Engineering Commons^™

Accessing The Relative Sustainability Of Point-Of-Use Water Disinfection Technologies Through Costs And Environmental Impacts, Bright C. Elijah

Electronic Theses and Dissertations

According to the World Health Organization, 785 million people lack access to basic drinking water facilities, and 144 million people rely on surface water which is prone to microbial contamination. Point-of-use (POU) water disinfection technologies can be adopted to help address these issues by treating water at the household level; however, navigating various POU disinfection technologies for a given water source or location can be difficult. While numerous conventional POU technologies exist (e.g., boiling water, POU chlorination), new emerging POU technologies (e.g., using novel materials or advanced processes) have been coined by developers to be lower cost with higher treatment …

Assessment And Prevention Of Bacterial Regrowth In Stored Household Water In Eastern Coastal Madagascar, Lauren Judah

USF Tampa Graduate Theses and Dissertations

As of 2020, diarrheal diseases were the leading cause of death in Madagascar. A major cause of diarrheal illness is contaminated water, and one crucial aspect of preventing contaminated water is safe household storage. Bacterial regrowth between point-of-collection and household storage has been well established in literature. A frequently implicated source of regrowth is the storage container’s biofilm, which is a community of varying bacteria enclosed in a “slimy” extracellular polymeric substance that forms on surfaces in wet environments and anchors bacteria to those surfaces. The overall goal of this thesis was to quantify and control bacterial regrowth in household …

Chlorine Taste Threshold And Acceptability As A Water Disinfectant Among Indigenous Ngäbe And Non-Indigenous In Rural Panama, Ashley Osler

USF Tampa Graduate Theses and Dissertations

More than two billion people globally still lack access to safely managed drinking water (WHO & UNICEF, 2021). Although gains in access to water service over the past two decades have been large, universal access to safe and affordable drinking water (SDG 6, target 6.1) is not on track to be achieved. In Panama, safely managed drinking water access has not been measured. However, the data on basic water access illustrates the large disparities between rural and urban areas of Panama. While 98% of urban Panamanian households have basic access to water, only 86% of rural Panamanian households, and 54% …

Visible-Light-Active Disinfection Of Surface Water Coliform Using Silver/Titanium Dioxide/Silver Bromide(Ag/Tio2/Agbr) As Photocatalyst, Ashraya Upadhyaya

University of New Orleans Theses and Dissertations

As human population becomes diverse, the need for sustainable, inexpensive, scalable, and decentralized water treatment technologies to supplement or replace conventional treatment methods are important, especially to satisfy the need of small, rural communities for safe drinking water. These challenges can be somewhat met with the use of semiconductor photocatalysis, especially if the process is driven by visible light energy. Visible-light-active (VLA) photocatalysis can be effectively applied in disinfection of drinking water. In comparison to traditional, energy-intensive, physical and chemical disinfection methods, VLA photocatalysis is capable of providing high disinfection efficiency with the use of cheaper energy, no harmful by-products, …

Electrocoagulation As A Pretreatment For Electroxidation Of E. Coli, William Lynn, Joe Heffron, Brooke Mayer

Civil and Environmental Engineering Faculty Research and Publications

Insufficient funding and operator training, logistics of chemical transport, and variable source water quality can pose challenges for small drinking water treatment systems. Portable, robust electrochemical processes may offer a strategy to address these challenges. In this study, electrocoagulation (EC) and electrooxidation (EO) were investigated using two model surface waters and two model groundwaters to determine the efficacy of sequential EC-EO for mitigating Escherichia coli. EO alone (1.67 mA/cm², 1 min) provided 0.03 to 3.9 logs mitigation in the four model waters. EC alone (10 mA/cm², 5 min) achieved ≥1 log E. coli mitigation in all …

Mechanisms Of Virus Mitigation And Suitability Of Bacteriophages As Surrogates In Drinking Water Treatment By Iron Electrocoagulation, Joe Heffron, Brad Mcdermid, Emily Maher, Patrick J. Mcnamara, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Emerging water treatment technologies using ferrous and zero-valent iron show promising virus mitigation by both inactivation and adsorption. In this study, iron electrocoagulation was investigated for virus mitigation in drinking water via bench-scale batch experiments. Relative contributions of physical removal and inactivation, as determined by recovery via pH 9.5 beef broth elution, were investigated for three mammalian viruses (adenovirus, echovirus, and feline calicivirus) and four bacteriophage surrogates (fr, MS2, P22, and ΦX174). Though no one bacteriophage exactly represented mitigation of the mammalian viruses in all water matrices, bacteriophage ΦX174 was the only surrogate that showed overall removal comparable to that …

Sequential Electrocoagulation-Electrooxidation For Virus Mitigation In Drinking Water, Joe Heffron, Donald R. Ryan, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Electrochemical water treatment is a promising alternative for small-scale and remote water systems that lack operational capacity or convenient access to reagents for chemical coagulation and disinfection. In this study, the mitigation of viruses was investigated using electrocoagulation as a pretreatment prior to electrooxidation treatment using boron-doped diamond electrodes. This research is the first to investigate a sequential electrocoagulation-electrooxidation treatment system for virus removal. Bench-scale, batch reactors were used to evaluate mitigation of viruses in variable water quality via: a) electrooxidation, and b) a sequential electrocoagulation-electrooxidation treatment train. Electrooxidation of two bacteriophages, MS2 and ΦX174, was inhibited by natural organic …

Bacteriophage Inactivation As A Function Of Ferrous Iron Oxidation, Joe Heffron, Brad Mcdermid, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Iron-based disinfection has been promoted as a potential low-cost, low-byproduct means of virus mitigation. This research is the first to establish that virus inactivation due to ferrous iron is impacted both by the extent of iron oxidation (from ferrous to ferric iron) and the rate of iron oxidation. Log inactivation of bacteriophages increased linearly with ferrous iron concentration at low doses (< 3 mg/L Fe), but higher doses limited disinfection, likely due to floc formation. The rate of iron oxidation was controlled by independently varying pH and dissolved oxygen concentration. Bacteriophage inactivation increased with the inverse of ferrous oxidation rate, suggesting that slower iron oxidation rates allow better contact between viruses and reactive ferrous iron. Ferrous iron showed potential for disinfection in conditions of low pH and dissolved oxygen, though these conditions preclude effective iron coagulation/flocculation.

Optimizing Chlorine Disinfection By Chlorine Injection Location And Pipe Diameter Selection In A Water Distribution System, Margaret Neff

Dissertations, Master's Theses and Master's Reports

Due to a variety of factors chlorination is common water disinfectant for community-scale distribution systems. The town of Suyo, Peru was already equipped with a gravity fed water system and drip chlorinator which achieved 4-log inactivation of viruses throughout the town, however, it was not providing 3-log inactivation of giardia cysts at all points of the system.

This project used an EPANET model to determine and compare the potential benefits of changes which could be made to the pre-existing water system in Suyo.

The model was used to compare current operating conditions of the Suyo system, 1.5 mg/L chlorine addition …

Applications Of Microbial Desalination And Photocatalytic Disinfection For The Removal Of Contaminants In Drinking Water, Kristen Shirlee-Ann Brastad

Theses and Dissertations

Trends in drinking water treatment in recent years have been moving toward the use of membrane separation in order to reduce contaminants in water. There are many forms of membrane separation technology such as ultrafiltration, nanofiltration, microfiltration, reverse osmosis, and extruded ion exchange membranes. These membranes have many different applications and may be used to remove many materials from water such as salts, viruses and bacteria, selectively remove cations or anions, or remove organics.

Microbial desalination cells (MDCs) are an emerging concept which use bioelectric potential produced from organics via microbial metabolism to accomplish desalination. MDCs consist of three compartments, …

Effectiveness Of In-Line Chlorination Of Gravity Flow Water Supply In Two Rural Communities In Panama, Kevin Orner

USF Tampa Graduate Theses and Dissertations

It is well established that water quality is directly linked to health. In-line chlorination is one technology that can be used in the developing world to potentially inactivate pathogens and improve water quality. The purpose of this study was to determine the effectiveness of the Panamanian Ministry of Health's in-line PVC chlorinator under three different operating conditions in a rural water supply system. Free and total chlorine were measured entering the storage tank, leaving the storage tank, and at three households along the transmission line of the water system in the two rural indigenous communities of Calabazal and Quebrada Mina …