Results

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

1. Background Sludge treatment processes typically incorporate physical, chemical, and biological unit operations to reduce sludge volume, odour, vector attraction, and pathogens in the product biosolids [1]. Biosolids are regulated with respect to pathogen, nutrient, and heavy metal content if land applied [2]. However, biosolids may also carry a wide range of anthropogenic chemicals such as pharmaceuticals, personal car e products, surfactants, plasticizers, flame retardants, and water and stain resistant coatings [3], collectively called emerging organic contaminants (EOC). The presence of trace levels of EOCs has been identified as a concern associated with their land application as they could potentially mobilize into soil, infiltrate into ground water, or be uptaken by vegetation [4]. While the long-term risks of exposure to humans are relatively unknown, some of the EOCs are known to be toxic, persistent and bioaccumulative [3,4]. Hence, an understanding of the occurrence and fate of EOCs in sludge handling systems that produce biosolids will provide a basis on which risks can be quantified. Further, most studies pertaining to EOCs and wastewater solids only document the contaminant presence in the product biosolids and there is little information on their removal through sludge processing systems. Further, the relative performance of different physical, chemical and biological sludge treatment processes is also largely unknown The objective of this study was to study the behavior of five major classes of EOCs: per- and poly-fluoroalkyl substances (PFAS), polybrominated diphenyl ethers (PBDE), alkyl phenols and ethoxylate derivatives, bisphenol A (BPA), and triclosan in common sludge treatment systems. The final paper will highlight the key findings from this multi-plant study and discuss the practical implications for biosolids management practices. 2. Study Design Samples of raw sludge and the final stabilized biosolids were collected from nine sludge treatment systems that included pelletization (P), alkaline stabilization (AS), aerobic digestion (AE1 and AE2) and anaerobic digestion (AN1 to AN5) processes. Grab samples were collected in glass jars on three consecutive days within a one-month period in each of 2015 and 2016 and shipped overnight on ice to the lab for contaminant analysis. The target analytes included 13 PFAS, 21 PBDEs, 4 alkyl phenols and ethoxylate derivatives, BPA, and triclosan. All the EOC analyses were conducted by SGS AXYS International (Sidney, BC) following stringent quality control procedures. 3. Major Findings The measured concentrations were used to estimate contaminant mass flows (mg/day) in and out of the system (contaminant concentration ng/g x solids flow kg/day) to assemble contaminant mass balance through the system. Percent removal was then calculated to evaluate the relative performance of the treatment systems. An overview of five major findings from this study are subsequently presented. A detailed discussion on the influence of the contaminant and treatment plant related factors will be included in the final paper. 3.1 All types of sludge treatment lead to EOC removal: While sludge treatment systems are primarily designed to prepare biosolids for subsequent disposition, the results of this study suggest that some removal of EOCs also occurs during the process. Up to 87% removal of triclosan was observed in AE2 during aerobic digestion. Nonylphenol monoethoxylate and diethoxylates were removed in both aerobic (Mono: 59 to 86%; Di: 84 to 95%) and anaerobic digestion (Mono: 35 to 79%; Di: 69 to 96%). Alkaline stabilization, where the raw sludge was stabilized at high pH using lime and cement kiln dust, was effective in reducing ΣPBDE mass flows by 53 ±12%. During pelletization, where the raw sludge was thermally dried and compacted, there were low removals of perfluorodecanoate (PFDA) (17%) and ΣPBDE (6%) mass flows. Hence, all treatments resulted in some degree of contaminant removal but removals differed between technologies. 3.2 Contaminant formation is possible during sludge treatment: The conditions established in sludge treatment can also lead to transformation of contaminants resulting in an increase in mass flows through the systems. Such an effect was commonly observed for selected PFAS where the average mass flow of the measured compounds increased by 59%, 19%, 2%, 264%, and 13% in AS, P, AE1, AN1, and AN5, respectively (Figure 1). Further, a net increase in mass flow of 4-nonylphenol was consistently observed in all five anaerobic digestion systems. Evidence of reductive debromination of fully brominated PBDE congeners into partially brominated PBDE congeners was also seen in anaerobic digestion systems. Thus, sludge treatment systems can transform precursors to increase contaminant mass flows through treatment. 3.3 Removal is dependent on sludge feed characteristics: The raw sludge fed to sludge treatment processes can differ because of differences in the inputs of contaminants to the sewershed and in the types of wastewater treatment processes generating the sludge. EOC use and release in a given sewershed will be reflected in the contaminant loading from the sludge treatment process. For example, BPA was measured in the raw sludge in all treatment systems except AE2. Since BPA was not detected in the raw sludge at AE2, this substance was also not detected in the biosolids at this treatment system. Differences in upstream wastewater treatment processes design can also impact the EOC content in the final biosolids. For instance, the biosolids where the raw sludge was predominantly composed of primary sludge had less diversity in overall PFAS composition compared to blended raw sludge feeds (primary and waste activated sludge) where a wide variety in PFAS composition was observed. Hence, differences in raw sludge properties were found to impact the biosolids quality following treatment. 3.4 Removal is dependent on the type of sludge treatment: The target compounds behaved differently in physical, chemical and biological treatments leading to different final biosolids quality. For example, while alkaline stabilization was effective in removing PBDEs, anaerobic digestion led to an increase in PBDE mass flows. In addition, the behavior of perfluorodecanoate (PFDA) differed between treatment systems with responses ranging from moderate removal (41%) to substantial formation (-264%). Even in the studied biological processes, there were distinctions between aerobic and anaerobic sludge treatments. For example, PFOA had low levels of net removal (< 25%) during anaerobic digestion (AN3 and AN5) and contrarily a net increase in mass flow by -68% and -282% in aerobic digestion systems (AE1 and AE2 respectively). The differences in transformations was found to impact the final biosolids quality. 3.5 Removal is dependent on the plant operations: Site specific factors, especially in biological treatment systems, such as the solids retention time, staging of the treatment processes and the active microbial consortia appeared to impact contaminant fate through treatment and hence biosolids quality. For instance, BPA was removed in AN2 with an average efficiency of 75% whereas formation of BPA was seen in other anaerobic digestion processes (AN1, AN4 and AN5). In aerobic digestion, there were low levels of average removals of perfluorohexanoate (PFHxA) (28%) in plant AE1, whereas AE2 reported low average levels of formation (-11%). A detailed discussion on the site-specific factors and operating conditions that may be responsible for the observed removals and biosolids quality will be presented in the full paper. 4. Significance of the findings This study evaluated contaminant loadings and removal of five major classes of EOCs namely PFAS, PBDEs, alkyl phenol, BPA, and triclosan in different full scale sludge treatment systems. The lessons learned will benefit all stakeholders of the biosolids industry in understanding the responses of EOCs thorough sludge treatment. The removal efficiencies presented in this study will enable the treatment plant managers to appraise the performance of sludge handling systems with respect to EOCs. The contaminant loading estimates could be used to communicate the significance of biosolids quality to end users. Further, there is little information describing contaminant mass balances and overall removal through sludge treatment. This study bridged this critical knowledge gap and addressed major questions related to PFAS, PBDEs and phenolics in physical, chemical and biological sludge treatment processes.

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

Introduction: SARS-CoV-2 RNA is excreted in the feces of infected persons, and thereby enters wastewater streams. In communities with developed sewage infrastructure, wastewater travels to wastewater treatment plants (WWTPs), where it is then processed to remove major chemical and biological pollutants. The treated effluent is then often released into nearby surface waters or reused (e.g. for irrigation). SARS-CoV-2 RNA is regularly quantified in the raw sewage influents of many WWTPs as a means of monitoring and predicting local infection rates; however, it has only rarely been quantified in treated WWTPs effluents. Therefore, there is limited data available regarding the removal and/or persistence of SARS-CoV-2 RNA during sewage treatment processes. The purpose of this research is to address this knowledge gap by comparing SARS-CoV-2 concentrations between raw sewage and treated WWTPs effluents. Sample locations: We collected samples from the raw sewage influents and final effluents of seven WWTPs in the Greater Chicago area: the Calumet, Terrence J. O'Brien (O'Brien), Stickney, Egan, Hanover Park, Kirie, and Lemont Water Reclamation Plants. The daily processing volumes and populations served by these WWTPs are shown in Table 1. Primary treatment at these WWTPs consists of mechanical filtration and aerated grit tanks followed by settling tanks at all seven WWTPs except Kirie, which does not include primary settling tanks, and Lemont, which does not include aerated grit tanks. All seven WWTPs utilize secondary treatment in the form of aerated tanks that facilitate the growth of aerobic heterotrophic bacteria, followed by additional settling tanks. In addition, the O'Brien and Calumet WWTPs utilize tertiary disinfection treatments in the form of UV exposure and chlorination/dechlorination, respectively. These disinfection methods are employed seasonally because the surface waters that receive outfall from the Calumet and O'Brien WWTPs are classified as recreational during warm seasons, making the discharges subject to additional regulatory limits for fecal indicator bacteria. At the O'Brien WWTP, disinfection was inactive between November 24, 2020 and February 20, 2021; at the Calumet WWTP, disinfection was inactive between November 24, 2020 and February 22, 2021. Disinfection was active at both the Calumet and O'Brien WWTPs during the rest of the sampling period, making it possible to compare the effect of treatment with and without disinfection at the same WWTPs. Sample processing: Samples were collected as 24-hour composites using autosamplers, with influent and effluent samples being collected simultaneously. At Calumet, O'Brien, and Stickney WWTPs, samples were collected once weekly from October 28, 2020 until December 9, 2020, and twice weekly from December 16, 2020 until March 2, 2021. At the Egan, Hanover Park, Kirie, and Lemont WWTPs, samples were collected twice weekly from December 16, 2020 until March 23, 2021. 25 mL of each sample was concentrated by filtration through mixed cellulose ester filters, with MgCl2 added to facilitate viral adsorption to the filter membrane. RNA extraction from the filter membranes was performed using the QIAamp Viral RNA MiniPrep kit. In order to quantify SARS-CoV-2 RNA concentrations, we amplified the N1 and N2 regions of the SARS-CoV-2 nucleocapsid gene using reverse-transcription quantitative polymerase chain reaction (RT-qPCR). We then compared SARS-CoV-2 RNA concentrations between influent and effluent samples. Additionally, to evaluate the impact of disinfection at Calumet and O'Brien WWTPs, we compared the effluent:influent proportions of SARS-CoV-2 RNA concentrations between the periods when disinfection was active versus inactive. Results: Median influent and effluent concentrations of SARS-CoV-2 RNA at each WWTP, the mean proportion of effluent:influent concentrations, and P-values from statistical comparisons between influent and effluent are shown in Table 2. For all WWTPs except Stickney, P-values are generated from Wilcoxon signed-rank tests comparing influent and effluent concentrations. Because Stickney had two influent streams which joined at the WWTP to produce a single effluent, a proportion of effluent:influent concentrations could not be calculated, and a Friedman test comparing the three sites was used rather than a Wilcoxon test. Effluent concentrations were significantly lower than influent concentrations at all seven WWTPs, with mean proportions of effluent:influent concentrations at each WWTP ranging from 6.35 x 10-3 to 3.39 x 10-1 for N1 and 1.61 x 10-2 to 8.42 x 10-2 for N2 (Figure 1). In order to assess the effect of disinfection at the O'Brien and Calumet WWTPs, proportions of effluent:influent concentrations were between samples collected on the same days, and the set of proportions from samples collected while disinfection was active was compared to the set collected while disinfection was inactive using Wilcoxon rank-sum tests. These comparisons did not show and significant differences related to disinfection status (Figure 2). Conclusions: For all seven WWTPs studied here, primary and secondary treatment significantly reduced SARS-CoV-2 RNA concentrations, but did not consistently eliminate SARS-CoV-2 RNA altogether. At the two WWTPs where disinfection was used, there was no detectable impact of either UV treatment or chlorination/dechlorination on the amount of SARS-CoV-2 RNA removed. The data presented here provide insight into the effect of wastewater treatment, both with and without disinfection, on SARS-CoV-2 RNA concentrations.

Population growth brings capacity issues, climate change brings increased frequency and intensity of storm events, and ongoing system blockages from FOG result in overflow conditions that impact our communities and the environment. Municipalities are subject to ever-tightening regulatory oversight where high cost consent decrees for sanitary sewer overflows (SSOs) and combined sewer overflows (CSOs) are becoming the norm. The typical response is expensive capital upgrades to collection system infrastructure and high frequency cleaning of collection system segments on a schedule. Faced with uncertainty, municipalities are staring down the prospects of significant infrastructure investments and billion-dollar consent decrees to protect residential property, local businesses and waterways -- without a significant increase in resources. Despite the potential penalties and the prospect of massive capital projects, the benefits they may produce are decades in the making and consume billions of dollars of municipal revenue. It is imperative, then, that we begin to understand the real-time operation of our existing collection system infrastructure to maximize utility, minimize costs and target investments to the appropriate and highest risk areas. For more than 500 sewers around North America, the solution involves innovative turbo charging of their collection system engine to take an aggressive stance on risk management. A data-driven early warning system designed combines a real-time view of the sewer and stormwater networks, weather and storm data and real time notifications allowing them to be proactive in responding to conditions and detecting emergencies before an overflow. Those who attend 'Turbocharged Engines' will learn how agencies of varying size are using real-time sewer monitoring technology to provide actionable information in order to protect the environment, safeguard public health and optimize investments in maintenance and capital improvements. Many collection systems adhere to the EPA's comprehensive capacity assurance, management, operations and maintenance (CMOM) programs to prevent CSOs and SSOs. Such measures include backup pumps, frequent cleaning in high-risk areas, capital projects and flow reduction measures that maintain the pipes at their design capacity. While these programs can be effective, they often do not allow utility staff to be proactive – particularly in the face of rapidly evolving events. To provide that next level of understanding, control and response, three cities in Texas turbocharged their sewer intelligence with real-time visibility into the status of their underground infrastructure. These municipalities deployed a network of SmartCover systems to provide real-time sewer level and trend analysis information to a centralized, online dashboard and mobile app. Designed with the unique challenges of a collection system in mind, the technology transmits data from a sensor in the manhole to a satellite in the sky to relay reliable sewer information throughout all conditions – a particular benefit in places like Texas where weather events can often disrupt terrestrial communications. The patented sensors are purpose-built to withstand the harsh conditions in sewer systems and can be installed and serviced without confined space entry. SmartCover provided each utility with an event management platform with localized weather data from the National Oceanic and Atmospheric Administration (NOAA) to rapidly respond to issues before they become environmental, public health and financial emergencies. This system architecture has revolutionized the utility's response, allowing changes in conditions to be monitored in real-time, while reducing the uncertainty around the conditions in the network. Knowing the level trends in the sewers has helped the utilities schedule maintenance when and where it is needed most, and more importantly has been critical in preventing overflow events. SILENT SENTRIES PROTECT ENVIRONMENT The City of San Marcos, TX, treasures the San Marcos River, a spring-fed river winding 75 miles providing a critical habitat for eight endangered species. Further, the region is of significant archaeological interest as one of the oldest continuously inhabited places in North America. Given the river's rich history and central role in the city, its protection is a primary focus. Yet, extreme weather events are making this increasingly difficult. Solution: To preserve the local waterways during extreme weather events, the city installed 10 SmartCover monitors in high risk spots and outflows. Results: Automatic advance notification of blockages has helped the city mitigate SSOs and monitor and report on CSOs, adhering to the Texas Pollutant Discharge Elimination System Small Municipal Separate Storm Sewer (MS4) requirements. SSO MITIGATION SEES IMMEDIATE ROI Heavy rain events contribute to sewer overflows in the City of Arlington, TX, damaging property, the environment and impacting public health. Solution: Installation of 10 SmartCover sensors and rain monitors to measure flow in typical sewer trouble spots. This event-driven system allows staff to react to any blockages and other potential overflow conditions before wastewater backs up into homes and businesses or overflows the system. Results: In the first few months, the City of Arlington was notified of three alarms that helped avoid sanitary sewer overflows-- more than paying for the systems in a short period of time. After a presentation to City Council, the initial deployment was expanded to 60 SmartCover units using NOAA rain data. CLEANING PROGRAM OPTIMIZATION RESULTS IN SAVING 95% San Antonio Water System was facing an EPA Consent Decree with an estimated cost of $1.2 billion. SAWS adopted the EPA's CMOM guidelines and instituted high frequency cleaning for their 110,000 manholes and pipeline segments. Effectively this meant SAWS established a program of cleaning high risk pipes with potential for overflows, and instituted routine cleanings at monthly, bi-monthly, quarterly, semi-annual and annual frequencies. As conscientious sewer operators, SAWS identified 200 high risk sites for regular monthly cleanings – whether the pipes needed cleaning or not. While prudent, the logistics, labor and equipment costs to maintain this level of effort was staggering. Solution: SAWS deployed 200 SmartCover sensors to collect data. SAWS effectively transitioned from a routine, calendar-based cleaning system, to a prescriptive 'as needed' cleaning program when automatically notified of blockages. Results: SAWS has experienced a 95% reduction in cleaning, ZERO SSO incidence and 216 SSO 'saves.' Nearly 1,300 cleanings were scheduled, but only 65 cleanings were identified and performed -- an estimated $1 million in savings. By trusting automated data analysis, the optimized maintenance schedule has led to significant positive benefits for the operator, environment, and communities served. Not only is SAWS effectively reducing wear and tear on pipelines from the routine cleaning, it's also allowing their operators to refocus on other pressing activities. CONCLUSION Operators in the City of San Marcos, City of Arlington and City of San Antonio have successfully turbocharged their collection systems with innovative technology. All cities reported reduced overflows and costs. These 24/7, silent sentries have brought peace of mind knowing sewers are being monitored, data is automatically analyzed and plenty of advance notice will be given.

Per- and Poly-Fluoroalkyl Substances (PFAS) are a large family of organic compounds, including more than 4,000 synthetic fluorinated organic chemicals used since the 1940s. PFAS have unique surfactant properties that make them repel both water and oil. Because of these properties, they have been used extensively in firefighting foams, surface coatings, and protectant formulations for consumer products, including paper and cardboard packaging products, carpets, leather products and clothing, construction materials, and nonstick coatings (ITRC, 2020). Manufacturers of these items often discharge to Water Resource Recovery Facilities (WRRFs). Landfill leachate discharge and household sewage are also common sources of PFAS in WRRF influent. Conventional WRRFs have proven to be relatively ineffective in removal of PFAS and discharge from WRRF is considered a major source of PFAS in the environment (Ahrens 2011, Chen et al., 2018). There is mounting evidence that continued exposure above specific levels of certain PFAS may lead to adverse health effects (USEPA 2016a, 2016b, ATSDR 2018a). PFAS concentrations in wastewater and sludge or biosolids are mass loading based. Long chain PFAS compounds discharged into WRRFs partition to the solids and end up in the resulting sludge or biosolids. The presence of PFAS in WRRF biosolids has raised a concern in the recent years for beneficial land application programs as PFAS could mobilize in soil, leach into run-off, infiltrate into groundwater or be taken up by biota (Lindstrom et al. 2011, Rich et al. 2015, Sepulvado et al. 2011). Within the PFAS family of compounds, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the two most common compounds and are a focus of Federal and State drinking water and environmental regulations. These compounds were commonly used in the manufacture of aqueous film forming foams (AFFF) for fighting aircraft fuel fires and other industrial and commercial products. In February 2019, the US EPA developed an action plan to limit human exposure to potentially harmful levels of PFAS in the environment. The short-term action plan includes testing for measurable PFAS and PFAS precursors in biosolids. The action plan was updated in February 2020 indicating that EPA is developing a risk assessment to better understand the potential public health and ecological risks associated specifically with PFOA and PFOS in land-applied biosolids. With mounting concern about the presence of PFAS in biosolids and the lack of specific guidance from the US EPA regarding the risks of these compounds within biosolids, some states have begun their own evaluations on this topic with suggested concentration limits of PFAS in biosolids used for land application. However, state regulatory agencies do not have a consistent approach to managing PFAS in biosolids. These concerns coupled with lack of consistent guidelines from the US EPA and state regulators has caused utilities to consider alternatives to eliminate the presence of PFAS in biosolids to minimize their risk exposure to potential future regulatory standards. As a result, technologies which can effectively destroy PFAS in biosolids based products are being investigated. One such technology is pyrolysis. Pyrolysis is the conversion or cracking of biomass or biosolids at high temperatures in the absence of oxygen. As most organics are thermally unstable, they can be split in a pyrolysis process by a combination of thermal cracking and condensation reactions into gaseous (pyrogas), liquid (bio-oil), and solid (biochar) fractions. With limited research available on the ability of pyrolysis to eliminate PFAS from biosolids and the fate of PFAS in the resulting effluents (solids, liquid, and air), there is a need to provide actual data for engineers and planners to evaluate as to the actual performance of the pyrolysis process with respect to PFAS reduction and fate. Jacobs and CharTech Solutions (CharTech) recently partnered to investigate the application of CharTech's High Temperature Pyrolysis Technology for biosolids management, and its efficacy in eliminating PFAS from the solid fraction. In addition, the transformation or elimination of PFAS compounds by measuring concentrations in the resultant bio-oil and pyrogas produced from the pyrolysis process were evaluated. This is one of the first analyses done using dried biosolids which captured PFAS data from the all output matrices including the resultant char, bio-oil and pyrogas fractions resulting from the pyrolysis of biosolids. Bench scale testing was performed in a continuously fed pyrolysis unit to compare the PFAS removal performance at 500 °C and 700 °C pyrolysis temperatures. Dried biosolids tested in the bench scale test were derived from un-stabilized waste activated sludge produced from two WRRFs operated by Jacobs. The solids were previously dewatered with belt filter presses to approximately 20 percent solids and subsequently dried in a batch thermal dryer fired with natural gas to evaporate water, resulting in a biosolids product that was approximately 93 percent solids. The dried biosolids material previously met Class A Exceptional Quality biosolids product status by achieving all pathogen and vector-attraction reduction requirements, as well as meeting the concentration limits of heavy metals according to the U.S. Environmental Protection Agency's (EPA) 40 Code of Federal Regulations (CFR) Part 503 Rule. Twenty eight of the most commonly measured PFAS compounds were analyzed in the feed biosolids, biochar, bio-oil and 31 PFAS compounds were analyzed in the pyrogas. Only six PFAS compounds (10:2 Fluorotelomer sulfonic acid, PFOS, N-Et PFO sulfonamidoacetic acid, N-Me PFO sulfonamidoacetic acid, Perfluorohexanoic acid, and Perfluoroundecanoic acid) were measured above the detection limits in the feed biosolids. Three PFAS compounds were detected in the biochar at the 500 °C pyrolysis temperature (Perfluorohexane sulfonic acid, Perfluorohexanoic acid, Perfluorooctanoic acid), all at less than 0.5 ppb (dry weight). No PFAS compounds were detected in biochar at the 700 °C pyrolysis temperature. PFOS was measured at 26.6 ppb in the feed biosolids but not detected in the biochar, bio-oil or pyrogas at either pyrolysis temperature. Although not detected in the dried biosolids, PFOA was detected at very low concentrations in biochar and pyrogas indicating a lack of complete destruction and/or transformation of precursor compounds during pyrolysis. Higher concentration of Perfluorohexanoic acid (PFHxA) in pyrogas at 500 °C compared to 700 °C was observed, suggesting greater destruction of PFHxA at a higher temperature. To better understand the PFAS fate through the pyrolysis process, mass balance analysis on biochar, bio-oil and pyrogas streams were conducted and removals of PFAS were estimated. The result of mass balance analysis indicated a total measured PFAS mass removal of 84.4% and 95.6% for 500 °C and 700 °C, respectively for all the PFAS tested in this study. This paper will describe in detail the testing apparatus and procedures used and provide a full description of the results measured. The information will be useful for engineers, planners, scientists, utilities, regulators and others interested in the evaluation of pyrolysis as a potential biosolids management alternative to minimize PFAS in biosolids.

This assessment and report was performed by Cameron Colby, P.E., a Master's in Environmental Engineering candidate from Clemson University and employee of Renewable Water Resources, with expected program completion and graduation on December 17, 2020. Dr. Timothy DeVol, PhD served as the primary advisor for this project. Background and Introduction Poly-and perfluoroalkyl compounds (PFAS) are an emerging category of synthetic organic contaminant first included in the EPA's Third Unmonitored Contaminant Monitoring Rule 3 (UCMR 3) in 2012 (Environmental Protection Agency, 2016). Six PFAS compounds, perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), and perfluorobutanesulfonic acid (PFBS) were named to UCMR 3 (Environmental Protection Agency, 2016). PFAS compounds have historically been used in firefighting foams and, more recently, widely used in numerous consumer items such as textiles, non-stick cookware, paper products, carpets, and cleaning materials (Hamid, 2016). Industrial uses are also prevalent, incorporating PFAS compounds into processes such as metal plating, electronics production, and photography (Hamid, 2016). At the time of this report, no studies were identified that assessed the fate and transport of PFAS from the land application of wastewater biosolids to a human receptor. It is imperative for water resource recovery facilities to be able to quantify and understand, on a scientific basis, the potential impact of PFAS contamination from the biosolid product stream as it pertains to groundwater, vegetation, livestock, and a human receptor. Where lifecycle quantification of a contaminant are not measured or modeled, managerial and operational decisions involving biosolids could be made arbitrarily or unnecessarily, leading to costly program burdens. This risk assessment sought to quantify the possible cumulative oral risk posed to a human receptor from the land application of biosolids from water resource recovery facilities owned and operated by Renewable Water Resources (ReWa). Six biosolids samples from each of four water resource recovery facilities were analyzed for the presence of PFOS, PFOA, PFNA, PFHxS, PFBS, and pentafluorobutanoic acid (PFBA), with the average concentration of each compound from each facility used in a risk assessment. Transport and fate of PFAS from the land application of municipal Class B liquid biosolids in the Piedmont region of South Carolina were modeled in one dimension using derivations of the contaminant transport equation through the vadose zone, groundwater, and vegetative pathways. Chemical partioning, diffusion, bioaccumulation, and transfer parameters were compiled from multiple peer reviewed studies. The level of impact to a human receptor was quantified as a dose in milligrams per kilogram per day of contaminant and compared to the oral chronic or sub-chronic established or proposed reference dose, where available. Summary findings Vadose zone transport velocity was found to be retarded by the compounds' calculated soil partitioning coefficients (KD), which are dependent on the fraction of organic carbon present in the soil. In general, compounds with longer carbon chains (C>7) experienced longer retardation than those with shorter chains and are expected to be present at higher concentrations in shallower soil than in deeper soil. PFOA was an exception, and the assessment predicted it reaching the groundwater table in approximately 40 years as opposed to PFOS, also containing an eight-carbon chain, which was predicted to reach the groundwater table in 128 years. Additionally, vertical transport appeared to occur more quickly than horizontal transport, which is a factor of percolation rate and can vary based on region specific rainfall amounts and soil attributes. Saturated transport below the groundwater table was less retarded than vadose zone transport, suggesting the air-water interface in the vadose zone may play an important role in a compounds' mobility. In general, and similarly to vadose transport, soil partitioning played a large role in the retardation of groundwater transport, with longer carbon chain compounds taking longer to reach a well located ten meters from the point of application when compared to shorter chain compounds. PFOA was again an exception to this pattern. Transport through the vadose zone and groundwater presented the most temporally varied behavior amongst PFAS compounds, largely due to differing organic carbon sorption behavior. Biosolid concentration levels resulted in a maximum modeled groundwater contamination level an order of magnitude below the EPA's current health advisory level of 70 parts per trillion for PFOS or PFOA, signifying a nominal risk. Groundwater consumption did not contribute to the exceedance of any oral chronic or sub-chronic reference doses. PFOS and PFHxS exhibited modeled concentration in cow's milk from the consumption of fescue and Bermuda grass on land application fields in excess of the oral chronic RfD and sub-chronic RfD respectively. PFHxS also exceeded the oral sub-chronic RfD in cow muscle tissue. This suggests that livestock and livestock products may be a source of potential exposure for utilities land applying biosolids and having those fields' products serve as feedstock or grazing space. Having a grasp of the end-use of vegetation from land application fields could become a critical component in biosolid program decisions. Additional studies are needed to firmly establish compound bioaccumulation and transfer factors. Municipalities should consider, where feasible, understanding the lifecycle of biosolid impact to local, regional, or nationally distributed livestock products, i.e. milk and meat, produced from animals fed hay and wet feed from biosolid amended fields. Model verification Soil samples in 3 locations from the field used in the risk assessment were collected to verify the model. Two six-inch core samples were taken at the outer boundaries of the field, with each separated into 3-inch sections for analysis. A third core sample was taken at the middle of the field and measured 24-inches, with analysis being conducted on 1-3-inches, 4-6 inches, 6-12 inches, and 12-24 inches. At the time of this abstract, results have not yet been returned. The expected result should verify that compounds with longer carbon chains (C>7) will have higher concentrations in the shallower samples than when compared to deeper samples, and shorter chain carbons (C<7) should be present at deeper soil depths. Final results would be incorporated into the presentation and final manuscript.

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

Air pollutants such as hydrogen sulfide and reduced sulfur compounds (RSCs) are a common by-product of wastewater collections and treatment. The transfer and processing of wastewater causes turbulent conditions which releases these odorous and corrosive compounds into the air. As development encroaches on wastewater treatment plants and pump stations, complaints from nearby residents and businesses are on the rise. In order to protect public health, quality of life and valuable investments in infrastructure, municipalities must develop strategies for controlling the release of these compounds. In recent years, the biological treatment of hydrogen sulfide and RSCs has become one of the primary methods for controlling odors and corrosion resulting from wastewater collections and treatment. The most common biological treatment technologies include biofilters and biotrickling filters. This presentation analyzes the unique features of each technology and introduces ways in which these biological treatment methods are now being combined into hybrid systems to improve performance and reduce life-cycle costs. A detailed analysis of multiple types of filtration media will be provided. Media types will be evaluated on such factors as cost, surface area, porosity and sourcing. An increased focus will be placed on recycled sources of filtration media. These types of media are in increased demand due to the favorable cost, availability and sustainability associated with them. Case studies will be presented comparing traditional and hybrid technologies on such metrics as odor removal efficiency, energy usage, filtration media type, water demand and nutrient addition requirements. Life-cycle analyses will be introduced to compare each technology on projected capital and operational costs. Operation and maintenance requirements for odor control systems vary widely and are often overlooked in the design process. Analyses of these requirements will be compared and presented as well. This presentation concludes with a survey of new innovations in biological odor treatment. Topics include microbiome DNA testing, smart controls and sustainable odor control systems.

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).