Engineering Commons^™

Understanding The Interfacial Processes Of Reactive Nanobubbles Toward Agricultural Applications, Xiaonan Shi

Dissertations

There is a growing interest in nanobubble (NB) technology because of its diverse applications (e.g., detergent-free cleaning, water aeration, ultra-sound imaging and intracellular drug delivery, and mineral processing). NBs have a higher efficiency of mass transfer compared to bulk scale bubbles due to the high specific surface areas. The high specific surface also facilitates physical adsorption and chemical reactions in the gas liquid interface. Furthermore, the collapse of NBs creates shock waves and the formation of hydroxyl radicals (OH).

However, it remains elusive why or how NBs are stabilized in water and particularly, the states of internal pressures of NBs …

Fouling And Aging In Membrane Filtration : Hybrid Afm-Based Characterization, Modelling And Reactive Membrane Design, Wanyi Fu

Dissertations

Membrane filtration has been extensively used in water and wastewater treatment, desalination, dairy making, and biomass/water separation. However, membrane fouling, aging and insufficient removal efficiency for dissolved organic matters remain major challenges for wider industrial applications. In order to tackle these challenges, this doctoral dissertation investigates mechanisms of membrane fouling and development of antifouling membrane filtration technologies. Specifically, four major research areas are explored: (i) nanoscale physicochemical characterization of the chemically modified polymeric membranes; (ii) quantitative modelling between membrane properties and membrane fouling and defouling kinetics; (iii) development of quantitative structure-activity relationships for membranes that undergo thermal and chemical aging …

Biologically Active Filters: An Advanced Treatment Process For Pharmaceuticals And Personal Care Products, Shuangyi Zhang

Dissertations

With the increasing concern of pharmaceuticals and personal care products (PPCPs) in source water, this study examines the hypothesis that existing filters and adsorbents in water treatment plants can be converted to biologically active filters (BAFs) to treat these compounds. Removals through bench-scale BAFs are evaluated as a function of media, granular activated carbon (GAC) and dual-media, empty bed contact time (EBCT), and pre-ozonation. For GAC BAFs, greater oxygen consumption, increased pH drop, and greater DOC removal normalized to adenosine triphosphate (ATP) are observed indicating a different microbial community compared to dual-media BAFs. ATP concentrations in the upper portion of …

Magnetic Seeding Aggregation To Enhance The Removal Efficiency Of Tio2 Nanoparticles From Water, Ashish Dhananjay Borgaonkar

Dissertations

Engineered nanoparticles, such as titanium dioxide (TiO₂), are important building blocks for the evolution of nanotechnology in industries and commercial products. Ever so increasing use of the engineered nanoparticles is bound to result in a substantial fraction of these nanoparticles ending up in wastewater; or surface water and groundwater, which are sources of intake for drinking water treatment. Removal of these engineered nanoparticles in wastewater and drinking water treatment processes is a very important step towards the protection of environmental and public health as well as protecting water treatment units from fouling and other issues.

Experimental studies showed …