This paper presents a comprehensive public and private Inflow and Infiltration (I&I) reduction pilot program implemented by the Regional Municipality of York. The program aimed to maximize private property participation. The Region employed a Model at the Source hydrologic and hydraulics (H&H) modeling approach to identify and quantify the sources of I&I. A 37- hectare residential area in northeast Newmarket, Ontario was used as a pilot study area. The modeling approach identified the sources of I&I, including mains trenches, lateral houseconnection trenches, house foundations, and maintenance hole lids. The H&H model was calibrated to the Region’s downstream permanent flow meter data and updated to represent the system’s condition after the application of several proposed I&I reduction technologies. The Region’s 25-year four-hour design storm was used to predict I&I reductions. A 33% reduction in peak flow and a 34% reduction in I&I volumes were predicted during the first 24 hours of the storm event when replacing or lining the house laterals from sewer mains to house connections. Continuous simulation for one year demonstrated a total volume reduction of 23%. The modeling approach also revealed that redirecting half of the splashing roof leaders away from house foundations could achieve an additional peak I&I reduction of 21.3% and a volume reduction of 12%. Alternatively, assuming foundation drains exist and can be connected to sump pumps, the modeling approach indicated that installing sump pumps in 25% of the houses could lead to a peak flow reduction of 24% and a volume reduction of 11%. Minimal impact on I&I reduction is indicated from plugging the pick holes of the maintenance manhole lids. Overall, this paper highlights the success of the comprehensive I&I reduction program in the Region, showcasing the effectiveness of various remediation measures on the private side and identifying further improvements to reducing I&I effectively. The private side I&I reduction pilot program is used by the Region to scale up to other locations by adapting a similar modeling approach and applying lessons learned from implemented I&I reduction activities

Improved settleability in activated sludge processes is an essential feature of new innovations. To accelerate the adoption of such technologies, the ability to link operational conditions with settling characteristics is needed to support process design and prediction of improvements in settleability. The previous works indicated that the threshold of flocculation (TOF) (Mancell-Egala et al., 2017a), which describes the collision efficiency of particles, was successfully introduced as a simple experimental method to calculate the flocculent settling coefficient (rp) in 1-D clarifier models and to enhance the ability to predict clarifier effluent solids. TOF also showed to have a clear relationship with effluent quality making it a useful operational parameter to detect flocculation limitations. In addition, extracellular polymeric substances (EPS) quality, most often expressed as a protein over polysaccharides ratio has been linked to flocculation behavior, densification and granulation (McSwain et al., 2005). This knowledge was used to develop an empirical function between the composition of (EPS) expressed as EPS-TKN/COD and TOF. This relationship between EPS composition and TOF was introduced as a means of linking biological process models (i.e. Sumo2C model) and 1-D clarifier models (Ngo et al., 2021b). Essential for this approach is the prediction of EPS amounts and quality from process models as a function of feast-famine, and other operational conditions as this defines settling behavior. This paper discusses three approaches for EPS prediction from process models and will provide insights on 2 which type of EPS modeling might be needed for different purposes. While this abstract describes different datasets tested for the different models, the full paper will provide a full comparison of the three models on the full-scale dataset collected at Blue Plains

Eagle River Water and Sanitation District’s (ERWSD) $49.6M Nutrient Upgrades Project at the 4.3 million gallon per day (mgd) Avon Wastewater Treatment Facility (WWTF) implemented a plan for sequencing nutrient removal improvements at the three interconnected WWTFs. Key challenges for this project included: 1) maintaining effluent permit compliance with units out of service while handling seasonal loading peaks, 2) improving access to underground and inaccessible aeration basins while maintaining structural integrity, and 3) sequencing work while mitigating impacts to neighbors. The project was delivered using the Construction Manager at Risk (CMAR) model, with collaboration from key team members at Moltz Construction, ERWSD, and Carollo. The Avon project, which achieved substantial completion in May 2023 after five years of planning, design, and construction, serves as a strong example of the value of operator involvement and CMAR delivery in maintaining operations during construction.

Many WRFs in California were built with investment following the Clean Water Act of the 1970’s. As such, many of the assets in these WRFs are now reaching the end of their useful life. Faced with aging infrastructure, new regulatory pressures, and increasing loads, these WRFs have had to realize more capacity from the same infrastructure. Computational fluid dynamics (CFD) modeling has been an indispensable tool in the evaluation, retrofit/design of clarifiers at numerous facilities in California. In many of these evaluations, careful consideration of the geometry of the clarifier is needed to understand the true capacity of the unit process. This paper will review case studies of unique. applications of CFD 2D and 3D modeling to assess clarifier improvements and design at three WRFs.

The McLoughlin Point Wastewater Treatment Plant (MPWWTP) in Victoria, British Columbia, Canada, is a greenfield tertiary treatment plant that services the Capital Regional District. The MPWWTP was commissioned and brought into service in autumn 2020, replacing an existing preliminary treatment system. During the commissioning effort at MPWWTP, challenges were posed by the small plant footprint and compact design, combinations of treatment technologies, stringent regulatory compliance requirements, decentralized facilities for residuals handling and screening, and the tight timeline for startup and commissioning. These challenges incited fastpaced problem solving, collaboration, and real-time learning for the project team. The successful commissioning of the MPWWTP was a result of strategic planning, consistent and thorough communication, and practiced flexibility. Despite various hurdles, the project was delivered to the client on schedule, and the resulting lessons learned are widely applicable to future full-scale commissioning efforts.

Stormwater retrofits that include green infrastructure are important tools in creating more equitable and environmentally-enhanced cities for communities experiencing environmental racism. Underserved communities within large municipalities often have denser populations and fewer open spaces. Due to aging infrastructure, these areas can also be more prone to flooding and sewer overflows. This leaves these populations more vulnerable to the ill effects of the environment than more affluent populations. Stormwater retrofits incorporating green infrastructure replicate natural systems by creating open, green spaces. These types of projects, particularly when project prioritization informed by environmental equity is incorporated, work to correct environmental inequity, improve water quality, reduce flooding, promote health, and increase community interaction and cohesion within these underserved communities. Stormwater practitioners are in an ideal position to invite change and promote innovation that benefits those impacted by environmental racism.

The study delves into the fundamental aspects of contaminant sorption onto microplastics by examining sorption kinetics and isotherm models. Notably, the research microplastics derived from primary plastics that contain additives. The investigation explores the influence of various conditions, such as ionic strength and pesticide concentration, on the sorption process. Additionally, the study explores the desorption of specific pesticides from plastic to gain insights into how this process unfolds in the environment, considering scenarios such as wastewater mixing or aeration tank exposure to air bubbles.

This paper provides an overview of the planning analysis, implementation steps, and the Inflow/Infiltration (I/I) reductions achieved by the City of Columbus at the conclusion of its pilot public and private I/I reduction program. The City's integrated plan, "Blueprint Columbus," targets the reduction of Sanitary Sewer Overflow (SSO), manhole flooding, and water-inbasement (WIB) incidents, aiming at a 10-year Level of Service (LOS). The City adopted the "Model at the Source" hydrologic and hydraulic (H&H) modeling approach to identify and quantify I/I sources, and to plan for the required I/I reduction to meet the LOS. The modeling approach quantified the contributions from the various I/I sources such as house foundations, lateral sewers, and sewer mains, and was used to plan the extend of the required I/I reduction technologies. The actual reduction needed to mitigate the SSO and basement backup conditions up to 10-year flow recurrence storm event condition was determined to be 28%. The integrated plan report projects a 40% reduction in I/I during a 10-year historical storm flow level, assuming the City of Columbus lines 90% of the main sewers and lateral house connections, redirects 50% of the house roofs' drainage away from house perimeters, and installs sump pumps in 25% of the residences. In 2015, the Clintonville Main 1 (CV1) basin was selected as the pilot area for the I/I reduction program. In the CV1 area, 95% of the main sewers were lined between 2007 and 2014, and 91% of the lateral sewers were lined between 2018 and 2021. Based on the implementation plan, 95% of the lateral sewer lining was extended into private properties up to the 4"x6" house connections. From 2018 to 2021, roof drainage was redirected to the street for 55% of the roof drainage area that were previously causing water accumulation around houses. Additionally, storm sump pumps were installed in 22.5% of the houses between 2016 and 2021. Post-monitoring analysis for the CV1 pilot study area confirmed the effectiveness of the Blueprint Columbus program. Post-rehabilitation condition models were calibrated using postrehabilitation monitoring data. The 10-year flow recurrence historical storm revealed a median peak flow reduction of 41%, surpassing the planned I/I reduction target outlined in the 2015 Integrated Plan report. The most impactful technology was the lining of the laterals between the sewer mains and house connections. The installation of sump pumps demonstrated limited effectiveness due to the lack of foundation drains and restrictions on installation locations within basements. The redirection of roof drainage proved beneficial, although its effectiveness was compromised in a few basins due to the poor condition of house gutters.

The Lulu Island WWTP Sludge Gas Treatment System upgrades surplus biogas produced from the digesters and delivers pipeline quality biomethane to the natural gas utility as a preference to flaring, to support the Board-established regional greenhouse gas emission reduction goal. The business case for the project is presented, which estimated a 16-year payback. The focus of this discussion is on the challenges faced during the design, construction, and operation of the treatment system, including technology selection, fluctuating surplus biogas flow, and process design and control considerations. Construction of the system was completed in September 2021, and it is currently in operation. This innovative project will contribute to regional environmental objectives, all without subjecting the region’s sewer ratepayers to unreasonable financial risk. The system has been consistently producing greater than 98% methane and is projected to generate 60,000 gigajoules (5.69 x 1010 BTU) of RNG for the natural gas utility each year, enough to supply 600 typical homes.

This study focuses on determining the minimum SRT maintaining significant bio-P activity, quantifying phosphorus removal methods, and evaluating sludge settling. This paper offers practical guidance on the implementation of HRAS systems for determining the actual bio-P phosphate removal through parallel contact stabilization assimilation reactors.

Microplastics (MPs) with accumulated Antibiotic Resistant Genes (ARGs) can be captured in biosolids and contaminate the terrestrial environment through biosolids land application. A field experiment with land-applied biosolids combined with rainfall simulations was conducted to control the biosolids loading, biosolids application methods, and rainfall events. The attached ARGs on MPs were analyzed from soil and runoff samples. Through biosolids application, some ARGs were significantly increased; tetW on MPs in soil increased 5-10 times. In runoff from biosolids-amended plots, the relative abundance of ARGs on MPs increased by 159% and 34%, as compared to the abundance in soil for spreading and incorporating plots, respectively. The biosolids application method affected the mobility of MPs and their associated ARGs to runoff, with surface spreading having the greatest mobility.

Charlotte Water, located in Charlotte North Carolina, is the largest sewer utility in the Carolinas with approximately 4,500 miles of gravity sewer. Charlotte has been implementing a substantial and aggressive long-term sanitary sewer rehabilitation program to reduce sewer system overflows (SSOs), correct historic maintenance problems, and reduce infiltration and inflow (I/I) into aging sewers. Charlotte’s rehabilitation program has a current annual budget of about $26 million, including an annual budget of approximately $10 million for small diameter sewer rehabilitation and approximately $6 million for large diameter sewer rehabilitation. Charlotte has developed a specific, systematic rehabilitation program and approach to renew and restore the sewer system. Charlotte’s rehabilitation approach has been focused on expediting the identification and prioritization of sewers to be rehabilitated and minimizing the lengthy review, analysis, evaluation, and reporting that is often done when implementing sewer rehabilitation programs. This paper presents Charlotte’s streamlined design and construction process.