Engineering Commons^™

Performance Evaluation Of A Coupled Photovoltaic-Thermal Solar Powered Desalination Pilot System, Martin Chavarin

Open Access Theses & Dissertations

A pilot scale coupled photovoltaic-thermal solar powered desalination system was evaluated at the Brackish Groundwater National Desalination Research Facility (BGNDRF). The pilot system consisted of a 3-kW photovoltaic-thermal (PVT) solar panel array and a 2.3 kW photovoltaic (PV) array coupled with a 4 gal/min single-stage 4 membrane reverse osmosis (RO) desalination system. A heat exchange system was in place to provide simultaneous cooling for the PVT system and heating to the RO system feed water. This system was evaluated with three objectives in mind. The first objective was to identify whether cooling of the PVT panels resulted in a significant …

Computational Modeling Of Patterned Membranes And Spacers For Improved Hydrodynamics And Fouling Reduction In Reverse Osmosis Water Treatment Processes, Zuo Zhou

All Dissertations

My research goal is to discover ways to improve the hydrodynamics of reverse osmosis (RO) membrane systems through creative membrane surface patterning and spacer designs. Since concentration polarization (CP) usually promotes membrane fouling, improving hydrodynamics would result in reduced fouling and better membrane performance. With computational fluid dynamics (CFD), we can explore dozens or even hundreds of models with different geometries and boundary conditions. Through plotting their velocity profile, streamlines, shear stress, pressure profile, concentration profile, and so on, we can determine which design would lead to the best performance.

At first, patterned membranes were evaluated and compared with flat …

An Exploration Of The Application Of Desalination In Disaster Relief, Emma Sager

Senior Honors Theses

This paper aims to explore the application of small-scale desalination systems to provide clean water in the wake of marine natural disasters. A lack of clean water is a devastating impact of many natural disasters. Desalination technologies, both thermal and membrane, show potential for being scaled down and self-powered by renewable energy. Desalination can transform ocean water and contaminated drinking water with a high salt content into drinkable, usable water. While these techniques are not perfected, and the solution to a need for clean water is multifaceted, desalination shows potential. Through further research and ever-advancing technology, small-scale desalination could develop …

Evaluation Of Electrodialysis Desalination Performance Of Novel And Conventional Ion Exchange Membranes, Ahm Golam Hyder

Open Access Theses & Dissertations

It was revealed from relevant recent literature that the electrodialysis (ED) desalination performance of commercial and laboratory-made ion exchange membranes (IEMs) had been studied previously but not in a systematic way so that the planners, designers, and engineers can evaluate a trade-off in selecting the suitable IEMs and optimum ED experimental conditions for their desired outcomes such as high ion selectivity, high salinity removal, high water recovery, low energy consumption, or low water transport. Furthermore, the existing conventional and laboratory-made IEMs reported previously showed various technical and economical limitations with respect to permeability, permselectivity, ion selectivity, electrical resistance, stability (mechanical, …

Sustainability Assessment Of A Pressure Retarded Osmosis System, Samar Al Mashrafi

USF Tampa Graduate Theses and Dissertations

Desalination has the potential to provide a stable supply of clean fresh water and meet the increasing water demands; however, this process does come with a few challenges such as high energy consumption, high energy cost, and a discharge of a highly concentrated brine. Pressure retarded osmosis (PRO) is a technology that could work as an efficient energy recovery technology for desalination since it can significantly reduce the energy consumption and dilute the brine before discharge. Studies have assessed the economic feasibility of PRO systems; however, these studies have not addressed the environmental sustainability of the systems. Thus, there is …

Desalination For Sustainable Water Production With An Emphasis On Low Pressure Distillation, Jessica Vivian Savage

Doctoral Dissertations and Master's Theses

Freshwater resources depletion is a growing concern. This freshwater scarcity motivates research into seawater desalination as a means for alleviating the stresses on water demands. The primary methods of desalination include filtration and distillation. This paper explores the potential energy savings of vacuum distillation for seawater desalination to reduce the amount of energy needed to achieve phase change.

Depending on the vacuum boiler design, the vaporization mechanism may be boiling, evaporation, or cavitation. There is very little literature on cavitation that involves mass transfer, so cavitation is not developed here. This thesis focuses on standard models for boiling and evaporation …

Surface Modifications Of Reverse Osmosis Membranes For Removal Of Bromide And Reduction Of Fouling, Joseph Seo

Master's Theses

Reverse osmosis (RO) is widely used for water reuse and desalination. Although RO membranes are known for their high salt rejection and practical permeate flux, their performance can be impaired by fouling, and their removal of some disinfection byproducts and their precursors (e.g., bromide, N-Nitrosodimethylamine [NDMA]) does not meet drinking water standards. RO membrane modifications have been widely studied to overcome these limitations. In this research, RO membranes were grafted with cationic polymers to induce a positive charge on the RO membrane surface. This modification aimed at enhancing the rejection of negatively charged bromide ions by removing them from solution …

Investigation Of New Forward Osmosis Draw Agents And Prioritization Of Recent Developments Of Draw Agents Using Multi-Criteria Decision Analysis, Jodie Wei Yu

Master's Theses

Forward osmosis (FO) is an emerging technology for water treatment due to their ability to draw freshwater using an osmotic pressure gradient across a semi-permeable membrane. However, the lack of draw agents that could both produce reasonable flux and be separated from the draw solution at a low cost stand in the way of widespread implementation. This study had two objectives: evaluate the performance of three materials — peptone, carboxymethyl cellulose (CMC), and magnetite nanoparticles (Fe₃O₄ NPs) — as potential draw agents, and to use multi-criteria decision matrices to systematically prioritize known draw agents from literature for …

Evaluation And Modeling Of Electrodialysis For High-Recovery Brackish Water Desalination, Shahrouz Jafarzade Ghadimi

Open Access Theses & Dissertations

This research investigates the feasibility of desalination of brackish water with electrodialysis (ED), using laboratory testing and mathematical modeling. Several experiments were performed to characterize ion-specific transport and to evaluate tradeoffs between salinity removal and specific energy consumption. A 200 cm2 Ameridia ED stack was used to perform desalination experiments with real brackish groundwater from the Kay Bailey Hutchison desalination plant in El Paso, Texas, and the results showed limiting current density of 160 A/m2 for 5 cm/s. A higher conductivity reduction was observed for flow velocity of 5 cm/s compared to 13 cm/s. Ion transport selectivity (based on relative …

Attributing Accelerated Increases In Salinity In The Mediterranean Coastal Zone To Climate Change And Seawater Desalination Brine And The Resultant Unsustainability Of Modern Desalination Technology, Brandon W. Harper

HCNSO Student Capstones

Anthropogenic climate change influences our oceans on a global scale and has brought about increased salinity levels in large areas of our oceans such as the North Atlantic (Dunbar 2009). Concentrations of large scale desalination plants around small bodies of water add to this pattern and have shown even larger increases in salinity due to desalination brine discharge (Purnama et al., 2005). Salinity profile data over time should show similar increases in salinity in the Mediterranean Sea due to climate change and localized data should show increased salinity due to brine discharge. This study aims to pinpoint the extent of …

Performance Of Carbon Aerogel/Fiber Paper As Capacitive Deionization Electrodes Under Variable Operating Conditions, Md Ashique Ahmed, Sanjay Tewari

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The capacitive deionization has garnered renewed interested with recent modifications resulting in efficient (energy and cost) alternatives to desalinate brackish water (salt concentration less than 10 g/L). Recent research efforts, to improve the technology, have been focused mainly on electrode material development and modifications of operational parameters for optimized performance. This research is focused on performance evaluation of carbon aerogel/fiber paper as capacitive deionization electrodes under variable operating conditions. The main operational parameters that were varied are applied voltage, influent temperature and initial concentration. The highest adsorption capacity achieved in this on-going study is 4.61 mg/g at 33.5 oC with …

Analysis Of Micromixers To Minimize Scaling Effects On Reverse Osmosis Membranes, Jeremy Walker

Wayne State University Dissertations

ABSTRACT

ANALYSIS OF MICROMIXERS TO MINIMIZE SCALING EFFECTS ON REVERSE OSMOSIS MEMBRANES

by

Jeremy Walker

December 2018

Advisor: Dr. Shawn McElmurry

Major: Civil Engineering

Degree: Doctor of Philosophy

Structural elements, typically mesh spacers, are required between membrane leaves in spiral

wound elements to ensure flow through reverse osmosis (RO) modules. The standard diamond-shaped

mesh spacer results in non-ideal hydrodynamics that can lead to fouling, which ultimately reduces the

flux of water through the membrane and the operational life of the unit. Additionally, traditional mesh

feed spacers do not allow for reverse flow cleaning due to obstructed flow paths and, once …

Cost-Effective Recovery Of Concentrated Cooling Tower Blowdown Using The Cerro Process, Lindsey Nicole Larson

Open Access Theses & Dissertations

The Concentrate Enhanced Recovery Reverse Osmosis (CERRO) process is a seawater-RO unit that can cost-effectively achieve extremely high recoveries from water high in silica, carbonate and sulfate concentrations. This relatively new technology takes advantage of the induction time of potential foulants to recover more water than what is normally achievable with a conventional desalination system. The scope of the project was to evaluate the efficiency of the CERRO process as a pilot study using cooling tower blowdown which varied in water quality parameters daily. It was found that the CERRO pilot could successfully achieve 85% recovery, and the main limitation …

Simulation Of Heat And Mass Transfer In Suns River Solar Distillation, Houman Azari

Open Access Theses & Dissertations

Many regions around the world have limited fresh water resources, and we need to desalinate brackish water resources for drinking and irrigation purposes. Most of the world is also facing energy challenges which encourages engineers and scientists to use renewable energy resources instead of hydrocarbon fuels. Arid regions such as the Middle East, many African countries, and the southwestern United States typically have abundant solar irradiance and brackish or saline water supplies. Solar-thermal desalination could be an important supply of fresh water in these regions.

The classic solar still is not efficient for providing large amounts of clean water for …

Dissolved Carbon Dioxide For Scale Removal In Reverse Osmosis, Erin Partlan

All Theses

Membrane fouling is a major operational issue in reverse osmosis (RO) desalination plants. In particular, plants treating brackish groundwater can encounter troublesome inorganic scales, including carbonates, sulfates, and silicates. A novel cleaning method is proposed to remove inorganic scales from fouled RO membranes usinag dissolved CO ₂ . As CO₂ molecules encounter membrane foulants, the surfaces serve as nucleation sites for small bubbles to form and shear off foulants. Dissolved CO₂ solutions were prepared by bubbling CO₂ gas into water held in a pressure vessel. Gas dissolution was confirmed by enhanced exit velocities for water containing CO …

Dimensionless Criteria For Selecting Tidally-Influenced Advective-Dispersive Desalination Brine Mixing Plume Characterization Models, Alireza Shahvari

Civil & Environmental Engineering Theses & Dissertations

The very nature of requirements for implementing a desalination process is highly spatial due to the need to secure both a source for the operation and sink for brine dilution. Thus, the applicable coastal location is bound to natural tidal mixing characteristics and subjected to a near- or a far-field availability for source and sink. Mixing characteristics of coastal waters are very different from one point to another due to the spatiotemporal tidal characteristic in loco in a manner that it can vary from being highly advective to completely dispersive dominant. Once a location is identified, estimation of corresponding water …

Reverse Osmosis Desalination With Integrated Compressed Air Energy Storage: Conceptual Design And Modeling, Pooja Mahajan

All Theses

Growing fresh water needs have led to an interest in water desalination using reverse osmosis (RO) membranes. Energy consumption has a large share in the expenses incurred to drive a reverse osmosis desalination system. With depleting fossil fuel reserves, tapping renewable sources of energy is a promising alternative to meet the energy requirements. Wind power coupled to an RO desalination system is a potential means of delivering clean water using sustainable energy. This work investigates modeling of a conceptual wind-energy-driven RO desalination system that is made possible because of an air-pressure energy storage mechanism. Bench-scale experiments were performed on an …

Treatment Of Ro Concentrate Using Vsep Technology, Guillermo Guadalupe Delgado

Open Access Theses & Dissertations

The city of El Paso has the largest inland brackish desalination plant in the world. The Kay Bailey Hutchison (KBH) Desalting plant produces 15 million of permeate water every day. Due to the excellent quality of the water, the permeate water is blended with brackish water producing a final volume of 27.5 million gallons of water every day. With an average recovery rate of 80%, the KBH plant produces an average of 3 million gallons of concentrated brackish water that is disposed of via injection wells 23 miles from the plant.

Conventional reverse osmosis (RO) systems are not capable of …