Results

Biofiltration involves the use of biofilms to aerobically oxidize air-borne pollutants using either a packed bed of natural or synthetic media. In these cases the air-borne pollutants diffuse into the biofilm established on the biomedia surface and biodegrade, eventually forming carbon dioxide, nitrates, nitrites, sulfates, etc. The overall biological treatment rate is usually affected by this diffusion rate into the biofilm, which is part of the mass transfer process. When the air-borne concentration of the pollutant is low, as in odor treatment, this diffusive flux into the biofilm becomes the rate controlling step. This also occurs when the molecular weight of the pollutant is high, which decreases its diffusivity into the biofilm. A convective biofilter is designed to allow the exhaust gas with its air-borne pollutants to flow through the biofilm, rather than past it, and this allows the pollutant to flow through the biofilm rather than diffusing through it. This eliminates the dependance of the overall treatment rate on the diffusive flux through the biofilm while providing oxygen, carbon and nutrients into the biofilm. In this paper, experimental data on the treatment of toluene through a convective biofilter will be presented. The convective biofilter was constructed using a highly porous, ceramic, activated-carbon coated, rectangular block which had holes from one end to the other end. Exhaust gas with toluene flowed into the porous block at one end, and we closed the other end of the holes, which forced the gas through the porous walls between the holes. When the biofilms were established on these porous walls, the contaminated air was forced to flow through the biofilms adhering to the porous walls, while the media was kept moist through humidification of air using aerosolized water. The control was a Diffusive Flow Biofilter Media (DFBM) in which the other end of the straight holes were not plugged, and this allowed the contaminated air to flow through the holes while the biofilms were established on the porous walls inside each of the straight passage through the block. By using a similar size media block and the same flow of contaminated air with identical influent concentration of toluene, the CFBM filter could be compared side-by-side with a DFBM biofilter. The CFBM performed consistently better than the DFBM at a toluene concentration level below 100 ppmv, indicated by higher removal efficiency and more carbon dioxide production. Mathematical models for the CFBM were developed to better understand the processes within the CFBM biofilter and the results of these simulations for both the CFBM and DFBM biofilters agreed well with the experimental data. Results of this study will be presented in this paper.

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 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).

The public and their civic leaders are often unaware of stormwater until a flood or a collapsed pipe triggers an expensive emergency response. As a result, stormwater program managers often react to the latest emergency rather than proactively plan and prioritize system investments. System planning is further complicated as the diversity and complexity of stormwater management issues increases, causing decision-making to be siloed in different departments with competing objectives and funding sources. This presentation will describe a comprehensive asset management framework (Figure 1) that uses a common set of criteria to define risks associated with poor system condition and performance. This framework, in turn, may be used to define the risk-reduction achieved by different system renewal and improvement alternatives, as well as identify cost-effective alternatives benefiting public safety, community welfare, and environmental integrity. Asset management supported by an integrated risk framework provides a defensible set of criteria justifying investments across a diverse range of stormwater projects: Stormwater Assets, both constructed and natural, typically are owned by different entities, and often operated to achieve to different objectives. An asset management approach recognizes how each asset fits into an integrated stormwater system and establishes complementary owner/operator responsibilities. Level of Service (LOS) Objectives establish stakeholder expectations for how the stormwater system should protect human life, aquatic life, property, and community well being. They are typically expressed as system performance expectations; system operation, maintenance, and renewal practices; and rules governing discharges into the stormwater system. Likelihood and Consequence of Failure Criteria (Figure 2) measure deviations from LOS objectives. Once defined, these criteria may be merged through unique algorithms to establish equivalent levels of risk for different asset failure modes (e.g., structural failure, flooding, erosion, water quality impairment). Capital Planning Priorities. Desktop evaluations generate surrogate criteria to establish initial asset risk levels and identify priority areas for detailed assessment and capital planning (Figure 3). Then, detailed risk assessments involving field inspections and modeling are conducted to further define priority areas for capital planning and/or system renewal. Risk-Based Cost-Effectiveness Evaluation (Figure 4) integrates three factors the risk-reduction associated with system improvement and renewal alternatives, their life-cycle cost estimates, and other associated economic, social, and environmental benefits to define an overall cost-effectiveness score used to select a preferred alternative and prioritize and/or phase preferred alternatives for implementation.

The City of Portland, Oregon partnered with DHI Water and Environment, Inc. (DHI) to develop an innovative approach to assessing risk and managing the assets of their stormwater system, both in the built and natural environment. Instead of initially focusing on physical assets as is often done in traditional asset management, the City first collaborated with stakeholders to understand the stormwater system and the services it provides. This insight allowed the City to look at the risks associated with failure to provide the identified services. The stormwater system in Portland is a complex network of engineered and natural assets that provide conveyance, protect water quality, and provide and protect habitat and biological communities. Assets in the stormwater infrastructure inventory include hundreds of miles of pipes and ditches, thousands of sumps, flow control and pollution reduction facilities (PRFs). Additionally, Portland relies on thousands of private facilities within the stormwater network that are not owned or controlled by the City as formal assets. Further, Portland's stormwater system depends on the management and expansion of the city's tree canopy and natural areas that intercept rainfall, keeping it out of pipes and filtering it naturally. Finally, acres of wetlands and thousands of miles of natural streams and drainageways are a critical part of the stormwater conveyance network. Applying asset management to the stormwater system, therefore, requires a comprehensive risk framework that considers ownership boundaries, natural resources and functions, multiple services and a myriad of risks born from the failure of those services. Asset management in the stormwater system requires a broader, holistic view of risk, and to do that Portland needed to expand the understanding of the services they provide, the assets they use to provide them, and a common language to evaluate impacts when those services or assets fail. Risks related to stormwater services include failure to safely convey water leading to nuisance flooding, erosion, landslide exacerbation, as well as habitat degradation, poor water quality, and community development impeded by system deficiencies. As these aspects of the stormwater system were explored and understood, DHI worked with the City to develop the Risk Assessment Framework Tool (RAFT). This dynamic software tool delivers automated GIS analysis of the stormwater system using dozens of input datasets, including LiDAR, ground cover, soils, pipe asset data, stormwater management permits, habitat data, and water quality samples, to produce comprehensive risk maps citywide. On the backend is an automated series of scripts, programs, and geodatabases which run weekly as input datasets are updated. This tool produces live risk maps that present information based on the latest data available. RAFT has proven to deliver valuable insight through several key outputs including a fully connected network of stormwater flow across the city via surface drainage, through piped infrastructure and, ultimately, to rivers or treatment plants. This output allows tracing of stormwater flow across the city as well as precise delineation of watersheds at all scales, thus the source and destination of stormwater at any location can be determined. RAFT also enables PRFs and other stormwater control structures to be included in the analysis. The tool allows the City to assess risk across service categories. A significant effort was made to make risk comparable across these categories. For example, levels of risk to water quality were made comparable to landslide risks or risks of nuisance flooding. This allowed the RAFT tool to combine risk from all service categories and produce a single map showing 'total risk.' With this map, hot spots can be identified, and users can select locations warranting further detailed analysis. The analysis is then used to propose and implement risk mitigation projects with the highest impact. This approach has helped to illuminate the multi-faceted nature of stormwater risk and the value of adapting asset management principles to instill transparency and efficiency into Portland's risk reduction strategies. Assessing stormwater risk requires looking broadly at service provision and the assets the City relies on to provide those services. This means valuing natural resources as both assets that provide services and suffer consequences of service failure. It can also mean that the lack of an identifiable storm system can lead to a multitude of problems and solving them has the potential to reduce multiple risks and provide multiple benefits. By taking a holistic, comprehensive view of the stormwater network and risk potential, the City of Portland is better prepared to plan and implement successful mitigation strategies.

Communities have extensive GIS data that can be used as input to storm sewer models. This presentation will walk through how communities can use this data to help plan, predict and mitigate flooding within their communities. The City of Burnsville (26.87 sq. mi.), like many communities throughout the Minnesota Minneapolis-St.Paul Metro, have a 1D City-Wide XPSWMM model. The City wanted to upgrade their 1D model into a 2D model to create a model with a higher accuracy for their complex storm sewer network. Burnsville was the first community within the Metro to develop a City-Wide 2D model. The 2D model allowed the City to have a better understanding of their flood risk that a traditional 1D model would not be able to identify (i.e. surface flow velocities, erosion susceptibility of overland flow areas, emergency overflow capacity issues in residential areas, and showing where overland flow conveyance points are most critical). The flood rasters and associated output data from the 2D model were then taken and integrated into a custom-built Resiliency Model evaluating the Consequence of Failure (CoF) versus the Likelihood of Failure (LoF) criteria, building on the techniques often used in water main and sanitary sewer asset management programs. The various CoF and LoF parameters were weighted based on input from City staff to determine the most critical aspects of their system such that the resiliency model would take these factors (weights) into account to determine which areas are the most critical to construct flood risk reduction projects. This approach removed any bias from the evaluation process allowing the City to develop a guiding document/living model the City can use for future planning & mitigation projects. All of the processes are fully dynamic allowing the 2D model and Resiliency Analysis to be rerun to re-prioritize the zones annually. Based on the outcome of the resiliency study, the city moved directly into constructing a large flood risk reduction project for a high-scoring area of the City's system. The Twin Lakes Flood Risk Reduction Project involved three major design components to alleviate flooding risk along a small chain of lakes. Given that these lakes drain to other flood-prone areas, at a minimum the project required that overall peak flows were maintained. The already-built city-wide 2D SWMM model allowed the design team to quickly develop the hydraulic design that reduced flooding in the Twin Lakes area and maintained downstream flows. Currently, evaluation of the next flood risk reduction project for a critical area is ongoing with design of that project expected to occur in 2022.

Issue: While managing solids is integral to all Water Resource Recovery Facilities (WRRFs), evaluating whole facilities and systems from a mass balance perspective is often challenging. All WRRFs must manage their biosolids whether it be for treatment or processing/handling at the end of the treatment process. To understand the quantity of biosolids that must be managed, utilities need a proper biosolids inventory. To further enhance the understanding of a biosolids inventory, a biosolids mass balance tool can be developed and applied to monitor performance. However, quality biosolids data is often not available at utilities through all process points, rendering a mass balance tool difficult to develop and calibrate. Objectives: This presentation will provide an approach to developing a biosolids mass balance tool to identify potential process limitations, support solids processing optimization and capital planning, and to evaluate data improvements. This approach will be demonstrated with a case study of a biosolids mass balance tool that was developed for the Philadelphia Water Department's (PWD's) three WRRFs and centralized biosolids processing facility. Utilization of PWD and its facilities within this case study provides a unique opportunity to address not only the benefits, but the challenges that present when constructing a biosolids mass balance tool for a large, public utility. Lessons learned throughout the process will be included for application to any utility seeking to develop a similar tool. Approach for Developing a Biosolids Mass Balance Tool: The development of an informative solids mass balance requires data gathering, quality assurance/quality control (QA/QC) of data, and annotation of assumptions. First a request for information is generated based on the unit processes utilized at the facilities of interest. Primary and secondary treatment data is gathered and reviewed by plant staff and engineers. This request is prioritized by grouping parameters into categories (e.g., 'must have', 'nice to have', etc.). QA/QC of the data is done by evaluating historic data trends to identify outliers or possible analytical errors. Following the initial data screening, a mass balance is built for each process based on the data received. When the mass balances around a process do not close (i.e., solids in does not equal solids out), further investigation is required to identify potential reason(s) for the error. Reasons may include metering errors, analytical errors, an indication of process inefficiency, etc. Assumptions must be made using engineering judgment and industry standards to calibrate the model based on observed data, fill in knowledge gaps, or resolve issues discovered during data analysis. Assumptions must be well documented to inform the mass balance user for current and future applications as more data/information becomes available. Once the mass balance is developed, key process metrics of the unit processes of interest can be compared to industry standards to determine process capacity/limitations. The mass balance can also be used to evaluate optimization/upgrade alternatives for planning purposes in a timely manner. Case Study: PWD, established in 1801, is a public water utility, providing integrated drinking water, wastewater, and stormwater services to the City of Philadelphia and several neighboring communities. PWD owns and operates three WRRFs with a combined permitted maximum daily average flow capacity of 783 MGD. Biosolids from PWD's WRRFs are anaerobically digested and sent to a central biosolids recycling center (BRC). The BRC is located on PWD property but operated by an outside entity. The BRC produces Class A pellets that are land applied throughout the east coast. To better characterize PWD's biosolids handling, understand system limitations, and support planning efforts, PWD collaborated with consulting teams HDR and AECOM on the development of a biosolids mass balance tool. The tool was developed to assess the individual WRRFs as well as the overall solids strategy among the three WRRFs and the BRC. Figure 1 presents a process flow diagram of the three WRRFs and the solids flows among facilities. As shown, this system is complex with respect to solids processing in that one of the three plants sends their sludges to another plant for processing, and the third plant conveys solids via barge to the processing facility. Like other utilities of its age and size, PWD faces the challenges of aging infrastructure and a changing regulatory environment that drives optimization of existing processes and adoption of new processes. These forces, coupled with the ever-present requirement of meeting NPDES permits, can make the prioritization of biosolids data collection and system optimization difficult. PWD and HDR employed creative collaboration strategies to secure the support and cooperation of PWD stakeholders as well as the data required to develop the biosolids mass balance tool. Within Figure 2 is the preliminary output from the mass balance tool calibration that tracks solids production, transport, and destruction across PWD WRRFs. During calibration, several processes were identified for further evaluation due to the mass balance not closing. Further investigation of these processes may lead to important improvements in process performance or process monitoring. Observed key process parameters were also compared to industry standards to identify system limitations and identify optimization opportunities. In doing this, potential inefficiencies were identified such as anaerobic digesters being organically underloaded but hydraulically limited, indicating potential improvement in performance and energy efficiency through further digester feed thickening. This presentation will discuss a process for developing and utilizing a biosolids mass balance to evaluate WRRF biosolids management, as well as present lessons learned from PWD's biosolids mass balance development and evaluation.

Background Howard County owns and operates the Little Patuxent Water Reclamation Plant (LPWRP), located in Savage, Maryland. The LPWRP is permitted to treat an annual average daily flow of 29.2 million gallons per day (mgd), with a current average daily flow of 20 mgd. Howard County historically generated a Class A Exceptional Quality (EQ) alkaline-stabilized biosolids product (through the RDP process), that was beneficially used in the bulk agriculture market. The RDP process and biosolids management was contracted to a third-party contractor (TPC). While the program was successful, it had challenges including generation of large quantities of biosolids to manage, elevated pH in soils routinely receiving the biosolids, a newly adopted winter ban on land application of organic materials (including biosolids), and specific limitations on existing agricultural outlets due to the implementation of Maryland's phosphorus (P) index. Objective Recognizing these challenges, the County engaged the HDR & Material Matters Team (Team) to complete a biosolids master plan (2013) and subsequent preliminary engineering report (PER) (2014). At the start of the project, the County developed the following project goal: 'Develop a Biosolids Master Plan that provides a framework for reliable, cost-effective, and socially responsible treatment and beneficial use of LPWRP biosolids in a changing and unpredictable regulatory environment.' To aide in selecting a technology best suited to meet the County's needs, Material Matters conducted a market analysis and regulatory review for Class A/EQ biosolids in Mid-Atlantic region. The objective was to identify the product or product(s) best suited to meet the project goal. Methodology Material Matters was responsible for conducting an initial market analysis in the local community, establishing product quality characteristics and specifications, and outside-the-gate costs as part of the initial Master Planning effort. Material Matters provided customer-preferred characteristics for each of the biosolids products based on the viable market requirements. A regulatory review was conducted to define/assess the current and future regulatory requirements for both Class B and EQ biosolids to confirm and clarify the meaning of new and proposed regulatory language. Bulk sale to soil blenders was identified as a primary outlet, driven by regulatory challenges related to phosphorus (P) content of the biosolids - bulk sales to soil blenders would not be impacted by new P rules. With the support of the market assessment findings, Howard County personnel concluded that anaerobic digestion with thermal drying was the technology combination best suited to meet the set goal. Multiple thermal drying technologies were evaluated as part of the PER and a second, detailed market assessment was completed to identify which dried biosolids product type was best suited for the local soil blending market (Figure 1). The County selected the Haarslev belt drying technology for the ultimate processing of its material to create a dried Class A/EQ product for the most promising non-agriculture market identified: soil blending (Figure 1). Findings and Current Status[ Material Matters was able to provide support for the project within budget based on taking advantage of our local experience with regional regulators and other utilities. The Material Matters team is currently revisiting these efforts to develop a details distribution plan to provide the County with a recipe to successfully distribute the product during the first years following dryer start-up. The distribution plan includes tools for Howard County to advertise the product (Figure 2), example distribution plan based on market findings (Figure 3), and an overall roadmap for continual program evaluation and improvement (Figure 4). As of the time of this publication, viable options include direct distribution to a local soil blender and large farm for a small net revenue. By 'Starting with the End in Mind' and continual pursuit of local market options, the Material Matters team has helped the County save up to $300,000 per year in outside-the-gate costs (Figure 5).

Best Management Practices (BMPs) are continually evolving with new technology being developed to treat stormwater runoff. The maintenance needs for all BMP types needs to be clearly understood for communities so they are able to maintain the water quality benefits they provide to the overall ecosystem. This presentation will walk through how one community recognized this need and developed a comprehensive BMP maintenance program to meet the challenges of a wide range of BMP types. The overall goal of the presentation is to: (1) educate individuals on the need to develop a comprehensive program to ensure budgets are adequately addressing the long-term costs, (2) taking this systematic approach to maintenance will ultimately save the community money in the long term and (3) how a community can go about setting their own program up. The City of Woodbury, is one of the fastest growing cities in Minnesota. As part of the development process, the City requires the creation of stormwater management best practices (BMPs) within the developments which has led to over 1,700 city owned BMPs within Woodbury. As the City's BMP system has expanded so have the stormwater regulations as well as the complexity of BMPs being used to meet the increasing requirements. This increased complexity of the system and maintenance needs created an opportunity for the City to step back from regular pond dredging projects and reconsider the system in its entirety. City staff from various departments worked together over the course of a year to understand the system, identify any challenges, and review best practice recommendations from external and internal sources to create the Woodbury BMP Maintenance Plan which takes a holistic approach at managing every part of the public stormwater system to meet the requirements within the current MS4 permit, manage the resources responsibly, and do so cost efficiently. Developed in collaboration with this plan are three guides for the City to use: 1) an Inspection and Maintenance Framework and Guides for each BMP type to be used to train new staff, to increase consistency between staff and to help inform private owners on operation of their systems, 2) a public engagement plan, which provides guidance to city staff on when and how to engage the general public on projects and 3) cost estimation model was created for staff to utilize and inform decisions on budget, capital improvement plan and utility rate adjustments. The findings from these guides will be shared in order to show how plan concepts can be turned in to usable materials. The Plan was published in October 2021 and the City completed their first annual BMP maintenance project using the plan in Winter 2021/2022. Submitted with this abstract are graphics from the plan and results from the initial use of the plan will be included in the presentation.

During 2021, eastern Colorado exhibited a severe drought period which prompted South Platte Renew (SPR) staff to re-evaluate the needs of its Beneficial Reuse (BU) Program and its overall resiliency to future scenarios that could inhibit biosolids land application. Because biosolids application rates are dependent on soil nutrient concentrations, crop uptake is the main driver of whether or not biosolids may be applied to a given plot of land. If a crop fails due to drought, infestation, or other factors, less nitrogen is removed from the soils, prompting lower, if any, agronomic application rates. SPR staff posed an important question: how many acres do we need to support plant operations and avoid landfilling? While this question seems simple, its answer is complicated with the uncertainty of how climate change will affect the frequency of drought conditions into the future. Being a data-driven organization, SPR utilized historical data on the past application rate, soil and biosolids quality, and weather patterns to develop a scenario-planning tool. This data tool was formulated internally with Microsoft's PowerBI so that the user can manipulate the data in order to investigate how lower application rates and reduced uptake will influence the acres that will be available for land application in the future. This talk will highlight the components of the data tool and how it can be used to manage and optimize SPR's BU Program in the future. A case study will also be presented, covering SPR's ability to use the tool to inform decision-making related to purchasing 4,000 additional acres of farm land.

The City of Cuenca is a large metropolitan City located in the high lands of Ecuador at about 2,560 meters above seal level. The wastewater collection and treatment system for the City consists of approximately 1,300 kms of sewage networks and 80 kms of interceptor networks that convey wastewater to various treatment plants, the Ucubamba WWTP being the largest of all treating approximately 95% of wastewater produced by the City. The rated design capacity of the Ucumamba WWTP is 1.8 cubic meter per second (m3/sec). The treatment process at the Ucumamba WWTP consists of preliminary treatment consisting of screens, followed by a 3-step biological process consisting of primary aerated lagoons, secondary facultative lagoons and tertiary maturation lagoons. Exhibit 1 is a process flow diagram of the Ucumamba WWTP liquid treatment process. The Ucumamba WWTP is challenged with accumulation of solids in the lagoons. In 2013 the City installed sludge removal and dewatering system to remove and process approximately 3,000 cubic meter of sludge per year (m3/year). However, the sludge removal and dewatering is capacity limited to remove and process sludge accumulated in the facultative lagoons. As a result, approximately 50% of the lagoon volume is occupied by sludge, thereby reducing the active hydraulic retention time, and leading to compromised treatment efficiency. To address challenges with reduced treatment capacity of the Ucumamba WWTP, reduce dependence on the Ucumamba WWTP to meet the City's treatment needs, and diversify treatment options to meet future growth, the City completed the design of the new Guangarcucho WWTP having a rated design capacity of 1.8 m3/sec. With the new Guangarcucho WWTP being operational, the City will be able to effeciently treat wastewater produced by the City and remove portions of the Ucumamba WWTP out of service for maintenance and sludge removal to restore capacity. Exhibit 2 summarizes the future wastewater treatment strategy for the City of Cuenca after the Guangargucho WWTP becomes operational. Wastewater biosolids are considered a valuable resource in Ecuador due to the high nutrient content and its benefit to the agricultural industry. Evaluation completed by the City indicate that the sludge removed from the Ucumamba WWTP is low in nutrients (nitrogen) due to the prolonged stabilization and meets EPA Part 503 Class B biosolids standards. As a comparison, the wastewater biosolids to be produced by the advanced Guangarcucho WWTP is assumed to have a high nutrient content and potential to meet EPA Part 503 Class A biosolids standards. The liquid treatment process for the Guangargucho WWTP consists of preliminary treatment (screening and grit removal), primary clarification, biological treatment, secondary clarification and disinfection. Primary sludge produced by the primary clarifiers will be thickened in gravity thickeners and waste activated sludge produced by the secondary treatment process will be thickened with gravity belt thickeners (GBTs). Thickened primary and waste activated sludge will be anaerobic digested and dewatered with centrifuges. Exhibit 3 provides the process flow diagram of the solids treatment process at the Guangarcucho WWTP. Limited quantity of biosolids currently produced by the Ucumamba WWTP is currently conveyed to the Pichacay Landfill for disposal. However, the Pichacay Landfill is nearing the end of its service life by 2031, and thus does not have the capacity to accept additional biosolids to be produced by the City's Ucumamba and Guangarcucho WWTP in the future. The City is currently challenged to find disposal or beneficial use options for biosolids produced by the two WWTPs. In addition, there are no regulations to regulate the general conditions and obligations to be fulfilled for beneficial use of biosolids e.g. land application. To address its biosolids management challenges, the City has initiated a Feasibility Study to investigate treatment and beneficial use options to manage biosolids that will be produced by the two WWTPs in the future. The treatment approach will focus on maximizing reduction in mass and volume of biosolids that will require outside the fence management, and produce high quality biosolids that can be beneficially used for agriculture and/or mine reclamation. Treatment solutions that will be investigated include thermal drying, solar drying, incineration and innovative treatment solutions such as pyrolysis and gasification to produce value derived products such as biochar. Beneficial use opportunities for biogas to be produced by anaerobic digestion at the Guangarcucho WWTP will also be investigated e.g. cogeneration, biosolids drying, etc. The paper will provide an overview of the current and future wastewater treatment for the City of Cuenca, and the challenges the City faces to sustainably manage biosolids that will be produced by the Ucumamba and Guangarcucho WWTPs in the near future. An overview of treatment options investigated to achieve a reduction in mass and volume of biosolids requiring end use management, advantages and disadvantages of the various alternatives and a triple bottom line evaluation to identify the most cost-beneficial alternative will be presented. Consideration of other factors such as operational and maintenance know how, energy requirements and costs, availability of manufacturer services and spare parts in Ecuador will also be considered in selecting the preferred treatment approach. The presentation will be useful to Utility Managers, Consultants and Engineers who also face biosolids processing and management challenges similar to the City of Cuenca. The paper will provide the attendees an understanding of a Citywide approach and initiatives to implement a sustainable biosolids management strategy in a resource constrained environment. The paper will also provide an overview of the City's existing and planned wastewater collection and treatment infrastructure.

The purpose of this presentation is to provide guidance for designing and constructing utility improvements in heavily urbanized areas. Working in urban areas has a unique set of challenges that should be considered during design and construction. If these items are left unchecked, project schedules, budgets and the overall project success can be impacted. This presentation will identify real-world issues and how various issues were or were not addressed. The City of Columbus signed two consent Decrees with Ohio EPA to address SSOs and CSOs in 2002 and 2004, respectively. The City of Columbus is the 14th most populous city in the United States, with a population of 900,000 people. The collection system consists of 6% combined sewers and 94% separated sewers. The majority of the combined sewers are located in the downtown area and the separated sewers extend into the suburbs. During the last 15-years, the City of Columbus has aggressively constructed projects to reduce CSOs and SSOs. These projects consisted of CSO modifications, private property work, green infrastructure projects, and pipe rehabilitation projects in some of the most populated areas of the city. The presenters have a combined experience of more than 30 years working on City of Columbus projects in urbanized areas. We will discuss procedures to implement in design and construction to mitigate issues throughout the project. The designer of urban projects must be aware of the current activities in the project area such as bus and garbage routes, corporate events and schedules, access points for vital businesses like hospitals and fire departments, business concerns, and the health and safety of residents working and living near the proposed construction sites. Communication and an active public outreach program are essential tasks during design phase of the project. The designer should be calling government agencies, schools, hospitals, and businesses in the project area to discuss the project objectives and the potential impacts to businesses or residents. The design phase is also the most cost-effective time to develop a plan to address local concerns/requirements. Delaying the coordination until construction will lead to more complaints, change orders and increased costs. During these discussions the designer should consider noise and odor impacts, access issues, security issues, site specific limitations, and traffic patterns. In construction, communication becomes even more relevant than the activities during design. Residents and businesses 'live' the construction activity on a daily basis and become immediately aware of the factors that impact their daily routine. The myriad of issues the design phase tries to anticipate will be minimized but a few others may grow in perception and yet other items not anticipated must be dealt with. A good rapport and continuous communication with those impacted residents will itself mitigate and minimize many of these unforeseen situations. A reminder that the public works being performed is for the betterment of the local project area, including themselves, which also hopefully engage their communal good will and public spiritedness. Most people do not like change or seek out disruptions to their daily routines, but consistent public outreach during the construction phase now engages the local residents and business owners as they travel along on the construction process journey. This engagement can go just as far, and sometimes further, than possible design changes or field adjustments for changed conditions to a project's overall success. In summary, the presentation will use real-world examples from the last 15-years of design and construction projects within the City of Columbus to demonstrate the need to coordinate, communicate and have an outreach program to address public comments and concerns. We will show examples of solutions that were effective in addressing business and resident concerns.