Results

Utilities around the world have navigated the challenges of the global pandemic by working collaboratively and taking new approaches to delivering on their organizational mission. Some are seeking ways to shift from near-term agility to long-term resiliency and sustainability. Washington Suburban Sanitary Commission's (WSSC Water) Strategy and Innovation Office (SIO) worked with their cross-departmental New Normal Taskforce (Taskforce) to think beyond the current challenges to examine emerging challenges and opportunities. Using scenario planning and virtual forums, the SIO and Taskforce identified six key business opportunity areas for investment that build from pandemic-driven insights and will position WSSC Water for success across a variety of potential futures. This effort demonstrated WSSC Water's ability to leverage crisis-based momentum and internal partnerships to move beyond near-term shocks to build resiliency for the future. WSSC Water is currently among the largest water and wastewater utilities in the nation, with a network of nearly 6,000 miles of water pipeline and over 5,600 miles of sewer pipeline. Their service areas span nearly 1,000 square miles in Maryland's Prince George's and Montgomery counties. They serve 1.8 million residents through approximately 475,000 customer accounts. Guided by their vision to be the world-class water utility 'where excellent products and services are always on tap' and commitment to ethical, sustainable, and financially responsible service led WSSC Water to form the Strategy and Innovation Office (SIO). The SIO is charged with accelerating organizational performance through strategic planning and execution, knowledge management, and organizational effectiveness. The SIO is made up of the Office of Innovation and Research, Strategic Performance Office, and Enterprise Risk Team. The Office of Innovation and Research is responsible for finding and accelerating new technologies and processes that reduce operating expenses, increase safe work practices, improve sustainability and create new revenue opportunities. The Strategic Performance Office leads strategic business planning, data analysis and process improvements. Enterprise Risk spearheads business risk assessments and mitigation planning to minimize challenges to implementation of WSSC Water's strategic business plan. The New Normal Taskforce was formed as a cross-departmental team to identify and address challenges associated with the global pandemic and operational challenges. The Taskforce included the SIO as well as representatives from human resources, asset management, diversity and inclusion, police and homeland security, finance, production and utility services departments. Throughout the pandemic, the Taskforce reviewed working conditions, business practices, and technologies to identify concepts to permanently adopt into post-pandemic operations. Arcadis was retained to facilitate a series of virtual sessions to engage the SIO and Taskforce in examining the emerging opportunities and challenges post-pandemic recovery plus ten years. This longer view was used to move beyond the current context and challenges of the pandemic to identify and to better position WSSC Water for long-term success. A key tactic in this exercise was scenario planning. Scenario planning is a method of using uncertainty in plan development and decision making. By using this tactic, leaders can make decisions or adopt strategies that play out well across several possible futures resulting in more resilient business plans. The WSSC Water-Arcadis team held a series of virtual workshops built on the key steps to scenario planning. First, the team developed framing questions that identified the most pressing challenges or questions facing WSSC Water. These questions included complex long-term topics (e.g., digital transformation, affordability, workforce development, community understanding) that do not have established or discrete solutions. The framing questions were used throughout the workshops to keep discussion anchored in the practical challenges of the utility. Second, the team developed and evaluated key national and regional trends that are outside the control of the organization but impact their decision-making. This analysis involved deep dives into nine trend areas including advanced asset management, alternative energy technologies, climate change, policy and governance, contaminants of emerging concern, customer expectations, intelligent water, revenue and pricing, as well as workforce development and upskilling. From these trends, the team selected two key themes to develop a scenario compass and four alternative future scenarios for use in the idea development sessions. Using a world café format and collaborative virtual platform, the team examined each alternative future scenario and generated ideas that leveraged existing resources to address each of the framing questions. Discussions included approaches to improve infrastructure management, operational efficiency, business continuity, workforce development, customer experience, and digital transformation. From these discussions, idea themes were identified and consolidated into potential innovation investment areas. Over 600 individual ideas were contributed through the virtual sessions which were consolidated into 19 primary idea themes. These themes were later grouped into six research and innovation investment areas including customer experience, infrastructure, stakeholders, operations, sustainability, and data & digital. Within each of these areas, the specific ideas were sequenced across three priority horizons: H1 — enhancing existing core functions, H2 — adopting new functions from partner or adjacent industry, and H3 — novel function or future aspirations. These horizon maps provide a roadmap for general exploration by the SIO. Lastly, using the six investment areas, the team developed tailored roadmaps for innovation investments regarding each framing question. The SIO will use the roadmaps to develop a strategy to assist WSSC Water leadership with investment in near-term innovation with long-term impact and reduction of risk posed by uncertainty. They will use the investment areas to assess and prioritize new ideas and technologies as well as guide decisions regarding resource allocations. The horizons within each investment area help set a cadence for needs assessments and functional requirements for external partnerships. Further, the collaboratively developed focus areas identify cross-departmental support and resources needed to implement these strategies. Lastly, the exercise provides SIO with a number of tactics that will support review of trends and alternative futures. As trends change, the updated roadmaps will provide a framework to guide revisions to investment areas or sequencing to improve organizational resiliency. In this presentation, our team will walk through WSSC Water's experience and outcomes. Participants will learn the fundamentals for applying planning tactics to leverage uncertainty and lessons learned during the pandemic to identify investment areas that will support long-term organizational resiliency.

Controlling odors and managing health risks associated with possible exposure to Endotoxins has always been a high priority for ERWSD. The Avon Wastewater Treatment Facility (AWWTF) has eliminated solids handling by discharging biosolids to the downstream Edwards facility, and is in the process of expanding the secondary facility, such that energy usage for heating and ventilating as it relates to odor control and meeting ventilation guidelines for the upcoming Nutrient Upgrade Project is an important element of the design. Design of the project is complete and construction has begun. Details of the design will be presented in this paper, where odor control has been integrated into the Nutrient Upgrade Project. Historically, comprehensive odor studies were conducted during each major process undertaking at Avon, including in 2104 before the plant shut down the Autothermal Thermophilic Aerobic Digestion (ATAD) process in 2016 and in 2018 during the planning stages of the plant expansion. The facility used an extensive odor control system in 2014 including three stages of chemical scrubber treatment for ATAD exhaust air and an Ozone oxidation process for the Headworks and Primary treatment processes. For the 2018 study, after ATAD was eliminated, ERWSD's goal was to meet a new standard of 'as near to zero community odors' as possible. The facility plan called for construction of a building over the aeration basins instead of keeping the flat basin covers, which significantly increases ventilation and exhaust air flow rates, therefore higher levels of odor treatment would be required to meet the goals. The ERWSD requirements were to provide full redundancy and multiple stages of odor treatment. This paper will present data, analysis of alternatives and the methodology used to meet these objectives. The design includes replacement of the ozone treatment system, which was found to be ineffective in treating odors (50% removal efficiencies) with a multiple stage carbon treatment train and the demolition of scrubbers that had reached the end of their useful life. Ozone was injected into the Headworks Building with 12 Air Changes per Hour (ACH) of outside air and exhaust from the primary and grit tank covers were also ducted to the Oxidizer chamber. Strobic Air fans will be used for the discharge of air from the Aeration Basin Building, providing dilution and a high emission profile. Modeling used in the project is presented below, showing improvements in community odors each time changes were made or planned for the facility. These are peak odor contours (Dilutions to Threshold -DT) for the 2014 plant, the 2018 plant and for the future expanded plant, in that order, showing improvement at each stage. Total plant Odor Emission Rates (OER) for each stage are as follows, with the increase in odor emissions for the expanded plant being the result of exhausting 33,000 cubic feet per minute (cfm) from the aeration building instead of a much lower exhaust rate from the existing flat covers: ERWSD has probably done more research and testing on Endotoxins at their plants, starting in the early 1990's and in the secondary clarifier buildings than any other municipality in the U.S. and has established limits on Endotoxin exposure for the buildings where workers are present. Endotoxins are lipopolysaccharides which are found in gram negative bacteria (some of which could be pathogenic) and exist in the outer membrane of the cell wall. These substances can cause respiratory or flu like symptoms so ERWSD keeps workers safe by providing sufficient ventilation to keep endotoxins below 90 Endotoxin Units (EU) per cubic meter (m3) for an eight (8) hour exposure based on 'no-observed-effect' health risk assessments performed in Europe. This paper will present monitoring data collected by ERWSD on Endotoxin levels inside buildings and from point sources. In this case, three (3) ACH's) was selected for the Clarifier Building to dilute Endotoxin concentrations with outside air below the 90 EU/m3 guideline At one point in this study, consideration was given to providing some make up air to the aeration basin from the unclassified clarifier building to save energy, but the consensus was to be safe and not use air that may contain some level of Endotoxins as make up air to another area. Odor control at wastewater plants is closely related to the heat and ventilation systems in the same areas. National Fire Protection Association (NFPA) 820, titled, 'Standard for Fire Protection in Wastewater and Collection Facilities' calls for a variety of fire safety systems, including guidance on how to mitigate hazards by ventilating spaces where fire risks are present. Areas upstream of the Avon WWTP primaries are ventilated per NFPA 820 with 100% outside air (OA) to mitigate explosion risks and are considered National Electric Code (NEC) Class I Division 2 areas, which require properly rated electrical equipment. However, areas downstream of the primary treatment basins are not required to have fire risk mitigation by NFPA 820 requirements. While not required to be ventilated by NFPA 820 to mitigate explosion risks, the areas downstream of the primary basins that can be entered by plant staff will be ventilated at rates to reduce risks associated with indoor air quality, such as limiting exposure to Endotoxins, mitigating buildup of corrosive fumes and meeting odor control goals. Ventilation can have a large impact on energy usage because OA may need to be heated or cooled to protect personnel and equipment inside the building. In Avon, a Colorado mountain town, the winter conditions can be extreme, requiring heating of the OA to prevent freeze and cold-temperature risks. There were a variety of ways to address the energy usage associated with ventilation at Avon including: --Heat the supply air with natural gas or electricity -- Heat the supply air with an existing wastewater-effluent-source heat pump system -- Air transfer ventilation using heated air from areas that do not have air quality risks, -- Energy recovery systems that transfer heat (but not contaminants) between exhaust and supply air This paper explores the various options at the Avon WWTP and how the design team settled on OA ventilation with supply/exhaust energy recovery for post-primary areas. The discussion will also describe how the use of supply/exhaust energy recovery resulted in a variance to IBC required building envelope insulation.

Introduction Per- and Polyfluoroalkyl Substances (PFAS) have been an increasing focus of the public, legislative bodies, and the regulatory community, and recent EPA activities highlight this focus with respect to biosolids(1). In October 2021 the EPA released its PFAS Strategic Roadmap, outlining EPA actions with respect to PFAS for 2021-2024: these activities include a risk assessment of PFAS in biosolids to be completed by 2024(1). EPA also announced its intent to pursue the classification of PFAS under the Resource Conservation and Recovery Act (RCRA). While it is no means certain that federal PFAS regulations for biosolids are forthcoming, some utilities have faced - or might face - increasing pressure to consider either i) reducing PFAS and microconstituent loads in biosolids, or ii) processes that provide an alternative product for land application. Conventional treatment processes such as anaerobic digestion or composting do not mitigate PFAS concentrations(2). Pyrolysis is an alternative solids process that is gaining interest as a possible approach to mitigate PFAS and microconstituents. Current literature is contradictory on the impact of pyrolysis on PFAS, with removal(3) and no removal(4) being reported. Thus, new experiments were conducted to determine the fate of PFAS during pyrolysis of biosolids, and results will be presented at the conference. In addition to knowing the impacts of pyrolysis on the fate of PFAS, practical considerations of pyrolysis such as generation of difficult-to-handle byproducts and side streams, dryer operations and costs, and product management need to be evaluated holistically. To approach this topic of PFAS removal via pyrolysis holistically, this presentation has three main objectives: 1. Define pyrolysis and the pyrolysis products generated from municipal biosolids 2. Determine the impact of pyrolysis on microconstituents, including PFAS, using novel, unpublished pyrolysis batch studies that investigate the fate of PFAS in biochar, pyrolysis-liquid, and pyrolysis-gas 3. Understand practical considerations for implementation of pyrolysis Objective 1: Define pyrolysis and pyrolysis products Pyrolysis is a thermal decomposition process that occurs at high temperatures (normally over 450ºC) under limited or no oxygen. Pyrolysis of biosolids generates solid, liquid, and gaseous products. The solid product, called biochar, is a carbon-rich product similar to charcoal that can be used as a soil amendment because it retains moisture(5). It can also adsorb nutrients from thickening filtrate and be used to improve grass growth(6). The non-condensable gases produced, called py-gas, contain energy rich constituents such as methane and hydrogen(7). The pyrolysis liquid can be composed of two phases: light non aqueous phase called bio-oil and an aqueous phase known as aqueous pyrolysis liquid (APL). The bio-oil, which can be used as a renewable fuel upon upgrading, is corrosive during combustion and difficult to handle, whereas the APL also contains organic compounds and sometimes high concentrations of ammonia that can be toxic to biological processes such as anaerobic digestion(8). Objective 2: Determine the impact of pyrolysis on PFAS and microconstituents Novel Research Approach Experiments will be conducted in a lab-scale batch pyrolysis system as described elsewhere(9). Dried municipal biosolids will be used as the influent feed, and effluent biochar, pyrolysis-liquid, and pyrolysis gas samples will be collected for PFAS analysis. In total, 37 PFAS compounds will be analyzed by PACE Analytical® in the solid, liquid, and gas phases to determine the impact of pyrolysis on the removal of PFAS from biosolids. These experiments will be completed by the end of 2021 and the analysis will be completed by March 2022. This experiment will be the first study to investigate the presence of PFAS in all three product phases (solid, liquid, gas) following pyrolysis. Results from Previous Lab-Scale Studies These results will be presented in light of Dr. McNamara's previously published data that found 3 possible fates of microconstituents during pyrolysis of biosolids: a. No removal: microconstituents reside with solids (e.g. metals) b. Volatilization: microconstituents leave solids and reside with pyrolysis liquid c. Transformation: microconstituents are chemically transformed Batch pyrolysis experiments revealed that pyrolysis removed triclocarban (Figure 1), triclosan, and nonylphenol from biosolids(10). Triclosan and nonylphenol volatilized away from the biochar and into the pyrolysis liquid; triclocarban was chemically transformed during pyrolysis. These results indicate that, while pyrolysis might likely remove PFAS from the solid biochar phase, PFAS might still likely reside with pyrolysis liquid requiring further downstream processing. The experiments and analysis to be completed by March, 2022 will confirm this hypothesis. Objective 3: Practical considerations for implementation of pyrolysis Pyrolysis has been extensively used for non-biosolids feedstocks but is not yet mainstream for biosolids applications, partly because of the overall operational complexity of these systems and cost considerations. Compared to biosolids land application, pyrolysis technologies represent a significantly higher capital investment for utilities since feed to pyrolysis must contain only 5 to 15% moisture, requiring thermal drying as a pre-requisite for pyrolysis. The capital and operational costs for drying could be very high depending on the moisture content of the influent biosolids(7). Including drying within the system boundary also makes the overall energy balance of a pyrolysis system less favorable. The energy available in pyrolysis gas and liquid products is approximately equal to the energy required for drying and pyrolysis of biosolids that are 20% solids. Based on anecdotal evidence from some of the demonstration facilities, phase-separation, i.e., separating the various pyrolysis products, downstream from the pyrolysis reactor can also be a challenge that could impact the quality of pyrolysis products for downstream applications. The bio-oil that is produced can be difficult to handle and potentially hazardous. To address the handling concerns with bio-oil, pyrolysis systems either need to run hot enough to not produce bio-oil or utilities need other plans for handling bio-oil post production. In short, while a potentially promising method for biosolids treatment, long-term operational viability of these systems for biosolids applications, sidestream characteristics, and emissions control requirements for these systems are yet to be proven. The potential benefits of pyrolysis include solids destruction resulting in less hauling costs, generation of pyrolysis-gas that could be co-combusted with digester gas or landfill gas, and generation of biochar which has potential as a value-added product and the potential to reduce PFAS. Biochar improves the soil characteristics by not breaking down readily, providing carbon sequestration and improving moisture-holding capacity of soils. Utilities considering pyrolysis have to weigh the potential benefits of the technology alongside costs and other operational considerations to determine the overall feasibility of the technology for full-scale implementation. Any government subsidies or credits to support PFAS removal, that might make pyrolysis more affordable to utilities, will also be reviewed and presented in this paper.

This paper will present a project in Novi, MI where 300 feet of 10-inch sanitary sewer was installed over a Peat and Marl Zone using a trenchless stabilization process and the pilot tube method of guided boring (PTM). The study is a comparison between the originally designed 'open excavation' project and the value engineered project using PTM and grout injection for the Grand River Road project (adjacent to two busy thoroughfares and a Cadillac Dealership). In 1996, the City of Novi, permitted development of a 10-acre parcel which included a sanitary sewer line that was added to their existing collection system. Located in Oakland County, this installation was originally constructed using PVC Truss Pipe at cover depths ranging from 10 to 12 feet. Below the pipe, the soil consistency was layers of peat and marl. In 2006, the site was redeveloped with an additional 10-foot of fill added to the area above the sanitary sewer line. This surcharge load affected the flexible pipe / soil structure as well as the peat / marl foundation below the pipe zone; the result was a failed pipeline. A new sanitary sewer line was proposed, designed, and bid as a conventional open trench excavation with 'over-excavation' of the marl zone. Soil borings indicated the existence of a peat/marl zone within the sewer elevation (on the west end) and below that, was a 5-foot layer peat zone above a 7-foot layer of marl. Moving to the east, the marl zone was just 2 foot below the sewer invert. The initial bid design required over-excavation of the peat and marl, the addition of a geotextile wrap, and 1-3 inches of backfill with crushed stone. This foundation improvement was required for pipeline support using conventional open-trench installation methods. This paper outlines the soil stabilization and installation method of PTM used to replace the sanitary sewer. The project was originally specified conventional open-excavation and the Contractor value engineered the project using grout injection and then used Pilot Tube Method of Guided Boring install the sanitary pipe.

The field of stormwater harvesting is evolving and expanding as utilities and communities consider viable alternatives to increase water supplies, improve resiliency of their water resources, and find multi-benefit and innovative approaches to addressing regulatory and stormwater quality challenges. In many cases communities turn to stormwater harvesting with a specific driver in mind, from water quality and local flood reduction to heat island mitigation. After further evaluation they often uncover many other benefits, many being of direct value to the community. Stormwater capture and use (SCU) projects can come in all shapes and sizes, as does the quality of the water when it gets to these stormwater harvesting projects. Current research in stormwater harvesting and the technologies fueling this sector's growth will be discussed in terms of their applicability and 'fit-for-purpose.' This presentation will highlight several significant projects and programs including the County of Los Angeles' Safe Clean Water Program, the City of San Diego's dry-weather diversion program to Pure Water, the Long Beach Municipal Urban Stormwater Treatment Project (LB-MUST), the City of Santa Monica's Sustainable Water Infrastructure Project (SWIP) and others. Key programs/projects include: County of Los Angeles' Safe Clean Water Program — In 2018 voters in Los Angeles County passed a parcel tax on impervious areas. The Program generates nearly $300M/year for capital projects; operations and maintenance; and technical studies. Most of the funding is distributed base on populations served by the agencies within the County. Approximately 40 percent of the funding is competitively awarded as Regional Projects based on load reduction, water supply benefits, community benefits and other criteria. Since capture and use projects score very highly with load reduction and water supply benefits, they often dominate the funding for Regional Projects. City of Long Beach's LB MUST — The LB MUST Project in Long Beach that captures and treats flows from 12,300 acres of urban watershed. With LB MUST the primary goal is to treat urban runoff (dry weather flow) and polluted stormwater (85th percentile average annual precipitation) to comply with the City's NPDES permit, which incorporates TMDLs. The project is expected to be complete in early 2024 and is a great example of a multi-benefit SCU project. Treatment processes including ceramic ultrafiltration and UV oxidation are used to produce non-potable water supply for various municipal and environmental demands. LEED recognized the project last year with Platinum Certification City of Santa Monica's SWIP — Santa Monica is densely populated beach community also within the County of Los Angeles. Beach water quality issues drove the City to create the SMURRF in the 2000s. Santa Monica also has significant groundwater and a goal to be self-sustainable with respect to water supply. Recent additions to the SMURRF (storage and advanced treatment) allow the City to capture and use more water. SWIP include facilities where pretreated stormwater is blended with wastewater for purification. Managed blending of stormwater with wastewater for treatment to non-potable reuse is quite popular in SoCal as deep droughts and conservation measures result in lower wastewater flows than many recycling facilities had planned for. Managed addition of stormwater and dry weather flows help to make up for this. City of San Diego's Planning for Stormwater to Pure Water — The City of San Diego's Pure Water Program is a phased, multi-year program aimed at providing additional local supply through expanded water reclamation and advanced water purification. The program will be implemented in several phases to eventually provide one-third of the area's drinking water needs by 2035. As currently planned, wastewater flows will be diverted to either new or existing water reclamation facilities to produce recycled water that will undergo additional treatment at a Pure Water facility. The resulting purified water will be stored in existing reservoirs and blended with imported and local water supplies. The water will be treated at existing drinking water treatment plants for distribution through the City's existing potable water supply system. Phase 1 of the Pure Water Program will be the first potable reuse project permitted in California for reservoir augmentation and future phases of the Program will likely rely on a similar approach. Local elected officials and NGOs have pressed for increased urban stormwater water capture and use options to enhance water supply and water quality in the Region. In addition, conservation measures and drought have resulted in reduced overall sewer flows for many agencies. As a result, the City is carefully evaluating the feasibility of capturing stormwater for diversion to the existing sewer system for use as an additional water supply. We will share how these projects were developed considering the required water quality for each application — from irrigation and recreational, to environmental demands. This presentation will also look at current research needs in stormwater harvesting. The presentation will conclude with a discussion of stormwater harvesting lessons learned and the application of a proven planning process can be valuable, and transferable, to other locations in North America.

The Detroit Water and Sewerage Department (DWSD) serves more than 230,000 accounts, including a residential population of nearly 650,000. DWSD's network consists of more than 2,700 miles of water main and nearly 3,000 miles of sewer collection piping within the city of Detroit. This presentation shall outline DWSD's Capital Improvement Program Management Organization (CIPMO) project. CIPMO's mission is to coordinate and execute capital project planning and project implementation across the City. CIPMO has taken a programmatic and collaborative approach to rehabilitate the water and sewer infrastructure with the goal of producing $500 MM worth of CIP projects over five years. In June of 2020, DWSD initiated a new, Geographic Information Systems (GIS) based procurement process intending to streamline procurement activities, increase the level of information provided to prospective bidders, and support the development of more accurate bids on capital projects. The newly implemented system is built on DWSD's existing enterprise GIS infrastructure, leveraging Esri's ArcGIS Online platform to publish and maintain a web mapping application that provides bidders with detailed GIS data on planned repairs, access to supporting documentation (including bid documents and plans), and base data that can be used to support the bid development process. This system provides bidders with the ability to interactively view data within the web mapping environment, query or filter data based on a variety of parameters, and export data and maps to support further analysis or assessment activities. This presentation will outline the previous procurement process, the development, implementation and management of the new platform, and detail DWSD's plans for future improvements to the procurement process. DWSD's Collection System includes lateral, connector/trunk, and interceptor sewers that collect and convey storm and sanitary flows throughout the service area through lift stations to the wastewater treatment plant. The sewers are generally a collection of clay, brick, concrete pipes ranging in size from 8 inch to 17 feet. The system has approximately 3,344 mile of sewers which includes 2,258 miles of lateral sewer, 559 miles of connector sewers, 483 miles of trunk sewers and 44 miles of interceptor sewers. The oldest of these sewers were constructed in the mid-1800s. The collection system services Detroit and 76 communities which include over 3 million people over approximately 904 square-miles in southeastern Michigan. DWSD's in-house crews perform routine maintenance of the collection system including open cut repairs to fix sewer collapses and sewer rodding/cleaning along with video inspection to identify areas/causes of flow obstructions and provide relief to customers. The Department utilizes contracts to carry out sewer assessments and construction for capital improvement and aid the in-house crews in performing emergency repairs. These contracts are also used by the Department to assist DWSD's crews in providing water-in-basement complaint investigations, sewer cleaning service and open cut repairs. These contracts are a good fit for the Department's short-term maintenance. Starting in the early 1980s, the DWSD began to use the Cured-In-Place (CIPP) method as an alternative to the open cut method in rehabilitation of the collection system. Segments of sewers determined to be structurally deficient were lined by the CIPP method. In the late 1990s, the Department initiated a larger scale CIP with the intention of rehabilitating up to 1% of the collection system annually. Prior to the inception of DWSD's current Capital Improvement Program Management Organization (CIPMO), the Department's Collection System CIP was managed and implemented through two sewer contracts divided between the east and west sides of the City. A quadrant of the collection system which represents approximately a quarter square mile in size was identified based on previous I/I study, water in basement complaints, cave-ins/collapse records and population density and assigned to the sewer contractor to assess, prepare and submit PACP reports, treatment strategies for DWSD's review and approval. Approved strategies for rehabilitation were also performed by the same contractor. The Department and its contractors utilized the open cut method, Cured-In-Place (CIPP) lining, Slip lining, Epoxy lining and Cementitious and Chemical Grouting methods in the Collection System CIP as the main methods of rehabilitation. The Department's annual renewal rate of the collection system was about ~150,000 linear feet of sewers per year, which was approximately 24% of what was recommended by the Department's Master Plan. DWSD's current CIPMO which was initiated in 2016 is taking a different approach to the capital renewal of the collection system. Instead of a single contract to perform sewer assessments, provide PACP reports, treatment strategies, design, and construction services; separate standalone contracts are procured to provide sewer assessment, data verification and acceptance, treatment strategies, design and construction. The details of DWSD's CIPMO process including emerging challenges, design & construction, resource management, procurement challenges, will be discussed in full at the conference. Beginning in June of 2020, DWSD initiated a new, GIS based procurement process that is intended to streamline procurement activities, increasing the level of information provided and supporting the development of more accurate bids on capital projects. The implemented web-based system provides prospective bidders with access to a contract-specific, interactive mapping application that details information on the planned repair, including needed replacement and rehabilitation work. This application also provides advanced functionality to support the export of data in tabular format, interactive toggling of map layers, and filtering or querying of data. As compared to the traditional approach of providing bidders with hard copy or static plans, the GIS-based procurement platform provides bidders with the following benefits to better prepare bids: Access to additional data on existing assets and proposed work. Access to a variety of basemaps (including aerial imagery, topographic, planimetric, and hybrid) to help provide better understanding of the construction activity areas. Ability to view geographic data interactively, at different map scales and/or combinations of layers. Flexibility to filter export data and maps to a variety of formats, including spreadsheet format, allowing for additional assessment and analysis to be performed Ability to 'bookmark' specific areas or locations, perform measurements, and make map markups that are specific to user logins This system also gives bidders the ability to access contract data on a variety of devices while maintaining data security through assigned, contractor-specific login credentials. Approved DWSD contractors are provided access to specific procurement sites on a contract-by-contract basis, minimizing the amount of effort required by DWSD to manage credentials and simplifying the login process for contractors.

Over the last 50 years, cured-in-place pipe (CIPP) has become the method of choice to rehabilitate old, crumbling, and leaking wastewater collection systems. Lower cost, speed of execution, reduced disruption, and long-term effectiveness of trenchless rehabilitation eroded support for the old 'dig and replace' approach. Today, CIPP is the most widely used trenchless method for pipe renovation. It is frequently specified by Utility Owners throughout North America, with Industry standards requiring minimum levels of quality, primarily flexural properties and chemical resistance. However, the question remains, 'is CIPP as good as new', and what steps are taken to protect residents from potentially harmful VOC emissions? Normally, sewer pipes and other pipes are manufactured in a factory under strict quality-control measures ensuring repeatability and consistent quality. CIPP, however, is manufactured in the field under less-than-ideal quality conditions producing less than ideal results. One CIPP might be tight fitting without blemishes or defects, while another has wrinkles, blisters, and delamination. CIPP can be installed and meet all requirements for physical and chemical resistance but might leak for the next 50 years. Significant opportunity remains to improve performance and overall quality of CIPP by simply changing the order of operations. The current trenchless model generally contemplates realizing comprehensive collection system rehabilitation meaning 'if you're going to control inflow and infiltration in a sewer collection system, you need to seal the entire system.' A number of issues can arise from sequencing events pursuant to current installation practices, whereby mainline rehabilitation occurs first and service pipes are lined thereafter. Clean outs are typically installed by the lateral lining contractor and are generally not in place when the mainline CIPP liner is installed. Some resulting issues involve public health and safety concerns, ranging from toilets blowing up during high velocity water jetting to homeowner complaints of headaches and paint smells during main liner curing operations. This can cause significant problems for the utility, the homeowner, and the contractor. Other issues arise when the main liner is cured but some or all service lines connected to it have not been temporarily plugged, which the author contends is a primary requirement if CIPP is produced with 'good as new' quality. In reality, under current CIPP practices, there are no substantive measures taken to ensure residents and businesses do not continue to discharge waste into the system while a resin-saturated liner is inserted and cured in the sewer pipe. Since the system is not taken out of service, not only is sewage allowed to flow and mix with the resin saturated liner, but VOC emissions amigrate up the service pipe, often contaminating air quality in a home or business. The adverse consequences of current municipal CIPP sewer rehabilitation projects include the following shortcomings where opportunities exist to improve quality, performance, and overall service life: - Sewage mixed with the resin-saturated liner may cause reduced physical properties and reduced chemical resistance. - Flow from service pipes can cause CIPP not to fully cure at service connections, leaving gooey resin that makes it difficult to reinstate the service properly. - Service pipes under head pressure can cause a 'lift' or bulge in the liner. - Main pipe sags collect condensation from steam curing, insulating the invert of the liner and preventing curing, resulting in a 'lift' The paper will argue that the solution is simple: change the order whereby segments of a collection system are rehabilitated by adhering to a specific Order of Operations with seven sequential steps: 1.Conduct a pipe survey including CCTV inspection, measuring pipe diameter, locating service pipes near private property lines, and marking exact locations for service cleanout installations; 2.Install a two-way clean out in each service line near the property line; 3.Divert system flow and take all service pipes out of service during CIPP; 4.Control groundwater influence on CIPP; 5.Install mainline CIPP after plugging service pipes and filtering emissions; 6.Install Lateral Lining after plugging service pipe and filtering emissions; and 7.Install Manhole Lining. The expanded role of the clean out drives the success of this new approach, providing the ability to plug the service pipe effectively taking the system out of service during CIPP rehabilitation. A two-way clean out allows for the inflatable plug to be positioned on the upstream side of the clean out. It also provides access to inspect, prepare, and rehabilitate the service pipe in the public right of way. An added benefit of the two-way cleanout is homeowners can have a contractor renew their private sewer from it. This more versatile clean out, adhering to ASTM F3097 and utilizing a minimally invasive installation method, is often used in conjunction with CIPP sewer system rehabilitation. A minimally invasive vacuum-excavated cleanout also answers sensitive homeowner concerns by eliminating conventional excavation, which often requires trench boxes and piles of dirt in the yard. Moreover, the minimally invasive cleanout provides for Same Day Restoration (SDR). SDR means the cleanout is installed by vacuum excavation, and landscaped areas, sidewalks and driveways are completely restored that same day, providing great benefit for all involved in the project. The first step of the Order of Operations is to conduct a comprehensive survey that measures, locates, and marks, ensuring solid knowledge of the system and its issues and the use of ASTM compliant components to tightly seal it 'good as new'. Installation of two-way clean outs on each lateral is next. They are thereafter used to improve main rehabilitation – using the cleanout to plug service pipes during main lining, together with bypass pumping of upstream basin flows, yields two improvements: 1.Removing all flows that might impair proper curing of the liner and its overall quality and performance; and 2.Bottling up VOC emissions so they do not enter structures which connect to the main through the adjoining service pipes. Moreover, it provides the capacity to filter emissions from curing operations, protecting workers and the public from potentially harmful fumes. Mainline lining then proceeds with the entire system taken out of service during insertion, inflation and curing of the new CIPP. Lateral lining then proceeds, with each service pipe plugged upstream of the cleanout during the CIPP lining process; the benefits described above are realized, ensuring CIPP is safe for residents and the public by filtering and monitoring all emissions. Finally, trenchless rehabilitation of manholes occurs. Though these changes are few and somewhat subtle, their impact is huge, yielding improved system rehabilitation, capturing and putting to good use advancements in trenchless technology, and improving the experience of those who live and work in a project area and of the utility as well.

The North River Wastewater Resource Recovery Facility ('WRRF') provides secondary treatment for 170 million gallons per day dry weather flow primarily residential wastewater for a population of approximately 500,000 residents in the New York City's Borough of Manhattan. The facility is unique in that a heavily used, 28 acre urban Riverbank State Park is located on top of the plant. New York City Department of Environmental Protection ('NYCDEP') conducted dispersion modeling analysis to evaluate the potential impact of the North River WRRF's emissions. Typical sources of airborne formaldehyde in an urban environment include direct formaldehyde emissions from incomplete combustion (oxidation) products, from motor vehicle exhaust byproducts, or indirectly from formation of formaldehyde in the ambient air from photo-oxidation of hydrocarbon precursors, also emitted from motor vehicle exhaust and other combustion sources. The NR WRRF has compression ignition reciprocating internal combustion engines for its raw sewage pumps and blowers and is thus a potential source of formaldehyde emissions. NYSDEC Air Guide 1 dispersion modeling analysis estimated the potential impact of formaldehyde emissions from the facility's compression ignition reciprocating internal combustion engines (RICE) may be >10 times of the NYSDEC Annual Guidance Concentration of 0.06 µg/M3 around the engines' exhaust stacks within the plant's rooftop Riverbank State Park. NYCDEP executed a stationary ambient air formaldehyde monitoring program at a location by the engines' exhaust stacks for a year started in September 2015 as follows: Stationary Formaldehyde Monitoring Using EPA TO-11A Method -- Two 12 hr samples at one location every 6 days -- Started 09/25/2015 and concluded 09/25/2016 The initial formaldehyde monitoring registered unexpected ambient air formaldehyde concentrations as high as 84 µg/m3, much higher than published results of a previous survey conducted in New York City. NYCDEP staff performed a top-down assessment of the sampling program and the elevated concentrations observed with the assistance of NYSDEC. NYSDEC installed a separate set of sampling equipment side by side with the NYCDEP sampling equipment to collect same samples on two days and sent the samples to a NYSDEC laboratory for analysis. The NYSDEC sampling and analysis results verified the NYCDEP monitoring data. The NYCDEP monitoring program was expanded to conduct portable sampling at up to 13 remote locations in and adjacent to the Riverbank State Park and the surrounding community: Additional Remote Locations Formaldehyde Sampling Using Modified NIOSH Method 2016 -- Two 1 hr samples per day and two days per week at initial 11 but expanded to 13 locations -- Started 12/15/2015 and concluded 09/22/2016 NYCDEP performed data analysis including spatial and temporal analysis and revealed the following: The stationary monitoring station data show an apparent correlation between measured formaldehyde concentrations, ambient temperatures and ozone concentrations The stationary monitoring station data show very limited difference between formaldehyde concentrations for day and night time sampling events The portable sampling data didn't show a correlation between measured formaldehyde concentrations, ambient temperatures and ozone concentrations, The portable sampling data show marginally higher concentrations at the east side of the park that is closer to the nearby NY 9A Henry Hudson Parkway The portable sampling data show no significant difference between average formaldehyde concentrations between locations The portable sampling data show that the highest formaldehyde concentrations at each locations were all registered when the wind was blowing from a southerly direction The portable sampling data and Pollution Rose analyses didn't show apparent impact contours of any point source NYCDEP has continued performing the stationary monitoring, and also performing the remote locations sampling at reduced effort. The data show a seasonable variation pattern of the ambient air formaldehyde concentrations, demonstrating that the elevated concentrations are likely due to formation of formaldehyde in the ambient air from photo-oxidation of hydrocarbon precursors, and emitted from motor vehicle exhaust and other combustion sources.

In Indianapolis, Indiana a developed neighborhood was seeing localized flooding during smaller rain events. When the neighborhood was built in the 1960's, almost no storm water infrastructure was built as the neighborhood was established. HNTB Corporation was selected to help the Indianapolis Department of Public Works(DPW) solve the neighborhood's drainage issues. At the start of the project, the goal was to improve the neighborhood drainage, introduce green infrastructure where feasible and provide a lasting solution. This presentation will focus on how the project came together, starting with the planning phases of the project. The presentation will focus on the collaborative effort to develop multiple alternatives and work with stakeholder groups to develop a preliminary solutions. As the presentation continues, we will discuss how we transitioned from planning to design. As we shift to the design portion, we will continue to focus on the collaborative process developed to ensure that all stakeholders were happy with the final product. As we start the design portion of the project, we will talk about the community involvement, design issues encountered, and schedule that resulted in the final product. While working through the design, the DPW reinforced its desire to include green infrastructure where feasible. We will step through the design process of including permeable pavers, rain gardens and other aspects of green infrastructure into the project along with the calculations involved to ensure that Indianapolis Standards were met. We will also discuss the areas where green infrastructure was not feasible and talk about why those options were not feasible. In the last phase of the presentation, we will discuss issues that came up during construction of the project and how those issues were resolved during construction. We will focus again on how the team worked collaboratively to ensure a final product. We will talk about some of the challenges faced and highlight how the project was finished. We will walk through how the project team was able to accomplish the initial goals of the project and provide a long-lasting, sustainable solution to the neighborhood's flooding problems.

Flow Metering -- A Powerful Tool to Build Smart Sewer Systems Benefits and Objectives Measuring real-time flow rates in a sewer collection system is like a doctor taking a pulse for a patient. Rapid advancements in flow metering and data gathering technologies have led to substantial improvements for real-time operational support and decision-making systems. This study undertook a review of current available flow metering technologies to optimize the operation and maintenance (O&M) of sewer collection systems, and also to identify potential methodologies and applications where flow metering provided significant insights and benefits to system evaluation. This paper provides a summary of the results from this study, and covers the following specific objectives: - Summarize the uses of flow metering techniques to reduce infiltration and inflow (I&I) and sanitary sewer overflows (SSOs), improve level of service, and reduce O&M costs - Provide general guidance and lessons learned for municipalities and utilities to develop and conduct flow metering programs for sewer collection systems - Equip operators, regulators, engineers, and scientists with tools to accurately characterize sewer flows and assess a sewer collection system's capacity and performance - Present several unique case studies of flow metering and flow data analysis. Methodology Flow metering principles and technologies -- Area/velocity flow meters typically utilize pressure or ultrasonic sensors to measure flow depth and doppler-type velocity sensors to measure velocity. The flow rate is determined through depth (from which area is calculated) and velocity measurements. Metering location selection -- The selection of flow metering locations is fundamental to assuring accurate representation of flows throughout the system. Flow meters are typically located along trunk sewers near major confluences. For inflow and infiltration studies, flow meters can be focused in the areas with known high I&I. Data analysis -- Dry weather and wet weather average and peak flows are calculated using flow metering data. Sanitary sewage flow, base infiltration, rainfall-derived infiltration and inflow (RDII) are calculated as well. The rainfall data from a rain gauge is also analyzed. General Applications Hydraulic model calibration -- Flow monitoring is often conducted to support hydraulic model calibration for master planning. Hydraulic models can be calibrated using both dry weather and wet weather flow metering data. Capacity assessment -- Simulations of dry weather and wet weather scenarios based on flow metering data provide information for capacity assessment, which ultimately can be used to identify alternatives for addressing capacity limitations. I&I study -- I&I analysis using flow metering data is able to identify areas of concern that need to be addressed. Design wet weather flow projections -- Flow metering and rainfall data could be used to develop a model to predict the wet weather flow for a 2-year or a 5-year storm event at a specific basin. Unique Case Studies Sewer Clogging -- A section of sewer pipe upstream of a lift station in a coastal city in New Jersey often experienced surcharges during high flow events. A level sensor (Telog) and a HACH Flodar meter were installed to evaluate the issue (Figure 1). A hydraulic model for this section of sewer was developed and calibrated using level sensor data and HACH Flodar data. The modeling results demonstrated that a clogged bar screen at the lift station appeared to be the cause of the sewer backup. The hydraulic modeling with flow metering data is a powerful tool to illustrate the impact of hydraulic restriction and head loss on upstream water levels. Plant influent flow meter validation -- A temporary flow metering study was conducted to verify the accuracy of an influent flow meter at a wastewater treatment plant in California. The comparisons of temporary flow metering data, plant influent, and effluent flow data are shown in Figure 2. It was found that the influent flow meter readings were higher than the temporary flow meter results. Recommendations were made to improve the accuracy of the existing plant influent flow meter. Hurricane event -- A major hurricane occurred during a temporary flow metering study in a coastal city in New Jersey in 2011. The flow metering data and the hydraulic modeling simulation provided a unique scenario for the hurricane event (Figure 3). Because of the magnitude of the storm and the regional power outages that transpired, all sewer lift stations were disabled during the hurricane. However, the monitoring and modelling revealed that the collection system handled the high flow very well, with only a small area of flooding due to the lift stations off-line. Pump station design flow determination -- A linear regression model (Figure 4) was development by plotting RDII volume against rainfall precipitation and used to predict wet weather flows under a 5-year storm event for a pump station. Lessons learned Field verification -- Before installation of flow meters, field verification should be conducted to validate the actual locations of the manholes for installing flow meters, as well as size, slope, invert elevation, and condition of the pipes. Meter maintenance -- Routine maintenance and regular inspection of flow meters (e.g., routinely check for clogging, meter cleaning, replacement of desiccants and batteries, etc.) is required to keep meters functioning properly. QA/QC -- The Manning equation can be employed to conduct QA/QC of the flow metering data. A scatter graph (velocity vs. depth) for a flow metering study in Indiana was created to compare the differences between metered flow and theoretical flow (Figure 5). Further field inspection found that a nearby lift station had experienced occasional back flow issues causing erroneous meter readings. In addition, the scatter graph indicated that the sewer experienced surcharges or potential overflows at this location. Rainfall data -- It was recommended to install a continuous-recording rain gauge for future studies. Conclusion The paper shows how adoption of a flow metering program enables wastewater utilities to improve productivity for inspection, condition assessment, optimizing sewer O&M efforts, and more effectively implementing asset management programs. With anticipated future advancements in sewer flow monitoring, utilities will be even better able to identify solutions to address capacity limitations or performance challenges.

APPLICABILITY Solids thickening is an indispensable unit process for process intensification of biosolids treatment. The fluctuations of feed sludge characteristics often impact the stability of the thickening process, reduce process capability, and increase operation and maintenance costs. Often, the optimization of sludge thickening is focused on meeting performance requirements as detailed in specifications. This study expands the assessment of sludge thickening by including both thickening equipment and its up- and downstream infrastructure from a process capability perspective. The presentation will benefit engineers and utility operators in better design and troubleshooting of sludge thickening processes with designed thickened sludge solids total equal to or higher than 6%. INTRODUCTION The practice of wastewater treatment is evolving to transform wastewater treatment plants into WRRFs with the adoption of advanced wastewater treatment and solids handling equipment, processes, and systems. Enhanced sludge thickening plays an important role in achieving footprint reduction, chemical and energy efficiency, and process control of solids handling [1]. Several studies have suggested that enhancing sludge thickening plays an important role in achieving energy self-sufficiency [2]. Studies showed that improvements in primary sludge (PS) and waste activated sludge (WAS) thickening significantly increased biogas production [3]. Thickened sludge with higher than 4% total solids could be sufficient for achieving a positive energy balance in two-step AD processes. Sludge thickening is taking an increasingly important role in process intensification in biosolids treatment, either through pass-through thickening prior to sludge digestion or recuperative thickening integrated with digestion processes. Centrifugal thickening is one approach to achieving high-rate sludge thickening. The control of the thickened sludge total solids (TS) usually involves the control of Relative Centrifugal Force (G-force), solids retention time, differential rotation speed between centrifuge bowel and screw, and polymer dosage. The application of an in-line density meter or pressure-indicating transmitter could provide control signals for optimizing the performance of centrifugal thickening through mechanical adjustment of the size of thickened sludge outlet [4] or adjustment of the specific gravity of thickened sludge through air injection [5]. Feed sludge characteristics have a significant impact on the performance of thickening centrifuges. The variables of the sludge characteristics include hydraulic loadings, solids loadings, and the mixing ratio between PS and WAS. The fluctuation of feed sludge characteristics could negatively affect the performance of thickening centrifuges and interrupt subsequent operations of biosolids processes. At the same time, fluctuations in feed sludge characteristics are expected and should be accommodated in the design of sludge thickening. The objective of this study is to investigate two cases of centrifugal thickening installations, respectively equipped with GEA and Centrisys thickening centrifuges. This study will provide practical recommendations for mitigating potential bottlenecks in achieving 6% TS of thickened sludge. This study will introduce the use of process capability assessment as a tool for O&M. METHODS Collection and organizing of site information. One challenge for thickening improvement is to systemically document and organize the site information associated with sludge thickening. This study investigates the design and operation of thickening centrifuges and the immediate upstream and downstream unit processes of the thickening centrifuges at two water resource recovery facilities (WRRFs). The design conditions of the two thickening centrifuges systems are summarized in Table 1. The process capability of sludge thickening is affected by both performance of the thickening centrifuges and the performance of up and downstream infrastructure, including wet wells, sludge transfer pumps, the design of process piping, and flow measurement devices. In this study, we developed a check list for a detailed documentation of the thickening unit process as well the immediate upstream and downstream processes, as shown in Table 2. Process capability assessment. Process capability assessment is a manufacturing tool to gain process performance knowledge by analyzing a measurable property of a process to the specification [6]. In this study, an easy-to-use process capability assessment tool is developed for operators to document the thickening performance as a record for understanding process performance and preventative & predictive maintenance of the thickening equipment on a monthly basis. RESULTS A scoring matrix is developed based on the assessment checklist (Table 2) for the evaluation of the positive and negative factors impacting efficient thickening for the two WRRFs. The scoring matrix is used as a survey and communication method to collect opinions from operating crew, maintenance crew, and engineers. Figure 1 shows an example of the scoring matrix. The scoring matrix will be further developed to document the progressive process improvement of sludge thickening. As it is not practical to adjust feed sludge TS in a controlled approach at WRRFs, the impact of solids loading on the performance of sludge thickening is evaluated through time series analysis and histogram analysis of feed and thickened sludges. Figure 2 shows the time series analysis of the feed sludge and thickened sludge TS. As illustrated in Figure 3, histogram analysis of the same set of data reveals the process operation in respective to specified performance (Table 1). Hydraulic loading of thickening centrifuges could be readily adjusted by throttling feed pump. The impact of hydraulic loading is evaluated in terms of solids recovery ratio under different thickened solids TS. As shown in Figure 4, a trade-off exists between hydraulic loading and the solids recovery under the same thickened sludge TS. The results of Figure 4 is based the WRRF 2. A similar curve will be developed for WRRF 1 for this study. Figure 5 shows the change of apparent viscosity as sludge is thickened to TS of 2.5%, 4.5%, 6.0%, and 8.5% respectively. The significant increase in thickened sludge viscosity leads to a higher transfer pump discharge pressure. Depending on different process piping design, the thickened sludge transfer pump's discharge pressure varies 90-110 PSI for WRRF 1 and 70-100 PSI for WRRF 2. It is necessary to size the thickened sludge transfer pump appropriately to minimize process interruption due to insufficient pumping capacity. Figure 6 provides an example of the developed process capability assessment method for monthly evaluation of the performance of thickening centrifuges. The assessment serves as a standard approach to understand the process stability and capacity in related to specified performance requirements. CONCLUSIONS This study documented the impact of sludge characteristics on the performance of thickening and subsequence sludge transfer. The significant increase of sludge viscosity when thickened from 4% to 6% TS requires a design of higher discharge pressure of thickened sludge transfer well. The findings of this study suggested that special attention is needed in the design of the process piping, pumping, and process controls to realize the capability of thickening equipment. The process capability assessment tool applied in this study provides plant operators with means to document and understand the performance of thickening centrifuges. The method developed in this study could be applied to the process capability assessment of other types of thickening technologies beyond thickening centrifuges in WRRFs. This method can serve as a communication tool between the operation and maintenance crews/departments, as the results addressed both process performance and equipment conditions. With the adoption of more advanced and sophisticated solids handling equipment, developing comprehensive process capability assessment tools for respective unit processes may lead to improved performance and reduced life cycle costs of solids handling at WRRFs. This study adopts process capability assessment in evaluating the performance of sludge thickening based on two types of centrifugal thickening machines with different control mechanisms. Attendance at this presentation will benefit design engineers interested in designing centrifugal thickening as part of the process intensification of solids handling in WRRF. The presentation will provide practical suggestions for understanding the process capability of installed thickening equipment for performance improvement.

Renewable Water Resources (ReWa) selected construction of a deep, hard rock-tunnel to improve long-term wastewater collection and achieve sustainable growth in Greenville, SC. The Reedy River Basin Sewer Tunnel Project (RRBST), better known as Dig Greenville, is designed to increase existing conveyance and storage capacity and mitigate wet-weather overflows for the next 100 years. The project commenced in March 2018 and is scheduled for completion in May 2021. The 5,950-ft hard-rock tunnel is located approximately 100-ft beneath the Greenville business district and represents the first deep tunnel constructed in upstate South Carolina for wastewater conveyance. After mining is completed, an 84-inch diameter carrier pipe will be installed in the 11-foot diameter tunnel and grouted in place. The deep tunnel option was selected after evaluating several options, including storage reservoir construction and microtunneling/open cut pipeline construction. Although the initial capital cost was higher than other alternatives, there were several advantages. Deep tunnel construction minimized impact to the public, which was especially important because the tunnel alignment passing beneath both residential and commercial properties intersects downtown Greenville. Open cut construction would have been highly disruptive to the thriving businesses in the city. The tunnel option was also deemed to involve the least risk because the design phase geotechnical investigation indicated competent rock conditions at the depth of the tunnel. Finally, long-term operational and maintenance costs were less for the deep tunnel. Ultimately, the tunnel option represented a cost-effective alternative to add both flow capacity and storage with minimal disruption to the community. The project scope also included construction of a 30-ft deep Access Shaft, 100-ft deep Drop shaft with vortex structure, upstream Diversion Structure, odor control system, downstream Junction Chamber, and near surface connections including approximately 400-ft of 60-inch gravity sewer and 1200-feet of 42-inch gravity sewer. Shaft construction and other near-surface work was primarily confined to two construction sites on the upstream and downstream ends of the tunnel. The downstream connection, including Junction Chamber construction and installation of the 60-inch sewer, required construction within sensitive greenspace near downtown Greenville. ReWa performed extensive public outreach and coordination with the City of Greenville to ensure minimal disruption during all phases of the project, including highly visible work near parks and greenways. Outreach efforts included development of a project website, use of social media, and public meetings. The project team later adapted to COVID-19 circumstances by hosting virtual meetings to keep the community informed about progress. Pre-construction surveys of near-by homes were also performed, which also allowed the project team to develop trust with community members. Construction started in March 2018 with excavation of the 100-ft deep Drop Shaft at the upstream end of the tunnel. Drop Shaft construction required drill-and-blast methods in hard rock, and ReWa worked closely with the surrounding community to manage concerns about blasting. During excavation of the Drop Shaft, the Contractor mobilized at the downstream site. Installation of an inclinometer for future monitoring of the downstream shaft excavation revealed more complex geologic conditions than anticipated. The drilling information indicated the bedrock surface was lower than expected, which precluded the launch of the tunnel boring machine (TBM) directly from the 30-ft deep downstream shaft. ReWa collaborated with the Engineer and Contractor to devise a path forward. Following additional geotechnical investigations and extensive coordination, construction of a 230-foot starter tunnel using drill-and-blast methods was selected because of anticipated mixed-face geologic conditions revealed by rock probing upstream of the hillside. Starter tunnel construction commenced in March 2019 and was completed in November 2019. The challenging mining conditions increased the total cost of the project and added 310 days to the contract schedule. However, the overall project cost remained under the estimated budget for the tunnel. ReWa and the project team also held frequent public meetings to communicate progress updates and schedule changes to near-by residents. Acoustical, dust, and vibration monitoring was also conducted throughout the project to protect the surrounding community. The TBM was launched in December 2019, and the tunnel is scheduled for completion in late September 2020. After construction of the starter tunnel in difficult ground conditions, TBM mining proceeded through competent rock with minimal weathered rock and groundwater infiltration, as indicated by the design-phase geotechnical investigation. The TBM achieved production rates of approximately 30-ft per day. Although there was a 4-week delay in mining for mechanical repairs to the TBM thrust cylinders, the mining progress remained relatively consistent despite slightly lower production rates than expected. During TBM mining, the project team also coordinated other design changes to improve project schedule and reduce costs. The project is currently scheduled to be completed in May 2021 after installation of 5950-feet of 84-inch diameter Hobas carrier pipe, flow diversion and near-surface connections, and final site restoration work. As the tunneling industry advances, the use of trenchless technology represents a cost-effective option for future collection system expansion projects. The deep tunnel option was utilized to reduce short-term public impact and long-term operating costs. Differing ground conditions are common for most underground construction projects, so planners should anticipate potential schedule and cost impacts. However, comprehensive geotechnical investigations, risk assessment, and communication can prepare stakeholders for uncertainty. ReWa successfully delivered the Dig Greenville project with a combination of pre-construction planning, community engagement, and adaptation to changing conditions.