A CHARACTERIZATION OF THE WATER QUALITY CONDITIONS AND POLLUTANT LOADS IN SURFACE WATERS NEAR THE NORTHEAST OHIO REGIONAL SEWER DISTRICT’S COMBINED SEWER SYSTEM IN CLEVELAND, OHIO

The Northeast Ohio Regional Sewer District (NEORSD, Cleveland, OH) serves over one million citizens through the operation of three waste water treatment plants. NEORSD provides this service through combined and separated sewer systems, which, during rainfall events, are known to deliver large volumes of untreated wastewater containing high concentrations of Escherichia coli (E.coli), ammonia nitrogen, and phosphorus. NEORSD is currently investing $3 billion over the next 25 years to mitigate its combined sewer overflows and plans to allocate additional funds to improve remaining pollutant sources related to its system, e.g. separated sewers. A suite of PC-SWMM pollutant loading models have been confirmed for their ability to represent the environmental impacts of NEORSD’s sewer system. The environmental benefits associated with infrastructure improvements are then predicted by the models to assist NEORSD in most efficiently spending financial resources

Simulating and optimizing stormwater best management practices in University of Louisville watershed.

Urbanization disrupts natural soil profiles and as watersheds are urbanized, their surfaces become impervious and this will result in reduction of infiltration. For this reason, many cities are facing problems with treating runoff water. Best management practices (BMPs) consist of built systems designed to reduce and control the quality of runoff water in urban areas and help to control the direction of it. This system guides water to a structural soil retention area beneath the pavement where it is then temporary stored. BMPs are based of rainwater withholding (such as infiltration basins) or infiltration into the soil (such as permeable pavement). In this project we are to create a stormwater management model for campus using a modeling software for the purpose of guiding future BMP types and locations by predicting different scenarios\u27 efficiency based on runoff water reduction

MODELING THE EFFECTS OF WASTEWATER INFRASTRUCTURE OPTIONS ON WATER QUALITY IN GREATER CLEVELAND, OHIO

The city of Cleveland, OH, and the Northeast Ohio Regional Sewer District are in the process of an ambitious engineering project designed to reduce the amount of untreated wastewater that is discharged into Lake Erie and its tributaries. The project involves the construction of seven tunnels that will intercept combined sewer overflows for transport to wastewater treatment plants, along with upgrades to the treatment capacity of these plants. This report will examine the water quality impacts of this project, as well as the impact of six additional proposed management options, on the streams of Greater Cleveland and the Lake Erie nearshore. Impact will be quantified using metrics developed here for total ammonia nitrogen, total phosphorus and E. coli based on standards set by the United States and Ohio Environmental Protection Agencies. Two mathematical models (SWMM for tributaries and SWMM/FVCOM for the Lake Erie nearshore) will be used to simulate water quality conditions for baseline conditions and under potential management options. Ultimately, this model-based approach will be able to pinpoint which management options are most effective in terms of their water quality impact, as well as where the potential trouble spots are located for pollutant concentration guideline exceedances

MatSWMM - An open-source toolbox for designing real-time control of urban drainage systems

This manuscript describes the MatSWMM toolbox, an open-source Matlab, Python, and LabVIEW-based software package for the analysis and design of real-time control (RTC) strategies in urban drainage systems (UDS). MatSWMM includes control-oriented models of UDS, and the storm water management model (SWMM) of the US Environmental Protection Agency (EPA), as well as systematic-system edition functionalities. Furthermore, MatSWMM is also provided with a population-dynamics-based controller for UDS with three of the fundamental dynamics, i.e., the Smith, projection, and replicator dynamics. The simulation algorithm, and a detailed description of the features of MatSWMM are presented in this manuscript in order to illustrate the capabilities that the tool has for educational and research purposes.Peer ReviewedPostprint (author's final draft

Doctor of Philosophy

dissertationControlling combined sewer overflows (CSOs) is one of the greatest urban drainage challenges in more than 700 communities in the United States. Traditional drainage design typically leads to centralized, costly and energy-intensive infrastructure solutions. Recently, however, application of decentralized techniques to reduce the costs and environmental impacts is gaining popularity. Rainwater harvesting (RWH) is a decentralized technique being used more often today, but its sustainability evaluation has been limited to a building scale, without considering hydrologic implications at the watershed scale. Therefore, the goal of this research is to study watershed-scale life cycle effects of RWH on controlling CSOs. To achieve this goal, (i) the life cycle costs (LCC) and long-term hydrologic performance are combined to evaluate the cost-effectiveness of control plans, (ii) the life cycle assessment (LCA) and hydrologic analysis were integrated into a framework to evaluate environmental sustainability of control plans, and (iii) the major sources of uncertainty in the integrated framework with relative impacts were identified and quantified, respectively. A case study of the City of Toledo, Ohio serves as the platform to investigate these approaches and to compare RWH with centralized infrastructure strategies. LCC evaluation shows that incorporating RWH into centralized control plans could noticeably improve the cost-effectiveness over the life cycle of drainage infrastructure. According to the results of the integrated framework, incorporating RWH could reduce Eco-toxicity Water (ETW) impacts, but caused an increase in the Global Warming Potential (GWP). In fact, incorporating RWH contributes to avoidance of untreated discharges into water bodies (thus reducing ETW) and additional combined sewage delivered to treatment facilities (thus increasing GWP). The uncertainty analysis suggests that rainfall data (as a hydrologic parameter) could be a significant source of the uncertainty in outputs of the integrated framework. Conversely, parameters of LCIA (life cycle impact assessment) could have trivial impacts on the outputs. This supports the need for robust hydrologic data and associated analyses to increase the reliability of LCA-based urban drainage design. In addition, results suggest that such an uncertainty analysis is capable of rendering optimal RWH system capacity as a function of annual rainfall depth to lead to minimized life cycle impacts. Capacities smaller than the optimal size would likely result in loss of RWH potable water savings and CSO control benefits, while capacities larger than optimal would probably incur excessive wastewater treatment burden and construction phase impacts

Modeling Impacts of Combined Sewer Overflows in SWMM in Cleveland, Ohio

Despite its legacy of pollution, the City of Cleveland, Ohio, has historically been at the forefront of water quality management. Today, the Northeast Ohio Regional Sewer District (NEORSD), which serves the Greater Cleveland area, is following a consent decree with the State of Ohio to minimize combined sewer overflows (CSOs), along with implementing an integrated Clean Water Act planning study to prioritize infrastructure improvements with a broader view of water quality objectives. This report summarizes an urban watershed modeling effort to support the integrated planning (IP) process. Specifically, the development, calibration, and validation of the EPA Stormwater Management Model (SWMM) for the NEORSD area is presented, followed by an application of the model under both uniform and spatially distributed rainfall inputs. Results show the importance of using spatially variable inputs for urban watershed modeling studies over large areas. Based on this work, several recommendations for future research are made, including expanding the scope of the simulations performed to all SWMM models used in the IP modeling to gain a deeper understanding of how distributed versus uniform rainfall impacts the total loads to Lake Erie; testing the SWMM models with fixed, free and time-variable downstream boundaries to understand how well SWMM can model the stream-lake interaction (backwater and reverse flow); and simulating loads into Lake Erie using rainfall scenarios that account for climate change

Water Integration for Squamscott Exeter (WISE): Preliminary Integrated Plan, Final Technical Report

This document introduces the goals, background and primary elements of an Integrated Plan for the Lower Exeter and Squamscott River in the Great Bay estuary in southern New Hampshire. This Plan will support management of point (wastewater treatment plant) and nonpoint sources in the communities of Exeter, Stratham and Newfields. The Plan also identifies and quantifies the advantages of the use of green infrastructure as a critical tool for nitrogen management and describes how collaboration between those communities could form the basis for an integrated plan. The Plan will help communities meet new wastewater and proposed stormwater permit requirements. Critical next steps are need before this Plan will fulfill the 2018 Nitrogen Control Plan requirements for Exeter and proposed draft MS4 requirements for both Stratham and Exeter. These next steps include conducting a financial capability assessment, development of an implementation schedule and development of a detailed implementation plan. The collaborative process used to develop this Plan was designed to provide decision makers at the local, state and federal levels with the knowledge they need to trust the Plan’s findings and recommendations, and to enable discussions between stakeholders to continue the collaborative process. This Plan includes the following information to guide local response to new federal permit requirements for treating and discharging stormwater and wastewater: Sources of annual pollutant load quantified by type and community; Assessment and evaluation of different treatment control strategies for each type of pollutant load; Assessment and evaluation of nutrient control strategies designed to reduce specific types of pollutants; Evaluation of a range of point source controls at the wastewater treatment facility based on regulatory requirements; Costs associated with a range of potential control strategies to achieve reduction of nitrogen and other pollutants of concern; and A preliminary implementation schedule with milestones for target load reductions using specific practices for specific land uses at points in time; Recommendations on how to implement a tracking and accounting program to document implementation; Design tools such as BMP performance curves for crediting the use of structural practices to support nitrogen accounting requirements; and Next Steps for how to complete this Plan

Impact of Sewershed Characteristics on Rainfall Derived Inflow and Infiltration

Cities rely on sewer systems to transport wastewater and stormwater, but sometimes these systems are overwhelmed, and their capacity is exceeded due to excess water in the system from rainfall derived inflow and infiltration. This can lead to overflows and backups that can be detrimental to health and property. Excess water from rainfall derived inflow and infiltration enters a sewer system through a multitude of ways, including downspout connections, foundation drains, pipe joints, and broken pipes. Identifying these sources individually can be time intensive and expensive if entire service areas need to be addressed. High level screening tools are therefore needed that can apply readily available data to identify areas and sources of rainfall derived inflow and infiltration in a sewer system. This study seeks to address this challenge by using monitoring data from Milwaukee, Wisconsin to derive correlations between known sewershed characteristics and rainfall derived inflow and infiltration. Results show that pipe length per acre, number of parcels, and medium intensity land use are positively correlated to inflow or fast direct flows into the system. In addition, imperviousness, pipe length per acre, low intensity and medium intensity land use are negatively correlated with infiltration or slow inputs from groundwater sources. These findings can be applied by water reclamation managers to narrow the search areas for rainfall derived inflow and infiltration sources within their sanitary sewer systems

Impact of short duration intense rainfall events on sanitary sewer network performance

Short duration intense rainfall causes an increase in rainfall derived infiltration and inflow (RDII) into aging sewer networks, which leads to Sanitary Sewer Overflows (SSOs). This study presents a generalised framework for assessing and mitigating the impacts of intense rainfall on sanitary sewer networks. The first part of the proposed framework involves a detailed hydraulic modelling to evaluate the performance of the sewer network. The second part deals with the development of SSO mitigation strategies based on Water Sensitive Urban Design (WSUD) approaches. This paper also demonstrates the application of the first part of the proposed framework for a case study catchment in Melbourne, Australia. The hydraulic performance of the case study sewer network during a wet and a dry year is presented. The analysis found that for the wet year, 11 manholes had sewer overflows, whereas 53 of 57 manholes in the network of 3.2 km had surcharges. Such a study will benefit the water authorities to develop mitigation strategies for controlling SSOs in their sewer systems