Conference Agenda

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.

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.

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.

Siphons are one of the most difficult sewer pipelines to maintain as they are designed to be continously full of water, often have little redundancy, and typically have very high flow rates. They are also located deep underground as they are designed to carry wastewater under roadways, channels, and water bodies. These factors make maintenance work, such as cleaning and inspections, very difficult and often costly. The construction and operation of inverted siphons will be explained, then an in-depth discussion on methods that can be used to dewater, bypass, clean, and inspect sanitary sewer siphons will be presented. Proactive maintenance best practices will be discussed, along with design ideas to improve the future construction of sanitary sewer siphons.

Learning Objectives:

1. Explain the construction and typical operation of sewer siphons

2. Explain cleaning methods based on siphon configuration

3. Explain inspection methods for sewer siphons

4. Present design ideas for building better siphons.

Condition assessment of sewer systems is critical to maintaining system structural integrity and functionality and to identifying pipes requiring rehabilitation before they deteriorate past the point of renewal. Inspection of wastewater collection systems is typically completed using closed-circuit television (CCTV) cameras to provide visual inspection of the underground infrastructure. Trained technicians then review the videos, identify defects, and provide a condition rating of each pipe that has been inspected.

The recent development of artificial intelligence (AI) tools have the potential to advance the state of the practice of sewer condition assessments. AI algorithms are being developed to automatically identify defects from inspection footage. AI can also be used to identify poor quality videos so that the pipes can be reinspected. AI algorithms for defect autocoding have the potential to improve the accuracy of defect coding and reduce the time required to complete defect coding and pipe scoring. However, the use of AI for autocoding defects is not widespread and the benefits have not been documented beyond a handful of pilot studies.

As part of the City of Salem’s Wastewater Collection System Master Plan, the City evaluated the ability of AI algorithms to automatically code CCTV video and obtain sewer condition assessment data. Two CCTV autocoding vendors were chosen for the pilot study. The pilot study included selecting a wastewater basin with available fully coded CCTV data, establishing testing parameters, and comparing the autocoded results to the City’s own coding. Results of the autocoded CCTV videos from each vendor were compared to results provided by the City in the following categories:

1. Recall: AI able to find any defect within one foot (plus or minus) of City defect.
2. Precision: AI able to find same defect within one foot (plus or minus) of City defect.
3. Accuracy: AI matches the same grade level of City defect.

This presentation will describe the approach taken to evaluate if defect autocoding is a viable option for their inspection of their sewer system. Results of the comparison along with lessons learned and recommendations for implementation of AI for CCTV autocoding will also be presented.

Reliably assessing the condition of buried pressurized sewer force main pipelines is one of the last remaining (and technically arduous) practical challenges for collection system managers. The failure modes for these assets can be complex and the consequences severe. This presentation will share how, as part of their proactive asset management strategy, the City of Portland, Ore. has begun a systematic approach to inspect all 100+ of the force mains in their system. The discussion will focus on the two key efforts of both building a framework in which all the assessment data may be used to calculate business risk to the City, and deploying the full suite of field investigation technologies presently available in the marketplace. To be successful, first the risk-based framework needed to be capable of distilling inspection data from multiple vendors, sources, and methods into meaningful insights for the likelihood of failure in different scenarios. The objective was to provide a framework by which the force main risk could be objectively compared (in “apples to apples terms”) to the risk posed by other assets in the City’s portfolio. Secondly, when it came to the field deployment of inspection tools, because most older force mains were constructed before inspection technologies were available, success depended on anticipating the necessary site-civil, pipe-mechanical, and operational/logistical updates needed for each investigation. This presentation will cover both these aspects of the program and provide two different perspectives: that of the municipal system owner responsible for overseeing the effort and ensuring that it addressed the resources and needs specific to the City; and that of the condition assessment service provider responsible for the execution of the program and analysis of the inspection data. Concepts for asset management best-practices related to force mains will be presented; as well as practical metrics for cost and schedule associated with implementing a force main field investigation program. The session will be geared towards collection system asset managers, operations & maintenance specialists, and conveyance engineers.

The City of Portland Bureau of Environmental Services (BES) Columbia Blvd Wastewater Treatment Plant (CBWTP) was first constructed in 1952 and continues to expand. Many process pipes and plumbing systems are original to the plant’s construction and had become forgotten brethren of CBWTP. Prior to this project, most pipes had not been inspected internally during their lifetime or assessed for their condition and remaining useful life (RUL)​. The CBWTP has experienced an increase in pipe breaks in the recent years causing process areas to be shutdown, creating a detrimental impact on plants operations and a sharp increase in financial expenditures​. Frequent breaks and leaks have also taken significant a toll on the operations and maintenance staff who are continuously patching piping systems to ensure reliable operations of the treatment plant.

BES condition assessment program has engaged with Kennedy Jenks consultants to prioritize, inspect, and assess plant process piping to move BES towards proactive management of its pipe assets. The primary goal of this project is to identify BES’s risk exposure due to these aging pipe assets to enable tailored and sustainable long-term replacement/ rehabilitation strategies.

This presentation will outline the vision and catalysts for this project, along with sharing success stories and how other utilities can adopt similar programs. Attendees will learn about developing a truly integrated asset management solution, from identifying pipe assets, managing these process piping assets in CMMS, developing GIS, 3D scanning and modelling tools, applying risk and prioritization tools, using advanced condition assessment technology and conducting this with careful coordination with plant scheduling restraints. Finally, the presentation will focus on the aspect of creating a cultural change in managing assets, one that proactively inspects piping systems and avoids unforeseen breaks and leaks through effective risk communication long after the team members have moved on.

Abstract Title

The Industry Misunderstanding of Low-Pressure Sewer: Flow Study and Analysis of Gravity vs Low Pressure Collection Systems.

Presentation Description:

FUDKnox serves 100,000 people in East TN. The collection system consists of 600 miles of line, 200 of which are low pressure sewer with 4000 low pressure pumps. After multiple years of sewer rehabilitation in the gravity system it became apparent that the lower pressure system was operating on a much more efficient and economic schedule due in part to almost nonexistent I/I. FUD Knox determined to validate what the finance and operational staff were observing through an analysis of sections of the gravity and low- pressure piping. A consultant was retained to evaluate flow data and operations cost.

FUDKnox has a comprehensive flow monitoring program that keeps 75 flow monitors deployed in the collection system. In 2016 flowmeters were installed at predetermined areas in both the gravity and low-pressure systems. Information collected for 12 months insured data from multiple rain events was captured. All operations cost were captured for the same time frame. At the end of the 12-month period all information went through engineering analysis and a technical report published.

The compiled information was even more surprising that suspected. During multiple heavy rain events, I/I was almost nonexistent in the 4 low-pressure subbasins where flow meter was installed and monitored. In the gravity subbasins that were analyzed, I/I was detected and had a direct effect on the wet weather peaking capacity at the wwtp.

KEY TAKEAWAY

The theme for the 2023 PNCWA Conference is “Catalyzing A Sound Future for Water”. One definition of catalyze is to cause an action or process to begin. The author of this abstract was once a Program Manager for a large consulting firm with an expertise in sewer rehab programs and consent order compliance. Low-pressure was never considered a viable solution because of no understanding of its functionality. Based on the number of service providers across North America that have contacted FUDKnox to better understand our low-pressure methodology, it appears the application of low pressure as a solution is gaining traction.

For over 50 years, pressure sewer systems powered by grinder pumps have emerged as an effective solution for septic tank replacement sewer projects.

A pressure sewer system consists of a network of small diameter pipes that are pressurized to move wastewater from individual homes or buildings to a central collection point, typically a treatment plant or a larger sewer system. Grinder pumps, which are installed at each individual property, are used to break down solid waste and pump it into the pressurized pipes.

One of the key applications of pressure sewer systems is in “septic-to-sewer” projects. In these projects, an established community has chosen to enhance environmental and public health quality with a wastewater collection system. Beyond the technical advantages of pressure sewers, the practical and logistical simplicity of deploying the system often results in a more affordable and sustainable solution for the community. Specifically, the footprint of pressure sewers is much smaller than alternatives like gravity sewers or septic tank effluent pumping (STEP) systems. Furthermore, the constructability of pressure sewers enables minimal disruption to the local communities, avoids damage to private property and existing vegetation, and returns valuable land back to the community.

This presentation will highlight the benefits and best practices of grinder pump pressure sewers in these septic-to-sewer projects. These best practices are the results of lessons learned over the last several decades of working in similar projects in the Pacific Northwest, across the United States, and across five continents. Examples of these best practices in action will be shared through various real-world projects and case studies.

At the conclusion of this session, the attendees should recognize the benefits, differentiators, common missteps, and keys to successful septic-to-sewer projects. By demonstrating these factors, the audience should gain an appreciation for how stakeholders can leverage pressure sewers and how the benefits of pressure sewers will be a catalyst to facilitate more septic-to-sewer projects as we collectively seek to improve environmental quality of life.

Utilities have been investigating new technologies to diversify their end products from water reclamation facilities (WRRFs) due to strict regulations around land application of biosolids and recent concerns on presence and accumulation of poly-fluoroalkyl substances (PFAS) in biosolids. Water above 374°C and 22.1 MPa becomes supercritical, a special state where organic solubility increases, and oxidation processes are accelerated. Supercritical Water Oxidation (SCWO) is a promising technology that converts organic material (biosolids) to inert gases, minerals and water.

SCWO has been recently shown to destroy hazardous substances such as halogenated compounds including PFAS. Studies showed a greater than 99% reduction of the total PFAS identified in a targeted compound analysis, including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) (Krause et al, 2022). As a destructive technology, SCWO is proposed as an alternative to incineration and other combustion processes and could be a permanent solution for PFAS-laden biosolids or solid matrices. However, additional investigation of reaction byproducts: water, solids and air emissions need to be conducted for a complete assessment of SCWO’s potential as a safe and effective technology.

Orange County Sanitation District (OC San) teamed with 374Water, Hazen and Sawyer, and Merrell Brothers to demonstrate this technology at their site. The demonstration unit was developed based on a Research and Development (R&D) unit installed at Duke University which has a capacity of one wet tons per day. The demonstration unit has capacity of 6 wet metric tons per day and manufactured by 374Water Inc., ready to be installed. The design of the demonstration project is completed by Hazen. The research team, including OC San, 374Water, Hazen and Sawyer, Yorke Engineering, Alliance Testing worked together to develop a rigorous test plan to support permitting, design and operations. This presentation will focus on the findings from the research unit located at Duke University and the test plan prepared to identify the emissions from SCWO process. It will also discuss the challenges and advantages of the technology. The information will benefit utilities that seeks sustainable solution for their biosolids management considering recent concerns on PFAS compounds.

King County Wastewater Treatment Division’s (WTD) West Point Treatment Plant (West Point), adjacent to Discovery Park on Puget Sound in Seattle, Washington, receives flows ranging from 60 to 440 million gallons per day (mgd). West Point treats combined wastewater produced by a mix of residential, commercial, and industrial customers. Solids are treated using BFP thickening, anaerobic mesophilic digestion, and centrifuge dewatering to produce Class B biosolids beneficially used through the King County Loop™ program.

Digestion at West Point is approaching capacity constraints and major assets are aging. Solids capacity solutions must address a broad range of needs and challenges, including affordability, equity, reliability and resiliency, on a highly constrained site footprint.

The study was executed in a systematic manner using a combination of economic and non-economic analyses. A vision statement developed collaboratively by the consultant/WTD team established project goals and informed decision-making criteria. Our team first evaluated the universe of solids handling options to determine the best method of addressing capacity constraints at West Point. Technologies included digestion pre-treatment, anaerobic digestion, dual digestion, composting, chemical stabilization, thermal drying, and thermal decomposition. Technologies were screened using a pass/fail analysis applying criteria such as technology maturity, end uses, technology footprint and state of the industry. A short-list of technologies passing the pass/fail step were carried forward for subsequent evaluation.

Six alternatives were retained, each including anaerobic digestion as the core stabilization process. Alternatives were categorized based on desirable outcomes each might achieve (e.g., maximizing existing assets, Class A biosolids requirements, emerging contaminant risk mitigation, or nitrogen site impacts). Capital costs, life cycle costs, carbon footprint, impacts to construction sequencing, process reliability during construction, etc. were evaluated. Secondary technical, environmental, and social evaluation criteria were developed and applied in a series of workshops using collaboration tools such as electronic polling and interactive sensitivity analyses. The interactive sensitivity analyses allowed the team to change criteria weights, to pose risk scenarios and see their outcomes, to better understand different priorities across the organization, and ultimately to reach consensus.

WRFs using chemical disinfection with traditional means of control (e.g. flow pacing), typically overdose disinfectant by a factor of two. This overdosing can result in issues of excessive disinfectant cost, excessive quenching cost, disinfection byproduct formation, inconsistent performance, and inadequate public health protection. Advanced Dose Control (ADC) is a model-based disinfection control technology that seeks to account for the variables that impact disinfection performance (hydraulics, chemical background demand, and disinfection kinetics) and, regardless of process variability, to normalize disinfection outcomes while optimizing chemical dosages to avoid both over-dosing and under-dosing. Furthermore, in a complicated procurement environment, where disinfection chemical shortages and rising chemcical costs have become the norm, ADC provides a means by which to more tightly control chemical usage and for POTWs to hedge against supply volatility. ADC control technology has been included in the study matrix for WERF's most recently announced disinfection study, where bleach, PAA, and PFA will be compared under multiple control scenarios.

This presentation will highlight the foundations of the technology and present plant-scale pilot data, as well case studies from existing users demonstrating its performance vis-a-vis flow-pacing with both bleach, peracetic acid, and performic acid, and furthermore, will illustrate the implications of ADC's use at facilities using chemical disinfection, including significant cost savings (40%-50%), improved reliability, reduced discharge of residual disinfectant, reduction in dechlorination chemical, byproducts, and ultimately, reduced risk of permit violation.

Lake Stevens Sewer District (LSSD) and Columbia River Carbonates have worked closely since early 2022 to pilot improved RAS alkalinity and pH control at their Sunnyside WWTP operating in Lake Stevens, WA. This facility uses state-of-the-art membrane technology, designed to meet or exceed Washington State Department of Ecology permitted limits for contaminants in discharged effluent.

In January 2022, the two began replacement of 25% sodium hydroxide with MICRONA^TM AquaCal 70, a 70% solids micronized calcium carbonate aqueous slurry for alkalinity and pH control of mixed liquor at the 5 MGD MBR Sunnyside WWTP. While operating this pilot, wastewater quality and membrane permeability have been closely monitored while maintaining all standard operating conditions.

Results from the MICRONA^TM AquaCal 70 pilot for mixed liquor alkalinity and pH control and have been noted to a) decrease variability of alkalinity and pH in MBR mixed liquor, b) produce consistent pH control, allowing better conversion of ammonia to nitrates/nitrites and reduction to final effluent with a significant decrease in MBR mixed liquor alkali requirement, c) increased Suez membrane permeability and better operating conditions, d) decreased plant energy consumption, e) decreased overall alkalinity reagent chemical spend. These will be fully documented and presented.

LSSD also completed a 9-month pilot replacement trial of 25% sodium hydroxide added to MBR mixed liquor using 60% magnesium hydroxide from April through December 2021 and found improvement in some but not all operating and effluent quality parameters discussed above with respect to MICRONA^TM AquaCal 70.

Based on the 2021-2022 evaluations of magnesium hydroxide and calcium carbonate, LSSD is moving forward with converting from usage of 25% caustic soda to the continued use of 70% calcium carbonate aqueous slurry because of its cost-effective, non-hazardous and easy to handle qualities as a wastewater mixed liquor alkalinity and pH control product. Additionally, the selection of calcium carbonate aqueous slurry at the Jacobs run Spokane County Regional Water Reclamation Facility and Sunriver Utilities Co. build confidence in the use of CaCO₃ for required alkalinity and pH control during secondary stage aerobic biological treatment by LSSD.

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. A key component of such improvements is to take advantage of existing assets through optimization. While potentially attractive, optimization is a daunting task and a comprehensive guide on implementing optimization has been lacking.

This presentation is part of the Water Research Foundation project 4973 “Guidelines for Optimizing Nutrient Removal Plant Performance” that developed a comprehensive guide on implementing an optimization strategy for water resource recovery facilities (WRRFs) with an emphasis on nutrient management (based on full-scale examples). The presentation focuses on a key component of the guide, the nutrient optimization decision trees that can assist WRRFs with navigating nutrient optimization.

The nutrient decision trees developed will be available on the Water Research Foundation’s website this calendar year as part of a web-based interactive tool. The decision trees ask the user a series of questions, whereby the responses inform the generation of a list of potentially viable optimization strategies for their WRRF. Each potentially viable strategy has a corresponding Fact Sheet associated with it to further assist the user as to whether such a strategy might work for their WRRF.

While more extensive detailed analyses will likely be required to verify/validate each potential strategy for facility specific applications, the decision trees expedite the optimization effort and help initiate the process. For example, the decision tools have been applied to satisfy the optimization planning requirements of the Puget Sound Nutrient General Permit (PSNGP). The decision trees benefit wastewater utilities by providing a comprehensive screening of optimization opportunities that efficiently narrow considerations to the most promising options. In this way, resources can be focused on the facility specific details of optimization.

As part of the presentation, the Water Research Foundation web-based interactive tool will be used in real-time to highlight the ease of using the tool. The audience should leave the presentation with an understanding on how to use the decision tree tool.

The City of North Las Vegas Water Reclamation Facility (CNLV WRF) uses a traditional Johannesburg process and a membrane biological reactor (MBR) aimed at removing phosphorus and nitrogen. During a recent capital improvement project to re-coat the MBR basins, the CNLV consolidated the number of basins in-service from 12 to 9 MBR trains. The basin consolidation impacted the stability of the biological phosphorus removal performance.

A study was conducted to identify and evaluate potential optimization opportunities to improve the stability of the biological phosphorus removal process. The study targeted key process parameters, such as chemical addition, solids retention time, hydraulic retention time, and oxidation reduction potential, all of which can also impact MBR performance. Seven optimization scenarios were developed focusing on three themes: peak flow management, solids loading in the MBR (chemical and biological), and dissolved oxygen concentration in the MBR and recycle streams.

All optimization opportunities were evaluated using a wastewater process modeling software with the intent of shortlisting several optimization alternatives to test on the full-scale process. The simulation results were used to estimate process performance, such as MBR permeate phosphorus, ammonia, and nitrate concentrations, under varying operational conditions.

This presentation will highlight the impact of peak flow management with the use of an equalization basin and the importance of balancing solids loading by optimizing chemical addition and dissolved oxygen concentration in the return streams by optimizing recycle rates.

Good water policy is informed by experience and expertise of the practitioners who work with resulting rules and regulations every day. Setting a course towards good policy frameworks and enforceable requirements begins with connecting those policymakers with their constituents. Learn to effectively advocate to state legislators regarding bills which affect your entity or area of expertise.

State codes governs a significant portion of what utilities are allowed to do, cannot do, and must do. In the northwest, these laws are written by part-time legislatures comprised of representatives from all areas of the state and all walks of life. Knowing how to effectively engage can make a big difference in educating state lawmakers, who are responsible for important water policy but often do not understand how it impacts utility operations.

Advocacy begins far before the legislative session, at the local level and continues year-round. Once the legislative session is underway, many bills are already far along in the drafting process with substantial support of various groups and voting blocs. Attempting to get a new idea off the ground or to redirect a flawed bill once it gains momentum are both challenging tasks. Clean water industry professionals provide a vital service by supporting members in navigating this process. A few of the activities we can pursue more effectively as an organization include:

• Anticipating emerging legislation and understanding potential impacts.
• Educating lawmakers to enhance their ability to create quality legislation.
• Supporting lawmakers in advancing legislation that supports and protects clean water goals.

Presenters will share advice on how to engage local legislators outside the legislative session, how to engage during the session itself, tools for monitoring the legislative process, and provide considerations to be taken when commenting on behalf of a public or private agency. The presentation will include both theoretical guidance and real-world examples from Government Affairs Committee members.

Water professionals from across the country descended upon the nation’s capital for Water Week 2023 (April 23-29) for a full slate of in-person events and meetings, including on Capitol Hill, which is now fully reopened to the public.

This year’s Water Week provided professionals with the opportunity to directly learn more from key federal officials about the implementation of the historical policy achievements secured by the water sector over the past two years, and significant actions on EPA’s regulatory agenda that will directly impact the water sector. It also provides the opportunity to build on this momentum and come together on Capitol Hill to advocate to Members of Congress the importance of ensuring all communities continue to have access to safe, reliable, and affordable drinking water and clean water.

PNCWA member visited Washington DC in-person furthering key water policy priorities such as sustained growth in federal infrastructure investment, addressing water affordability, supporting water research & development and advancing sound science-based solutions, and making our critical infrastructure more resilient.

Each states delegates will speak to who they met with, what they learned and how that impacts the Pacific Northwest. As your representative, the Government Affairs Committee member in attendance will provide vital information on federal legislative action and how you elected congress is approaching legislation and how we can better advocate for important water policy. We will talk about the individual meetings with legislatures and their staff, share information form keynote speakers like Radhika Fox, with the US EPA and how Washington DC is grappling with issues that impact us like PFAS, climate change and infrastructure funding and affordability.

Abstract Summary:

The purpose of this presentation is to share the issues, corrective actions, and lessons learned during the startup and commissioning of steam boilers that feed three thermal hydrolysis process (THP), designed to process 375,750 dry lbs/day.

Background:

The Achilles heel of the Thermal Hydrolysis Process (THP) system are the ancillary support systems (potable water, compressed air, steam etc.). The THP system cannot be tested, commissioned or started-up without steam. The boiler system and associated infrastructure is as crucial for facility operation and reliability as the THP system. Consequently, any delay in the testing can result in a day-for-day loss to the project schedule.

With an increase of THP systems across the country, the demand for industrial sized steam boilers at Wastewater Treatment facilities has also increased. The addition of large boilers can pose new and frustrating challenges that are unique to the boiler industry, and uncommonly encountered in municipal facilities. This presentation will delve into the challenges that arose during the commissioning and startup of three 16 million BTU Firetube steam boilers. Specifically, gas supply challenges, gas regulating valve placements, excess head loss and steam supply issues for injection into the Deaerator.

This boiler system case study consists of three boilers, a deaerator, three feed water pumps, a chemical dosing system, and a water softener system. Serving as the installing Contractor and the Commissioning Manager, MWH led the startup and testing of the boilers, troubleshooting and coordination between project stakeholders. Due to the criticality of boiler system reliable operation, MWH was responsible for collaborating with stakeholders to develop work arounds and final infrastructure corrections.

This presentation will outline the issues that arose, the troubleshooting steps taken to determine the route causes, steps used to ensure the boilers were ready to support the startup of the THP systems, and finally, review crucial lessons learned throughout the process.

Over the past 10 years I’ve had the unique opportunity to both write electrical and I&C testing specifications as a design engineer and execute those testing specifications in the field working as a C&SU manager on multiple water/wastewater projects.

It’s often we find the specifications to be lengthy and most owner’s and general contractors don’t understand the effort required to execute the testing in the specification, nor do they even know what the testing entails. Owner’s and general contractors become extremely reliant on their EI&C subcontractors to tell them when and how to execute the work. This typically isn’t a problem until the project team is up against the deadline to start-up the plant or the individual piece of equipment, and their subcontractor is holding them hostage. I often get asked, what testing really must be done to start a piece of equipment? How much time should be allocated in a schedule to account for this testing? How should all the testing predecessors be tracked allowing for a green light for the commissioning phase? In what order should the testing be conducted? All these questions have led me to spend the last several years of my career, looking at how to optimize this process and how best to communicate the requirements with owners and contractors who may not speak the EI&C language.

This presentation will cover testing requirements/types at a high level, then I’ll take a deeper dive into the order in which testing should be executed and where there might be opportunities to expedite testing in the schedule.