommended struvite sequestration to control unintended struvite formation. A struvite sequestration process has been constructed after digestion and before dewatering of the biosolids. This facility was brought into service in the fall of 2020.

Summary: This presentation will detail the key challenges Jefferson County faced in constructing a completely new wastewater treatment plant and collection system. Attendees will gain knowledge of strategies for implementing a large project involving multiple grant funding agencies, as well as bidding strategies for an inflationary climate.

Abstract:

Jefferson County, Washington, is implementing a new sewer utility and constructing a sewer system in the unincorporated area of Port Hadlock, south of the City of Port Townsend. Port Hadlock is a moderately developed rural area that is currently served by on-site septic systems. Jefferson County has worked diligently with the community and with funding partners to develop an affordable project at a sensible scale to provide a financially sustainable wastewater system that meets community needs.

Topics that will be discussed:

• Value Engineering—This project implemented value engineering recommendations to include updated planning requirements and industry advances in modular MBR treatment processes to accommodate “just-in-time” implementation of current and future treatment capacity.
• Equipment Vendor Selection—Jefferson County pre-selected an MBR vendor and contracted a price in advance of construction. This process included a scope of work for vendor design services, flow and treatment design criteria, system expansion requirements, and pricing.
• Construction Contracting Strategy—Jefferson County broke the work into several contracts and phases to ensure bidding opportunities for contractors, to attract bids from local and regional contractors, to ensure competitive bids, and to track and manage the spending of grant funds from several funding sources more efficiently. The project was divided into four contract bid packages: Treatment Plant Site/Civil, Treatment Plant Construction, Pressure Sewer Collection System, and On-Site Grinder Pump Installation.
• Results—The Treatment Plant Site/Civil contract is bidding in March of 2023 and will be under construction by June 2023. By September of 2023, Jefferson County expects to have the Treatment Plant Construction and Pressure Sewer Collection System contracts bid and construction under way. The presentation will describe the status of construction and lessons learned on the processes to get construction initiated.

As we’ve come out of the COVID era, supply chain shortages for many types of materials, equipment, and labor have persisted, increasing the likelihood that your equipment will be significantly delayed, creating missed deadlines and challenging construction. In order to avoid these pitfalls resulting from expected and unexpected long lead times, early procurement has become more critical than ever. Alternative delivery methods such as design-build and CMGC are one way to perform early procurement. However, many owners are unwilling to go to alternative delivery creating a need for a more aggressive pre-procurement strategy for conventional design and delivery (design-bid-build) process. Pre-purchases under conventional delivery are often more challenging than for alternative delivery, adding risks to owners and design engineers. This presentation will identify some of the issues we currently face when taking on pre-procurement, review lessons learned from the good and bad case studies and propose some strategies to increase certainty, reduce delays, maximize the likelihood of a quality product and minimize the risk of pre-procurement.

As owners small and large grapple with generational infrastructure projects to respond to climate change impacts, deteriorated infrastructure and increasingly stringent regulations, more and more are looking to Progressive Design-Build (PDB) as the delivery model of choice. A well-planned, transparent, and organized procurement process rooted in the owner’s priorities and drivers is critical to setting the stage for successful PDB delivery. For those new to PDB, or those who use it infrequently, getting started is daunting; the need for immediate and practical guidance has never been more important. The Water Collaborative Delivery Association (WCDA, formerly the Water Design Build Council) has recently revamped its PDB Procurement Guide, which provides owners with user-friendly RFQ and RFP templates for use as well as advice on how to procure the right PDB delivery partner.

This presentation will provide an overview of the WCDA PDB Procurement Guide and discuss specific activities and best practices to procure a PDB delivery partner, including:

- Appropriate timing of procurement and market engagement activities

- The importance of early development and disclosure of contract terms and risk allocation and providing opportunities for market feedback

- How to tailor RFQ and RFP requirements to match owner goals and objectives

Learning Objectives:

- Understand how early market engagement, tailored RFQ and RFP requirements and confidential meetings increase the likelihood that owners select the delivery partner best suited to tackle their specific project challenges.

- Define the value of securing proposer input on draft contract and commercial terms in establishing a balanced contract and fair allocation of risk – which is critical to setting the stage for successful PDB execution

- Discuss how to incorporate request for pricing information in a way that produces apples-to-apples submissions from Proposers and supports successful project execution.

- Understand what tools exist to support development of quality RFQ and RFP documents

Digital Twins for WWTPs are live, automated process models running hourly with new data from the plant. They can predict the future, assess instruments, recommend control strategies, and be used to evaluate scenarios with high load, tanks down for maintenance, or anything the user can dream up! Through two case stories and a live demonstration, We'll discuss the advantages of digital tools for meeting energy and cost saving targets and upskilling operations staff, and evaluate shortcomings based on the current state of digital twins and sensors for process control with automated calibration.

Advancements in mathematical bioprocess models and data collection, processing, and storage, have significantly improved the successful implementation of real-time management and control of water resource recovery facilities (WRRFs). The integration between online measurements, modelling, prediction, and decision support can be referred to as a Digital Twin. In this abstract, we present the concept and the results of two implementations in Italy and Denmark, both providing decision support towards improvement process, energy and resource efficiency. The Digital Twin in Italy enables stakeholders to evaluate alternative operational strategies and identify the most suitable ones based on process and energy efficiency optimization. The Digital Twin in Denmark incorporates an accurate description of automatic control logics as well as an influent prediction tool, relying on weather forecast, to provide for 48-h predictions of the process status and key-performance indicators. These experiences show the advantages of using Digital Twins alongside conventional operation to improve understanding and management of the treatment plant.

While there may be a long way to go for Digital Twins to be extensively applied, our experience suggests that they can be useful to different stakeholders, from less experienced operators who can be trained in virtual environment, to veterans who can use DT to test and implement advanced control strategies, up to managers who can monitor and evaluate effluent quality, energy consumption and production, use of resources in real-time through a variety of key performance indicators.

Traditional wastewater treatment plant design typically did not solicit the input of Operations & Maintenance (O&M) staff. However, over the last two decades engineers have come to realize the communal experience held by O&M staff. Their daily exposure to performance and reliability issues generates specialized knowledge that many engineers do not possess. O&M staff input can lead to more operable, more dependable, and therefore more efficient and cost-effective plants. Today, O&M staff integration into the planning, design, and construction of wastewater projects is a key component to their success. O&M staff should be giving ample opportunity to provide input throughout a project’s development and be a key voice in the decision-making process to ensure wastewater treatment plants are easy to operate and maintain. Engaging O&M staff early helps engineers understand the nuances of specific plant operations which can be the difference between a good design and a great design Finally, including plant O&M staff in the design of any wastewater treatment project creates a sense of ownership and pride the will be transferred to future staff for years to come. This has never been more present than during the design and construction of the Secondary Treatment Expansion Program (STEP) at the Columbia Boulevard Wastewater Treatment Plant. Starting during conceptual design, plant O&M staff have actively engaged in workshops, campouts, field investigations, documentation review, and the decision-making process. Their input to the project has been invaluable and is a key component to its success. This presentation will encourage audience participation by pulling the audience to the front of the room, incorporating a short icebreaker, asking stimulating questions, and adding a touch of humor. A goal of this feel-good presentation is to give homage to plant operations and maintenance staff everywhere for their continuous efforts in the field to keep our WWTPs running and recognizing the knowledge and often creative solutions they bring to the drawing board.

Clackamas Water Environment Services (WES) owns and operates three pump stations and force mains, constructed in the 1980s, that collect sewage from West Linn, Oregon, and pump it across the Willamette River to an interceptor sewer in Oregon City. One of these pump stations, the 5.0 MGD Bolton Pump Station, includes a 16-inch-diameter ductile iron force main.

The force main experienced breaks in both May 2017 and February 2021 in the heavily-wooded area of Maddox Woods Park. After the second break in the force main, WES faced a decision to either remove many mature fir and cedar trees to replace the section of the force main that had experienced the breaks or realign the pipeline to follow a walking path that increased the static head on the pumps. Knowing the pump station needed additional maintenance and reliability improvements, WES decided to protect the trees and kick off a more comprehensive project.

This presentation will tell the story of the force main repairs and the follow-up evaluation and improvements to increase the pump head limits, increase firm pumping capacity, and replace additional sections of the force main that had significant corrosion. It will outline the approach to provide interim backup pumping, accelerate the schedule to procure long lead equipment, and report on the construction phase improvements. The audience will also learn about the unique system hydraulics and the use of an intertie connection with another pump station to assist with bypassing during construction.

The City of Sandy is a small community (population 11,000) located in the foothills of Northwest Oregon’s Mount Hood. The City operates 38 miles of sanitary mainline pipe, six pump stations, and a single wastewater treatment plant. Challenges facing this wastewater system include influent flows that frequently exceed plant capacity during wet weather, deferred maintenance on the plant, and a limited six-month discharge permit that results in dilution violations during the shoulder months (April and October).

In 2019, the City completed a Wastewater Facilities Master Plan for the City, which recommended balancing investments between improving treatment facilities and reducing flows from the collection system. Soon after the plan was published, the City commenced with an effort to reduce inflow and infiltration (I/I) from their collection system in order to minimize the need for increasing treatment plant capacity. At the same time, the City moved forward with much-needed improvements to the existing plant.

Because of regulatory and development pressures, the City moved forward with an I/I reduction program that leveraged alternative delivery to fast-track the construction, including work on private laterals. The City also implemented a flow monitoring program aimed at demonstrating the success of the rehabilitation to reduce flows. The flow monitoring allows for recalibration of the model and definitive quantifiable evidence of reduction of I/I during peak wet-weather events storms.

Less than four years later, the City has proactively rehabilitated over half of its collection system, including sanitary gravity mainlines and service laterals up to the structures they serve.

This presentation will discuss the planning efforts leading up to the development of an I/I program, the use of alternative delivery to assist with fast-tracked rehabilitation, the monitoring and modeling efforts needed to demonstrate compliance, the actual reductions achieved, and the funding mechanisms needed to finance the work.

ART – FOR THE VITALITY OF THE PUGET SOUND
IF IT HITS THE GROUND, IT HITS THE SOUNDS – A local community-focused stormwater pollution prevention awareness campaign
ABSTRACT –
Every year, millions of pounds of toxic pollutants flow into the Puget Sound. Rain washes yard chemicals, vehicle fluids, pet waste, and more down street drains directly into the Sound. For over ten years, the City of Tacoma has actively participated in the regional Puget Sound Starts Here stormwater awareness campaign, partnering with other NPDES-permitted cities and counties throughout Puget Sound. Yet despite these efforts, in 2017, a community satisfaction survey conducted by the Environmental Services Department indicated that 50% of Tacoma residents still believe stormwater is treated before entering into our waterways. However, in reality, 90% of stormwater is not treated. In 2020, the City of Tacoma, Environmental Services (ES) embarked on a hyper-local stormwater awareness campaign to supplement Puget Sound Starts Here and engage our community through the work of local artists. The campaign is called “If It Hits the Ground, It Hits the Sound.”
Through this campaign, art is incorporated into pavement murals, vehicle wraps, catch basin stencils, t-shirts, and videos, to communicate the impacts of stormwater pollution in more visual and cross-cultural ways. The artistic format is especially impactful because local artists generate the art to raise awareness within their own communities. In addition to art, ES hosted events to create space for community members to learn about the issues and share experiences and ideas. While providing jobs to local artists, the campaign also brings public art installations into underserved neighborhoods, transforming community eyesores into assets, discouraging vandalism, and enhancing pedestrian thoroughfares,
This presentation will describe the genesis of the pilot campaign, as well as the next steps in building on campaign awareness by pointing community members to pollution prevention actions and support resources provided by Environmental Services, evaluating campaign effectiveness, and hopefully soon utilizing GIS data, including Tacoma’s Equity Index map and Watershed Prioritization tool to prioritize neighborhoods for future art installations.

In 2020, The City of Lakewood completed an update to the FEMA hydrologic and hydraulic model for Clover Creek, located in Lakewood, Washington. The update revealed the 100-year floodplain for Clover Creek is significantly larger than previously modeled. The newly identified floodplain has the potential to completely close critical infrastructure, life-safety and commerce routes such as Interstate 5 (I-5), Pacific Highway, Sound Transit rail lines, and transportation routes to Lakewood’s only hospital.

The City of Lakewood completed a planning level study to evaluate potential alternatives and their resiliency, to reduce flood extents and protect existing buildings and infrastructure. The goal of the study was to build a foundation for the development of measures to protect the City and infrastructure through a resilient and sustainable project.

Working collaboratively with the tribes, public, regulating agencies, and impacted entities, the study initially screened and prioritized more than twenty potential options. Once screening was completed, a more in-depth assessment of four mitigation measures was conducted which included: stream and channel enhancements; construction of new levees: one near I-5 or one near the creek; and a do nothing alternative.

The Stream and Channel Enhancement Alternative identified riparian areas and disconnected floodplains that could be expanded and reconnected to enhance the capacity of Clover Creek to reduce flooding and provide environmental uplift. The I-5 Levee Alternative identified a new levee to limit floodwaters from and west of I-5, while land east of I-5 would remain within the floodplain limits. The Clover Creek Levee Alternative is a setback levee that would limit nearly all flooding and protect critical infrastructure providing the most comprehensive flood protection. The Do Nothing Alternative provides no improvements to mitigate flooding likely resulting in a regulated floodway across I-5 and require many owners to secure new flood insurance.

Each alternative was evaluated with basic assumptions and geometry modifications appropriate for each model run, to understand potential benefits/impacts for each alternative. The presentation will discuss how the selected alternative provides the greatest benefit and most resiliency for the City of Lakewood.

An ongoing challenge for municipalities and public agencies is developing long-range capital project cost estimate projections during early planning and conceptual design phases. All too often, initial estimates cannot fully consider the large number of project variables and potential future changes that may impact the completed project. Estimators in the early phases of a project must rely on limited and conceptual scope information that is often subject to speculation, influenced by prior project experiences, and affected by unpredictable market forces.

Historically King County’s Wastewater Treatment Division (WTD) used project request forms to collect project needs and anticipated costs. A review of those projects, from initial budgetary request through preliminary design, revealed cost fluctuations of at least 200% by the time the capital project was constructed and operational, sometimes higher for large complex projects. Further investigation revealed that costs increased due to a combination of limited project definition and unforeseen scope changes, assumption of lowest cost technical options, and lack of inclusion of future external cost and schedule drivers (e.g. environmental permitting, regulatory changes, community relations, constructability). This fluctuation and discrepancy in cost made it difficult to forecast capital borrowing, set utility rates, or better manage the larger project portfolio.

To improve capital project budgeting, WTD developed the Project Formulation Program (Program) and later a Portfolio Planning and Analysis unit. The Program uses a dedicated team and consistent approach to develop a defined project need and objective that can be the basis for a Class 5 estimate. The intent is to identify and evaluate a feasible technical approach and consider the external inputs needed to develop more informed initial, pre-funding estimates. The project’s current scope, assumptions, opportunities, risks, and basis of costs are consistently documented in highly defined cost estimate tools and basis of estimate documents.

Large capital projects move slowly, and few formulated projects have been implemented since the program’s start in 2016. However, recent project estimates appear to be closer to expected actual project costs, leading WTD to consider how best to expand the Program.

The City of Tacoma, like many wastewater utilities in the Pacific Northwest today, is facing big decisions about investments that are needed to meet new regulations, address aging infrastructure, and adapt to changing conditions; the scale of which haven’t been experienced in decades. These decisions will impact the utility, its ratepayers, and the surrounding community for decades to come. However, they also present opportunities to foster understanding of the importance and value of wastewater services, bolster support and buy-in for continued delivery, and prioritize investments in a way that meets broad community values and utility goals.

To support decision-making, the City is developing a Comprehensive Wastewater Plan to balance concurrent investment needs, achieve success in its goal areas, and meet the expectations of internal and external stakeholders. In this presentation, we will review the plan development process and how we are taking broad community values and incorporating them first into utility goals that align with City initiatives and resonate with the community and, second, into measurable technical targets that demonstrate success and can be used for capital planning. At its outcome, success for this planning process means not only developing and implementing a capital improvement plan, but demonstrating to the community that the utility is meeting its commitments in a responsible way that supports broad community values and continues to provide an essential community service.

We will present the comprehensive planning process, the big decisions the City of Tacoma is facing, and the opportunities they have to solve them using transparent and repeatable methods that produce defendable and supported solutions. We will make the case for incorporating broad community feedback into the planning process and show how it sets us up for a sound future.

“Forever Chemicals,” parts per trillion, Health Action Levels, “over 5,000 chemicals,” “found in everyday products”—these phrases are common in articles and communications about PFAS to the public. To the general public, they are hard to put into context. They can be confusing, if not frightening, leading to lots of questions that are hard to answer. With the technical nature of PFAS removal and the developing research about PFAS health impacts, providing clear concise information to the public is challenging.

Meanwhile the water and wastewater industries are working hard to reduce the amounts of PFAS in drinking water, treated wastewater, and biosolids; doing research to know more about risks; and developing and testing new technologies for PFAS removal. It is increasingly critical for the public to understand risks and the steps that their utilities are taking to work on this issue.

There is a strong need for clear, timely, and proactive communication on PFAS removal. Public awareness can build support and the understanding water utilities will need to invest in and implement programs to address PFAS and other future challenges.

Becca Fong and Rachel Garrett will show how using best communications practices creates an increased level of engagement and an understanding of PFAS risk in wastewater and biosolids. They will present examples of how to integrate strategic engagement early in the process, how to work with technical teams to support the development of sound messaging and provide examples of how stakeholder engagement and community outreach work together to create clear, accurate, and timely risk communications for positive outcomes.

PFAS are a contaminant of major concern for WRRFs due to current and imminent state and federal regulations as well as increasing concern from the public. Because WRRFs are not designed to destroy or remove PFAS, source control will be an extremely important mechanism for reducing PFAS concentrations at WRRFs. For effective source control, an understanding of the dominant sources of PFAS to the WRRF is critical. However, PFAS are frequently detected in domestic, commercial, and industrial wastewater discharges with varying concentrations and are complicated by the presence of ‘precursors’ and PFAS-like compounds. A method is needed for identifying and addressing the site-specific dominant sources of PFAS to a WRRF.

While some states have propagated regulations to land-application of biosolids due to PFAS concerns, little is known about the fate of PFAS in land-applied biosolids, and even less is known about the fate of PFAS in land-applied reuse water. To protect the environment as well as protect beneficial biosolids and reuse applications, a better understanding of the fate of PFAS is needed in soils, groundwater, and surface waters.

Since 2019, Clean Water Services (CWS) has been conducting regular PFAS monitoring at the WRRFs, the collection system, and industries. Some of the results of this study were presented at PNCWA in 2022. Since that time, CWS has expanded the monitoring to include soils at biosolids and reuse land-application sites, groundwater at reuse irrigation sites, surface waters around the watershed, and more industries. CWS also has been collecting PFAS data from sewersheds dominated by a single land-use to help identify the dominant sources of PFAS to the WRRFs. Throughout the monitoring, CWS has been working with industries with high measured PFAS and/or high flows to develop PFAS Management Plans. Much has been learned about the contribution of WRRF discharges to the PFAS burden in surface waters, the fate of PFAS in land-applied reuse and biosolids, the dominant sources of PFAS to the WRRFs, and the effectiveness of outreach efforts. This talk will report the findings of these efforts since last year, lessons learned, and our PFAS roadmap for the next three years.

Several WWTPs have been practicing co-digestion with FOG or food wastes to increase biogas production and subsequent energy. A main effect of co-digestion is the impact on biogas quality. Depending on the quality of the organic waste used, co-digestion may alter the concentrations and/or introduce additional impurities to the biogas. Such change in biogas quality can impact (i) compliance with regulatory requirements and (ii) treatment needs for various end uses of biogas such as co-generation, vehicle fuel, and pipeline injection. However, limited to no information is available on complete characterization of biogas produced from co-digestion of different feed stocks with wastewater sludge. The Water Research Foundation (WRF) project focused on investigating the relationship between a wide range of organic wastes and the resulting biogas quality from their co-digestion. This presentation will highlight: field and bench scale co-digestion of wide range of organic wastes and impact on biogas quality and quantity, complete biogas characterization including major components, siloxanes, VOCs, alkanes, ketones etc, guidance to estimate emissions more accurately from co-digestion and evaluation of biogas quality parameters to assist with permit compliance.

Clean Water Services (CWS) is pursuing an opportunity to use available digestion capacity of the Rock Creek Water Resources Recovery Facility (WRRF) by developing a Co-digestion Program. This program serves two purposes: (1) it allows CWS to better serve the district by creating and strengthening relationships with surrounding industries as well as with local contributors that can provide High Strength Wastes (HWS) and, (2) it increases the overall biogas generation to a quantity that allows CWS to consider Renewable Natural Gas (RNG). This is mutually beneficial, as this service can lower the discharge costs of the industries’ byproducts and their environmental impact. Furthermore, our biogas system infrastructure is aging, which makes shifting to RNG and partner with Northwest Natural an attractive prospect.

Multiple groups within CWS are collaborating in this program to systematically identify, characterize and select wastes that can contribute to gas production goals for RNG without compromising digestion capacity and stability. The evaluation process consists of:

1. Defining the capacity of the system and gas production goals. This has allowed us to stablish an initial requirement of 4.4 ft3of gas/gallon of HSW.
2. Identifying sources of HSW within our service district. We engage with contributors to determine the reliability of their practices and consistency of their product.
3. Assessing potential impacts to operations and maintenance of the digesters, and infrastructure requirements. This is achieved through: a) novel bench-scale testing approach, b) pilot testing and, c) evaluation of the physical characteristics of the HSW.
4. Selecting the HSW and negotiating with suppliers.

This presentation will focus on the challenges associated to implementing this program, which include: coordinating efforts from multiple groups within and outside CWS, pushing a recalibration of the organization’s culture to get staff buy-in, and to make data-driven decisions based on results from relevant testing. Additionally, we will talk about our operational experience using fats, oil and grease at the Durham WRRF that has helped define our HSW selection criteria.

Anaerobic digesters are typically operated with limited process information and rely on industry standard values and long detention times to minimize the impact of any perturbations. Understanding the risk of failure is particularly important when these are operated under variable loading conditions or close to their design capacity. Our ability to identify the causes of upset events and remedy them, is affected by the limited number of online parameters that can be used to characterize digestion performance, the restricted ability to make visual inspections, and the use of laboratory measurements that can sometimes be unreliable and take time to be completed.

Over the previous years, Clean Water Services has developed and implemented a bioassay to monitor the digesters of the Durham and Rock Creek Water Resource Recovery Facilities to better understand digestion performance and health as it relates to capacity. The bioassay consists of measuring the ability of the microbial communities to use a key intermediate over time, such as acetate, and can help identify conditions of stress caused by organic or hydraulic overloading. The indicators generated can provide a unique insight about operational strategies that help maintain stability. This bioassay has been proven to be reproducible, relatively easy to implement, and it can generate indicators of digestion health within 12 hours.

The experimental development of the bioassay and initial results were presented at the Pacific Northwest Clean Water Association Conference in 2022. This presentation will include an evaluation of the bioassay indicators against conventional full-scale operation metrics and will focus on addressing the following questions:

- What are some of the challenges CWS has had using traditional metrics to identify unstable conditions?

- What are some of the insights that have been generated from using the bioassay over the past year of operation?

- How can these indicators enhance the information provided by conventional metrics?

During water resource recovery, primary and secondary solids are commonly stabilized in anaerobic digesters utilizing bacteria to convert organic materials to biosolids and biogas, both having beneficial uses. The digestion process runs optimally with near uniform conditions, requiring complete mixing of digester contents with minimal short-circuiting and maintaining contact between the tank active biomass and incoming feed. Mixing efficiency is assessed post construction through tracer testing, and measurement of temperature and solids profiles. Industry has reported similar levels of mixing for a wide range of power inputs and types of mixing systems. Oversized mixing systems lead to high construction and operating costs, while under-sized systems lead to subpar performance. Understanding mixing in a more fundamental way can reduce costs while delivering desired performance aiding in design of right-size mixing systems that reduce energy consumption while maximizing biogas production and organics destruction. In addition, newer types of mixers have entered the market that may have high efficiencies. Understanding actual mixing provided by systems allows designers and utilities to compare technologies, determine the limits of mixing innovation, and ultimately select the best solution that balances cost, performance, and risk. A recent new digester installation in South San Francisco used two different mixing technologies in two otherwise similar tanks and included detailed startup testing, providing ideal data for developing computational fluid dynamics (CFD) modeling approaches to study internal mixing details.

CFD is a promising tool to optimize mixing system selection and design, as it allows us to “see” inside the tank, visualize the mixing, identify dead spots or areas of over-mixing, and provide an easy platform to customize and compare different technologies or designs. Development of CFD models for different types of mixing systems and comparison of model outputs to actual field-produced data could allow for refinement of this tool and for expanded use in digester system design and optimization. This talk will focus on the development of CFD modeling approaches for evaluating digester mixing. Key physics will be reviewed. Model results will be presented comparing model simulated mixing with field measurements.

Anaerobic digesters are the most common solids stabilization technology in municipal wastewater treatment facilities. Although they are relatively low maintenance, routine cleaning every 5-10 years helps maximize performance and prolongs the useful life of the tank. However, restarting a digester is a complex process requiring careful oversight and detailed knowledge of the plant processes. This presentation will cover best engineering practices for taking a digester out of service and restarting the process safely and efficiently. Stopping and restarting a digester require careful coordination of digester gas, mechanical processes, solids management protocol, and digester biological health. Specific procedures vary depending on the presence of other operating digesters, fixed vs floating covers, the type and quality of solids produced at the facility, and other factors. Step-by-step instructions for managing digester maintenance will be provided, along with a case study of a recent digester startup.

The Grant’s Pass Wastewater Treatment Plant in Oregon recently restarted their digester using seed sludge from a nearby wastewater treatment facility. The startup presented several challenges, including concurrent upgrades to the digester heating system, cold weather, and a floating cover digester. To maintain safety, a water seal was formed using primary effluent and seed sludge was added to the digester in batches over a two-week period. A temporary recuperative thickening process was installed to expedite the startup process. Key digester health parameters such as digester gas production, digester gas characteristics, volatile acids, alkalinity, etc. were tracked to guide the startup process.

The toxicity of copper depends on complex water chemistry interactions. Water bodies with low ionic strength, organic carbon, and pH can have relatively low copper water quality criteria, resulting in associated low effluent limits for water resource recovery facilities (WRRFs) discharging to them. The Forest Grove WRRF faces low effluent copper targets owing to the water quality characteristics of its receiving stream. Clean Water Services (CWS), which operates the WRRF, conducted a study examining opportunities through source control, design, and operations to ensure that discharges have no reasonable potential to contribute to a water quality standards exceedance.

Further reducing WRRF effluent copper at low levels is challenging and some mechanisms are not well understood. Approaches explored at various facilities have included decreasing loadings from the collection system, solids retention time adjustment, chemically enhanced primary treatment, pH control, and use of targeted chemical precipitants in secondary clarification.

In this study, researchers analyzed historic operational data and conducted full-scale sampling, bench testing, and pilot testing to develop a multi-pronged copper strategy incorporating source control, enhanced treatment, and adjustment to effluent quality. Copper loading data was evaluated to determine the potential impact of enhanced source control on influent and effluent copper. A ten-year dataset was reviewed to analyze and compare removal efficiencies in different treatment processes at the four WRRFs operated by CWS. Additional sampling was carried out to study primary and secondary treatment copper removal during high flow events and to characterize concentrations in mixed liquor suspended solids. A full-scale pilot test of effluent pH control was conducted to determine the impact on copper toxicity thresholds calculated via the Biotic Ligand Model. In addition to full-scale monitoring, jar tests were conducted to evaluate the potential for chemical addition to enhance removal of dissolved and particulate copper in primary and secondary clarification. Trials were also run using settling columns to compare copper removal between bench and full scale and to estimate the copper removal performance of future clarifiers at a range of surface overflow rates.

This presentation will discuss full-scale and bench-scale findings and the resulting approach being pursued for effluent copper management.

Trickling filters have been used in wastewater treatment for more than 120 years and has evolved into a modern solution to meet today’s wastewater treatment needs. Major changes including introduction of lightweight, high-surface-area plastic media and speed control distribution have significantly improved the treatment efficiency of trickling filters. Yet with all these changes, there has been little increased understanding of the added capability provided by TFs. Information from design engineers and end users on trickling filter improvements has been largely unrecognized or poorly reported. Myths of trickling filters may have influence design engineers. This presentation provides an comprehensive overview of the major changes of trickling filter design and clarifies the common misconceptions and myths about trickling filter technology.

This presentation also discusses energy efficiency and carbon footprint based on an extensive literature review. Energy consumptions data from several wastewater treatment plants in the states of Hawaii, Washington, Virginia and Georgia with different biological treatment technologies will also be summarized and analyzed.

An innovative trickling filter system will also be introduced in the presentation. Bethel Park wastewater treatment plant in Pittsburg area, Pennsylvania has two trickling filters in series, which were retrofitted from the original rock filters. Significantly improvement of nitrification has been observed since the retrofit in 2010. Annual average ammonia-N concentration in the effluent has been consistently less than 1 mg/L. A high level of nitrification can be achieved at an ambient temperature of 0 ◦F. The improved nitrification performance can be attributed to the improved oxygen transfer and heat retention features of the system. Dissolved oxygen (DO) in the trickling filter system effluent has consistently been close to saturation or oversaturation. The DO-rich environment promotes nitrifier growth and results in a higher level of nitrification.

Modern trickling filters are environmentally friendly and reliable biological treatment systems that should be given full consideration in 21^st century wastewater treatment plant design. With proper engineering, operation, and maintenance, trickling filters can provide many years of simple, effective, and low-cost treatment.

This presentation will examine the use of disc filters, continuous backwash granular media filters, and compressible media filters at three different facilities. Each case study will provide an overview of the technology and discuss why the technology was selected, project objectives, how the system was designed, how the system is/will be operated, measured/expected performance, and unique challenges for the application. The first case study is addition of cloth disc filters at the 5.6 MGD Redondo WWTP owned and operated by Lakehaven Water and Sewer District, which completed construction in 2022. The Redondo WWTP utilizes primary clarifiers, trickling filters, and secondary clarifiers followed by UV disinfection for treatment. The second case study is improvements to enhance performance of existing continuous backwash granular media filters at the 12.7 MGD City of Marysville WWTP, which is currently in construction. The Marysville WWTP utilizes lagoons for biological treatment and UV light for disinfection. The final case study will be replacement of existing continuous backwash granular media filters with compressible media filters at the 2.8 MGD City of Snohomish WWTP, which is currently in design. The Snohomish WWTP utilizes lagoons with submerged fixed-film media for biological treatment and peracetic acid for disinfection.

Base Infiltration (BI) can substantially hinder a collection system’s ability to convey wastewater. It is a capacity thief hiding in plain sight that operates 24 hours a day. Wastewater flows from some basins evaluated by the author have been found to be comprised of more than 60% BI. The expanding interest in modeling the performance of collection systems over extended periods has enhanced the need for more accurate estimates of BI contributions. Also, with the expanding popularity of trenchless rehabilitation methods, there is an increasing need to verify post-construction BI reductions. However, there is no clear-cut universally accepted method by which to determine or otherwise verify degree of BI from collection system basins.

This presentation addresses four empirical methods used to determine degree of BI based on sewer flow data, including % Minimum Method, the Wastewater Production Method, the Stevens-Schutzbach Method, and the Min Factor (Mitchell) Method. Each method is evaluated using 45 case study system basins. The basis and assumptions of each method will be shown. These empirical methods were tested against a chemical parameter verification method that involves regressing hourly parameter concentrations (TOC, BOD, TSS, and COD) with sewage flow rates; regression graphs of which will be presented.

The simple-to-use empirical Stevens-Schutzbach equation is recommended as a universal, yet conservative BI quantification Method and the Min Factor or Mitchell Method is based on WEF guidance and considered to be an accurate and defensible method.

The City of Bellingham’s Roeder Lift Station is located near the industrial area along Bellingham Bay and serves much of the northern part of the City. The existing lift station was suspected to be operating under reduced reliability conditions during peak storm events. The City contracted with Carollo Engineers to complete an alternatives analysis and design to increase the existing lift station’s pumping capacity from approximately 8 million gallons per day (mgd) to 18 mgd.

The existing dry-pit/wet-pit station is located on a small city-owned parcel of land surrounded by Port of Bellingham (Port) and Burlington Northern Santa Fe (BNSF) railroad properties. The station’s existing 18-inch diameter force main is routed through a City utility easement on Port and BNSF properties including crossing under a BNSF spur track to reach the discharge manhole location. Two lift station retrofit alternatives and one new submersible lift station alternative were evaluated, including installation of a parallel force main alternative. The selected alternative included a new submersible lift station 1,100 feet northwest of its current location. The lift station design included a combination of variable speed driven non-clog submersible pumps and screw centrifugal pumps in self-cleaning pre-rotation basins with a pumping range of 1 to 18 mgd. Other improvements included 2,500 lineal feet of parallel 14-inch and 28-inch diameter force mains with trenchless installation beneath the railroad, installation of a 36-inch diameter gravity sewer main and manholes, and miscellaneous 24-inch diameter water main replacement.

One of the challenges of designing the new lift station included impacts from the 100-year flood plain, sea level rise, and the potential for tsunami flooding. Based on available mapping, the location of the new lift station is within the FEMA 100-year flood plain and the Tsunami Design Zone. The FEMA flood maps do not take into consideration future long-term change due to climate change and the rising sea level. In addition, the project needed to consider impacts related to potential tsunami flooding. As such the new station was elevated 9 feet above the existing grade. This presentation will summarize the analysis and design related to the proposed improvements.

Equipment can vibrate when not properly installed. Many times, the root cause of the problem is incorrect installation of the equipment base to the concrete foundation – which was the situation for the case study that this presentation will cover.

Initially, the team removed the old steel base, put in a new stout base, and installed it properly with jack screws and high-strength flowable grout. While this seemed, at first, to solve the problem, over the course of 8 hours, the vibration on the pump increased and the pump had to be shut down.

The engineering team and client maintenance staff then decided to bring in the “big guns” and performed a vibration and modal analysis of the newly rebuilt pump, as well as three other pumps (700 HP and two 1000 HP pumps).

The three major issues identified were: 1.) Grout holes in the steel base but no grout visible in the grout holes or smaller vent holes; 2.) The base was not level and exceeded the Hydraulic Institute/ American National Standards Institute (HI) and American Petroleum Institute (API) criteria of 0.004 inches; 3.) Leveling nuts were used to level the steel base frame. This held the steel frame in the air with no solid support.

This presentation will focus on the vibration equipment used, the data collection methods employed, and the analysis performed to determine the cause of the excessive vibration of the pump bearings.

The current National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permits in Oregon (Permits) include significant new requirements for stormwater design standards that impact the design feasibility, facility footprint, and effectiveness of stormwater facilities. The Permits require prioritization of low impact development, green infrastructure, and retention in stormwater design standards. For retention, permittees are required to develop a Numeric Stormwater Retention Requirement (NSRR) that retains stormwater onsite and minimizes offsite discharge of pollutants. This presentation will cover methods and data assumptions used in evaluating local rainfall data to identify appropriate design storms for sizing Permit-compliant stormwater retention and water quality facilities.

For one permittee, an NSRR design storm was selected using the annual average runoff-based method to retain 80 percent of annual average runoff. The analysis considered hourly rainfall data from two local gages. The design storm was estimated using two rainfall analysis methods for comparison: a rolling 24-hour method and a storm-event method. The results were sensitive to the analytical methods and the assumptions used as input parameters for those methods such as inter‑event times and period of record from the two local gages. Design storm results differed in size by as much as three times.

For another permittee, after completing a rainfall analysis, a sensitivity analysis was conducted to look at the impact of a proposed NSRR on stormwater facility footprints for scenarios that included a range of infiltration rates, drawdown time limitations, and development types. Facility footprints varied by as much as four times depending on the scenario.

The selection of a design storm for onsite retention requires an understanding of the nuances and significant implications related to different rainfall analysis methods and associated assumptions. It is also important to understand the development characteristics where the retention design storm will be applied. Design storm selection based off a clear understanding of methods and assumptions will best support goals for sizing facilities. This will allow facilities to meet requirements for runoff treatment, address feasibility constraints for implementation, and right-size facilities to effectively manage stormwater runoff and protect water resources.

The questions we ask and answer in the planning and design of stormwater retrofit projects fall into two general categories:

1) What do we need? We usually call this planning.

2) What do we get? We usually call this design.

In stormwater management the answer to what we need is rapidly changing. When many of our storm systems were first built the answer was “we need to get water away as quickly and as cheaply as possible to prevent flooding.” Today, the answer is closer to “we need a multi-use solution to retain water on-site, limit impact to surface and ground water hydroperiods, reduce pollution and erosion to protect and enhance our natural and built environments, provide community assets for place-making and access to greenspace, and prevent flooding.”

When our understanding of what we need is rapidly changing, it is challenging to set goals at the beginning of projects because we don’t know what we can get, especially in highly constrained built-out environments with limited space. The goals must adapt and evolve through the design process. Therefore, the success criteria are less goal oriented, “Did we meet our goals?” and more process oriented “Did our process optimize our solution for functionality and value?”

What we need versus what we get are the two rails of communication that must be advanced together to navigate a successful project with multiple and competing constraints and goals. If one rail gets too far ahead of the other then progress can easily be stalled, sidetracked, or derailed. So how do we tie these rails together to get what we need? We usually call this modeling.

Recent stormwater management planning and design projects will be used as case studies to discuss how modeling practices such as initial conceptualization, identifying constraints and boundary conditions, making explicit simplifying assumptions, and identifying the right approach and level of detail at the right time can be used to determine if we can need less, or if we can get more to achieve successful project outcomes.

Hydrologic and hydraulic models are typically deterministic, making assumptions about input parameters and calculating a single result for each output. However, this simplification may result in cost-increasing overly conservative assumptions. Additionally, this approach is unable to quantify risk presented by low probability events.

For example, ODOT’s guidance for inlet spacing calculations is to use either 30% or 50% as a clogging factor, depending on inlet type and location. Wouldn’t it be nice to know how resilient a collection and conveyance system is if some inlets are more substantially clogged during large storms?

In this talk, Seth will present the basic theory of probabilistic/stochastic approaches to modeling and disucss some applications this is already considered best engineering practice. He will show examples using Monte Carlo simulations with common tools like EPA SWMM and HEC-RAS to create probability curves of the model outputs. The talk will include specific references to open-source Python toolkits that will help others considering creating probabilistic models.

Finally, the talk will address potential uses including risk informed decision making processes, especially with regards to climate change risk, and sensitivity analysis applied to existing deterministic models. It will also discuss some of the limitations of this approach and seek feedback from the audience members who may use similar approaches.

Public agencies and technical teams are being tasked with integrating equity into the planning and design of infrastructure projects. Even with good intent, teams often struggle to identify how a project interfaces with vulnerable communities and what changes can be made to improve outcomes for those communities. Equity in Design provides a process for identifying a project’s equity interfaces and developing a solid plan for integrating these interfaces into the planning, design, and delivery of the project, resulting in positive outcomes for vulnerable communities.

The Alderwood Pump Station Replacement project, which is a current task order for Brown and Caldwell (BC) under the Price Agreement for Pump Station (PS) Improvement master services contract with the City of Portland (City), is the pilot project for the City to develop an Equity in Design framework. Our subconsultant, The Formation Lab (TFL), identified potential equity interfaces for this project, including minimizing conflicts with the houseless community, supporting pedestrian access, and supporting bicycle access. Based on these interfaces, equity criteria were developed for use in the site selection process. These interfaces are the foundation of the Equity Plan, identifying key actions and milestones for fostering equitable decisions during the design and construction phases, as well as supporting COBID (Certification Office for Business Inclusion and Diversity) certified team members during project delivery. The Equity Plan is a living document that is refined during the project to guide the Consultant team, led by BC, in meeting the City’s equity goals.

This presentation will share the Equity in Design approach, and lessons-learned through the pilot application of this approach, to the Alderwood Pump Station Replacement project.

Decisions that operators, engineers and managers make are typically financially constrained. An intuitively good project idea can prove difficult to justify when using only net present value and similar financial tools to demonstrate return on investment (ROI). This is where the concept of “Real Options” comes into play. By identifying the characteristics of an option and assigning a financial value and probability to its selection or rejection, the decision maker gains insight into the decision that would otherwise be missed.

During this presentation, you will learn:

• What is a financial option, and how does it relate to a Real Option
• Types of Real Options and how to spot them
• Three methods to value a Real Option
• A rigorous approach to calculating probabilities of outcomes
• Case studies to support where Real Options have been used to support project decisions
• Case studies showing where Real Options could have been used for more favorable outcomes.

Clean Water Services (CWS) operates three water resource recovery facilities (WRRFs) that are subject to thermal load and daily maximum 1-hour average effluent temperature limits under their watershed-based NPDES permit. Current compliance strategies include water quality trading, flow augmentation, wetlands treatment, and riparian shade and recycled water programs. The recent discovery of the invasive emerald ash borer is expected to decimate the population of Oregon ash trees, a major riparian shade species. To expand their temperature management portfolio and compliment these “outside the fence” strategies, CWS is conducting studies to better understand temperature dynamics in WRRFs and explore potential “inside the fence” mitigation strategies.

Several models have been published that account for the major heat gains and losses from the activated sludge process. These models were reviewed and adapted into a spreadsheet that allows the temperature dynamics of each unit process in the WRRF to be modeled. The model was calibrated to three months of data collected at the Durham WRRF.

The calibrated Durham temperature model shed light on the relative contribution of each unit process to the overall thermal balance of the WRRF and was used to identify the most significant heat sources and losses in each. The aeration basins were the largest contributors to increased effluent temperature. The secondary and tertiary clarifiers gained heat during the day and lost it overnight. In contrast, the covered primary clarifiers largely followed the influent temperature with less extreme daily temperatures.

Basin shading was explored as a potential peak hour effluent temperature mitigation strategy. First, solar radiation was reduced by 90% in the model, which suggested peak hour temperature reductions > 0.5°C were possible. Second, a two-month pilot study was conducted at the Rock Creek WRRF. Two basins were evaluated side-by-side. One was left uncovered while the other was covered with a shade cloth with a 90% UV reduction rating. The peak effluent temperature from the shaded basin was lower than the unshaded basin by 0.2°C on average.

This presentation highlights the insight gained from temperature modeling in WRRFs and highlights basin shading as a promising low-capital, low-energy temperature mitigation strategy.

Clean water agencies, regulatory agencies, and watershed stakeholders are searching for innovative approaches and best practices to address water quality challenges due to nutrient enrichment and a changing climate. Through a series of interactive workshops in three different geographic regions, this Water Research Foundation project developed a framework to advance nutrient management that fosters innovation and new opportunities. The project goal is to focus on approaches that may be applied nationally and tailored to address unique water quality improvement needs and varying watershed contributions from point and nonpoint sources.

The culmination of Water Research Foundation Project No. 4974 is a new framework to improve holistic watershed nutrient management through Practices, Policies, and Partnerships. "Practices" refers to the technical considerations related to nutrient removal wastewater treatment, best management practices for nonpoint sources such as stormwater and agricultural land uses, and nutrient processing and impacts on receiving water environments and the atmosphere. "Policies" refers to the regulatory, institutional, and administrative aspects that govern nutrient management. This includes nutrient discharge permitting and compliance with receiving water quality standards, as well as watershed management requirements. "Partnerships" refers to the potential for collaboration, building relationships and trust, and leadership in nutrient watershed management. This includes consideration of diverse stakeholders with varied interests that may, or may not, be aligned.

This nutrient management framework provides a structured process with key success factors that can be tailored to develop holistic watershed-based nutrient reduction plans. Balanced nutrient reduction plans that integrate practices, policies, and partnerships should yield more effective and efficient implementation focused on consensus-based outcomes that provide greater net environmental benefits. The framework also provides a diagnostic lens to identify missing elements of existing nutrient reduction efforts that have not achieved planned outcomes.

Impacts of climate change and environmental justice (EJ) challenges were overarching themes that are addressed through this framework and within each element. Climate change complicates water resources management in multiple ways, from extreme weather events to potentially more significant responses to waterbody nutrient inputs (e.g., harmful algal blooms). The overarching issue of EJ spans all three nutrient management factors (practices, policies, and partnerships).

The production of biogas, a renewable resource, was increased using the microbial hydrolysis process (MHP) with anaerobic digestion. Anaerobic digestion performance was enhanced with the MHP using Caldicellulosiruptor bescii (C. bescii), a hyper-thermophilic bacterium. The innovative MHP enhances any anaerobic digestion process by adding a bioaugmentation stage. Digestate from an anaerobic digester (AD) is fed to a hydrolysis tank populated with C. bescii for a hydraulic retention time of 2 days at 75 degrees Celsius (C). The C. bescii hydrolyses cellulose and other recalcitrant volatile solids that are otherwise resistant to digestion into volatile acids. These volatile acids are returned to the AD where methanogens convert them into biogas. MHP was tested at lab-scale and pilot-scale with anaerobic digestion of solids from three water resource recovery facilities (WRRF). The three WRRFs were the City of Gresham Wastewater Treatment Plant in Gresham, OR with mesophilic anaerobic digestion (MAD) and fats, oils, and grease (FOG) addition; Encina Water Pollution Control Facility (WPCF) in Carlsbad, CA with MAD; and Oakland County’s Clinton River WRRF in Pontiac, MI with thermal hydrolysis process (THP) and MAD. These WRRFs had high performing full-scale AD systems averaging 58-60 percent volatile solids reduction (VSR). A test AD system with MHP was compared to a control AD system without MHP. The addition of MHP enhanced the AD performance of all three WRRFs from a VSR of 60 percent to over 75 percent. Enhanced performance would result in a 25 percent increase in biogas production and corresponding reduction in biosolids production. A conceptual design was completed for implementation of MHP at VCS (VandCenter) Denmark’s Ejby Mølle Water Resource Recovery Facility (EMWRRF). A calibrated whole-plant model was used to evaluate MAD performance with and without MHP. The model incorporated VSR results from lab-scale and pilot-scale testing of MHP. Results of modelling at EMWWRF predicted an increase in VSR from 55 to 75 percent corresponding to a 36 percent increase in biogas production.

“Empresa de Acueducto y Alcantarillado de Bogotá (EAAB)”, Bogotá, Colombia, is responsible for the implementation of the Bogotá River Sanitation Program. EAAB currently operates the 90-MGD Salitre WRRF, located on the north end of the city, which is undergoing an upgrade to expand its capacity to 160-MGD. This plant will treat 30% of the city’s wastewater. EAAB recently completed the design of the 370-MGD Canoas WRRF, to be located in the southern end of the city. The Canoas WRRF will treat the remaining 70% of the city’s wastewater, with a total service area population of 7.2 million.

The Canoas WRRF secondary treatment facilities designed include activated sludge step-feed aeration, secondary clarification, and chlorine disinfection. The associated solids train include sludge thickening, sludge pre-dewatering, thermal hydrolysis process (THP), anaerobic digestion (AD), biosolids dewatering, beneficial utilization of biosolids and a Biogas Co-generation facility.

The solids line for the Canoas WRRF was designed with two main objectives: 1) minimize Biosolids production, 2) maximize beneficial utilization and energy recovery.

A critical component of the solids train is the THP/AD system. This process allows less sludge to be generated versus conventional anaerobic digestion, given the greater VSS destruction and improved sludge dewaterability, generating biosolids which can be classified according to its pathogen content as Class A biosolids. This baseline design scenario was later compared with other biosolids minimization processes (thermal drying, solar drying, and incineration, among others), together with a preliminary market study of potential uses of the end product, to determine the most cost-effective solution.

The design also considered biogas utilization for onsite co-generation. The use of Combined Heat and Power (CHP) is anticipated to utilize the biogas for electric energy generation as well as production of the steam required for the THP system. An estimate of 12 MW of electrical power will be generated to cover plant uses (close to 2/3 of the plant’s electrical power requirements). Heat from the exhaust gases of the turbines will be recovered and used to produce the vapor needed for the THP, thus maximizing the energy recovery in the plant, and saving critical electrical energy costs.