Conference Agenda

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.

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.

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.

Looking to improve cybersecurity and SCADA system resilience, the cities of Gresham and Medford used a holistic approach to match funding opportunities with their capital projects. With so many funding opportunities, it can be overwhelming to determine where to focus, especially when the newer programs from recently passed legislation are still developing the rules and guidelines. This presentation will give an overview of both agencies’ successes and share lessons learned that will benefit other municipalities.

Federal water infrastructure funding opportunities include Water infrastructure Finance & Innovation Act (WIFIA), Infrastructure Investment & Jobs Act (IIJA), FEMA Building Resilient Infrastructure and Communities (BRIC), Inflation Reduction Act (IRA) of 2022. There are also state and local utility programs for renewable energy and energy efficiency. In Oregon, funding opportunities includes the Water/Wastewater Financing Program and Special Public Works Fund (SPWF) through Business Oregon; the Clean Water State Revolving Fund (CWSRF) through the Oregon Department of Environmental Quality; the Community Renewable Energy Grant Program through the Oregon Department of Energy; and multiple renewable energy/efficiency programs through the Energy Trust of Oregon.

Capital program assessments documented eligibility, available funding options, terms/interest rates for loan programs, and local match requirements. Projects were categorized and ranked with regards to funding evaluation criteria, including security, resilience, and renewable energy.

For Gresham, their Digestion and Cogen project has a waste-to-renewable-energy focus, so that effort included an assessment of the various federal and state programs including the new Renewable Energy Generation Tax Credits under the IRA. Applicable funding was integrated into the business case evaluation to guide selection of a renewable energy approach to provide the City with the most value.

For Medford, a formal BRIC grant application was developed requesting $22M for seismic upgrades and backup power to reduce natural hazard risk. They will also apply for additional funding to improve cybersecurity and resilience of the SCADA system.

The City of Tacoma Environmental Services Department (City) maintains over 800 miles of wastewater sewers, 45 pump stations, and two wastewater treatment plants including the 60 MGD regional Central Wastewater Treatment Plant (CTP). In November 2015, a 15-minute power outage at the CTP resulted in a sanitary sewer overflow, discharging untreated sewage to the environmentally sensitive and commercial waters. Immediately after the event, the City commissioned Carollo Engineers to prepare an Electrical System Analysis Study that showed that CTP’s medium voltage electrical infrastructure was past its anticipated design life, did not provide independent redundancy, and could suffer a catastrophic outage leading to dangerous emergency situations threatening plant staff and the environment. The City prioritized and implemented the first level of recommended improvements including operating the plant with split power feeds and eliminating single points of failure at several process areas.

Subsequently, the City decided to build new infrastructure that provides independent electrical feeds, replaces the aged switchgear infrastructure, and eliminates other identified single points of failure. Advertised for construction in March 2020 and substantially completed August 2022, this joint City/Carollo presentation will address how this $33 million Electrical System Upgrade project overcame several key challenges during implementation:

1. Construction throughout a built-out site – includes replacement and centralization of the main plant switchgear, construction of a new electrical building, and routing of over 3,000 LF of concrete encased, medium voltage electrical duct banks.
2. Funding – low-cost loans from WIFIA and SRF programs. Project is one of the first complete WIFIA projects in the nation.
3. Keeping plant operational – planning between contractor, owner, and engineer to implement 74 power and utility cutovers impacting every process at the operating plant.
4. Construction during COVID-19 pandemic – partnership with contractor to keep the project on schedule and budget.
5. Easement negotiations – easement modifications and land acquisition with USACE and private railroad.

As utilities strive to perform efficiently while maintaining compliance with fewer resources, the importance of a reliable SCADA system in today’s cyber security environment has increased dramatically over the last ten years. Major upgrades to these critical systems is driven by component obsolescence, evolving industry standards, demand for new features, and requirements for increases in system resiliency and cybersecurity. System upgrades often include improvements to programmable logic controllers (PLCs), SCADA HMI graphic systems, communication infrastructure, network and computer systems, and even facility improvements to construct secure server and control rooms.

Implementation of SCADA improvements in existing operating process systems not only requires careful planning, design, and significant investments in material, construction, software programming labor, and field testing, but also educating managers and elected officials. In today’s environment, additional challenges with long material lead time and price inflation add complexity to management of project budgets and schedules.

Clark Regional Wastewater District (Vancouver, Washington) used a multi-phase, multiple-year, programmatic approach to perform SCADA system upgrades at the Salmon Creek Wastewater Treatment Plant. The initial project replaced the plant’s obsolete PLCs with a new state-of-the-art Allen-Bradley ControlLogix platform. The second phase constructed network improvements, including replacement and reconfiguration of the plant’s aging fiber optic cable, construction of dedicated and secure server and control rooms, and implementation of new network and computer systems. A final project phase is replacing the plant’s existing SCADA graphics with a new Inductive Automation Ignition platform, including configuration of all new graphics. Each phase provided updated system documentation to support long-term O&M. The work required significant planning for scope development, budgetary approvals, and implementation phasing, but the outcome has been overwhelmingly successful. The utility is currently working on projects to upgrade SCADA systems at their other wastewater facilities to apply the approaches from their Salmon Creek Treatment Plant as a uniform standard.

As data volumes and reporting requirements increase, municipal wastewater utilities are faced with a rapidly changing technology landscape. A comprehensive data management master plan (DMMP) can provide strategic guidance for utilities grappling with core data topics such as governance, architecture, quality, security, integration, and analytics.

Development of a data management master plan can be a time-consuming process that delays integration of systems and delivery of business intelligence products. This presentation identifies practical approaches to efficiently developing a DMMP for utilities covering a broad spectrum of technology readiness levels. The key to selecting the right approach is to calibrate the process to match the utility’s needs and capacities.

A traditional structured process will typically feature identification of data sources, ownership, responsibilities, data maintenance workflows, quality requirements, and governance policies. This is followed by the design of a data architecture that ensures data integrity, security, and accessibility while meeting the end user’s analytical, reporting, and dissemination needs. The design should consider both existing and planned data repositories and associated software tools, and often features a platform evaluation component. Finally, a DMMP includes a roadmap for recommended data system improvements that provides sufficient time for procurement, development and testing and considers options for phased or incremental development focusing on priority reporting needs first. On the human side, the roadmap should include training, change management, introduction of field computing tools, streamlining of workflows, and stewardship.

Utilities seeking to accelerate the delivery of improvements to daily planning, operations, and reporting may consider a streamlined approach in which data system integration and analytical tool development proceeds concurrently with data management master planning. This approach is more tangible for system stakeholders as it focuses on the delivery of functioning data tools rather than the codification of abstract principles.

This iterative and collaborative approach is particularly suitable for utilities that have multiple core enterprise data silos but lack a comprehensive data analytics platform. By leveraging commercial off-the-shelf software and platforms, data from these enterprise sources can be transformed and stored in managed, curated, and reliable datasets. These datasets can then serve a wide array of downstream needs.

Many WRRFs do not have consistent or sufficient VFA content available in the influent wastewater because of a low organic content or seasonal variability of the influent characteristics. The lack of influent VFA content has driven facilities to modify plant operations to generate their own VFA, utilizing embedded carbon, ensure consistent EBPR and maintaining low effluent phosphorus concentrations.

This presentation reviews two WRRFs that recently upgraded their traditional anaerobic selectors to inline fermentation reactors to produce VFA and improve EBPR.

In November 2021, South Granville Water and Sewer Authority in NC upgraded their anaerobic selector to an intensified fermentation tank by alternating a short mixing cycle with a long non-mixed deep anaerobic cycle. The generation of additional VFA lead to the proliferation of PAOs, which stabilized the EBPR process, resulting in lower and more consistent effluent total phosphorus. In addition, the plant realized a 90% reduction in mixing energy demand for the anaerobic reactors. In November 2022, having gained confidence in EBPR process, the plant initiated a plan to lower the alum feed rate 10% each month, and continues to monitor performance and lower the alum to further optimize savings.

The Warren, MI Water Recovery Facility performed a similar upgrade in 2021. The system maintained exceptionally low ORP, generated excess VFA, and utilized a unique mixing regime to transport VFA throughout the reactor without disturbing the fermentation process. In addition to achieving consistently low phosphorus effluent, well below the 1 mg/L requirement, the facility also reduced ferric consumption by 73%.

While generating VFA in the fermentation blanket is important, it is equally important to transport VFA to the PAOs throughout the reactor. The unique approach used by both plants included an update to the control logic to switch from continuous mixing to intermittent mixing. This new mixing approach operates cyclically, with complete mixing events occurring every 8-12 hours, and intermittent low-energy pulses occurring hourly during the unmixed phases. The periodic gentle pulses of low energy mixing from the fermentation blanket are used to transport excess carbon to the bulk liquid providing availability to PAOs throughout the anaerobic reactor.

Enhanced biological phosphorus removal (EBPR) is a critical component of modern wastewater treatment strategies to protect aquatic ecosystems and capture valuable nutrients. However, EBPR process instability can create challenges for meeting stringent effluent phosphorus limits. Previous work has shown that monitoring phosphorus uptake kinetics can provide an early warning of instability events. While these methods provide a useful indicator of the functional health of the EBPR system, they do not always elucidate possible mechanisms responsible for instability events. Accordingly, we compared microbial population dynamics and their gene expression during periods of stable and unstable EBPR operation.

MLSS samples were collected from the Rock Creek Advanced Water Resource Recovery Facility during both a process upset and a stable period in 2021. Relevant process performance data at the time of sampling was also recorded. Nucleic acids were extracted and sent for shotgun metagenomic (MG) and metatranscriptomic (MT) sequencing. Metagenome assembled genomes (MAGs) were assembled from the MG data to allow for more complete identification of the microbial community. Good quality draft MAGs served as the references to determine relative abundance and gene expression rates from the MG and MT data, respectively.

Bioinformatic analysis highlighted two novel microbial populations (strain 1 and strain 2) that were very abundant across both MT and MG datasets. Both were distinct members of the Accumulibacter genus based on analysis of their respective MAGs, including genes for polyphosphate accumulation as well as volatile fatty acid (VFA) metabolism and PHA synthesis. Further, strain 2 appears to be capable of denitrification. Gene expression for VFA uptake and carbon metabolism appeared depressed in the unstable samples relative to the stable samples, while stored phosphorus utilization activity remained somewhat stable. This could be due to decreased total VFA load during the upset event. Chain elongation activity also dropped substantially, further indicating insufficient carbon availability. Overall, gene expression profiles during the upset are supported by process data.

This presentation will offer an introduction to the use of genomics for process stability, followed by a case study describing key EBPR-related populations at Rock Creek and the response of these organisms to a process upset.

Biological phosphorus removal (BPR) is a powerful method to meet effluent phosphorus requirements. At Clean Water Services (CWS), BPR is capable of producing effluent ortho-phosphorus concentrations below 0.1 mg/L, however at times, the performance degrades and effluent phosphorus concentrations can exceed 2 mg/L. Previous CWS work has shown measurements of the phosphorus uptake rate at the end of the aeration, which we’ve termed the residual phosphorus uptake rate (RPU), correlate well with BPR stability. Higher RPU rates correspond to more stable BPR and decreases in RPU can predict impending increases in the secondary effluent orthophosphate concentration. Because phosphorus uptake in some phosphorus accumulating organisms is driven by the amount of stored polyhydroxyalkanoate (PHA), it was hypothesized that the health of the BPR process is related to the biomass’ ability to store excess PHA, allowing them to better manage variable loading conditions. CWS has recently optimized a PHA analysis method, allowing us to investigate this hypothesis further and to ask wider questions into the behavior of the BPR process.

For approximately 6 months, the PHA content of the biomass has been measured with each RPU batch test. Contrary to our original hypothesis, there does not appear to be a consistent relationship between RPU and the total amount of PHA in the biomass. We have therefore started characterizing the relationship between phosphorus uptake rate and PHA content at other locations along the basins. A more clearly defined relationship was identified between uptake rates measured early in the aeration basin and the polyhydroxyvalerate (PHV) concentration. We continue to explore the dynamics of phosphorus uptake and PHA content along the length of the aeration basins to build a better understanding of the relationships and variability that may be observed.

PHA data can provide further information into the behavior of the BPR process and suggest shortcomings in our understanding of key operational parameters. This paper will present the current status of the CWS PHA research and investigate other factors that may be influencing the interrelationship between phosphorus uptake rates, PHA storage and PHA utilization.

Stringent nutrient limits can be achieved while also providing for energy efficient process operation. The secondary upgrade at the Budd Inlet Treatment Plant (BITP) owned and operated by LOTT Clean Water Alliance in Olympia, Washington is a prime example. Upgrades to the instrumentation, aeration system, and controls associated with ammonia-based aeration control (ABAC) enabled staff to implement low-DO simultaneous nitrification and denitrification. This resulted in improved effluent quality, approximately 50% lower methanol use for nitrate polishing, and reduced aeration demand in the second aeration step. This presentation will describe the upgrades and how they can achieve extremely good nitrogen removal in the first stage of treatment, reducing loading to the second stage as an example for how similar success can be achieved at other plants in the area.

The BITP has stringent total inorganic nitrogen (TIN) limits of 3 mg/L in spring through fall, as well as total maximum daily load limits which are potentially more restrictive, depending on flow. Before and after the recent upgrades, treatment was accomplished with a 4-stage Bardenpho process. Prior to the upgrades, the first anoxic and first aeration zones were in separate tanks and aeration was controlled on a per-treatment-train basis. The upgrades combined the first anoxic and aeration stages into the old aeration tank, including new swing zones to adjust aerated volume, significantly reducing the energy required for mixed liquor recycle and reducing the treatment volume. Additional instrumentation and control were added to the new process, including influent and mid-train ammonia probes as well as dissolved oxygen (DO) probes and airflow control in each zone.

These changes provided the operators great flexibility and insight into the control of their process. Come learn how the staff put the improvements to use as they dialed down the oxygen supply using ABAC control, adjustable recycle ratios, and the swing zones. Eventually, the process moved into simultaneous nitrification denitrification (SND) giving further reductions in energy and methanol use in the second stage. Effluent TIN was maintained at 1.5 mg/l or less throughout.

Increased dewatered cake solids will save approximately $1 million per year in biosolids hauling costs at the Columbia Boulevard Wastewater Treatment Plant (CBWTP). By 2045, CBWTP will thicken up to 724,000 pounds and dewater 260,000 pounds every day. The existing solids handling facility was built in 1970 on a foundation of wood piles, and the aging equipment was in need of replacement. The project presented an opportunity to upgrade primary sludge thickening in addition to WAS thickening to improve digestion performance.

Alternatives to rehabilitate the existing solids processing building were evaluated and due to desire for increased seismic resiliency and operation during construction, the decision was made to build a new solids treatment facility. There are site constraints at the CBWTP, ideally the new solids facility would be located near the existing facility, which is boxed in on multiple sides with existing infrastructure. This led to design of a unique multi-story triangular shaped solids handling facility, with a bridge across an existing channel and additional supports on the other side to allow trucks to pass underneath.

The co-thickening system design includes eight 3-meter-wide gravity belt thickeners, blend tanks, feed pumps, thickened sludge storage tanks and pumps, polymer facilities, and cameras for monitoring. The dewatering system design includes five 29-inch-diameter dewatering centrifuges, feed pumps, polymer facilities and conveyors to hoppers and the loadout facility. Operations and maintenance (O&M) staff were engaged at all stages of design to provide input on access and O&M needs. This led to multiple monorails, bridge cranes, and an elevator to allow for access to all of the equipment that is located on various floors of the new facility. The new biosolids storage and loadout facility provides redundancy and allows automated biosolids hauling 24-hours per day through monitoring/instruments including hoppers equipped with ultrasonic level sensors and weigh cells as well as full-length truck scales in each of the two loadout bays.

The presentation will walk through the decision process for this new state of the art solids handling facility, operations and maintenance considerations, and a live model fly-through of the unique multi-story solids facility.

Located between the cliff and a river, the City of Lewiston’s wastewater treatment plant had little room for expansion. The City’s dewatering system was undersized and required frequent maintenance. The City had a contract with a composting company to provide biosolids within an acceptable solids range. To compound the problems, the belt filter press was located on the second floor of a very small room in the center of the plant. The City was looking for an ideal solution that could fit into the existing space, reduce maintenance for the plant operators, and meet both the capacity and performance requirements.

As part of a performance-based evaluation process, the City selected HUBER Technologies, Inc.’s Q-PRESS 800.2 units. The new screw presses were among the first to include the high-capacity auger system, which consists of two design advances from previous models. The first design advancement being an elongated filtration zone in the inlet area which allows for a relative improvement in free water drainage. The second advancement is a more aggressive auger flight pitch which provides the unit with a higher solid conveyance capacity. These advances allowed the screw presses to dewater sludge 20% faster, reducing the required footprint and time of operation. This presentation will highlight the plant constraints, selection process, and also demonstrate the enhanced performance provided by the new screw presses.

Erratic climate patterns coupled with aging sewer infrastructure has caused many utilities to worry about their wet weather management strategies. One of the major contributors to wet weather flows is Infiltration and Inflow (I/I) which is a function of pipe material, pipe age, groundwater level and precipitation. In some cases, when groundwater level is above the invert elevation of the sewer collection pipes, I/I can also result in increased dry weather flows. With many utilities across the country planning major infrastructure sewer network upgrades due to ageing infrastructure, areas with highest I/I are usually a low hanging fruit to minimize wet weather flows. However, quantifying the benefits of such sewer upgrades is often difficult due to limited flow measurements typically available across sewersheds where upgrades are performed. The lack of flow measurements coupled with climate variability year over year render the use of simple ‘before’ and ‘after’ comparisons ineffectual. To avoid the bias and uncertainty due to climate variability, a different methodology is required to compare data and quantify impacts. This study investigates an alternate methodology of using pump station energy consumption data in lieu of flow measurements for quantifying the benefits for approximately $20 million in investments made by a utility¹ for rehabilitation of 210,000 linear feet of sewer pipe across six (6) sewersheds. This paper will review the approach of using a “control sewershed” i.e. a sewershed not having undergone any repairs, with similar characteristics as that of the sewershed undergoing rehab, to eliminate bias and using this alternate approach to quantify reduction in flows as a result of the I/I repairs. This paper will also review the approach for quantifying the return on investment for the rehabilitation as well as cost savings as a result of deferred treatment capacity expansions for the receiving wastewater treatment facility.

Note: 1. Approval to disclose the utility name is anticipated to be received ahead of the conference presentation.

This presentation will dive into a case study from Gresham, OR where deep infiltration was used to reduce the strain on an overwhelmed MS4 system. This site had shallow perched groundwater but beneath the silt layers were permeable sands and gravels that were perfect for infiltration. By drilling deeper, the stormwater can infiltrate and reduce the burden on the existing MS4 system.

This deep infiltration system was also installed in an existing residential street, which had tight existing utilities. By minimizing the footprint of construction and surgically targeting the location of the drywell, the construction timeline is shortened, and the risk of damaging existing infrastructure is reduced.

These deep infiltration systems are designed to protect groundwater quality by having a minimum of five feet of vertical separation between the bottom of the drywell and the high seasonal groundwater level. Results from monitoring this deep infiltration system will also be shared.

The City of Boise’s (City) water renewal utility, Water Renewal Services (WRS), has used a Business Case Evaluation (BCE) tool to inform capital project alternative evaluation and selection across their facilities since 2016. Following significant updates to their Level of Service (LOS) goals and Capital Project Delivery Model (PDM) through their Utility Plan development and implementation, they recognized the need to update their BCE tool’s criteria and processes to align with these new organizational values and processes.

In June 2022, the City engaged Brown and Caldwell (BC) to update their BCE tool to better align their organization-wide goals and commitments. The team improved user experience and drive tool adoption by refining usability and standardization. As a result, the new BCE:

• Aligned BCE tool assumptions, risks, and benefits with LOS
• Translated LOS goals into risk monetization criteria for inclusion into the tool
• Updated existing monetization assumptions and improve data source transparency
• Improved ease of use and overall BCE tool accessibility
• Increased the efficiency and defensibility of the decision-making process

This presentation will discuss the approach and results of the BCE tool update, outline how to translate high-level LOS goal language into quantifiable and monetizable evaluation criteria, and highlight opportunities for scaled application across other organizations.

The presentation will also provide the opportunity for other utilities and municipalities to consider how a BCE may help translate organizational values into decision-making criteria to support consistent application of LOS or other priorities throughout projects related to climate goals, utility resilience, employee experience, and more.

Known as the Emerald City, Seattle is famous for picturesque views, coffee culture and rain. Located on the shore of the Puget Sound in Discovery Park, the West Point Treatment Plant (WPTP) is the largest wastewater treatment plant in the Pacific Northwest, providing treatment for up to 440 million gallons per day of combined storm and sanitary flows. Operated by King County’s Wastewater Treatment Division (WTD), it is relied upon daily to protect the environment and the public health of approximately 750,000 residents and businesses in Seattle and northern King County.

Constructed in 1966 and expanded to secondary treatment in the early 1990’s, the WPTP needs significant investment over the next 10 years to improve resiliency and replace aging asset. As the workhorse of WTD’s treatment facilities, any construction that could affect the plant’s ability to provide peak treatment capacity is limited to each year’s “dry-season,” between April and September. Also, the facility is on a 32-acre site with land, water, height and depth constraints limiting available space for construction activities.

In June of 2020, WTD started to develop the West Point Capital Program (WPCP) with the vision to deliver projects at the WPTP in a coordinated manner, improving schedule performance, fostering better relationships between operations and project delivery staff, elevating project delivery procedures and reducing risks.

Implementing a programmatic delivery approach for the WPTP helps WTD to manage dependencies between projects, and provide consistent and integrated tools and documents to all project teams in real time. The program also improved communication across project teams, and enabled a broader management approach to identify, anticipate and manage schedule impacts and overall risks. This presentation will describe some key tools and processes that have served the WPCP well and contributed to the results obtained to date. It will also identify the challenges and lessons learned that the team faced while setting up the program and running the initial 2 years of the WPCP, and where the program will go from here.

Current Clean Water Act regulations affecting municipal wastewater and stormwater discharges inhibit collective efforts as individual stakeholders are forced to address rigid and narrowly focused regulations. EPA's Integrated Municipal Stormwater and Wastewater Planning Approach Framework that applies systems thinking based on a one water principle, coupled with local accountability. A more effective one-water regulatory framework can create more economical and sustainable outcomes that result in better overall water quality. Integrated planning is a concept that supports prioritization of capital investments in all forms of water infrastructure designed to protect human health and the environment, and to incorporate societal objectives in the most cost-effective, affordable way. Integrated planning also provides more coordination and up-front planning at the local level along with local stakeholder accountability. The result is less cost to achieve ultimate goals, compliance with regulations, and successful outcomes. While the framework has existed for a decade and is now part of the Clean Water Act, less than 0.5 percent of communities are taking advantage of it.

The Water Environment Federation established the Integrated Planning Task Force (IPTF) to provide effective and focused leadership about integrated planning through collaboration with WEF committees, WEF members, regulators, municipalities, and other stakeholders. A long-term goal for the IPTF is to increase incorporation of integrated planning in the development of municipal National Pollutant Discharge Elimination System (NPDES) permits and consent decrees in enforcement actions under the Clean Water Act.

The Roadmap for Integrated Planning purpose is educating this audience about integrated planning and helping utilities and regulators understand how integrated planning could benefit the utility, the regulatory agency, the community, and the environment. This session will provide an overview of the content of the Roadmap and the plans to help both utilities and regulators become more knowledgeable about integrated planning and to begin using it for NPDES permitting and enforcement actions. Participants will learn about when integrated planning is likely to be most successful, reinforced with case study experience, and how an integrated plan can be efficiently developed for a community.

The paper will summarize the IPTF's plans for taking the roadmap "on the road."

There’s never been a better time than now for utility leaders to examine and improve business processes throughout their organization. With many utilities experiencing on-going staffing and funding challenges, the Water Environment Federations’ (WEF) WISE program for Utility Management provides utility leaders with a framework and methodology to create greater value and improve performance. This comprehensive approach to improve management and performance in water sector utilities encourages full systems thinking. It provides greater value to stakeholders, improves senior leadership’s ability to make an impact, and increases employee engagement and thus their motivation to add value to the organization. It is a collaborative peer-to-peer effort that includes leading utilities from all over the U.S. including Charlotte Water, Louisville MSD, Great Lakes Water Authority, San Francisco, DC Water, the City of Portland and others in the US as well as utilities in Canada and the United Kingdom.

One of the greatest strengths of the WISE program is the collaboration among the participating utilities: the Utility Partners. Subject Matter Experts from the Utility Partners have created leading practice models for Capital Improvement Programs, Asset Management, Capital Project Business Case Evaluation, and several other business processes. The presentation will include an overview of the methodology and several case studies where utilities have successfully employed elements of the approach as well as the findings of current pilot projects. Participants will learn how they can become part of the consortium of utilities improving their business practices in meaningful and comprehensive ways.