Conference Papers

Background: In 2018, the City of Temple, Texas, and the Environmental Protection Agency (EPA) agreed upon an administrative order for the purpose of compliance with the Clean Water Act (CWA) regarding sanitary sewer overflows (SSOs) from the City's sewer collection system. The City of Temple's wastewater system consists of over 2.1 million linear feet of gravity sewer mains, over 95,000 linear feet of force mains, 4,000 linear feet of pressurized siphons, twenty-eight lift stations, approximately 6,400 sanitary sewer manhole structures, and two wastewater treatment plants all divided into six sanitary sewer basins. As part of the administrative order, the City of Temple is to conduct a condition assessment of the existing sanitary sewer infrastructure and perform rehabilitation/replacement of defective infrastructure. With a system of significant size, data collection and management processes for the condition assessment become of utmost importance. The City of Temple partnered with RJN to execute the condition assessment requirements and develop a remedial program. This presentation will provide an overview of the data collection, management, analyses, and data delivery methods undertaken in this multi-year condition assessment project and how the City of Temple is utilizing the data to mitigate Infiltration/Inflow (I/I) from entering their system and reducing SSOs. Methodology: Data collection involves various field activities. Data collection began with flow monitoring of the entire system. In Spring 2019, thirty-six meters and eight rain gauges were used to collect wastewater flows and rainfall for a 74-day period for the hydraulic model calibration. Over 23,000 data points were collected through the flow monitoring. Data collection for the condition assessment includes manhole inspections, closed-circuit television (CCTV) inspections, smoke testing, and dye testing. A portable manhole scanner was the technology selected for manhole inspections as it eliminates the risks involved with man-entry inspections and provides multiple views of the entire manhole, which is useful during quality control. To date, over 3,500 manholes have been inspected and coded using the National Association of Sewer Service Companies (NASSCO) Manhole Assessment Certification Program (MACP) method. Per the administrative order, CCTV inspections are required only for the non-plastic sewer pipes. To date, over 275,000 linear feet of non-plastic sewer pipe has been inspected and coded using the NASSCO Pipeline Assessment Certification Program (PACP) method. The dual-blower method was selected for the smoke testing with GPS points collected at the defect location through an iPad and a survey form. To date, over 1,120,000 linear feet of gravity main sewer has been smoke tested, with over 2,500 defects identified. Dye testing (20 setups) was used to quantify I/I from significant defects identified during smoke testing. All the collected data is integrated into various programs to assist in the management and analysis. The flow monitoring data was used in the hydraulic model with Innovyze® InfoWorks ICM. Using the hydraulic model, an I/I analysis was performed using the collected flow monitoring and rainfall data that helped identify the I/I within each basin. RJN utilizes its proprietary software, RJN Project Management (RPM), to keep all records of the manhole inspections along with smoke and dye testing observations. This helps keep track of the progress and findings from the field investigations. Two analyses are performed, an I/I analysis and a rehabilitation analysis. For the smoke and dye testing, RPM is used to perform both the I/I and rehabilitation analysis. Because the manhole and CCTV inspections use MACP and PACP coding, the I/I and rehabilitation analyses are performed through Innovyze® InfoAsset Planner. Through this program, RJN developed rehabilitation decision trees that utilize the MACP and PACP databases to determine asset-specific rehabilitation or replacement recommendations. At the end of the first year, the data deliverable consisted of the manhole scans, CCTV videos, smoke defect photos, and MACP and PACP Access databases. This method provided the data in separate formats, some of which required a further understanding of Access databases. By the end of the second year, RJN had developed an online platform, Clarity®, that provides the data in one location in a user-friendly format and gives the City of Temple access throughout the project allowing city staff to view the progress from data collection to finalization. The City of Temple uses Clarity® to view the GPS location of service line defects and verify proper sector categorization. They also pull images and datasheets for easy uploading to their Cityworks® work order system. Using these programs, RJN and the City of Temple are using data-driven decisions in the plan development and execution of the condition assessment program. The I/I analysis results from the flow monitoring data were used to develop the multi-year condition assessment program based on the excessive I/I identified within each sanitary sewer basin. Prioritization for the condition assessment was given to the basins with the highest I/I, along with consideration of annual budgets. The I/I and rehabilitation analyses for the condition assessments of each basin provide a data-driven remedial action plan, which include operations and maintenance (O&M), rehabilitation, or replacement. In addition, asset rehabilitation prioritization for each of the inspected assets is determined based on cost-effectiveness where the estimated contributing I/I and the cost of rehabilitation are compared. These developed prioritization metrics assist the City of Temple in determining which remedial actions to complete first and which can be done in-house or have a contractor perform the repair. Conclusion: Although using multiple programs for the data collection, coding, management, and analysis, these programs facilitate tracking the collected data, evaluating the identified defects and asset conditions, determining the appropriate remedial recommendation, and presenting the data to the City of Temple. Condition assessments using these methods and programs have been completed for two sanitary sewer basins, and we are currently working on the third. Through the collaboration and data transparency with the City of Temple staff, RJN has been able to improve the data deliverable to a user-friendly format for integration with Temple's work order system. The City of Temple has addressed the high-priority rehabilitation recommendations as provided by RJN for the defects identified through smoke testing from the first year's project. The City of Temple is also working on completing the manhole and sewer line rehab, also categorized as high priority. Although not all the remedial recommendations from the first condition assessment have been addressed, Temple has realized a 50% reduction in SSOs in this first basin proving the metrics derived for the remedial prioritization successful.

The Narragansett Bay Commission (NBC) owns and operates Rhode Island's two largest wastewater treatment plants along with extensive infrastructure of interceptors, pump stations, and combined sewer overflow (CSO) structures. In 1992, NBC entered into a Consent Agreement with Rhode Island Department of Environmental Management (RIDEM) that established a three-phase CSO control plan with the goal of reducing annual CSO volumes (98%) and shellfish bed closures (80%). Phases I and II of the CSO Control Program were completed in 2008 and 2015, respectively. Phase III, the final phase of the program, commenced with a re-evaluation of the original plan in 2015, including a financial capability assessment to incorporate NBC's affordability goals into the Phase III implementation schedule. Phase III final design phase started in 2018 for 12 projects, and the first projects started construction in 2021. The largest of these projects is the 2-mile long, 30-ft finished diameter, 150-ft deep rock Pawtucket CSO storage Tunnel, which is being delivered as a design-build project. The tunnel construction is scheduled to be completed in early 2024, and construction of the tunnel dewatering pump station and screening facility will start in early 2024. This presentation will provide a program progress update, diving into construction challenges and lessons learned including the following: -Sequencing of design of tunnel with follow-on work: design development of tunnel elements at interfaces with surface projects; -Regulatory coordination: multiple approvals and permits in a dynamic project delivery environment; -Management of excavated tunnel material: what do you do with one million tons of 'muck'? -Material and labor cost escalation: balancing schedule vs. cost impacts to labor and materials; -Groundwater dewatering and treatment: approach to managing and pre-treating groundwater from large excavations prior to discharge; -Inspection and repair of existing Providence Tunnel: taking a look at condition of the existing tunnel in operation since 2008. The presentation will conclude with a look ahead to the schedule for completion of the remaining near surface projects and anticipated commissioning and start-up of the Phase IIIA system in 2027.

Introduction The waste activated sludge (WAS) produced in Washington Suburban Sanitary Commission's (WSSC Water) Water Resource Recovery Facilities (WRRFs) is historically known to have relatively poor digestibility, even with thermal hydrolysis pretreatment (THP). In agricultural waste management, it has been a common practice to co-digest a poorly biodegradable feedstock with an easily biodegradable feedstock to improve the overall digestibility of the former (Karki et al., 2021). Since primary sludge (PS) generated in WRRFs usually possesses much better digestibility over that of the WAS, this study tested the hypothesis whether blending PS with WAS can increase the biodegradability of WAS. Because WRRFs need to use more coagulants such as alum to precipitate more PS for the blending, the impact of alum on the WAS biodegradability was also taken into consideration. Therefore, this study investigated the effects of PS:WAS blending ratio and alum doses on the WAS digestibility in a THP-anaerobic digestion system. Meanwhile, this study also tested the hypothesis that blending PS with WAS may produce more recalcitrant dissolved organic nitrogen (rDON) as a result of Maillard reaction in THP (Zhang et al., 2020). Maillard reaction occurs between the carbonyl groups of reducing sugar and the amino groups of proteins (Hodge, 1953). Since PS and WAS are mainly composed of carbohydrates and proteins, respectively, and the typical THP temperature at 165 0C is ideal for Maillard reaction, it is a reasonable prediction that more rDON may form within THP fed with PS and WAS blending than without. Materials and Methods Experimental design Dewatered WAS and PS cake samples with around 20% total solids (TS) were collected from two WRRFs of WSSC Water. Depending on the Al that came with each type of cakes, additional Al was supplemented according to the Al doses designed in Table 1. Basically, more Al was supplemented when more PS was blended to simulate the scenario when more alum was consumed for more PS production. A jar test was performed to estimate the Al dose it took to produce enough PS for the blending ratio in Table 1. Then, the PS and WAS cake samples were either individually processed in THP-anaerobic digester (AD) systems as controls or blended according to the blending ratio as summarized in Table 1 to study the blending effects during this three-phase study. All cake feedstocks were diluted to 16% TS prior to feeding into the CAMBI pilot THP system operated at 165 oC for 30 min. The THP effluent was further diluted to 9% prior to being fed into the four pilot mesophilic AD systems. These ADs were inoculated with fresh effluent sludge from a full-scale THP-fed mesophilic AD at DC Water. The steady-state digestates were analyzed for understanding the impacts of PS:WAS blending ratio and alum doses on WAS digestibility. In general, four phases of studies described in Table 1 were performed with controls to understand the effects of 1:1 blended with low Al in phase I, 1:1 Blended with high Al in phase II, and 3:1 Blended with high Al in phase III. rDON determination The four AD effluent samples from Phase II study in Table 1 were subjected to a rDON test. This test was divided into two steps including air stripping and aerobic incubation. The goal of air stripping was to reduce the total ammonia nitrogen (TAN) of the AD effluent to lower than 200 mg/L. This is because the TAN concentration is significantly greater than that of dissolved organic nitrogen (DON) and thus may overshadow the DON level readings which are calculated as the difference between soluble Kjeldahl nitrogen and TAN. The aerobic incubation aimed to remove the biodegradable DON, and in turn the remaining DON in the system can be regarded as rDON. Results WAS digestibility The volatile solid reduction (VSR) has been used as an indicator of sludge digestibility (Luo et al., 2022). Hence, the steady-state VSR of all digesters were determined. Assuming the VSR of PS does not change with and without blending, the blended WAS VSR can be calculated and compared to the control WAS VSR without blending and Al supplementation to assess whether the WAS digestibility has been improved. As can be seen from Figure 1, the WAS VSR did not change with and without blending with PS at a 1:1 ratio without external Al addition. This means blending PS at this low ratio does not improve the WAS digestibility. When a low dose of Al was added to increase the blended sludge background Al level from 1.49 to 1.95%, it can be seen that WAS VSR decreased about 2%, indicating the inhibitory effect of Al on WAS digestion. The reduced hydrolysis rate as a result of binding between Al and protein in WAS has been regarded as the reason accounting for the WAS digestibility decrease (Luo et al., 2022). This conclusion was reinforced by the fact that WAS VSR substantially decreased to 15% when further increasing the background Al level from 1.95 to 2.85% without changing the blending ratio (Figure 1). It is interesting to see that tripling the PS blending ratios can bring WAS VSR back to 28% even when the same high Al dose (2.85%) was used in the sludge mixture. These observations suggest that co-digesting PS with WAS does not directly improve WAS digestibility; however, adding more PS does mitigate the Al inhibition on WAS digestion. It was reported in a previous study that Al is expected to play greater binding effects on WAS than on PS because the affinity of Al to proteins in WAS is higher than that to the polysaccharides in PS (Luo et al., 2022). Therefore, PS might be able to prevent the binding between Al and protein in WAS by acting as a barrier. Hence, the reduced binding potential between Al and protein in WAS could mitigate the Al inhibition on WAS digestion. rDON The centrates containing DON generated from all four digesters in phase II study (Table 1) were exposed to aerobic incubation for 14 days. Profiles in Figure 2a showed that centrates from PS only and blended sludge with high Al addition contained the least DON. PS does not contain much protein and thus is reasonable to produce less DON. Al ¬ is known to be capable of precipitating DON (Zhang et al., 2020), which may explain the low DON level in centrate with high Al addition. In contrast, the DON levels in both WAS only and blending sludge without external Al addition were two times greater. The same trends were also observed with the residual DON, namely rDON in Figure 2b. It should be pointed out that the rDON level in blended sludge was actually substantially greater than the average level from the two individual sludge without blending, indicating extensive Maillard reaction might have occurred when PS and WAS were blended. Conclusions It can be concluded from this study that blending PS does not directly improve the WAS digestibility. Instead, blending more PS did mitigate the inhibitory effect of Al on WAS digestion. However, blending PS with WAS promoted rDON formation due to Maillard reaction between the two types of sludges.

As recognized by WEF Immediate Past President Lynn Broaddus, 'stormwater management is one of the most dynamic segments of the water business.' In this evolving field, one of the best ways to move the industry forward is to identify and promote successful and innovative practices that make a meaningful and lasting impact on the world around us. To that end, the National Municipal and Green Infrastructure Awards (the Awards) were established in 2015 to recognize and highlight high-performing municipal separate storm sewer system (MS4) programs and communities that are incorporating, developing, or innovating best practices for others to emulate. These awards provide greater momentum to the stormwater industry by providing publicity and peer recognition to the industry's 'best and brightest.' Every year, WEF accepts applications from MS4 programs across the country to be evaluated and considered for these awards. Applications are reviewed by a work team made up of sector experts with a broad collective background in stormwater practice. Programs are recognized for performance in the categories of innovation and program management, as well as combined high scores in both categories. This year the City and County of Honolulu (Hawaii) MS4 Program took first place in the Program Management category for Phase I communities, and the Central Massachusetts Regional Stormwater Coalition, was scored highest for Phase II permittees. Gwinnett County (Georgia) Department of Water Resources was the Phase I winner for Innovation, and the CIty of Alexandria, Virginia took home first for Phase II communities in that category. Finally, Anne Arundel County (Maryland Bureau of Watershed Protection & Restoration and the Capitol Region (Minnesota) Watershed District took home Overall Performance wins for Phase I and Phase II communities, respectively. This session will briefly detail the history and impetus for the Awards. From there, we'll quickly describe how programs can apply to be considered for the awards, and the review process that the work group undertakes to review applications. The bulk of the presentation will be spent highlighting this year's winners and why they were chosen. For this session, winners of the 2021 Awards have been invited to present their program aspects that go above and beyond their regulatory requirements, and three of the winners have indicated that they will be able to participate.

Pressurized pipeline infrastructure (both water and wastewater) throughout the US is reaching a critical stage of critical condition. The outlook of this infrastructure as recently described in ASCE's 2017 Report Card (and statewide individual report cards in each successive years) shows that the trend line of system deterioration is getting worse for both water and sewer conveyance systems. This trend will not change direction in a positive manner, unless a number of critical steps are undertaken. The report insists that the only feasible way to address this rapidly increasing rate of pressurize pipelines for both water wand sewer infrastructure deterioration is through asset management. Specifically, it states that 'Asset management provides utility managers and decision-makers with critical information on capital infrastructure assets and timing of investments. Some key steps for asset management include making an inventory of critical assets; evaluating their condition and performance; developing plans to maintain, repair, and replace assets; and funding these activities'. The ones that are hardest are also the ones that are, for the most part, pressurized 24/7/365. To turn this corner and establish better and more reliable information on the actual condition of these buried and essential pressurized assets, several recent (and very cool) advances in performing both external and internal inspection and assessment of water mains, force mains, valves, hydrants and other ancillary facilities has moved the level of understating condition and remaining useful life (RUL) to new levels. With these technologies and established protocols for determining their associated risks, cities and utilities are starting to bring this all together under effective asset management (AM) planning so that the three pillars of AM can be managed: sustainability, reliability, and efficiency. This presentation will highlight and describe both established and new technologies in the industry's large and ever-expanding toolbox to cost-effectively move through even the largest system representing several hundred miles of pressurized pipeline in a tiered or stepwise strategy to identify those assets that are considered highest in priority and in eminent state of operational failure. This process is illustrated in the following Exhibit A.We will discuss those technologies that fit under the four stages of assessment including those that are particularly effective using science-based systems such as acoustics, correlators, HDCCTV, sonde, GPR, ultrasonic tomography, electromagnetics, and transient wave propagation. These technologies represent a wide spectrum of manufacturers and providers. The presentation will then show how date from these sources can be used, alongside of updated and newly developed NASSCPO PACP codes to compile information from each level of assessment, transform this information into meaningful and representative condition grades and scores and then create prioritized reports for capital improvement and planning projects. The work flow process that will be discussed is shown in Exhibit B. Time permitting, we will show one additional step in the process of moving everything toward an asset management program which will enhance capital improvement, create prioritized planning (again based on risk-managed approach using a traditional risk matrix), and develop preventative maintenance activities and their relative work order frequencies. By using advanced field-based inspection technologies and incorporate them in a sequenced manner, the resultant engineered data will provide water and wastewater utilities with much better information to do PMP for the daily, weekly, monthly, and yearly planning and scheduling. Figure C shows how specific assets identified in the highest risk cells of a risk matrix are polled and integrated into CMMS for work orders and inventory management. In its essence we will show how utilities can logically and sequentially budget and fix buried pressurized before they fail using RISK and high-end technology for field, data assessment and prioritization. Two project examples will be presented to attendees.

Over 54,000 community water systems face the inevitable cost of pipe repair and replacement. The United States EPA states that nearly 60% of the total system costs are found in the distribution and transmission pipe lines. Infrastructure asset management is an approach which can help utilities bring together the concepts, tools, and techniques to manage assets at an acceptable service level at the lowest life-cycle cost. The water industry has seen many types of academic surveys and studies on water main replacement programs and the benefits of asset management and prioritization. However, many utilities have not historically tracked all of the elements of water main break data. Over the past 20 years, most utilities have come to realize the importance of tracking all aspects of their infrastructure in a GIS system and have records of what kinds, sizes, and repair history of all pipes. As this trend continues, more data and analysis will be available to the industry to improve water distribution system repair and replacement decision making. One factor used to quantify the occurrences of failing underground pipe networks is water main break rates. Water main break rates are calculated for all pipe materials used in water delivery to create a measurement to judge pipe performance and durability. Water main break rates can vary year to year and by utility. However, in aggregate, break rates produce a compelling story which can aid our prudent decision making as it relates to repairing and replacing our underground pipes. This presentation reviews the newest water main break study metrics and findings including comparisons between typical surveyed data to actual AI/Machine Learning findings which can also help benchmark an organizations' break rates.

With many municipalities having excess anaerobic digester capacity, anaerobic co-digestion (AcoD) provides an opportunity to improve biogas recovery while potentially reducing landfilling of organic municipal waste streams. In the United States, 12% of municipal solid wastes are yard trimmings (YT), which are often sent to landfills or composting for disposal (US EPA 2021a). However, YT landfilling and composting releases 475-1100 and 20-130 kg CO2 eq. per dry ton of fugitive methane (CH4) and nitrous oxide emissions per year, respectively (Brown and Chang 2014; Zhu-Baker et al. 2017). Utilizing yard trimmings as a co-digestion stream improves energy recovery, meets higher renewable energy credits (REU) credit standards than food waste and fats/oils/grease, and reduces climate impact due to fugitive emissions of CH4 and N2O. In this work, we developed nature-inspired bacterial enrichments for cellulose degradation and use them to pretreat common yard wastes to the Southwest and a stock chemical cellulose mixture. We evaluate the impacts of pretreatment using our inoculum and its improvement of CH4 production and landfilling offsets through sludge reduction as part of AcoD with thickened sludge. We cultivated lignocellulose-degrading batch inoculum over 10 generations based on feces obtained from Oryctolagus cuniculus domesticus, who primarily eat hays, grasses, and leafy matter with a digestive retention time of about 4 days. The inoculum were exposed to a variety of typical Phoenix yard waste & lantana and grass & or purchased cellulose. Each generation of inoculum was inoculated for 10-14 d, and then 1/10 of the total volume was added as seed for the next inoculum generation. An inoculum was used as the seed for fermenting reactors with 5-14 d hydraulic retention times (HRTs). Rehydrated plant matter was fed into the fermenters at 40 to 80 g DW/L each of lantana, grass, and cellulose. Fermented material was also fed to anaerobic co-digesters. Thickened sludge and seed anaerobic digester inoculum were provided by the City of Mesa, Arizona's Northwest Water Reclamation Plant (MNWWRP). To test pretreatment coupled with anaerobic digestion, AcoD reactors were fed the same amount of thickened sludge as the control plus an additional amount of material from the fermenters to maintain a 19.2-d HRT. We had two controls in the system: (1) only thickened sludge fed to control reactor was operated at a 25-d HRT to mimic MNWWRP; and (2) the same amount of thickened sludge was fed as a control plus 80 g DW/L undigested plant matter at a 19.2-d HRT. The reactors were allowed to operate at least 3 HRTs to achieve steady state prior to taking the data reported here. To ensure reactors would not sour, the pH in all reactors was kept at 7.5 ± 0.2 using NaOH for pH adjustment and CaCO3 to improve buffering capacity. We monitored pH, total and soluble COD (TCOD; SCOD), total and volatile solids (TS; VS), CH4, hydrogen gas, the volatile fatty acids (VFAs) of formate, acetate, propionate, butyrate, valerate, and caproate, and lignocellulose content based on an Ankom 2000 fiber analyzer. YT prefermentation provided increased solubilization of plant matter to VFAs and with negligible biogas production. For example, VS decreased an average 29% at a 14-d HRT with 80g DW/L loading of YT. At the same time, SCOD increased 20% leaving the reactor, with 6.3% being converted to VFAs. While the analysis is still in process, it appears that proteins in the leaf matter and some hemicellulose were hydrolyzed to soluble forms. Our initial results show that AcoD fed prefermented YT has higher CH4 production and better volatile solids reduction than the control or AcoD with untreated YT. As an example using the prefermented YT discussed above, Figure 1 shows that AcoD fed prefermented YT and thickened sludge averaged the highest CH4 production, 330 mg CH4/d, versus 270 mg CH4/d for the control and 160 mg CH4/d for AcoD with untreated YT. The AcoD with prefermented YT also achieved the highest sludge reduction, 52%, versus 40% with the control and 43% AcoD with untreated YT. At the same time, the AcoD with prefermented YT had a lower yield of CH4 per g VS reduced (610 mL CH4/g VS) versus the control (914 mL CH4/g VS). This lower yield is likely due to lignocellulose being highly recalcitrant. The encouraging results with AcoD fed prefermented YT could have far reaching impacts on the wastewater and AcoD community. Based on these results for 4000 m3 (~879,000 gallon) capacity anaerobic digester, AcoD fed prefermented YT produces 184,000 m3/yr more CH4 than the control and 805,000 kg/yr of YT diverted from landfilling. In addition, the gas produced from YT qualifies for D3 cellulosic RIN credits as part of the EPA's Renewable Fuel Standards program versus other co-digestion streams like food waste and fats/oils/grease (FOG), which qualify for D5 RIN credits. Based on September 20, 2021, data, D3 RINs were worth $1.13 more than D5 RINs (US EPA 2021b).

Accepted Practices for Mitigating SSOs For decades, utilities have established and implemented the EPA CMOM guidance of regular, scheduled cleaning 1. It recommends that the total collection system be cleaned on an ongoing basis, annually for smaller systems and on a multi-year cadence for larger systems. Additionally, it states that collection systems which have segments where rapid build-up occurs, often referred to as 'hot spots', and that could result in blockages, should be cleaned at higher frequencies e.g., monthly, bi-monthly, and quarterly. To establish the cleaning frequency rate, utilities relied on the known history of a given segment's build-up and established a schedule to stay well ahead of the historical trend 2. Of note, in order to stay ahead of potential blockages, some or many segments are cleaned on a high frequency schedule. This occurs irrespective of the actual segment conditions and results in overcleaning - cleaning pipes that do not require it. The primary reason for this rest with the field maintenance team not knowing segment conditions for a segment. Yet, while it might be wasteful of resources, the high frequency cleaning approach has proven effective for reducing SSOs 3/4. Unprecedented Disruption There may be no adequate way to describe the disruption that the pandemic brought to our lives, business, and so much more, with virtually no element being untouched. Water and wastewater were no exception. During the initial weeks, shutdowns occurred in rapid succession. Yet, water/wastewater operations had to continue, as they were deemed an essential industry by the Department of Homeland Security and in conjunction with EPA in 20155. Keeping in mind that utilities built their processes, staffs, and resources such as trucks and equipment around the EPA CMOM cleaning guidelines, the pandemic created widespread challenges. The Water Environment Federation (WEF), for example, sponsored a series of online webinars in May and June of 2020 whereby utilities outlined a confluence of challenges: - securing personal protective equipment (PPE), - managing reduced staffs due to the necessity to implement staff isolation Moreover, a significant increase in sewer-unfriendly objects started to appear in the collections system and pump stations. So-called flushable wipes, face masks, and latex gloves accumulated in these structures increasing the amount and severity of blockages 6. To illustrate this, one Tennessee utility would normally clean a wastewater pump station once per month and now found that cleaning was required twice per week, an eight-fold increase. The occurrences of rapid and unexpected sewer system build-up only added more pressure on already challenged maintenance teams. It was the perfect storm of less available resources and more challenges to meet. An Emerging Hypothesis Over the course of the past five years, a small but growing number of utilities have been studying and adopting new O&M cleaning processes. Their goal was to gain increased insights into actual remote segment conditions and use this information to determine when a segment needed to be cleaned. They hypothesized that they could conserve maintenance resources and vector these to other urgent tasks or projects. In effect, they were seeking increased productivity. In order to test this hypothesis, utilities (three cited herein) adopted a smart technology approach where sensors were installed at remote locations, capable of continuous communication of flow-depth to web-enabled devices. Supervisory and managerial staff had continuous access to sensor-site data showing actual segment conditions. Using available predictive, machine learning analytics, a staff member could be notified of locations that would need cleaning and, doing so, well in advance of any possible blockage developments or issues that could lead to an SSO. Testing the Hypothesis Examples of three utilities demonstrate how the application of smart technology as the determinant of when to clean, enabled them to supplant their older schedule-driven process. As stated, field maintenance resources were potentially being wasted as these teams cleaned a pipe segment strictly based on the requirement of a schedule to do so. They lacked visibility of the segment's actual condition and could well be cleaning already clean pipes. The new approach enabled continuous visibility of flow-depth behavior. [Note: hydrographs will be shown.] All of the pilot studies were set-up in similar fashion. High frequency cleaning locations were chosen (usually monthly frequencies but in one pilot weekly locations were included). Monitors were installed at each location with depth measurement frequencies set at 15-minute intervals. These were communicated to a cloud-based software that also contained analytics capable of detecting depth measurement pattern anomalies, indicative of the development of a future blockage. If detected, a dashboard displayed the location and urgency for action. In this case, the cognizant staff member would create a work order to clean, having days or even weeks for scheduling. Results The earliest pilot was comprised of ten (10) test locations for a duration of six-months. Using the older, schedule-driven method, the utility would have cleaned 60-times during this period (6-monthly x 10 locations). Upon completion of the pilot, the utility cleaned a total of 12-times, an 80% reduction. The second pilot tested twenty (20) locations. Eight (8) of the locations were scheduled to be cleaned weekly, while twelve (12) were on a monthly schedule. The pilot duration was four (4) months and during that time scheduled cleaning was reduced by 94% for all 20 locations. The third utility installed monitoring at 25-monthly locations. In the first year alone, scheduled cleaning was reduced by 92%. The common result for these three utilities was a dramatic decrease in cleaning and with no SSOs at any location. All were able to allocate their maintenance resources to other tasks. Thus, with the same total resources, each utility was able to accomplish more and realize increased productivity. One Unexpected Benefit The subject of the pandemic, raised earlier, illustrated how smart technology had a significant and positive effect on otherwise difficult challenges. The aforementioned third utility maintains almost 3,000 miles of gravity sewer. To do this they have more than 20 combination (cleaning) trucks. They employ both a first and second shift plus a smaller third-shift that's primarily dedicated to urgent cleaning. When the pandemic shutdown started, operations had to be cut-back severely for three weeks. All regular scheduled cleaning stopped as all employees were instructed to shelter in-place (at home). They had a single team to respond to emergencies-only. Yet, this utility had already implemented the 'Optimized Cleaning' process using monitors at their critical locations. Over the course of the three weeks of lock-down, the supervisor reported that he was at ease knowing that the critical locations were monitored. Moreover, if any needed attention he had advanced notice and could schedule his single team to performance maintenance. In fact, during that time, two sites indicated that cleaning was necessary. Moreover, potential SSOs were avoided. Final Thoughts What these three examples demonstrate is that through knowing actual segment conditions, effectiveness and utilization of maintenance resources increases. Moreover, the sudden and drastic changes created by the pandemic underscored that in the face of extremely limited maintenance capacity, smart technology offers an alternative that minimally protects from SSOs but can also right-size maintenance demands. For utility managers, there is a fundamental advantage for updating old O&M processes when their organization can increase productivity and, in the case of severe challenges, gain peace of mind. References 1.Guide for Evaluating Capacity, Management, Operation, and Maintenance (CMOM) Programs at Sanitary Sewer Collection Systems, United States Environmental Protection Agency, Office of Enforcement and Compliance Assurance (2224A), EPA 305-B-05-002, pp.2-29/30, January 2005. 2.I&I Magazine, Cole Publishing, January 2019; Jay Boyd and Paul Forsthoefel. 3.Sanitary Sewer Overflows: What They are and How to Reduce Them, Environmental Protection Agency, Office of Wastewater Management, EPA 832-K-96-001, p. 5, Summer 1996. 4.Sewer System Management Plan, Central Contra Costa Sanitary District, CIWQS WDID: 2SSO10105, Nov. 2017. 5.Water and Wastewater Systems Sector-Specific Plan, US Department of Homeland Security and United States Environmental Protection Agency, per Presidential Policy Directive 21; 2015. 6.Epidemic of Wipes and Masks Plagues Sewers, Storm Drains, Associate Press Release, June 4, 2020; Claudia Lauer, and John Flesher.

Recognizing the operational and financial benefits of converting their aerobic solids treatment process to an anaerobic co-digestion process, the Altoona Water Authority (AWA) is constructing an integrated anaerobic digestion and biogas-fueled thermal biosolids drying complex at their Westerly Wastewater Treatment Facility (WWTF). AWA is implementing this project, scheduled for a September 2022 completion, using a collaborative project delivery method through Pennsylvania's Guaranteed Energy Savings Agreement (GESA) legislation. What began as a feasibility assessment of high strength waste (HSW) co-digestion evolved into a cradle-to-grave water resource recovery strategy that incorporates waste recycling and reduction to achieve a sustainable biosolids management solution for AWA and the surrounding region. This presentation describes how the collaborative development process was used to connect new treatment assets to the revenues and savings associated with the regional waste and biosolids disposal markets. The Westerly WWTF is an 8 MGD (average daily flow) Biological Nutrient Removal (BNR) facility. Through a 2018 GESA procurement, AWA selected an an Energy Services Company , Energy Systems Group, to design, build, and guarantee financial outcomes associated with the new assets. The GESA law requires that the project's revenue and savings equal its associated debt service and operating costs. The initial premise was a co-digestion complex that would convert biosolids and HSW into renewable energy in the form of biogas. The financial value would be in the form of tipping fee revenue and savings and/or revenue associated with the conversion of biogas to usable energy. It became clear during the early assessment phase that that AWA's Class B biosolids disposal practice (agricultural land application) had become a costly, unsustainable alternative as their costs to dewater, store, test and transport, and land apply as escalated in recent years. Achieving Class A biosolids became a project requirement, with biogas-fueled thermal drying as the technology to achieve that outcome. The design challenge was thus connecting the front end HSW co-digestion to the back end solids drying with a 100% renewable thermal energy source. The process modeling established that there would be sufficient biogas to expand the dryer capacity threefold beyond the AWA plant sludge, creating the potential for a regional facility with merchant sludge revenue. The collaborative delivery process accommodated a regional assessment in parallel with the design progression, not as a separate feasibility study that would have delayed the schedule. Other municipal authorities in the region were identified with the potential of transferring biosolids to the WWTF fore drying. While presenting potential challenges to drying due to the differing cake solids properties, the potential revenue from the biosolids tipping fees was important in the cash flow for the project. Specifically these facilities were producing different types of sludge and biosolids that could potentially foul the dryer. These included primary sludge, waste activated sludge (WAS), a high purity oxygen WAS that has properties similar to a primary sludge, as well as a primary sludge with a high concentration of cellulosic fiber. Based on the results of drying these various biosolids in a pilot dryer, different strategies were developed to manage these multiple feeds. These include mixing biosolids from multiple sources upstream of the dryer, hauling the sludge with the high concentration of cellulosic material into the facility as thickened WAS and anaerobically digesting it prior to dewatering and drying, and metering multiple biosolids feeds into the dryer by way of biosolids cake pumps. Not only did this approach provide the AWA with the flexibility to fashion a project in real time that addressed its evolving needs, it provided a performance guarantee that limited risk and helped this innovative project become a reality. Figure 1 is a tabular summary of the projected revenue and savings associated with the project. Figures 2 and 3 show the digester complex construction progress in April and September 2021, respectively. The project will result in an annual positive cash flow for AWA. In addition to new hauled waste tipping fee revenue, it will generate sufficient renewable biogas to provide the thermal energy demands of the treatment processes, buildings, and thermal drying. Lastly, it is providing the region a stable biosolids disposal option, with predictable long term biosolids disposal costs.

Background Wastewater infrastructure plays a critical role in urban communities, providing for the safe and efficient conveyance and treatment of sewage to protect human health and the environment. In the United States, over 16,000 centralized wastewater treatment plants serve approximately 74% of the population (Environmental Protection Agency, 2004). The majority of these plants provide at least secondary treatment of wastewater before discharging to local water bodies. Some plants may also provide advanced treatment to remove additional constituents that could impair the quality of receiving waters (EPA, 2004). Wastewater treatment plants (WWTPs) are strategic infrastructures that remove contaminants from wastewater, thus supporting human health and environmental protection (Panico et al. 2013). Majority of the wastewater treatment plants are generally located in low elevations to facilitate the conveyance of wastewater flows to the plant by gravity to minimize the number of pumping stations and the cost of wastewater treatment. Due to its location, wastewater treatment plants are more vulnerable to the extreme weather events such as floods, sea level rise and hurricanes. These extreme weather events could increase or decrease the wastewater flows to the plant, increase or decrease the pollutant concentration and increase or decrease the wastewater temperature depending on the type and severity of the events whether it is high precipitation and flooding or drought conditions or snow melt. During these events, the performance of the wastewater treatment plants can deteriorate or fail completely when it is stressed beyond the design or operation conditions, consequently impacting the human health and environment. The objective of this paper is to focus on the operational strategies that could be implemented at the wastewater treatment plants to face the challenges of extreme weather events to be more reliable and resilient wastewater treatment system. Objectives: During the extreme weather events, the operational failure and deterioration of effluent quality can occur due to high influent flows or pollutant concentrations. Some typical reasons for plant performance degradations are (NYCDEC 2000): loss of biomass from the aeration tanks and secondary clarifiers, overloading of the aeration system from high biochemical oxygen demand (BOD) loadings caused by solids washout, electrical overload of mechanical surface aerators, and decreased BOD removal efficiency due to shortened hydraulic retention time in the aeration tanks. The objective of this work is to illustrate how the operational strategies such as blending of the partially treated effluent with biologically treated effluent, increased aeration, increased chemical use, increased return sludge recirculation, controlling sludge retention time (SRT), use of unused or redundant tanks for aeration can be utilized to handle the increased influents flows and pollutant loads during the high precipitation (rainfall) associated with the extreme weather events. Methodology, Results and Discussions Influent flows and pollutant concentrations significantly influence the performance of the wastewater treatment plants in maintaining effective treatment to provide the desired effluent quality. High precipitation rates will result in increase in influent flows into WWTPs due to flow from combined systems and I&I. While the volume or 'flow' of the wastewater increases due to increased stormwater infiltration, the mass of pollutants in the wastewater may remain the same, resulting in a dilution of the influent to the WWTP which can affect biological treatment processes and solids separation process. Typically, the wastewater treatment plants are designed to handle the maximum month average daily flows while the plant is designed hydraulically to convey the peak hourly flows which is expected last few hours in a day. During the extreme weather events, the plant inflows may be expected to receive the peak flows for several hours or even few days depending on the severity of the weather event. In this work, a hypothetical conventional activated sludge plant of 5 MGD was created using the process modeling software BioWin 6.2 (Figure 1) to determine the performance and maximum treatment capacity of the wastewater treatment plant in response to the increased influent flows and pollutant concentrations (BOD, Ammonia-nitrogen, Total Suspended Solids (TSS) and Total Phosphorus (TP)) for the extended period of time under the following operational strategies: Diverting and blending partially treated wastewater: Flows that exceed the maximum biological treatment capacity of the aeration basin is diverted after the preliminary treatment system, treated at the primary clarifier, and blended with the biologically treated effluent from the main process. This strategy will be effective on facing the challenge of high flows as the pollutant concentration will be more diluted due to the extraneous stormwater mixed with the wastewater. Increasing Return Activated Sludge Recirculation: During the high flows, the sludge blanket at the secondary clarifier is likely to increase resulting high TSS leaving the effluent and impacting both the effluent quality and the biological treatment process in maintaining mixed liquor suspended solids. Increasing the RAS recirculation rate will alleviate this problem in maintaining the effluent quality in a short run. Increased aeration: During the high flows, although the pollutant concentration is likely to be low, the mass loading still could be relatively high resulting increase in high aeration demands. Increasing the airflow rate can remove BOD and increase the nitrification to remove the ammonia-nitrogen. Controlling Solids Retention Time: Solids Retention Time (SRT) is one of important operational parameter of the wastewater treatment plant operation in accomplishing desired BOD and nitrogen removal. SRT is dependent on several other operational parameters such as mixed liquor suspended solids in the aeration basins, excess waste activated sludge wasted from the secondary clarifier, influent flow rate, influent wastewater characteristics and RAS recirculation rate. Maintaining the SRT at desirable range by controlling other operational parameters could be an effective short-term strategy to deal with the increased flows from the extreme weather event. Increased chemical use: During the high influent flows, the chemical treatment can be used for improving solids separation and also for removing phosphorus by addition of the iron or alum along with polymers as a short-term strategy to improve the effluent quality. Use of unused or redundant tanks for use as aeration basins: Unused tanks, if any, at the wastewater treatment plant or back up tanks can be added at the wastewater plants to increase the hydraulic retention time (HRT) and SRT to provide the effective treatment. Conclusions This work will demonstrate how the operational strategies discussed in the above section can be used to determine the maximum handling capacity of a hypothetical 5 MGD wastewater treatment plant to prepare for the plant for the high influent inflows during the extreme weather events. The illustrative case study will provide the quantitative examples with limiting treatment capacities for each of the operational strategies discussed above using the process simulation results from the BioWin 6.2 Software that was used for creating the process model for the 5 MGD plant. The methods and operational strategies demonstrated in this work can be extended to the advanced wastewater treatment (AWT) facilities.

APPLICABILITY Treatment and the security of disposal/beneficial use options for biosolids is constantly evolving due to more stringent regulations as new contaminants in wastewater raise concerns about potential migration into biosolids and subsequent impacts. Advancements in treatment technologies and development of new markets for different types of biosolids products offer opportunities to mitigate risks to current biosolids management options while maintaining a certain level of institutional control. Economics and utility-specific drivers and constraints play key roles in selecting the right combination of treatment technology and end use. DEMONSTRATED RESULTS/CONCLUSIONS JEA, one of the largest utilities in the State of Florida, has been highly proactive in evaluating and looking to the future with their biosolids program. In 2017, JEA prepared a master plan to evaluate replacing their aging biosolids handling facilities while charting a path for the future. The existing biosolids handling facilities are located at the Buckman Water Reclamation Facility (BWRF), JEA's largest WRF. The facility handles sludge from 9 of the 11 JEA owned and operated WRFs. Solids from the two remaining WRFs are dewatered and the cake is hauled to nearby landfills for disposal using separate, third-party hauling and disposal contracts. Currently, liquid sludge from JEA's three larger WRFs is pumped long distances via dedicated sludge force mains and received at the BWRF headworks. The solids are captured in the primary clarifiers at the BWRF and pumped to a raw sludge holding tank (RSHT). The solids from the remaining five JEA WRFs are hauled as liquid sludge and received at the RSHT. The existing biosolids handling facilities at BWRF include thickening, anaerobic digestion, dewatering and a thermal drum drying system producing a Class AA product. The Class AA product is hauled by a third party for polishing and product marketing for beneficial reuse. All the existing solids handling equipment is retrofitted in an old incinerator building that has also reached the end of its useful life. Since the equipment was retrofitted in an existing building, the layout has inherent inadequacies that result in operational challenges. Further, the thermal drum drying facility only includes a single drum that also reached its end of useful life, providing no redundancy. The 2017 master plan recommended decommissioning of the old thermal drying system and instead hiring the services of a third-party to receive the anaerobically digested Class B dewatered cake. The third-party would take full responsibility for further processing and final product marketing and ultimate disposal. The master plan recommended construction of a new solids handling building with new thickening and dewatering equipment to replace the aging infrastructure. However, this approach resulted in undue dependence on a third-party for cake hauling, further processing, and appropriate disposal of the biosolids, thus leading to uncertainty in capital and long-term operating costs, adherence to future regulations, and impacts of market conditions/changes on disposal of the product. As a result, in 2020, JEA revisited the findings of the earlier master plan. The 2020 master plan evaluated several short-term and long-term biosolids management strategies and recommended replacing the existing thermal drum drying system with two larger drum dryers providing greater process reliability and redundancy while continuing to produce a Class AA product with substantial volume reduction for ease of product transport and disposal. The 2020 master plan ultimately recommended constructing a new regional biosolids handling facility at BWRF, that can handle solids from all 12 WRFs owned and operated by JEA, thereby providing JEA the desired level of control for their biosolids handling and disposal options. Such regionalization could be adopted by other utilities seeking certainty and control for their solids treatment and disposal options. As part of the short-term strategy, JEA has refurbished several of the thermal drum drying system components. The utility is also in the process of rehabilitating the existing building for operator safety and extending the life of the building for the next 5 years until the completion of the new biosolids handling facilities. A new multi-story biosolids treatment facility (BTF) has been designed and is under construction as the long-term permanent solution for JEA. This facility, shown in Figure 1, will house new thickening equipment (5 gravity belt thickeners), new dewatering equipment (4 centrifuges), and two new thermal drum drying systems (evaporation rate of 10,000 kg/hr) with pellet storage and a truck loading station. As illustrated in Figure 2, the new BTF will be a regional facility sized to accommodate all solids generated by the 12 JEA WRFs. Unstabilized dewatered cake from three remote facilities will be shipped to the new BTF where plant effluent from BWRF will be used to dilute the dewatered cake to thickened sludge consistency and added to the anaerobic digestion process. This is intended to maintain a consistent feed to the drying process such that high-quality pellets are consistently produced and dust and fines formation is reduced. PROJECT INNOVATION A full-scale pilot of an in-line high-shear dynamic mixer coupled with a density meter was successfully conducted onsite to re-wet the dewatered cake solids (~21% total solids) from remote plants with plant effluent to produce a consistent product with a total solids concentration of ~4 to 5% to feed to the existing anaerobic digesters. This cake mixing concept, shown if Figure 3, could be a game changer for agencies seeking to ship their un-stabilized dewatered cake to regional facilities for stabilization and further treatment, while reducing transportation costs, truck traffic and avoiding significant capital expense at the smaller surrounding plants. This type of system could be integral to the regionalization that may be necessary to accommodate changes in biosolids management that could necessitate costly thermal processes to reduce potential impacts from constituents of emerging concern like PFAS.

The prevention, mitigation, and management of combined sewer overflows (CSO) continues to be a focal point for municipal wastewater utilities throughout the country. Regulatory requirements are constantly evolving and continue to increase emphasis on public alerting. Modern digital solutions can be used to improve the way that utilities notify the public about the occurrence and effect of CSOs in their communities. This presentation will provide examples of enhanced CSO prediction and notification tools that leverage predictive analytics and machine learning to improve transparency in CSO management. In the first example, an alert system was developed to inform community members of the risk of high bacteria levels downstream from CSOs. The alert tool uses publicly available information that is fed into an algorithm developed with historic data and relationships, including time of travel and decay constants, specific to the river. The tool has been validated against several overflow events and predicts downstream bacteria concentrations within a reasonable and useful accuracy. The results of the predictive tool are available on a public website hosted by the regional planning agency. Innovative tools that leverage existing engineering information are effective at informing the public about the real-time contamination risks of combined sewer overflows. The second example demonstrates how surrogate modeling using machine learning can predict collection system flows, and associated CSOs, in real time. This example also maximizes the use of existing available data and information to create a modern prediction tool. A calibrated hydraulic model of a combined collection system was used to train a machine learning model to produce predictive flows based on real-time weather forecasts. The knowledge of when, where, and how much combined sewage is predicted to be released into local waterways can be used to alert the public of impending closures and advisories. This type of tool can also be used by utility managers and operators to plan for upcoming overflows and increased inflow to wastewater treatment facilities.