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Full-Text Articles in Engineering

Peroxi-Electrocoagulation For Treatment Of Trace Organic Compounds And Natural Organic Matter At Neutral Ph, Donald R. Ryan, Patrick J. Mcnamara, Claire K. Baldus, Yin Wang, Brooke K. Mayer Nov 2023

Peroxi-Electrocoagulation For Treatment Of Trace Organic Compounds And Natural Organic Matter At Neutral Ph, Donald R. Ryan, Patrick J. Mcnamara, Claire K. Baldus, Yin Wang, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Iron-based oxidation technologies can be advantageous for mitigating trace organic compounds (TOrCs) during water and wastewater treatment due to their production of hydroxyl radicals. However, iron-based oxidation often occurs at acidic pH to promote Fenton's reaction, which limits the processes' feasibility for treatment applications. This study focused on utilizing iron-electrocoagulation (EC) paired with ex situ H2O2 addition (peroxi-electrocoagulation [EC:H2O2]) to promote oxidative reactions at neutral pH conditions. The hydroxyl radical probe para-chlorobenzoic acid (pCBA) was used to gauge oxidant activity and serve as a representative TOrC. The impact of water …


Impact Of Corrosion Inhibitors On Antibiotic Resistance, Metal Resistance, And Microbial Communities In Drinking Water, Lee K. Kimbell, Emily Lou Lamartina, Stan Kohls, Yin Wang, Ryan J. Newton, Patrick J. Mcnamara Sep 2023

Impact Of Corrosion Inhibitors On Antibiotic Resistance, Metal Resistance, And Microbial Communities In Drinking Water, Lee K. Kimbell, Emily Lou Lamartina, Stan Kohls, Yin Wang, Ryan J. Newton, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Corrosion inhibitors, including zinc orthophosphate, sodium orthophosphate, and sodium silicate, are commonly used to prevent the corrosion of drinking water infrastructure. Metals such as zinc are known stressors for antibiotic resistance selection, and phosphates can increase microbial growth in drinking water distribution systems (DWDS). Yet, the influence of corrosion inhibitor type on antimicrobial resistance in DWDS is unknown. Here, we show that sodium silicates can decrease antibiotic resistant bacteria (ARB) and antibiotic-resistance genes (ARGs), while zinc orthophosphate increases ARB and ARGs in source water microbial communities. Based on controlled bench-scale studies, zinc orthophosphate addition significantly increased the abundance of ARB …


Antibiotic Resistance In Urban Stormwater: A Review Of The Dissemination Of Resistance Elements, Their Impact, And Management Opportunities, Kassidy N. O'Malley, Walter M. Mcdonald, Patrick J. Mcnamara Sep 2023

Antibiotic Resistance In Urban Stormwater: A Review Of The Dissemination Of Resistance Elements, Their Impact, And Management Opportunities, Kassidy N. O'Malley, Walter M. Mcdonald, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

The public health crisis of antibiotic resistance is a growing threat across the world that is only expected to intensify in the coming years. The cycling of antibiotic resistance genes (ARGs) in the environment via urban stormwater runoff is one means by which humans are exposed to resistant bacteria as traditional gray stormwater infrastructure facilitates the transport of resistance elements into water bodies utilized by the public. In this review, existing research on the occurrence of ARGs in urban stormwater runoff is critically reviewed with the goal of determining the role of stormwater in the dissemination and development of antibiotic …


Pyrolysis—A Tool In The Wastewater Solids Handling Portfolio, Not A Silver Bullet: Benefits, Drawbacks, And Future Directions, Patrick J. Mcnamara, Zhongzhe Liu, Yiran Tong, Hari Santha, Lynne Moss, Daniel Zitomer May 2023

Pyrolysis—A Tool In The Wastewater Solids Handling Portfolio, Not A Silver Bullet: Benefits, Drawbacks, And Future Directions, Patrick J. Mcnamara, Zhongzhe Liu, Yiran Tong, Hari Santha, Lynne Moss, Daniel Zitomer

Civil and Environmental Engineering Faculty Research and Publications

Pyrolysis is the process whereby carbonaceous materials, such as biosolids, are heated between 400°C and 900°C in the absence of oxygen. Three main products are generated: a solid product called biochar, a py-liquid that consists of aqueous phase and non-aqueous phase liquid, and py-gas. The biochar holds value as a beneficial soil amendment and sequesters carbon. The py-liquid is potentially hazardous and needs to be dealt with (including potentially reducing it on-site via catalysis or thermal oxidation). Py-gas can be used on-site for energy recovery. Pyrolysis has gained recent interest due to concern over per- and polyfluoroalkyl substances (PFAS) in …


An Inexpensive, Reproducible Method To Quantify Activated Sludge Foaming Potential: Validation Through Lab-Scale Studies And Year-Long Full-Scale Sampling Campaign, Grace K. Scarim, Emily Lou Lamartina, Kaushik Venkiteshwaran, Daniel Zitomer, Ryan J. Newton, Patrick J. Mcnamara Apr 2023

An Inexpensive, Reproducible Method To Quantify Activated Sludge Foaming Potential: Validation Through Lab-Scale Studies And Year-Long Full-Scale Sampling Campaign, Grace K. Scarim, Emily Lou Lamartina, Kaushik Venkiteshwaran, Daniel Zitomer, Ryan J. Newton, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Activated sludge is a conventional treatment process for biochemical oxygen demand (BOD) and total suspended solids (TSS) removal at water resource recovery facilities (WRRFs). Foaming events are a common operational issue in activated sludge and can lead to decreased treatment efficiency, maintenance issues, and potential environmental health risks. Stable foaming events are caused by biological and chemical drivers (i.e., microbes and surfactants) during the aeration process. However, foaming events are difficult to predict and quantify. We present an inexpensive and easy-to-use method that can be applied at WRRFs to quantify foaming potential. Subsequently, the method was applied over a year-long …