Results

Regional flooding has been controlled within the Coachella Valley in Southern California since 1915, with existing facilities built or improved in the 1970s following severe floods. The Coachella Valley Water District provides stormwater protection for a 590 square mile area within the valley by using approximately 135 miles of channels along with a number of dikes and retention basins that can convey approximately 80,000 cubic feet per second of flow from the surrounding mountains into the Whitewater River. In 2017, the District partnered with Black & Veatch to launch an extensive asset inventory and support implementation of their asset management system. This presentation will show how the rapid growth of CVWD's asset management system has benefited their stormwater management program by: 1) Showing the importance of data structuring and establishing a data collection protocol for a successful asset management program. 2) Engaging stakeholders across their business to create an expansive and robust registry which supports current and future programs. 3) Providing data to justify capital improvements and preventative maintenance decisions; shifting away from reactive maintenance and developing defendable investment prioritization. The Project has completed a field-based inventory, baseline full-system condition assessment, development of risk-based prioritization criteria, and mapping business processes. The stormwater assets were collected over a 4-week field effort with zero injuries. To execute these efforts, Black & Veatch leveraged an off-the-shelf ESRI product tailored so the final asset inventory seamlessly integrated with the District's CMMS software. CVWD staff were involved in each step of the project, helping structure data hierarchies and dictionaries, collecting field data, and incorporating institutional knowledge into business process mapping and prioritization criteria development. Data management was key as the final inventory contained over 80,000 data points including sub-meter accuracy GPS coordinates, field documented asset specifications, over 1,500 photographs, opinions of replacement costs, and baseline likelihood of failure and consequence of failure criteria. Post collection, the District's forces now have verified asset locations and attributes that provide reliability to day to day efforts. Scalability was built into the implementation to support on-going and future development of the asset management system.

Abstract Anaerobic digestion serves as the linchpin for much of the wastewater solids treatment in the United States. In many major metropolitan areas, digesters were constructed between the 1950s and 1970s, and are reaching the end of their useful life. As utilities seek to increase resource recovery and intensify digestion, these older vintage digesters may not be able to accommodate simple upgrades that allow for higher temperature or higher total solids operation. Introduction Anerobic digestion sits at the nexus between traditional wastewater treatment and modern utility climate goals, including greenhouse gas (GHG) reduction, landfill diversion, and green energy generation. Utilities performing solids and energy planning around these goals are typically relying heavily upon their anaerobic digesters to be efficient and high performing, often seeking to intensify digestion so as to accommodate imported feedstocks (e.g. fats, oil and grease, food waste, outside sludge, etc.) or simply to provide capacity for future flows and loads within the same tankage. In many major metropolitan areas, digesters were constructed between the 1950s and 1970s, and are reaching the end of their useful life. As utilities seek to increase resource recovery and intensify digestion, these older vintage digesters may not be able to accommodate simple upgrades that allow for higher temperature or higher total solids operation. Results and Discussion When seeking to achieve higher loading rates (either due to increased population in the service area or a desire to import high strength wastes), it is typical for utilities to start the planning process by assessing the potential of existing anaerobic digestion tankage. Intensifying digestion via established processes such as thermophilic digestion or thermal hydrolysis can be an appealing way to expand capacity (see Figure) with a seemingly incremental investment (e.g. heat exchangers, thermal hydrolysis skid). The ability to intensify digestion can be especially important in older cities where sites may be constrained and expansion of a digester complex is not possible. Despite these advantages, however, digestion infrastructure may not be capable of realizing the full potential of intensification due to either structural inadequacy or suboptimal configuration. As a general industry practice, digester tanks are expected to remain in service for 50 to 75 years, with the associated mechanical equipment having a shorter service life of approximately 20 years. Factors that can affect this service life include freeze/thaw cycles, which can weaken concrete, and seismic activity. In addition, many older digesters were constructed with floating covers, and cover integrity, as well as interior and exterior coating integrity, can expose the digester structure to wear inducing conditions. While not a hard trigger, replacement of the digesters prior to reaching 75 years of life serves as a sound rule of thumb. Very few comparable facilities have digester structures of this age operational, although a small number remain in service with plans to replace prior to 2030 (e.g., San Francisco's Southeast Water Pollution Control Plant). In addition, considerations about capacity, given that older digesters were simply not designed to perform at the higher loading rates needed for codigestion applications, amplify the need for eventual replacement of these structures. Other unknowns, including structural vulnerabilities, could accelerate this replacement timeline. Operating conditions associated with higher rate digestion that can be problematic for older digestion infrastructure include higher gas production rates, biogas entrainment, and changes to viscosity. Older gas mixing systems, for example, are likely inadequate for realizing the full active volume of a digester generally, a condition that is exacerbated by sludges of higher total solids content. Changes to viscosity associated with higher total solids content (thicker sludge) and/or inclusion of food waste can, in addition to impacting mixing performance, can entrain biogas, contributing to acute operational issues such as digester foaming. Changes to sludge rheology will also impact ancillary systems, such as pumps and heat exchangers, which should be assessed for upgrades. Higher digester loading limits could potentially be realized if existing digesters are upgraded with features such as improved mixing and surface withdrawal, both of which will help realize the full active volume of the digester and minimize gas and foam entrainment (see Figure). Such upgrades can be included in existing digesters, assuming the structural integrity of the tank is intact. A detailed condition and structural assessment is recommended prior to implementing digester enhancements intended to accommodate higher rate digestion. Conclusions When assessing the capability of existing digesters to process higher organic loads, a thorough assessment must be undertaken. This includes a robust condition assessment, as well as an evaluation of retrofits that can maximize the benefits of intensification. Full costs of such upgrades should be compared against the cost and feasibility of construction of new, modern digesters to help utilities realize their full plans for resource recovery.

Introduction:
GM BluePlan Engineering Limited (GMBP) was retained by the Town of Niagara-on-the-Lake to complete an investigation in two urban watersheds containing seven storm sewer outfalls with elevated levels of Escherichia Coli (E. coli). The results from the 3-year storm sewer water quality monitoring program are applicable to all municipalities' management of wastewater assets by incorporating condition information and risk management for water protection initiatives. Successful water quality improvement was demonstrated with yearly reduction in E. coli levels ranging from 85-100% at various locations. Project Locations: 1.Site #1 ' Queens Royal Beach storm outfall was flagged by the Niagara River Remedial Action Plan as an Area of Concern (AOC) due to elevated levels of E. coli. GMBP's objective was to reduce the E. coli loading to the catchment through investigation of infrastructure condition on municipal and private property and remedial actions to eliminate and reduce sewage contamination to four storm sewer outlets. The success of this project led to removal of the AOC designation. 2.Site #2 ' Water quality near Garrison Village was monitored from 2010 to 2015 by the Niagara Peninsula Conservation Authority which flagged three stormwater outfalls with high E. coli concentrations. The investigation and rehabilitation process reduced E.coli from 500,000 Human DNA copies/100mL to Below Detection amounts. Project Stakeholders & Objective: Stakeholders included the Ministry of the Environment Conservation and Parks (MECP), Niagara Peninsula Conservation Authority, Environment and Climate Change Canada (ECCC), Public Health, Region of Niagara, and Town of Niagara-on-the-Lake.

GMBP completed the following activities:
1.Developed and implemented a water quality sampling program to understand the existing and post-rehabilitation state of the storm sewer watershed area.
2.Investigated and collected wastewater asset condition information through unique field investigations and existing digital data.
3.Developed a prioritized list of rehabilitation recommendations for infrastructure improvements to reduce E. coli loading to the catchment area.
4.Implemented infrastructure improvements for 'Quick Wins' and short-term recommendations for E. coli reduction and monitored resulting water quality improvement.
5.Developed and implemented prioritized recommendations requiring greater capital budget and implementation time. 6.Provided bi-monthly meetings to convey project progress to all stakeholders. Unique Solutions Implemented: GMBP developed a systematic study approach to identify sources of contamination, sub-catchment areas for improvement, and monitor the subsequent effect of rehabilitation action items.

The following unique solutions were implemented for each project site:
1.Water Quality Sampling using DNA Analysis ' GMBP utilized an innovative water quality grab sample analysis for the storm sewer catchment area. Monitoring was completed bi-weekly for both dry and wet weather conditions. Grab samples underwent a digital PCR analysis which categorized the E. coli to be Gull DNA (Seagulls), Human DNA (sanitary sewer contributions), or Other Animal Source (e.g., horses, racoons, rats, dogs, geese).
2.Prioritizing Assets for Rehabilitation ' GMBP developed an in-house tool (DARRT) to provide a prioritized list of recommended rehabilitation options (open cut, CIPP Liner, Spot Repair, etc.) with estimated costs for each pipe. The DARRT tool uses NASSCO standard PACP or LACP databases to examine every defect to determine each asset's overall condition. This analysis reviews defect type, severity, and proximity across the sanitary and storm systems to assist in identifying high risk areas for water quality degradation in the storm sewers.
3.Unique Field Investigations ' Work included smoke testing, dye testing, investigation during subzero temperatures to identify storm sewer locations with enough heat to emit steam, dry weather flow analysis of the storm sewer network to identify sanitary influence (diurnal flow pattern), and lateral condition assessment from both the mainline and private property. All field inspection results were digitized in GIS and overlaid with CCTV condition inspection data and water quality monitoring results to make data driven decisions for rehabilitation locations and budget prioritization.
4.Improper Connections ' Located and removed improper connections to the storm sewer system which included a wading pool, sanitary lateral and mainline connections.
5.Sanitary and Storm Mainline Rehabilitation ' Work included trenchless technology for sanitary lateral lining completed from the mainline, with open cut for defects which were too large, Ultra-Violet (UV) lining of mainline storm sewers to avoid styrene byproduct to natural watercourses, and manhole structural lining.
6.Fauna Protection ' Inlet and outlet protection of the storm system was implemented using WaStop Check Valves to prevent racoon inundation.
7.Low Impact Development ' GMBP designed and installed a Biofiltration Facility along with Smart Sponge catchbasin inserts which were effective in a 95% reduction in remaining fauna E. coli loading due to runoff from a tourist horse carriage route.

Impact and Future Initiatives:
The success of the project has led to encouragement from MECP to share GMBP's investigation method and findings with other municipalities. Through this process, GMBP has identified: -No regulation for stormwater outfall discharge currently exists in Canada. -No monitoring or sampling required of stormwater outfalls (retroactive approach). -Storm sewer system is typically the first to receive budget cuts. -Storm sewer digital records are typically lacking or incorrect. -Storm sewers are the least likely to have CCTV condition inspection data. -Historical infrastructure practices affecting storm sewer water quality: use of clay material, sanitary assets installed at an elevation above storm assets (risk increase leaking defects), improper connections and no-fill abandoned of historic mainlines which contribute to cross-connection flow between assets.

Closing:
Sewer systems are critical infrastructure and asset management through regular inspection and maintenance will detect issues, improve operational efficiencies, and enable planned improvements before defects result in system failure. Essential to this process is establishing and maintaining accurate records which provide the basis for making data driven decisions and support timely allocation of adequate funding. Storm sewers have a greater risk to discharge human waste directly to natural watercourses if upstream assets are not properly maintained. As the climate changes, with increased likelihood of more frequent and intense rain events, it is imperative that infrastructure is managed effectively to avoid the social, environmental, and economic costs related to water quality degradation. These suggested practices are an investment in system resiliency through inherent improvement of system knowledge, operation, and condition.

The Chagrin River-Lake Erie Direct Tributaries (CHALET) Stormwater Master Plan (SWMP) Study advanced the Northeast Ohio Regional Sewer District's efforts to protect Lake Erie, critical infrastructure, and over one million residents by addressing flooding, erosion, and water quality problems associated with stormwater runoff in the Cleveland Metropolitan area. Regional assets that receive and convey stormwater were evaluated throughout the 86-square-mile drainage area using a combination of field inspections and hydrologic and hydraulic (H&H) models. Field geomorphic inspections of waterways and stormwater basins were conducted through streamlined technology. Fifteen subwatershed models of the study area were also developed to identify flooding problems. Condition ratings for assets within the regional stormwater system (RSS) were then developed using standardized GIS data processing that integrated field inspection and modeled flooding results. Areas with poor ratings were grouped to define problem areas, and cloud-based GIS access facilitated the development and evaluation of alternative improvement projects. The resulting CHALET SWMP delivered a prioritized list of construction projects and operation and maintenance activities to reduce flooding and erosion risks and enhance stream health throughout the region. This presentation will focus on how inspection data and modeled flooding results were classified following the District's standards, integrated, and shared among the project consultant team to systematically compare risks across the study area and develop improvement plans. This process will be illustrated by focusing on one of the resulting 47 problem areas. This case study demonstrates how structural, hydraulic, and sedimentation and debris risks were flagged throughout the RSS and holistically considered when developing improvement projects. Key technologies that facilitated data collection, asset performance evaluation, and alternative development will also be highlighted. During the data collection process, culverted streams were inspected using closed circuit television, while stormwater basins and open channel streams were inspected through the ArcGIS Survey123 platform. These inspections produced numerous videos and photographs that were shared back with the District and hosted on their ArcGIS Online (AGO) platform. These inspections resulted in condition assessments with ratings for structural integrity and sedimentation and debris. These ratings for basins and streams were added into the GIS dataset used in the subsequent performance evaluation. In addition to the inspection data, open channel spherical imagery was collected throughout the study area. These 360-degree views of the streams were linked to a GIS dataset so that the consultant team could easily verify inspection results and develop improvement projects. This Google Street View-like tool proved invaluable for increasing the efficiency of desktop-based analysis, thus minimizing the need for return trips to the field. The CHALET SWMP team developed 15 H&H stormwater models using PCSWMM. These models drew on field inspections, flow monitoring, and spherical imagery. The PCSWMM models were used to predict flooding with the planning focus being, when feasible, to develop solutions that would avert flooding at the 100-year design storm event. Hydraulic condition ratings for RSS assets (culverted stream, basins, crossings, and streams) were based on the flooding depths of nearby buildings, roads, driveways, and other transportation assets. Using the District's standards, a condition rating related to flooding depth and a criticality rating related to asset importance were assigned to each building and transportation asset. More important buildings and roads, such as hospitals and highways, had higher criticalities than less important assets, such as residential garages or local streets. Condition ratings and criticalities of the RSS and associated buildings and transportation assets were combined to develop business risk exposure (BRE) scores in a comprehensive GIS dataset. Assets with high criticalities and poor condition ratings for structural integrity, hydraulic performance, and/or sediment and debris resulted in the highest BRE scores. Problem areas were delineated where multiple assets in close proximity had high BRE scores. Improvement alternatives were then developed for each area. Standardizing GIS data management of inspection results, generation of condition ratings, assignments of criticalities, and calculation of BRE scores supported data-driven performance evaluations and solution development. One problem area in the Euclid Creek East subwatershed serves as a case study for how comprehensive data management facilitated evaluating asset performance and improving regional stormwater management. Along this portion of Euclid Creek East Branch, inspections identified debris accumulation at a basin inlet, a failed crossing, and high criticality buildings near an eroding stream bank. Modeling predicted flooding of local roads. When considered together through the GIS database operational performance evaluation, this portion of the East Branch was flagged for problems stemming from hydraulic performance, structural integrity, and debris accumulation, and a problem area was defined. A set of baseline recommendations and two alternatives addressing flooding were created. The alternative that reduced the risk most effectively and efficiently was then recommended to the District in the SWMP. With standardized GIS data delivery, recommendations from this SWMP, in addition to the District's three previous SWMPs, can now be integrated and shared with internal District stakeholders, enabling the District to comprehensively present problem areas and recommendations across their entire service area. ArcGIS Online and the Enterprise Portal offer a dynamic and interactive method for effectively sharing SWMP recommendations. Results from this data-driven planning process now serve to prioritize nomination of improvement projects to the District's design and construction plan or for advanced stormwater planning.

Introduction: In December of 2008, the City of Buffalo, MN began to beneficially use their biosolids as a fuel source at the Buffalo Wastewater Treatment Facility (WWTF). The biosolids treatment system at Buffalo consists of both thermal drying and thermal oxidation processes to reduce the amount of material leaving the site while minimizing overall fossil fuel consumption. The objective of this paper is to discuss the process, project background and to provide an update after more than a decade of operation. The Buffalo system is one of the only North American WWTFs that uses dried biosolids onsite for energy recovery and has a long successful operational track record. With ever increasing interest in reducing fossil fuel energy consumption and concerns related to emerging contaminants, particularly perflorinated compounds such as PFAS, there is a renewed interest in thermal destruction processes such as the one operated by the City of Buffalo. Project Background: Buffalo, MN is located about 30 miles west of Minneapolis and the City of Buffalo's WWTF consists of a conventional extended aeration activated sludge process designed for hydraulic capacity of 4.3 MGD. Prior to the biosolids system upgrade, the City had a combination of biosolids treatment processes using reed beds and liquid Class B land application. The municipality was receiving complaints associated with hauling biosolids out of the facility and it was increasingly difficult to locate farmers willing to accept the biosolids. Because of the difficulties with the Class B land application program, the city became interested in thermal drying to reduce volume of product and odors at the facility. However, the City was very sensitive to conserving energy, so the typical dryer system energy demand was considered unacceptable. After a review of available technologies including systems in operation in Europe, it was found that belt drying systems were being operated in combination with furnaces at similar capacities required by the City of Buffalo. Biosolids Process Description: The City of Buffalo produces only secondary sludge. The plant contains a large aerated sludge holding tank that provide enough capacity for several weeks of sludge storage. From the aerated sludge storage tanks, biosolids are dewatered to approximately 18-20% total solids (TS) via two belt filter presses. After dewatering, the biosolids are dried to greater than 90% TS in a BioCon belt dryer and then combusted in a reciprocating grate furnace where the fuel value of the dried biosolids is utilized to fuel the drying process by recovering energy from the hot flue gas exiting the furnace. The process is known as the BioCon® energy recovery system (ERS). This process combines a medium temperature belt dryer with a biomass furnace, which uses the dry biosolids as a fuel. The intent is to completely combust all organic material and recover process heat for the belt dryer. This integrated dryer and ERS is depicted in Figure 1. The thermal treatment process consists of several steps which are depicted in Figure 2. Dewatered biosolids are pumped from a storage silo, into the dryer cabinet through oscillating depositors, and onto a slowly moving belt located inside the dryer. Heat is transferred to the biosolids by circulating air between an air to air heat exchanger that recovers energy from the furnace flue gas and the dryer cabinet. Moisture is removed from the drying air by continuously extracting a portion of the air from the dryer, transferring it through a condenser and returning it back to the dryer. A portion of the air from the condenser is removed from the system to maintain a negative pressure on the drying system. The foul air is blended with fresh air and used as combustion air in the burners and furnace eliminating the need for separate odor control systems. Screw conveyers transport dried product from the dryer to a buffer silo that feeds a reciprocating grate furnace. The flue gas from the furnace passes through an air to air heat exchanger, where the energy is recovered for the drying process. From the air to air heat exchanger, the flue gas passes through a dry flue gas treatment system that consists of activated carbon and lime injection and a bag filter before being discharged out the stack. The ash from the furnace is transported via conveyors to a storage hopper. The residuals from the bag filter are transported via conveyors to a two bag packing station. Start-up and Performance Testing: During system start-up several issues were observed. The largest two issues were related to molten ash or clinker formation in the furnace and fouling of the air to air heat exchanger. Optimization of the furnace feed, cycling and temperature control were required to mitigate the clinker issue. The air to air heat exchanger initially had sonic horns meant to prevent ash fouling but this was found to be ineffective and heat transfer efficiency would drop after just a few days of operation. Ultimately, the sonic horns were replaced with pneumatic firetube soot blasters which prevented heat exchanger fouling allowing for long term reliable operation. Other issues that were noted during start-up included modifying the level sensor in the dried biosolids feed bin and replacing the packing on the progressing cavity pumps to a mechanical seal to reduce leakage. The performance testing was conducted in two parts. The first was related to energy consumption and natural gas savings by using the ERS system. The guarantee was based on dewatered total solids and that the natural gas consumption would be 574 British thermal unit per pound water evaporated (Btu/lb H2O evap) at 18% TS feed and 164 Btu/lb H2O evap at 22% TS feed. The energy consumption is compared to 1,400 to 1,600 Btu/lb H2O evap which is expected for a typical dryer system. The performance test which was conducted with 18% TS feed showed approximately 200 to 300 Btu/lb H2O evap was required during steady state operation as depicted in Figure 3. The second part of the performance test was the emission testing. The permit limits, summarized in Table 2, were based on volatile organic compounds (VOC's), particulate matter, and mercury. The performance during the stack testing exceeded minimum requirements and it should be noted that the mercury limits were lower than the limits required for new fluid bed incinerators as shown in Table 2. Operation and Lessons Learned: Since completing start-up, the system has now been in operation for more than a decade. Because of the large volume of storage available onsite and equipment capacity, the plant currently runs the system four to six times per year for extended periods of time which is desired for this process due to the high temperature in the furnace as numerous start and stops would reduce life off the equipment. During start-up, the furnace temperature increases at a rate of 80 degrees per hour up to 1,500 F to limit wear on the refractory. Operation temperatures higher than 1,600 F creates clinkers at the bottom of furnace, resulting in bottom conveyors having difficulties with both the size and hardness of ash chunks that need to be removed. The dryer starts on natural gas but at steady state operation it is supported by heat recovered from the furnace exhaust. Improvements to the system dewatering ultimately reduced fuel requirements as initially determined during system performance testing. The operational experience has shown the system is reliable, but several improvements have been made over the years. Some modifications to the system include: - Replacing mild steel conveyors and aluminum duct with stainless steel, - Replacing ERS grates that had worn air holes that allowed too much short circuiting. Additional modifications were made to have all grates moving in synchronization for better fuel agitation, - Adding a shredder after the rotary valve to improve uniformity of dry product from dryer which improved fuel use in the furnace, - Replaced sprinkler system inside the dryer with stainless steel and replaced solenoid valve with ball valve, - Added mixers to the sludge storage tanks to homogenize liquid sludge prior to dewatering, - Modified polymer system to improve dewatering performance. These improvements and lessons learned from the decade of operation will be discussed in the detail in this paper. Conclusion: The Buffalo ERS system is an example where dried biosolids have been successfully used as a fuel source for energy recovery for over a decade. The process provides many benefits and reduces future risks associated with fuel price volatility and biosolids beneficial use reliability. As the industry continues to focus on reduced fossil fuel consumption and concerns associated with emerging contaminants, particularly PFAS, interest in these types of thermal process is anticipated to increase.

Following an EPA 308 Letter of Violation in 2014 citing high rates of SSOs within the collection system, Winston-Salem/Forsyth County (WSFC) Utilities identified system condition as a key driver of gravity sewer failures. A rehabilitation plan was quickly developed and implemented to assess and rehabilitate poor condition assets within the system. Five years later the plan has underwent significant changes. By understanding the basis of this program and using the results to date to improve the initial plan, a sustainable long-term collection system has been developed to achieve WSFC Utilities level of service goals. Initial rehabilitation needs were projected using a Statistically Significant Sample Survey (4S) which sampled the variety of pipes in the system to determine which features correlated with the poorest condition. Based on these findings, rehabilitation yield rates were developed for the system. Areas with assets most likely to yield high volume of rehabilitation work were prioritized for assessment and rehabilitation measures were developed based on these asset-specific inspections. This allowed WSFC Utilities to prioritize the inspection of assets most likely to be in poor condition, maximize the number of asset failures identified, and efficiently address these failures to improve overall system condition as quickly as possible. Five years later findings indicated changes from those initial assumptions. Pipes were yielding nearly double the rehabilitation requirements. Additionally, the cost of rehabilitation had begun to escalate quickly. Initial plans were no longer appropriate and needed to be modified to be sustainable over the long-term. Figure 1 shows where data has and has not been collected to date. Using the much larger data set that now included five years' worth of condition assessment data in addition to initial 4S findings, a variety of statistical and machine learning approached were used to update rehabilitation yield rates. The types of rehabilitation required for poor condition assets could now be projected as well. These improvements, combined with updated unit prices, were used to develop a update cost of bringing the system up to target service levels. Updated failure rate projections of initial asset classes can be seen below in Figure 2. Understanding the high levels of investment required to fully improve the condition of the collection system to target levels of service, WSFC Utilities elected to focus their rehabilitation program on the worst performing asset classes. By targeting condition assessment and rehabilitation activities on these poorest condition assets, overall system can be improved most efficiently. Challenges exist in collection of data on these assets only. Throughout the collection system these in-program assets are intermixed with non-critical assets. To assess condition and rehabilitate these in-program assets only would be inefficient. Even for sub-basins with the highest concentration of in-program asset classes non-critical asset data is captured. When accounting for this factor the total cost of condition assessment and rehabilitation for all in-program asset classes is approximately $158M in present value, as illustrated with Figure 3. This cost must be spread over multiple years. Resource constraints, including funding and workforce limitations, prevent the rapid deployment of these rehabilitation activities. However, as the timeline for this investment is extended the system continues to deteriorate. A sustainable long-term rehabilitation plan must invest enough resources to offset normal condition deterioration and improve conditions to target levels of service. By modeling condition deterioration and existing rehabilitation needs, WSFC Utilities can test funding scenarios to develop a plan that balances long-term service needs with financial limitations, as illustrated in Figure 4.

With the advent of powerful sewer process modelling tools, the range of physical, chemical, and biological processes occurring within sewers can reliably be tracked across large sewer networks and over changing conditions. These processes include:
Heterotrophic Growth,
Particulate COD hydrolysis,
Fermentation,
Sulfate conversion to sulfide,
Carbonate cycle chemistry,
Sulfur cycle chemistry/biochemistry,
Denitrification, Sulfide precipitation by metals, Natural ventilation,
Air emissions, and
Sulfide corrosion of concrete.

Heretofore, sewer process modelling has focused on sulfide generation and fate for the purpose of mitigating problems related to odor and concrete corrosion. Recently, the development of powerful and complete sewer process modelling tools has expanded to include additional capabilities such as tracing wastewater plant upset conditions upstream to identify industrial discharge release events attributable to the plant upset and anticipating the fate, transport, emissions, and exposure to the public of chemical warfare agents within a sewer network. These modelling capabilities represent a new field of inquiry designated 'forensic process modelling'. Forensic process modelling implements sewer process modelling in combination with treatment plant process modelling and atmospheric dispersion modelling to address such challenges as busting industrial pre-treatment permit violators and averting terrorist attacks. This paper illuminates the topic of forensic process modelling by demonstrating its application in two case studies. Tracing an Acid Spill to its Source The Albuquerque Bernalillo County Water Utility Authority's main water reclamation facility faces challenges related to their lower effluent pH limit. In general, the problem is kept well in hand through careful dosing of magnesium hydroxide to the collection system which, in addition to improving plant effluent pH, augments sulfide control in the collection system. Recently, a sudden pH drop at the plant was detected and the drop appeared unrelated to any process or chemical in the control of the water authority. It was suspected that an industrial discharger caused the event. To test this hypothesis and identify the culprit, the Water Authority's WATS model (Wastewater Aerobic/anaerobic Transformations in Sewers), which was developed as part of their recent sewer odor and corrosion control master plan, was adapted to represent influent conditions corresponding to the measured pH upset. Then, each industry discharger was screened to identify those which deal with acidic waste streams. WATS model scenarios were then run to represent an acid spill from each of the short-listed industry dischargers. These scenarios allowed quantitative comparison of an acid spill which could cause the plant upset to the acid waste streams of potential culprits. WATS modelling scenarios resulted in identification of the industry discharger which could be attributed to the pH upset. This forensic inquiry culminated in actionable evidence toward enforcement of the violator causing the pH upset. Anticipating a Phosgene Attack Owners of civil infrastructure have long been charged with protection of public health and safety. Unfortunately, owner responsibilities have of late expanded to include anticipating and mitigating against terrorist attacks. In the case of water treatment plants, nuclear facilities, or other facilities enclosed within a defendable fence line, attack preparation may include target hardening and increased site security. But what of sewer networks for which there is no fence line and little separation between the public and the facility? Every household has anonymous access to the sewer system through its lateral connection. Also, the sewer headspace ventilates to the ambient atmosphere with serious implications for exposure to the public. The situation represents a uniquely intractable security problem in the face of a terrorist attack seeking to use the sewer network as delivery mechanism for a chemical weapon attack. DC Water in particular, due to its symbolically important location, must anticipate terrorism. Also, they own a number of odor control systems which force ventilate air from the sewer headspace to the ambient environment. For these reasons the trajectory of a chemical attack on their sewer network is of particular interest. In this case study, a phosgene attack was simulated using the WATS model. Phosgene is a chemical warfare agent which also has wide application in the plastics industry meaning that it is potentially obtainable by individuals (as opposed to foreign governments). Phosgene degrades the pulmonary tissues and victims may not be aware of receiving a lethal dose before it is too late. The DC Water WATS model, which was developed as part of their corrosion control and asset management program, was adapted to represent the chemical and physical properties of phosgene which determine fate and transport within a two phase (liquid stream and gas headspace) sewer network. The scenario tracks a 200-gallon release into a lateral clean-out connection upstream of one of the interceptor odor control stations. Dispersion modelling was used to estimate public exposure at a neighboring facility based on WATS model predicted concentrations from the odor control stack. The case study culminates on an assessment of the possibility of lethal exposure to the public based on this relatively small poison gas attack.

As we await the Biden administration's review and approval of the Lead and Copper Rule Revisions (LCRR) promulgated on December 22, 2020, it is time to start familiarizing yourself with the proposed revisions, which seek to better protect children and communities with more effective requirements. At a glance, the revisions will require water suppliers to identify the most impacted areas by conducting a Lead Service line (LSL) inventory; strengthen drinking water treatment and corrosion control practices; replace LSLs; increase sampling reliability; improve risk communication; and better protect children in schools and childcare facilities. Through exploring how three communities proactively addressed the risk of lead in drinking water, attendees will gain a better understanding of what to expect when the LCRR is in effect, what are federal mandates, and how to get a head start. New York City Parks and Recreation Department conducted a robust testing program to sample more than 3,500 interior and exterior drinking water fountains at its public spaces across the city's five boroughs, within 3 months. Existing asset data allowed the project team to leverage GIS and compatible mobile applications to identify fountain sites, track stagnation, and manage testing and results in real time. The extensive data management required for this project provides valuable insight for managing LSL inventories and workflows around the find and fix philosophy as proposed by the LCRR. In 2017, the Massachusetts Department of Environmental Protection (MassDEP) assisted the city of Lynn in mapping facilities and conducting baseline sampling for lead and copper at more than 600 fixture locations in 25 public school buildings. After receiving the baseline sampling results, a phased approach was developed to address fixtures with elevated lead levels on a priority basis. Beginning in late 2019, the city entered the second phase of their program addressing lead in school drinking water and began replacing more than 400 drinking water and non-drinking water fixtures throughout its schools. School closures due to COVID-19 proved beneficial to this project as it allowed for school-wide water shutoffs that resulted in an accelerated replacement program. Approaches to comply with LCRR in absence of readily flushable connections which is often the case within schools will be addressed. California's El Dorado Irrigation District (EID) conducted a bench study to proactively evaluate alternatives for their drinking water corrosion control treatment. The district added zinc orthophosphate (ZOP) at its three water treatment plants to reduce in-house plumbing lead corrosion. The study assessed the feasibility of converting to a phosphoric acid corrosion inhibitor in lieu of ZOP to reduce zinc loading to the distribution system and subsequently to wastewater. This included development and implementation of a distribution system monitoring plan designed to assess potential impacts to distribution system corrosion with a particular focus on areas with asbestos cement piping. The results of the study were utilized by EID, in collaboration with the California Department of Public Health, to improve the District's overall corrosion control strategy to specifically address the upcoming LCRR requirements. Participants in this session will learn how these three entities with different goals and limitations approached comprehensive investigations to reduce lead exposure to consumers and worked proactively to make changes that improve water quality in advance of the forthcoming LCRR. The presentation will also provide brief insight on the impact of 'potential revisions to the microbial and disinfection byproduct rules' from the LCRR, with emphasis on proposed minimum oxidant residuals and common measures to control lead, microbial levels and DBPs.

Introduction
The Harris County Flood Control District (District) initiated a comprehensive asset management (AM) program that is changing their approach to operating, maintaining, and investing in infrastructure assets that reduce the risk of flood damage to Harris County, Texas. The AM program requires business transformation throughout the District's organization that will drive operations and maintenance (O&M) and capital investment decision-based activities. The program is intended to be a living and actionable strategy that allows for continuous improvement as the organization grows and the program matures. The District is using a phased approach for the development of the AM program. The initial phase (Phase I) of the project, which was completed between March 2021 and August 2021, developed interim AM program components and demonstrated the AM program approach applied to concrete-lined channels (Figures 1 and 2) which are a subset of the District's overall asset portfolio. Phase I formulated and documented the District's AM Policy, formulated elements of a first-generation Strategic Asset Management Plan (SAMP) and developed preliminary long-term maintenance and capital renewal estimates for concrete-lined channels included in federal and non-federal Channels Inspection Reports. The project team documented the Phase I efforts and findings and outlined anticipated future efforts in an interim report. The second phase of the project (Phase II) is focused on further developing the AM program while approximating long-term maintenance requirements for as many District assets as possible to support the District's maintenance budget request for the upcoming two fiscal years. Phase II will be completed by September 2023. AM program development is following best practices established through the International Organization for Standardization (ISO) 55000 series of standards for AM. This presentation will provide a summary of the Phase I efforts and results. The presentation will also provide a detail the planned Phase II efforts and status to date which is anticipated to include a discussion of asset inventory, inspection methods, and the District's current approach to long term maintenance cost estimating. Phase I - Interim Development As an initial step to implementation, the project team developed interim policies and strategies, initiated cross-organizational buy-in, developed an improved asset hierarchy (Figure 3) and created an asset registry associated with concrete-lined channels (Figure 4). A cornerstone of AM program, the risk framework, was also developed. The risk framework is anticipated to be used in the District's decision criteria to prioritize major maintenance projects, where, with all other factors equal, assets with a higher risk will be first in line to be repaired or replaced. The interim framework was based on five risk criteria for promoting an equitable application of maintenance funding: social vulnerability, historic structural flooding, channel level of service, development age, and development intensity. These five criteria were used to measure risk and to apply a total risk score to assets associated with concrete-lined channels (Figure 5). Phase I - Results For the interim phase, program outcomes were demonstrated by performing life cycle cost modeling for the District's approximately 140 miles of concrete-lined channel. The estimated cost to replace these District-owned assets 'in-kind' was approximately $1.098 billion as determined by planning-level replacement costs using attributes from the asset registry and District pay items and unit costs. The life cycle cost modeling simulated the concrete-lined channel assets over a 100-year period with funding scenarios that included major maintenance, vegetation management, and end of life renewal. Four different funding scenarios were simulated to demonstrate funding requirements needed to achieve various average long-term performance levels (conditions) of the concrete-lined channel assets in the model. The interim results (Table 1) demonstrated that while an annual O&M budget of $14M will maintain the concrete-lined channel assets in a 'Very Poor' condition, an annual $34M O&M budget will maintain the concrete-lined channel assets in a 'Good' condition over the long-term. The interim results provide an example of life cycle cost modeling results that are anticipated to be used to both optimize available O&M funding and to routinely evaluate various O&M budget levels and their resulting long-term effects on the condition of the District's asset portfolio.

Phase II - Current Activities
The project team is currently evaluating District assets associated with their open channel network for three watersheds: Little Cypress Creek, Halls Bayou, and Vince Bayou (Figure 6). District assets associated with these open channel networks include channel, outfall, manhole, inlet, conduit, and control structure assets. For these watersheds and associated open channel assets, the project team is developing a detailed AM register of assets, preparing a condition assessment framework based on industry best practice, conducting field inspection/condition assessment activities, developing long-term maintenance estimates, and identifying maintenance projects for 2 fiscal years. The current effort will test and further define future approaches to the District's AM program. The presentation will provide a detail the planned Phase II efforts and status to date which is anticipated to include a discussion of asset inventory, inspection methods, and the District's current approach to long term maintenance cost estimating.

Results and Conclusions
The AM program is shifting the District's current approach of estimating future maintenance costs based on past expenditures to a forward-looking approach based on accurate and up-to-date District asset data. The approach allows the District to optimize application of available O&M funding to achieve the best long-term condition of District assets. The program also provides a method to routinely evaluate various O&M budget levels and their resulting long-term effects on the condition of the District's asset portfolio. The results of the program will allow decision makers to plan future O&M budgets based on desired asset condition and available funding.

Stormwater systems are increasingly stressed due to the growing number of high precipitation events and the pressure on aging stormwater system capacity. Now, more than ever, efficient stormwater asset management is crucial to public safety and regulatory compliance. Unfortunately, the cost and effort of conducting field inspections and collecting accurate and comprehensive data is an ongoing challenge for municipalities. Radio frequency Identification (RFID) technology has been widely used in many industries for its unique ability to track items without needing direct visual confirmation. Passive RFID tags don't require power and can be affixed to nearly anything. Today, RFID is rapidly becoming the solution to bridging the gaps in field data collection workflows for stormwater management. This session will explore on-going deployments using RFID-enabled asset marking for stormwater assets in combination with mobile data collection and GIS-based asset management systems. Initial pilots indicate that RFID-enabled asset marking reduces the time, cost and errors in field data inspections. Several deployments will be reviewed, including how the approach performed when used with Esri's ArcGIS Online to manage water sampling stations; and when a range of assets are tagged, including catch basins, hydrants and manholes. The system consists of: RFID-enabled tags placed on assets RFID readers tied to mobile devices via Bluetooth Software apps (web or software) that run on the mobile device The workflow is as follows: 1. RFID tags are placed on the asset 2. The RFID tag is accessed through the reader and specific information is written to the RFID tag, including asset owner, date/time, lat/long 3. Then the tag data is connected to its specific asset record in ArcGIS through web apps or a widget on the mobile device which then launch inspection/maintenance forms for completion in the field. This data can be accessed and managed in the office or in the field, creating a direct link between physical assets and data. Additionally, accurate geolocation and asset performance data removes the guess-work from future location and maintenance. At the conclusion of this session, participants will be better able to: Understand the use of using RFID-enabled technology to enhance stormwater infrastructure asset locating maintenance, monitoring and management.

A new development towards the first worldwide guideline on the assessment of odor exposure by using dispersion modeling is taking its first steps. At this stage, there are many initiatives around the world related to dispersion modeling but there is no specific guideline for odor modeling to our knowledge. Modeling odors is complex and many of the guidelines on modeling published around the world fall short in treating this vector. Odor modeling often requires forgetting traditional dispersion modeling operating modes and focusing on exposure. Odors are perceived in seconds or minutes, not hours, and this is key in calculating their impact on ambient air. Most odor incidents are generated during calm or very low wind speeds which do not facilitate the dispersion of an odor and that makes modeling challenging. There are also elements that need to be further investigated, such as the chemical mechanisms of odors to avoid conservative treatment of odors, perhaps grouping 'odor types' by their chemical nature, so that it will be possible in the future to treat odors emitted by a WWTP differently than those produced by a composting facility. Last, but not least, there is a need to investigate the role of Instrumental Odor Monitoring Systems (IOMS) on the evaluation of model performance. Development of this guideline is an initiative promoted by over 36 experts around the globe in the area of modeling odors. The group is led by Dr. Gunther Schauberger and Ms. Jennifer Barclay. The first meeting took place in August 2020, and there are planned monthly meetings. The aim of this paper is to report on the advances being made for this initiative.

Background:
Situated between the Kansas and Wakarusa rivers, Lawrence, Kansas has an area of nearly 35 square miles divided into 11 tributary watersheds and 59 sub-watersheds. The 2020 Census population of approximately 95,000 reside within city limits, which is primarily developed with single family residential being the primary use. A large portion of the city is occupied by the University of Kansas and its associated properties. The enclosed stormwater system is comprised of over 17,600 structures and approximately 265 miles of piping, including both public and private infrastructure. The City of Lawrence, KS, is required to comply with a National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Program as part of the federal Clean Water Act. Historically, the common practice was to hire a consultant to evaluate stormwater data, run pertinent calculations, publish a report of projects that the City will get to when budget allows or enough concerns are raised to address. The City of Lawrence challenged that process and looked to its consultants as partners to provide holistic and interactive stormwater solutions to find a balance for the stormwater system. Approach: Managing a stormwater system requires balancing financial resources and physical system needs based on available data. The Stormwater System ID, Assessment & Model Creation Project, undertaken by the City of Lawrence, KS is an innovative approach to identifying stormwater assets condition, criticality, and serviceability. This data, along with modernized stormwater modeling methods, is helping identify cost effective solutions to managing the stormwater system. The project team, consisting of engineering consultants and City Engineering Staff have learned several lessons during this comprehensive project. This session will highlight lessons learned from a private consultant and municipal engineer's prospective and help others become wise from our mistakes and help you find balance in stormwater management.

What makes this project unique?
The City of Lawrence wanted to better understand its entire stormwater system, which encompasses the entire City, all 59 subwatersheds across nearly 35 square miles. All the asset inventory and condition information will reside in one primary database, Utility Network by ESRI. This dataset is shared with other utilities within the City, helping level the informational knowledge. Additionally, every structure will have a 3D digital model allowing users to visually confirm condition and routing. What can be learned from this project? There are evolving technologies in managing a stormwater system, but they all come back to having a good map and a plan of action. The foundation of this project, which can be used on other projects is a solid repository for data, aka a map. From that foundation, project engineers and asset managers can start piling on information to make the map more detailed, especially in a digital environment. One of the first benefits to a digital, ESRI based map, was the ability query quantities and assign statuses to assets. The project team created live dashboards that recorded a host of statuses which helped track progress and identify a punch list of structures or lines that needed attention prior to being labeled 'Inspection Complete.' The second foundational piece of the project was a plan of action. The scope of assets to be identified and appraised, initially seems to be an endless list of letters and numbers. Using digital maps and isolating work to be done in a specific watershed at a time, helped make the task of collecting all the data attainable. A prioritization of tributary watersheds was created, and field crews worked across the basins systematically. Another foundational cornerstone is communication. The project team and sub-teams held regular status meetings and huddles. These interactions allowed the entire team to maintain visibility on progress, areas that needed attention and successes. Having an engaged team across the variety of individuals contributing was key to consistency. The field team included staff from one of the consultants and from the City, this required coordination and communication of procedures and standard language. The data team processing and performing QA/QC had to communicate with field teams and modelers to ensure field data was accurate and incorporated into the models.

Innovation and Technology at Work
The mapping technology and ability to see and find additional details on assets is a game changer. But investing in innovation was important to the City of Lawrence for several reasons. -Data collection was done without having to put City or contractors at risk during manned entry of a confined space. -Asset physical measurement information, as well as condition assessments can be done with one touch of the structure while in office. Saving time and reducing field data collection errors. -TREKK 360 scans and models provide a snapshot in time to the current conditions of structures to be compared to future scans. -Modeling experts have a variety of easily accessible data to tune their model. -The affordability and simplicity of deployment allowed multiple crews to collect data simultaneously and rapidly. Reducing the field time and negative impacts of weather delays. Better understanding the stormwater system from an asset identification standpoint, aided the ability to accurately model the system. These steps were critical to understanding the status quo and what improvements will be required to improve the level of service across the City of Lawrence. Balancing the financial resources and setting an acceptable level of service will be the second presentation by our team members of Burns & McDonnell.