Conference Papers

The Southeast Michigan Council of Governments, SEMCOG, recently finalized a 7-county analysis of water infrastructure investment needs through 2045 for linear drinking water, sanitary sewer and stormwater assets. Based on the findings, an estimated $3.5 billion is necessary for continued protection of public health. Combined with transportation investment needs, the total annual investment is nearly $5 billion just to keep linear assets in good condition. This does not take into account other significant investment needs to address water treatment, wastewater treatment and extreme flooding events. With recent (June – July 2021), severe flooding events in the 7-county, Southeast Michigan Region, regional flood mitigation planning for future infrastructure investments has risen to the forefront. To support local, regional and state infrastructure planning efforts, SEMCOG is utilizing results from a future precipitation analysis, a flood risk study, and a regional asset data collection and condition assessment effort to address increased rainfall and extreme flooding events. Based on the future precipitation analysis, it is expected that the lack of stormwater collection capacity and flooded property and roadways will be exacerbated unless there are significant investment efforts and implementation of a collaborative management strategy. This presentation will share findings and products from that address regional climate resiliency including: - Precipitation estimates using regional climate models for 2050 and 2100; - A flood risk tool for transportation assets including roads, bridges, culverts, and pump stations; - A flooding app to track localized flooding locations; - A regional guidance document with alternatives to addressing future rain events in infrastructure planning and design; - Water infrastructure investment need estimates and background methodology for continued updates; and - A collaborative capital improvement project coordination tool across public and private utilities for future infrastructure planning. These regional projects represent valuable insight into the interwoven practices of transportation planning, stormwater management, and capital improvement investment. Learning Objectives Attendees of this session will learn about the methodology to estimate investment needs across a large regional metropolitan area. They will also learn about the flood risk tool for roads, bridges, culverts and pump stations; the flooding app to track local flooded locations; and their applicability in the long-range transportation planning process. Additionally, participants will learn of the future precipitation estimates for the region for small and large rain events and understand alternative approaches to integrating these estimates into planning/design efforts. Finally, attendees will understand how the region is supporting more coordinated project planning efforts for long-term cost savings and protection of public health.

Designing odor control systems for operation in cold weather climates requires additional considerations to ensure success. Overlooking these details can lead to decreased performance and even failure. Webster Environmental Associates (WEA) has been designing and testing odor control systems throughout the country for over 35 years and we've learned a number of lessons along the way. This presentation will provide a road map for evaluating the potential effects of cold weather on odor control systems and will include the following: -Seasonal effects on odor control loading -Odor control technology comparison for cold weather conditions -Estimating inlet air temperatures -Freeze protection options -Adjusting airflows for seasonal changes -Backup power supply requirements -Startup issues in cold weather -Provisions for re-acclimation of biological systems This presentation will include case studies and lessons learned. One case study that will be included in detail is a recent project located in Michigan that WEA designed with Tetra Tech. The design of this project was completed in 2018 and construction was completed in 2019. This project included the design and installation of a 9,000 cfm carbon adsorber and a 10,000 cfm bioscrubber. The carbon adsorber treats air from a series of rotating biological contactors (RBCs) and the bioscrubber treats air from primary clarifiers, a septage receiving facility, headworks, a grit facility, sludge storage tanks, and a series of channels. The first challenge of this project was that the client requested that the system be able to continually operate at ambient temperatures of -20 °F which was the historic low for the area. This requirement caused us to take a closer look at what the inlet temperatures to the odor control systems could be at this condition. We went back to the site during very cold weather and took temperature readings at the different sources. One of our surprise findings was that some of the channels didn't always have water in them, especially in the middle of the night when flows were low (and of course this would be the coldest time!). During that condition, the temperature of the air coming from the channels would be near the ambient temperature. We had a mechanical engineer on the team conduct heat loss calcs based on the data we collected and he determined that the inlet temperature at the bioscrubber could go below freezing when the ambient temperature is -20 °F. We evaluated multiple solutions, including an inline heater, capturing waste heat from another source, etc. In the end the most cost-effective solution was to provide an auxiliary heat source that would add heat into the primary clarifier (see Figure 1 below). This option was the least expensive as it utilized a standard makeup air unit (MAU). The MAU would be controlled by the bioscrubber control panel and only come on when needed. The below is an excerpt from the specified control logic: The MAU shall provide additional heat to the foul air system when the inlet air temperature goes below 36°F. Bioscrubber shall send signal to MAU to turn it on. The bioscrubber will turn off the MAU after 4 hours and re-evaluate the inlet temperature. If the inlet temperature again falls below 36°F, then the bioscrubber will initiate the MAU again for another 4-hour cycle. This cycle will continue until the inlet air temperature remains above 36°F without the MAU.
The next challenge that we faced was the significant seasonal fluctuation in hydrogen sulfide (H2S) levels. Prior to initiating design, WEA conducted an odor study which included two rounds of testing, one in the cool weather and one in the warm weather (see Figure 2 and 3). The results of the testing revealed that H2S averaged 34 ppm during the warm weather testing and 5 ppm during cool weather. However, we did some additional spot testing as design was proceeding during colder weather (in February) to verify loadings and found that the H2S actually drops below 1 ppm throughout facility during the winter. This created a challenge as the bioscrubber may struggle to stay acclimated over the winter, depending on how long the H2S stays depressed. In order to address this potential issue, the design required that the system have the ability to operate in a once-through or recirculation mode without any modification of piping or the addition of any equipment. If needed, the bioscrubber could easily be switched over to a recirculation mode temporarily in the spring to allow the bioscrubber to re-acclimate.
Several other hurdles were also encountered, including the need for the duct to be insulated and acclimation during the early spring. These will all be discussed in detail in the presentation. In addition to the Michigan project, we will also be presenting lessons learned from other projects in cold weather climates as time allows. Additionally, an overall comparison will be made between different odor control technologies operating in cold weather and provisions that need to be made to ensure efficient performance.

The City of Houston is the fourth largest city in the nation. Houston Water within the Houston Public Works department operates and maintains a large water and wastewater system. Its wastewater system includes approx. 39 treatment plants (WWTP) with a combined permitted capacity of 564 MGD, 5900 miles of sewer pipes, 127,000 manholes, and 385 lift stations spread out over 650 square miles to serve about 2.3 million customers. City of Houston's 311 Call Center receives an average of 1800 wastewater customer complaints per month. Issues may range from odor complaints, cave-ins to sewer backups in bathtubs. Houston Water is responsible for addressing these issues by mitigating the impact on public health and environment. Houston Water has a long history of using state-of-the-art technologies for managing its huge water and wastewater infrastructure. For Wastewater, it relies on systems such as; Infor IPS to manage work orders, service requests and tracking SSO records, HachWIMS to manage regulatory reporting, Infor EAM for facilities work order management and Enterprise GIS to support asset management for collection system. Recently, Houston Water introduced ArcGIS Online and Business Intelligence Tool, Power BI in every aspect of full-cycle process- starting from receiving customers call to satisfactory resolution of the problems.

THE PROCESS
Initial Call It all starts when a possible SSO is reported to the City of Houston's 311 Call Center. The 311 operator generates a service request (SR) which is logged into the Infor IPS. Once a service request is initiated, the clock starts ticking for the first responders, wastewater inspections team to respond to the request. Depending on the type of request -- a priority level is assigned to each Service Request. As an example- 'High Priority' is assigned to an active SSO that is threatening to enter a storm drain. A 'Medium-Priority' may be assigned to an odor complaint. First Responders Wastewater inspectors are equipped with a tablet to notify them of newly created SR through Infor IPS dashboard and also to enter field data into the Infor system. Inspectors are responsible to identify the type of SSO- Public or Private, where it occurred, the volume, flow rate, status of manholes upstream and downstream of the incident location and the possible cause. Inspectors create an SSO incident in the Infor platform for the stoppage team to take further action. The start times and flow rate data are recorded in real-time and cannot be edited to maintain the integrity of data. Stoppage team- Further Investigation Stoppage team are equipped with jetting and vacuum trucks to clear a blockage, stop the SSO, clean and disinfect the area and report the confirmed cause of the SSO. Stoppage crew is also equipped with tablets to enter details of SSO such as confirmed cause, actions taken to mitigate the SSO, and request for work orders. Depending on the needs work order could be issued for televising the line or installing bypass pumps. Quality Checking the Data for Regulatory Purposes Data is validated and confirmed in a weekly SSO meeting before weekly reports are sent to State Regulatory Agency- TCEQ. The meeting is attended by various stakeholders that includes regulatory team, inspection and stoppage team, customer service and Houston Health Department (HHD). ArcGIS Online and Power BI Dashboards provide the real-time and historical reference information. Recurrence Prevention through Analysis Greater than 70% of all public SSOs are preventable SSOs as they are caused by the accumulation of grease and rags/non flushable wipes in the sewer pipelines. Repeat SSOs are plotted on a dynamic ArcGIS map to identify SSO hot spots. This makes it easier for the wastewater analysis group to target high priority areas for Preventive Maintenance (PM) cleaning. A sample hotspot snapshot is shown in Exhibit 1, which illustrates the effectiveness of the PM cleaning program by reducing the preventable SSOs from 63 SSOs in 2018 to 29 SSOs in 2019.

Tracking Wet Weather SSOs
SSOs are also caused due to hydraulic capacity constraints in the collection system. Power BI is used to track the high volume (over 100,000 gallons) and number of repeat SSOs (3 or more) occurred during wet weather in previous three years in one manhole, as shown in Exhibit 2. This information is used to develop a capacity remedial measures plan. Fats, Oil and Grease (FOG) Program Houston Water's FOG outreach group uses ArcGIS Online based tool for targeted campaigns. HHD administers FOG Generator Interceptor Inspection program. HHD maintains a database for the Grease Trap inspections that are used by the FOG Outreach group to identify target areas that includes apartment complex and Food Service Establishments. Both, HHD and FOG outreach group use similar density maps as seen in Exhibit 1 for their respective needs. Intelligent Manhole Covers Houston Water uses intelligent manhole covers to provide real-time water levels to pro-actively detect a potential SSO that helps to mobilize maintenance crews to prevent SSOs from occurring. The continuously monitored manhole covers provide information to determine the rate of accumulation of debris in the pipes that eventually helps to develop PM cleaning program. The data from the manhole covers along with the lift station SCADA data are also used for verification of the collection system hydraulic models. Business Intelligence software such as Power BI and ArcGIS Online Dynamic mapping tools are used to efficiently process, visualize, analyze and share the outcome to present in a meaning way to effectively use the resources. The experience and effectiveness of using these emerging techniques and technologies, some of which are free, would be beneficial for water and wastewater utilities of all sizes.

The City of Clive is rich in water resources. The geography of the watershed graces the city with miles of creekside bike paths and recreation. However, that same benefit of proximity, also creates a challenge for protecting property and assets during rain and high-water events. The challenge with this project was to create a framework and program to comprehensively address the needs of the traditional stormwater network while also addressing the surface water, creek condition, and various green stormwater controls throughout the City. The project included a modeling evaluation to prepare for extreme weather flooding events, examining staffing to address the full service needs for all stormwater drainage assets, fully developing an asset management inventory, creating a financial plan that adequately address the needs of the City utility, and creating communication tools to share this information with both the City's citizens but also with critical partners in the Walnut Creek Watershed and Des Moines River Basin. Financial responsibility is a cornerstone of the City's value system. The current stormwater utility has near zero debt service and a positively growing fund. City construction projects comply with uniform standards for stormwater management required of development projects. The City selected a new project evaluation methodology to continue to be forward thinking and financially sound. The comprehensive analysis will support decision making, equity in rate structure, and policy to support the shared benefits and burdens of the water resources assets. The Water Resources Master Plan took care to reflect the authentic vision of the City and its citizens. The approved vision includes statements regarding the City's relationship with the greater watershed, its approach to resiliency, the quality of life provided for its residents, and creating amenities where one can recreate safely. The vision statement laid the foundation for the evaluation criteria for all capital improvement projects. A defensible score to compare varied projects was necessary for the utility. The benefit score was then balanced with the financial obligations and needs of the utility. The financial evaluation tool created for this project allowed for multiple scenarios and approaches to be evaluated and compared quickly. Finally, the implementation plan including a tactical step-wise approach for how to implement sustainable change and a dashboard to track key performance indicators was developed to monitor and measure progress year to year. The presentation will highlight the challenges and provide others a guide to how we incorporated previous studies to break department silos and make final recommendations cohesive to the utility, adapted a public engagement plan to pivot from broad education and instead associate education with a direct action (impervious cover with rate changes, infiltration potential with incentive program, and green stormwater infrastructure controls with a targeted pilot plan), and finally how we designed our management tools to be adaptive. Over time, we should improve and consequently, our goals should change. Our targets will be adjusted. Our tools reflect reality and therefore are not static.

The BlueKolding utility in Kolding, Denmark (population ~90,000) has implemented global real time control in 19 basins in the combined sewer network. The objective of the implementation was to reduce combined sewer overflows, minimize the risk of flooding in the city and at the same time reduce the needed extension of basin volume from 5,000 m3 to just 2,000 m3 to fulfill the demands and maintain the same level of service. This system has now been running, tuned and operated with success. BlueKolding has decided to take the next step and introduce cloud-based model predictive control in the system (Jess, 2018). The goal of this is to further reduce CSOs in the system, make it easier to implement and calibrate new control points, maintain the system and prepare for future developments. Background: The control algorithm used in BlueKolding, was developed in its original form during the Storm- and Wastewater Informatics project (Vezzaro and Grum, 2012; Vezzaro et. al., 2013). Since then it has been tested online and gone through several upgrades, which have added more robustness into the algorithm. The updated cloud-based control algorithm in Sewerflex is now part of AQUAVISTA, Veolia Water Technologies' global digital offer for real-time performance optimization of water treatment facilities. Methods: The MPC routine: The Sewerflex MPC routine is performing a coordinated 'smart' usage of the retention basin volumes in order to minimize combined sewer overflows. The control strategy is based on a dynamic risk assessment where the risk of overflow is calculated for every retention basin every 5 minutes, based on:

-- Actual retention basin filling and total retention basin volume
-- Predicted runoff volume from dry weather and rainfall forecast
-- The relative cost due to overflow (depending on i.e. recipient sensitivity)
-- Possible hydraulic emptying capacity of the retention basin equivalent to fixed gate position and/or pump operation
-- The actual hydraulic capacity of the downstream wastewater treatment plant.

Using a simplified model of the sewer system (Figure 1.1) together with a genetic optimization algorithm, the total overflow risk (all retention basins combined) is minimized, by changing the emptying capacities of the retention basins. The simplified model contains the retention basins, the catchment to the retention basins, the sewer connections between the retention basins and a downstream boundary (the wastewater treatment plant). By using a relative cost for overflow (cost/m3) at each location, the optimal solution - predicted optimal flows in connections between retention basins - takes into account which retention basins are more 'expensive' to use than others. This will try to locate any unavoidable combined sewer overflows at 'low cost' locations -- being the most environmentally robust locations. These settings can be changed at any time by the operator, allowing different CSO priority during the year to prioritize e.g. bathing waters and beaches in the summer time. Implementation and Operation: As the first step in the implementation, Sewerflex performance has been evaluated on 120 rain events, in an offline test environment where the MPC interacts with a hydraulic model representing the sewer network of Kolding. Performance of Sewerflex MPC is evaluated based on stability of calculated set-points and from calculated CSO volumes compared to similar calculations based on the current calibrated and tuned Sewerflex 1.0 code implemented in Kolding. In this test environment the Sewerflex MPC has improved the overall performance by approximately 10% based on CSO volume. In order to allow 'proactive' control, where the Sewerflex MPC algorithm can prepare the sewer network for future rain events before they occur (Water Smart Cities 2016), the algorithm will use both online measurements from the system, and weather forecast information. All these input data are visualized through SewerView, see Figure 1.2. As default, the SewerView map gives basic live information about the state of the sewer network, e.g. rainfall, flood risk and overflow. Following the test environment, the algorithm will be launched in 'offline cloud mode', meaning live visualization but no optimization of the sewer network. This phase of the project will allow for everyone to feel comfortable with the information given before online operation. The online operation is expected to be carried out in steps, allowing a slow transformation from the current online control to the cloud-based algorithm. The current RTC control will be kept as a fallback strategy. Further upgrades: The downstream WWTP is also upgraded to a cloud based real-time performance optimization using AQUAVISTA Plant, thereby achieving a holistic solution of a full optimized wastewater system. In dry weather, an ongoing development project (2017-2020) called 'BlueGrid' will add the functionality of flexible power consumption using demand/response at both the WWTP and sewer network, thereby achieving a flexible 'all weather optimization' which minimizes CSO during rain events and reduces costs for power consumption during dry weather (BlueGrid 2017).

This presentation provides an update on the progress of two PFAS fate studies through high-temperature biosolids processing systems. PFAS testing at two full-scale sewage sludge incinerators was recently completed under Water Research Foundation Project #5111 and results are expected for publication at the end of 2023. Preliminary PFAS sampling was conducted at the Silicon Valley Clean Water biosolids pyrolysis system and a lab-scale unit commissioned to mimic its operating parameters under a Water Environment Federation collaborative research project. Formal PFAS sampling is expected to occur this summer for the lab-scale unit and early 2024 for the full-scale pyrolysis system. This presentation presents several insights into test plan development and the status of analytical tools available to characterize the fate of PFAS through these systems. Key considerations include identification of relevant operating parameters and emission control devices for process technologies, limitations in reporting limits for gross organoflourine assessments, and recommended best practices for reporting PFAS detection and destruction and removal efficiency data.

For the past several years, the Water Environment Federation 'Recommendations to Improve the Stormwater Program in the U.S.' included 'Improve[ing] Stormwater Infrastructure Needs Data Collection.' The recommendation asks State Revolving Fund program managers to ensure that stormwater assets are included during Clean Watershed Needs Survey (CWNS) data to support advocacy for increased stormwater funding. Historically, less than half of states have reported stormwater asset needs in the CWNS. Today, few communities conduct proactive condition assessment and comprehensive master planning for stormwater systems and lack an understanding of long-term compliance costs. For stormwater needs to receive national recognition, program managers need to understand the condition of their assets, short and long-term costs, and the staffing and labor necessary to sustain their programs. If we can't clearly define our infrastructure, resiliency, compliance, and planning needs, we can't expect to get critical funding for it. In 2022, the EPA is conducting the next round of CWNS. This is an important opportunity for stormwater programs. The states often relying on local wastewater utilities to generate documentation that meets EPA standards. To meet these standards, all documents must clearly define the NEED, the SOLUTION, and the COSTS of the solution. Typical wastewater supporting documents include Asset Management Plans, Intended Use Plans, various grant and loan applications, and Facility Plans, among others. Stormwater programs may have documents like Preliminary Design Reports for clean water obligations under Combined Sewer Overflow Long-Term Control Plans, Watershed Management Plans (name varies among states) for impaired waters with implementation cost estimates, grant or loan applications, or Stormwater Master Plans, among others. Many stormwater programs, however, do not have these more traditional engineering reports or capital. EPA has suggested that alternative documentation is permittable, if approved by the agency. This presentation will provide an overview of alternative documentation approaches considered in EPA Region 1, the documentation generated for stormwater needs, and a detailed overview of the approach taken with the state CWNS coordinators. It will complement the EPA CWNS update proposed in an abstract from the EPA National Office, providing additional details on alternative documentation. It could be set up as part of a panel discussion suggested by NMSA on the future of the CWNS and how the stormwater community can better position for future needs documentation.

Municipal wastewater treatment plants (WWTPs) generate and emit greenhouse gases (GHG) throughout the plant via a number of activities and operations such as pumping, aeration, mixing, and sludge dewatering and digestion. As part of the collective efforts to achieve a 2050 'net-zero' emission goal, public utilities such as New York City, City of San Francisco (CA), City of Edmonton (Alberta), City of Calgary (Alberta) and Salt Lake City (UT) have started including quantitative sustainability indices as important factors to be evaluated when major capital improvements and O&M modifications are being planned for their water infrastructures. GHG emissions is one important sustainability index. In Canada, GHG emissions from major WWTPs are required to be reported to Environment and Climate Change Canada. A typical WWTP produces three major types of GHG: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), both directly and indirectly. Direct GHG emissions occur at the site due to fuel consumption and the physical, chemical, and biological treatment processes. Those emissions are fugitive, heterogenous, and time-varying. Currently, three approaches are available for estimating GHG emissions from WWTPs. The first approach uses 'emission factors', such as the IPCC database, to estimate the rate at which a pollutant is released into the atmosphere (or captured) as a result of specific process activities. The second approach involves 'engineering principles and judgement' to estimate emissions based on engineering principles and judgment, using knowledge of the chemical and physical processes involved. Neither the first nor the second approach involves direct measurements. Rather, empirical coefficients are assumed which, often times, are not representative of the actual emissions at specific treatment facilities. The third approach may utilize emission monitoring systems such as the flux chamber method or the tracer method, which unfortunately are all based on point sampling, unable to capture the spatial and temporal heterogeneity of the GHG emissions at WWTPs. Due to the lack of monitoring method, so far, water utilities still rely on using the first two approaches for estimating their GHG emissions. Therefore, a robust field measurement approach is needed that is capable of capturing the dynamic, fugitive emissions at WWTPs. To achieve this, we have developed a hybrid method integrating the long range open-path Optical Remote Sensing (ORS) technology and inverse Dispersion Modeling (iDM) to continuously quantify GHG emissions from the wastewater treatment facilities on a real-time basis. The ORS instrument used in the field campaign consisted of an open-path tunable diode laser spectroscopy (OP-TDL) for CH4, a CO2 sensor, a portable meteorological station and 3-D sonic anemometer to record temperature, air pressure, relative humidity, and wind vector, and an open-path fourier transform infrared (OP-FTIR) for N2O. Both the OP-TDL and OP-FTIR scanned along multipaths to capture the 'big picture' of GHG plumes for dispersion model input for emission estimation. Backward Lagrange Stochastic model (bLS) was used to estimate the methane emission rate in real time. The system was first applied in the Bonnybrook WWTP, with an average daily flow of 324 million litre per day, located in Calgary Canada. Field measurements were conducted in autumn 2021, and spring of 2022. Signals were continuously captured and inverted to calculate the path-integrated concentrations of GHGs, with which the iDM model calculates the emission rates. The measured emission rate for methane ranged from 64-97 kg/hr, with the corresponding emission factor of 0.04-0.06 kgCH4/kgBOD5. For carbon dioxide, the measured emission was averaged at 0.29 ton/yr. Seasonal variations have been noticed. The team is currently working on calibrating a BioWin process model for simulating/predicting GHG emissions using the field measured emission data. Additional field measurements are also planned at a WWTP located in southeast US. This presentation will describe the newly developed ORS-iDS methodology and present the detailed results of continuous measurement from the field campaigns conducted during different seasons. The site-specific emission factors (EFs) developed based on the measurements have been compared with the literature and the IPCC values, which will also be presented to show the inaccuracy of using empirical, non-site specific emission factors. The diurnal and daily variation of emissions will also be characterized and presented.

Purpose/Goal: This presentation will provide knowledge for all utilities, but more specifically medium to smaller communities who do not have the in-house experience and expertise to establish how much data should be collected and when data should be collected to maximize their funding to develop a comprehensive Capital Improvement Plan (CIP) and Operations & Maintenance (O&M) Program. Benefit: Participants will learn how to provide self-evaluations of the capabilities of their utility, what their goals are (i.e., Project specific, long- term planning or O&M) and selecting the right Investigations and/or inspections to perform, understanding when it is the right time to perform this work and what to consider before selecting their next steps in the planning process. Yes, having a lot of data can be exciting but too much data can be detrimental and costly to a Utility. Overview of Presentation: Utilities continue to ask the age-old question 'How can I afford to fix my aging sewer system?'. In the 2017 ASCE Report Card, our National Wastewater System was given a D+ grade with a projected investment of $4.59 Trillion (Yes, Trillion Dollars) to fix our aging infrastructure. Our collection systems are the 'veins' to our wastewater system. Without the needed investment communities are facing failing sewer systems which could potentially result in injury or loss of life impact on water quality and environmental impacts. It is unfortunate there are still so many people who do not understand the value of water and prioritize cell phones and cable as a necessity over water. This results in unpaid sewer bills decreasing available funding to provide even the basic of O&M on our collection systems. While the COVID-19 Pandemic raised the awareness of how testing of our wastewater provided the ability to track and identify hot spots for focused testing and reporting to hospitals in the impacted areas, many people have been left without jobs and the ability to pay their sewer bills. This has added another layer of unpaid bills on top of existing challenges further decreasing available funds to do even basic work in the collection system. While Federal and State Finance is available, funding is often limited for many medium- to small utilities to complete their projects. In addition, some communities are facing EPA mandates forcing them to focus on immediate needs leaving well needed O&M and upgrading of assets left even further behind. You are probably asking yourself 'what does this have to do with 'What Factors Should I Consider Before Performing Inspection and/ or Investigations of my Sewer System?'?'. Well, it all comes down to collecting the right data at the right time. Our industry loves having discussion on 'Big Data'. 'Big Data is defined in our industry as having a large volume of data. Having a large volume of data for engineers and analysis is intriguing and exciting but can become overwhelming for a utility. As previously mentioned, funding is limited for many utilities and project priorities may (more than likely will) change over a handful of years. While many utilities rely on consultants and manufacturer to guide them in the process of collecting data some choose to collect the data on their own to hopefully save money. Whether a utility elects to perform data collection on their own or choose to hire a consultant/manufacturer it is important for several factors be considered including: - Why are we doing this work? - What are the results we are looking for? - What do we want to do with the Data once collected? - How do we know what data to collect? - What Investigations and/or Inspection do we need to do? - What in-house experience and expertise do we have? - Do we have the time and resources to analyze the data once collected? - What technologies work best for what we needs? - What is our available funding this year, next year or in five years? These are not simple questions and require a thoughtful process by the utility. Too many times utilities share their stories of system failures that have had varying results and have been costly to the utility. In some cases, the data exist but due to lack of resources, time, or inexperience to evaluate the data the problems in the system were not identified. Many times, data is collected too far in advance of available funding to complete projects. For example, spending money during a planning phase to identify specifics on ovality, wall thicknesses etc. provides the utility with good data, but more than likely will be repeated once funding is available for the project to determine the exact type of rehabilitation. The money spent early on, could have been used to design and construct another project. The presenter will bring their experience in working with utilities for over 32 years helping to guide them through the process. Status/Conclusion: This presentation will provide utilities with steps on walking through the process of establishing a successful program, by understanding the above listed factors.

PFAS in biosolids have undoubtedly become a major topic and concern for the public and the industry. Some state regulations are outpacing federal regulations, forcing utilities to consider alternative biosolids management strategies. Therefore, interest in thermal technologies has grown substantially. New incinerators are difficult to install, rendering torrefaction, pyrolysis, and gasification as possible treatment process options. However, information is scarce on the mass balance of PFAS, and specifically fluoride, through these processes and their end products. This project will i) develop methods to quantify PFAS, total organic fluorine, and inorganic fluorine in end products, ii) generate lab-scale data on the fate of PFAS and fluorine through torrefaction, pyrolysis, and gasification, and iii) generate an LCA tool that is user friendly to incorporate critical aspects (e.g. energy, carbon footprint, as well as PFAS fate) for assessing thermal technologies.

Introduction Greenhouse gases (GHGs) such as methane and carbon dioxide are common byproducts of chemical reactions within collection systems but are less commonly considered by municipalities during sustainability analyses. Understanding the scope of the impact of these GHGs requires an understanding of their relative effects on global warming. The Intergovernmental Panel on Climate Change (IPCC) created the Global Warming Potential (GWP) metric to compare different GHGs via an equivalency to carbon dioxide (CO2e), the reference gas. Methane has a GWP of 28, meaning that it has 28 times the impact on global warming as compared to carbon dioxide. After outlining and studying the theoretical reactions of sulfide generation in wastewater collection systems and calcium nitrate dosing for sulfide prevention, we hypothesize that dosing calcium nitrate for odor and corrosion control significantly reduces the overall impact of GHGs emitted by wastewater within collection systems. Objective In the proposed paper, we will set the groundwork to understand the theoretical mitigation of methane generation resulting from calcium nitrate dosing in US wastewater collection systems, as well as test the theoretical mitigation with a use case in Manatee County, FL. Theoretical Methodology In an untreated collection system, an anaerobic BOD reduction occurs in the wastewater as follows (all reactions assume methanol as carbon source for simplicity and consistency in comparison): SO4= + 4CH3OH → S= + 4H2O + 2CH4 + 2CO2 In a collection system being dosed with calcium nitrate for sulfide prevention, the intent is to drive an anoxic BOD reduction in the wastewater instead of anaerobic, which occurs as follows: 6NO3- + 5CH3OH → 5CO2 + 3N2 + 7H2O + 6OH- While more CO2 is generated in this reaction versus the anaerobic reaction, no methane is produced. Based on the comparison of these reactions and the GWP of methane, for every 1 lb of sulfide prevented, 25.25 lbs of net CO2e is prevented. Assuming that all GHGs are fully released from the wastewater into the atmosphere, we calculate that a maximum of 11.83 lbs CO2e can be prevented per gallon of 3.5 lb NO3-O/gal solution dosed into collection systems as part of an odor prevention program. In fiscal year 2021, theoretically a maximum of 71,887 metric tons of CO2e could be prevented as a result of all the chemical shipped to customers in the US by Evoqua for use in odor prevention. While it is recognized that a municipality choosing an odor prevention program will be incurring additional GHG emissions via transportation, manufacturing, provision of service, etc, the analysis of the use case study will focus explicitly on changes in GHG emissions specifically related to the theoretical reactions described above in relation to calcium nitrate dosing into the collection system. Application Manatee County Utilities (MCU) operates an expansive collection system involving over 800 lift stations (LS) with many long retention time force mains. The collection system conveys over 22 million gallons per day (MGD) of flow across three service areas to a corresponding wastewater reclamation facility for each service area. To significantly reduce corrosive conditions, MCU set a target atmospheric hydrogen sulfide (H2S) control objective of 20 ppm average and 50 ppm peak. MCU utilizes multiple solutions within their program, including calcium nitrate and pH shift technologies, to achieve these goals. For additional knowledge and to establish a baseline, we decided to also test the methane mitigation from dosing other chemicals by testing sites treated with magnesium hydroxide and calcium hydroxide. Four portions of the collection system were selected for sample testing. Two portions, N4B force main to N1B LS and Greenbrook 2 force main to Lakewood Ranch Riverwalk LS, are treated with calcium nitrate. Another section, Pope Road Master LS, receives flow treated with magnesium hydroxide. The final section, Tara 20 LS, receives flow treated with calcium hydroxide. A portable H2S gas monitor was deployed at each injection point and each control point to log continuous sulfide measurements. Grab samples were taken for dissolved sulfides, pH, temperature using gas detector tubes and a calibrated Hach portable pH probe. Gas samples were collected from the headspace of the wet wells using tedlar bags and CO2/CH4 concentrations analyzed via GC/MS by a certified third-party lab. Samples were collected at periodic intervals based on route efficiency and record keeping. Results and Discussion From six sample sets taken from the N4B force main to N1B LS, five showed a decrease in methane concentration from the injection point to the calcium nitrate-treated control point, with an average decrease in methane concentration of 38%. Half the samples showed an increase in CO2 emissions at the control point. Similarly, five of the six sample sets collected at the Greenbrook 2 force main to Lakewood Ranch Riverwalk LS saw a decrease in methane concentration with an average decrease of 13%. CO2 results from Greenbrook 2 mostly decreased in concentration, but only by small fractions. More data is needed to draw conclusions regarding CO2 results. Overall, methane was broadly reduced with nitrate treatment, with an average of 24% reduction in methane emissions during nitrate dosing. The CH4 concentrations at Pope Road Master LS treated with magnesium hydroxide were similar to that of the control points treated with calcium nitrate but showed lower CO2 values. The CH4 and CO2 concentrations at Tara 20 LS treated with calcium hydroxide were similar to the results obtained from the control points of N4B force main to N1B LS and Greenbrook 2 force main to Lakewood Ranch Riverwalk LS. This paper will go further into the analysis of the results, discussing outliers, testing challenges, and comparing test results to theoretical assumptions. We will also discuss the immediate and future steps to support the project, such as utilizing a continuous method of data collection for more robust data to decrease standard deviation. Another municipality has expressed interest in continuing the research within their collection system, which will provide more information on methane mitigation regarding different collection system designs, climates, and wastewater characteristics. We will also discuss the long-term sustainability target of evaluating GHG emission impacts from the full life cycle of calcium nitrate dosing for odor control, including manufacturing and transportation impacts. Benefits The theoretical mitigation calculation method would allow any municipality to calculate the methane mitigation they are achieving as a result of their odor control program utilizing calcium nitrate, making it easier to quantify the sustainability benefit of the program and communicate it with their community. As sustainability metrics become more important, including GHG metrics, these calculations can play a critical role in quantifying the overall GHG impact of the wastewater treatment and collection system and providing an additional method of GHG reduction. In the case of Manatee County (the County), the benefits are less theoretical. The County conducted a GHG Audit that was completed in June 2020, and while it took into consideration the wastewater treatment plants and overall utility operations, it did not examine GHG emissions from the collection system. This audit recommended a reduction of nearly 3,000 metric tons of CO2e a year to reach net zero by 2040. Understanding GHG emissions and particularly methane mitigation of the odor prevention program could allow MCU to demonstrate a more robust view of the wastewater contributors towards GHGs for the County as well as provide potential solutions towards the recommended reduction goal through a method that neither party may have considered beforehand. Whether or not wastewater authorities or utilities have their own GHG goals, they can provide benefit to their municipalities that are more likely to have them, as well as build public support through communicating the sustainability impacts of their operations.

Introduction: The Truckee Meadows Water Reclamation Facility (TMWRF), serving the cities of Reno and Sparks, Nevada, has had historic difficulty of their dewatering operation with their biosolids averaging just over 16% total solids (TS). This poor performance is largely the result of TMWRF running an enhanced biological phosphorus removal (EBPR) process, which has limited their maximum mechanical dewaterability due to the large amount of dissolved phosphate and volatile solids in their centrifuge feed. Centrifuge replacement in 2015 further exacerbated the dewatering performance with the newer machines requiring high polymer dosages and delivering consistently poor centrate quality. Since June of 2020, TMWRF has carried out an alternative strategy to their dewatering operation by sending the thickened waste activated sludge (TWAS) produced in their EBPR process directly into their centrifuges, bypassing all digestion. The impacts of this change have been major and wide-reaching with effects on biosolids character and volume, chemical usage, plant wide nutrient removal, biogas production and quality, and centrate treatment. This presentation will discuss the background of the facility including their historically low-quality performance as well as the many facets that have been positively impacted by carrying out this change to direct TWAS dewatering, This presentation will also examine the role of this operating strategy in the long-range planning of the facility. Dewatering Background: TMWRF, a 30 million gallon per day (MGD) facility, had operated the same three centrifuges since 1983, producing just over 15% TS biosolids with a centrate quality of slightly over 400 mg/L total suspended solids (TSS). To improve both process parameters and energy demand, a centrifuge replacement took place in 2015. While the centrifuges were specified to produce a 22% TS biosolid from a polymer input of 23 active pounds per dry ton of solids, these machines have averaged 16% TS biosolids with a typical dosage of 44 active pounds per dry ton of polymer. While some marginal improvement occurred in the biosolids, the centrate produced from these machines worsened, averaging approximately 1,100 mg/L TSS which has burdened downstream centrate handling processes. With continued struggles to produce a higher solids content product from the centrifuges, in August of 2019 TMWRF submitted their sludge for further laboratory analysis to determine the maximum mechanical dewaterability. The results indicated that the sludge grab sample had a maximum achievable TS content of 15.8%. Also noted was the high phosphate concentration (292 mg/L) and volatile solids content (73.8%) present in the sludge liquor. Streaming current detector measurements were carried out to quantify polymer demand and indicated an optimal polymer dosage of 40 active pounds per dry ton. Direct TWAS Dewatering Study and Results: Given that many of the factors negatively affecting dewaterability stemmed from the TWAS sludge and were independent of the centrifuge, a study commenced to determine to what extent this sludge could be dewatered directly. With no beneficial reuse customers, the only standard to meet for TWAS biosolids was to pass a Paint Filter Liquids Test in order to be landfill compliant. After several discrete trials demonstrating this was possible, full-scale direct TWAS dewatering was implemented on June 9, 2020. After the passing of several detention times within the digesters, TWMRF experienced marked improvement in sludge dewaterability of their digested sludge with it being solely comprised of primary sludge. This digested primary sludge demonstrated the ability to consistently produce over 20% total solid biosolids with the highest achieved solids content of 28%. The waste activated sludge has shown to have nearly the same level of dewaterability as the historic sludge, averaging near 15% total solids without presenting any disposal concerns. In the time since beginning the experiment, there have been profound impacts throughout the treatment plant. The centrate, which had historically provided nearly 30% of the ammonia loading to the facility, saw a rapid and sustained decrease of 47%. This has significantly improved the nitrification and denitrification operations present at TMWRF as well as enabled more capacity for their nitrifying trickling filters. This reduction in ammonia translates to a lower loading into the denitrification process, resulting in an annual methanol savings over $200,000. Through the direct dewatering of the TWAS, a sharp decline in concentration of orthophosphate within the centrate has also been observed. This concentration has reduced from approximately 250 mg/L to less than 100 mg/L and as a result has removed the need for centrate sidestream phosphorus removal. The decommissioning of this additional treatment and associated chemical consumption has created a benefit of nearly $250,000 per year. The other large impact to chemical usage that TMWRF has experienced is a reduction in polymer usage. Waste activated sludge is thickened in a dissolved air flotation thickener and had previously utilized polymer to maximize TWAS total solids. This dosing has since been discontinued since the centrifuge design parameters require a lower feed solids content. Overall, this has led to a 20% reduction in polymer use, creating an annual savings of approximately $170,000. The continued duration of this project has identified other numerous benefits such as a 26% reduction in the hydrogen sulfide of the digester biogas, consistent phosphorus loading reducing aluminum sulfate demand, ability to achieve higher centrifuge hydraulic loads, and realized capacity of the digestion process. The demonstrated benefits of this full-scale experiment have resulted in its recommended implementation in TMWRF's latest facility plan, prompting an addition to TMWRFs Capital Improvement Program to begin analysis for making it a permanent process. This paper will outline the common challenges that EBPR sludge has on dewatering and the historical poor performance solids processing of TMWRF. Insight will be provided on a variety of operating configurations such as pure TWAS dewatering versus TWAS/digested primary sludge blended centrifuge feeds and the impacts of these on centrifuge outputs and total biosolids volumes produced. Detailed discussion will occur on the utilization of direct TWAS dewatering as an effective nutrient removal process not only for ammonia and phosphorus, but also for organic nitrogen.