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USF Tampa Graduate Theses and Dissertations

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Full-Text Articles in Engineering

Morphology And Detection Of Corrosion On Stainless Steel Reinforcement In Concrete, Julio J. Saire Yanez Jun 2019

Morphology And Detection Of Corrosion On Stainless Steel Reinforcement In Concrete, Julio J. Saire Yanez

USF Tampa Graduate Theses and Dissertations

Stainless steel (SS) has emerged as an alternative corrosion-resistant reinforcement in concrete instead of the commonly used carbon steel (CS). The biggest advantage of SS is that it takes more time for corrosion to initiate than for CS. An additional benefit from the use of SS in concrete may be derived from the period after the corrosion started until the concrete structure reaches a limit state. This period is called corrosion propagation stage (CPS) and it has been hardly studied in SS reinforced structures. The duration of this period could be related, among other factors, to the morphology of corrosion …


Estimation Of Number Of People Living In Developing Countries That Received Water From A Spring Source, Prapti Shinde Mar 2019

Estimation Of Number Of People Living In Developing Countries That Received Water From A Spring Source, Prapti Shinde

USF Tampa Graduate Theses and Dissertations

In the year 2000, 170 countries decided to stand together and solve some primary and common global problems like poor health, water, and sanitation. Obtaining access to safe drinking water is every individual’s right. The UN defines safe drinking water as “the water required for each personal or domestic use must be safe, therefore free from micro-organisms, chemical substances and radiological hazards that constitute a threat to a person's health” (UNDESA, 2014). This thesis focuses on identifying the number of people who potentially receive spring water from a piped source in rural mountainous areas. There are three significant steps and …


Development And Application Of Decision-Making Tool For Rural Spring-Sourced Gravity-Fed Community Managed Water Systems, Oswaldo Galicia Mar 2019

Development And Application Of Decision-Making Tool For Rural Spring-Sourced Gravity-Fed Community Managed Water Systems, Oswaldo Galicia

USF Tampa Graduate Theses and Dissertations

People all over the world still lack access to safe drinking water service. Those with access experience several issues during the first few years of installation that impede on their overall access. In order to improve water services, not only is a proper decision-making tool necessary, taking into account key factors that impact sustainable water service, but proper monitoring and evaluation is also important in ensuring service for the long term. There are several developed assessment tools used for monitoring and evaluation of water systems post-construction, applicable in various scenarios. However, there are only few tools available to facilitate the …


Low Temperature Multi Effects Desalination-Mechanical Vapor Compression Powered By Supercritical Organic Rankine Cycle, Eydhah Almatrafi Jan 2019

Low Temperature Multi Effects Desalination-Mechanical Vapor Compression Powered By Supercritical Organic Rankine Cycle, Eydhah Almatrafi

USF Tampa Graduate Theses and Dissertations

Utilizing low grade heat sources such as geothermal, solar or waste heat has received a high attention in recent years. A lot of research has discussed using Organic Rankine Cycle (ORC) as subcritical or supercritical in power generation. However, very few studies extend their research in utilizing ORC in other applications such as desalination. For reverse osmosis (RO) desalination, which is considered a membrane technology, the use of supercritical-ORC in low grade heat sources is more favorable than subcritical-ORC. Thus, studies of utilizing either subcritical-ORC or supercritical-ORC for thermal desalination that use power and heat from Rankine cycle are rare …


Wastewater In Context: Systems-Based Approaches To Improving Wastewater Infrastructure Transitions, Christine Prouty Nov 2018

Wastewater In Context: Systems-Based Approaches To Improving Wastewater Infrastructure Transitions, Christine Prouty

USF Tampa Graduate Theses and Dissertations

Coastal communities and ecosystems around the world are some of those most vulnerable to the impacts of climate change. In particular, the wastewater treatment systems in these areas are on the forefront of the effects of increasing frequency, duration, and intensity associated with extreme weather events. As such, decision making about adopting new wastewater technologies or transitioning to an improved treatment portfolio is an important area of research for coastal communities because they are critically linked to the health of the nearby aquatic ecosystems (i.e. tourism, fishing, cultural heritage, climate protection).

The decision making process about technology adoption and transitions …


Application Of A Floating Membrane Algal Photobioreactor For Freshwater Aquaculture, Hsiang-Yang Shyu Oct 2018

Application Of A Floating Membrane Algal Photobioreactor For Freshwater Aquaculture, Hsiang-Yang Shyu

USF Tampa Graduate Theses and Dissertations

As the global population grows, water and food demand also increase. The intensive aquaculture industry has helped to mitigate these problems. In order to make aquaculture sustainable, it is necessary to remove the abundant nutrients produced by fish in the water. In this study, the role of the microalga of Chlorella vulgaris in the Isolated Cultivation of Algal Resources Utilizing Selectivity (ICARUS) membrane photobioreactor was evaluated for nutrient control in the aquaculture system. The production of algal biomass, the removal rate of nutrients, and the impact of microalgae on cultured organisms were monitored during the operation of aquaculture systems. At …


Numerical Analysis Of Leakage Through Defective Geomembrane Liners In Embankment Dams, Sarper Demirdogen Oct 2018

Numerical Analysis Of Leakage Through Defective Geomembrane Liners In Embankment Dams, Sarper Demirdogen

USF Tampa Graduate Theses and Dissertations

Placing a geomembrane liner in the core of a dam is an alternative construction technique to traditional clay core types. This study aims to assess the performance of such internal geomembrane sealing systems in an earthen dam. Two-dimensional (2D) numerical analysis was performed to evaluate leakage through defective seams within an earthen dam. Five possible applications of internal geomembrane systems were initially modeled to locate the zero-pressure lines in an earthen dam. Then, another application where the geomembrane is placed on the upstream face was modeled to compare the upstream and internal geomembrane systems. The results of this study show …


The Role Of Forests In Securing Hydropower Needs Of Cambodia, Mohit Kaura Oct 2018

The Role Of Forests In Securing Hydropower Needs Of Cambodia, Mohit Kaura

USF Tampa Graduate Theses and Dissertations

Hydropower relies on protection of watersheds to regulate water and sediment yields. Deforestation accelerates the rate of soil erosion, thereby increasing the amount of river sediments heading to the dam's reservoir, decreasing the longevity of the dam. In Cambodia in particular, recent deforestation rates are among the largest on the planet, and forests are expected to disappear within the lifespan of proposed dams. The cost of protecting and restoring forested watersheds can be considered as an annual investment towards sustainable reservoir management and hydropower generation. A modeling framework is developed to estimate the sediment accumulation in reservoirs from deforestation-driven soil …


Caregiver Perception And The Role Of Seasonality In Under-Five Childhood Diarrhea Incidence In Svay Rieng Province, Cambodia, Brian S. Wells Jun 2018

Caregiver Perception And The Role Of Seasonality In Under-Five Childhood Diarrhea Incidence In Svay Rieng Province, Cambodia, Brian S. Wells

USF Tampa Graduate Theses and Dissertations

Diarrheal disease has long been known to be a burden to children worldwide. Although child mortality rates as a result of diarrhea have decreased over the past two decades, overall diarrhea incidence has remained relatively stable. In Cambodia, diarrhea was the third most prevalent outpatient diagnosis for children under five in 2012, with a reported incidence rate of 12 per 100 children, up from 7 per 100 children in 2008 (Ministry of Planning Cambodia, 2012). Cambodia is an agricultural country with 80% of the population living in rural areas (National Institute of Statistics Ministry of Planning, 2013). Many are also …


Framework Integrating Climate Model, Hydrology, And Water Footprint To Measure The Impact Of Climate Change On Water Scarcity In Lesotho, Africa, John W. Pryor Jun 2018

Framework Integrating Climate Model, Hydrology, And Water Footprint To Measure The Impact Of Climate Change On Water Scarcity In Lesotho, Africa, John W. Pryor

USF Tampa Graduate Theses and Dissertations

Water scarcity is a problem that will be exacerbated by climate change. Being able to model the effect of climate change on water scarcity is important to effectively plan the use of future water resources. This research integrated the Soil and Water Assessment Tool (SWAT), climate model, and water footprint analysis to measure the impact of climate change on future water scarcity. This was achieved through two objectives. The first objective was to create a modeling framework that links the output from climate model to SWAT and combined streamflow outputs from SWAT with water footprint analysis to measure how climate …


Selection Of Energy Systems In Aquaculture Through A Decision Support Tool Considering Economic And Environmental Sustainability, Youngwoon Kim Mar 2018

Selection Of Energy Systems In Aquaculture Through A Decision Support Tool Considering Economic And Environmental Sustainability, Youngwoon Kim

USF Tampa Graduate Theses and Dissertations

Aquaculture had already been distinguished as an important component of global food security and economics. However, aquaculture has expanded at the cost of natural resources and the environment. The vulnerability of the aquaculture industry due to the consequences of global environmental changes and energy price fluctuations has been addressed in various studies. The identification, planning, and implementation of sustainable energy systems are important to ensure the long term economic and environmental sustainability of aquaculture.

This research investigated sustainable energy systems for aquaculture using a life cycle approach, allowing for the identification of the most sustainable energy options under different geographical …


Assessment Of Drinking Water Quality Management And A Treatment Feasibility Study For Brick By Brick Water Storage Tanks In Rakai Uganda, James V. Murduca Mar 2018

Assessment Of Drinking Water Quality Management And A Treatment Feasibility Study For Brick By Brick Water Storage Tanks In Rakai Uganda, James V. Murduca

USF Tampa Graduate Theses and Dissertations

Reliable access to safe drinking water is one necessity for humans to live without concern for major health risks. The overall goal of this research is to improve the public health, through improved drinking water, for communities in the Rakai District in Uganda, directly, and other communities in the world, indirectly, via dissemination of knowledge. This study specifically assessed the knowledge of drinking water quality in regards to public health, their sanitation measures, and water treatment methods for users of Brick by Brick rainwater harvesting tanks in the Rakai District (N = 28) by using a knowledge, attitudes, and practice …


Promoter Effects On Iron-Based, Sba-15 Supported Ultra-High Temperature Fischer- Tropsch Catalysts, David P. Weber Mar 2018

Promoter Effects On Iron-Based, Sba-15 Supported Ultra-High Temperature Fischer- Tropsch Catalysts, David P. Weber

USF Tampa Graduate Theses and Dissertations

Promoter effects on SBA-15 supported iron Fischer-Tropsch catalysts were investigated for their potential to improve high temperature catalyst performance. FTS catalysts promoted by manganese (0.15%-1.4%), copper (0.15%-1%), and potassium (0.5%-3%), with all percentages stated on the basis of mass percentage of final catalysts, were prepared and tested at 430°C and ambient pressure in a fixed bed reactor. Manganese showed the ability to promote the FT reaction, increasing both the CO conversion and the average chain length of hydrocarbon products. Compared to the unpromoted catalyst composed only of iron supported on SBA-15, 1.4%Mn (mass) promotion of 15% (mass) iron on SBA-15 …


Field Testing Of Affordable Well Head Protection For Locally Manufactured, Self-Supply Pitcher Pumps On Manually Driven Tubewells In Madagascar, Michal Usowicz Mar 2018

Field Testing Of Affordable Well Head Protection For Locally Manufactured, Self-Supply Pitcher Pumps On Manually Driven Tubewells In Madagascar, Michal Usowicz

USF Tampa Graduate Theses and Dissertations

Lack of water access is an issue of global importance. The WHO and UNICEF’s Joint Monitoring Program estimated that in 2015 71% of the world’s population used a safely managed drinking water source and 89% of the world’s population used an improved water source within a 30-minute round trip of home. Madagascar’s national statistics lags far behind these global statistics with 54% of the population using improved water sources, 31% using unimproved water sources, and 16% with no service at all.

This research studied water access in Madagascar with self-supply Pitcher Pumps attached on hand-driven tubewells. The term self-supply in …


Design And Implementation Of A Ferrocement Improved Cookstove In Rural Panama, Josh Donegan Mar 2018

Design And Implementation Of A Ferrocement Improved Cookstove In Rural Panama, Josh Donegan

USF Tampa Graduate Theses and Dissertations

Household air pollution contributes to the premature death of more than 4 million people annually. Improved cookstoves are one technological intervention that can potentially reduce exposure to household air pollution. However, improved cookstove implementation programs need to consider measures to increase sustainability and promote long-term adoption. The objectives of this research were 1) to develop and implement a new ferrocement cookstove for Peña Blanca, a rural indigenous community in the Ngäbe-Bugle region of Panama, 2) to evaluate its potential sustainability in comparison to the most common cooking technologies observed in the community, 3) to prepare a construction manual for the …


The Control Of Water Contaminants Assisted By Natural Materials, Wen Zhao Nov 2017

The Control Of Water Contaminants Assisted By Natural Materials, Wen Zhao

USF Tampa Graduate Theses and Dissertations

Natural materials can be used to remove water contaminants by applying proper physical, chemical, and biological water treatment processes. This study involves using natural materials, as they are considered to be more environmentally benign and cost-effective than synthetic materials. This dissertation concentrates on monitoring five major water quality parameters—ammonia, fluoride, turbidity, pH, and fecal indicator bacteria (FIB) —in two major applications where clean water is needed. The focus is on meeting the water quality requirements for each contaminant. The overall objective of this study is to control the levels of ammonia in aquaculture wastewater, and adjust fluoride, turbidity, pH, and …


Water, Sanitation, And Citizenship: Perceptions Of Water Scarcity, Reuse, And Sustainability In Valparaiso De Goias, Brazil, Paola Andrea Gonzalez Nov 2017

Water, Sanitation, And Citizenship: Perceptions Of Water Scarcity, Reuse, And Sustainability In Valparaiso De Goias, Brazil, Paola Andrea Gonzalez

USF Tampa Graduate Theses and Dissertations

Access to reliable water and sanitation are two important goals to improve livelihoods around the world. Providing access to improved and safe water resources that are equitable and appropriate to local needs is important to improve sustainability long-term. In addition, framing access to water and sanitation as basic human rights is often used as a rationale in developing new water, sanitation, and hygiene interventions in developing countries around the world. But not all countries consider access to safe water and sanitation as a human right. In the thesis, the politics of improving and investment in water access and sanitation provision …


An Evaluation Of The Water Lifting Limit Of A Manually Operated Suction Pump: Model Estimation And Laboratory Assessment, Katherine C. Marshall Oct 2017

An Evaluation Of The Water Lifting Limit Of A Manually Operated Suction Pump: Model Estimation And Laboratory Assessment, Katherine C. Marshall

USF Tampa Graduate Theses and Dissertations

With 663 million people still without access to an improved drinking water source, there is no room for complacency in the pursuit of Sustainable Development Goal (SDG) Target 6.1: “universal and equitable access to safe and affordable drinking water for all” by 2030 (WHO, 2017). All of the current efforts related to water supply service delivery will require continued enthusiasm in diligent implementation and thoughtful evaluation. This cannot be over-emphasized in relation to rural inhabitants of low-income countries (LICs), as they represent the largest percentage of those still reliant on unimproved drinking water sources. In that lies the motivation and …


Sustainability Of Community-Managed Rural Water Supply Systems In Amazonas, Peru: Assessing Monitoring Tools And External Support Provision, Jacob E. Mangum Oct 2017

Sustainability Of Community-Managed Rural Water Supply Systems In Amazonas, Peru: Assessing Monitoring Tools And External Support Provision, Jacob E. Mangum

USF Tampa Graduate Theses and Dissertations

Globally, there is still a large number of people without access to safe drinking water; a known health risk. In rural areas of countries like Peru, when potable water systems are built the responsibility for maintaining these systems is given to volunteer water committees. Despite its prevalence as a management model, there is a consensus that community management alone cannot ensure sustainable water service. Therefore, the overall goal of this research is to assess the sustainability of community-managed water systems in rural areas of the department of Amazonas, Peru. Specifically, this research examines two mechanisms that have been shown to …


The Effect Of Antigen Polymorphisms On Serological Antibody Detection Assays Based Upon The, Kristi M. Miley Jun 2017

The Effect Of Antigen Polymorphisms On Serological Antibody Detection Assays Based Upon The, Kristi M. Miley

USF Tampa Graduate Theses and Dissertations

Onchocerca volvulus is a filarial parasite transmitted to humans by female Simulium spp. black flies. Infection with this parasite can cause blindness and severe skin disease among humans in Africa and the Americas. Enzyme-linked Immunosorbent Assay serological testing of OV-16 antigen is a diagnostic tool for determining effective elimination of the parasite. Programs typically rely on OV–16 ELISA to evaluate the progress towards interruption and/or elimination of disease by mass drug distribution of ivermectin and vector larvicidal control efforts. As elimination grows closer, monoclonal antibody positive controls for OV-16 ELISA become important to develop for Onchocerca testing due to the …


The Sustainability Of Ion Exchange Water Treatment Technology, Adib Amini Apr 2017

The Sustainability Of Ion Exchange Water Treatment Technology, Adib Amini

USF Tampa Graduate Theses and Dissertations

This research investigated using a life cycle environmental and economic approach to evaluate IX technology for small potable water systems, allowing for the identification and development of process and design improvements that reduce environmental impacts and costs. The main goals were to evaluate conventional IX in terms of life cycle environmental and economic sustainability, develop a method for improving designs of IX systems from a environmental and economic sustainability standpoint, evaluate potential design improvements, and make the research findings accessible to water professionals through user-friendly tools and frameworks that take into account their feedback. This research provides an understanding, from …


Pepper Mild Mottle Virus As A Surrogate For Enteric Viruses: Implications For Assessing Water Quality, Erin Michelle Symonds Nov 2016

Pepper Mild Mottle Virus As A Surrogate For Enteric Viruses: Implications For Assessing Water Quality, Erin Michelle Symonds

USF Tampa Graduate Theses and Dissertations

Less than 10% of the world’s domestic wastewater is disinfected prior to discharge into surface waters; therefore, human exposure to diverse wastewater-related pathogens results in millions of cases of illness each year. Among the enteric pathogens, viruses represent an important group of emerging pathogens and are frequently the cause of food- and water-borne outbreaks of illness. Although the World Health Organization and many government agencies mandate the use of bacterial indicators to identify poor microbial water quality, it is well known that these indicators poorly correlate with fecal pollution contamination events and risk of disease. The field of public health-related …


Development Of A Decentralized And Off-Grid Anaerobic Membrane Bioreactor (Anmbr) For Urban Sanitation In Developing Countries, Robert Alonso Bair Jul 2016

Development Of A Decentralized And Off-Grid Anaerobic Membrane Bioreactor (Anmbr) For Urban Sanitation In Developing Countries, Robert Alonso Bair

USF Tampa Graduate Theses and Dissertations

Urbanization has led to rapid and uncontrolled growth of informal housing settlements in many developing countries. As most slum growth is unplanned, these areas tend to lack basic infrastructure including sanitation. The high user rates, lack of water and electricity infrastructure, space limitations, and scant financial resources make sanitation provision a major challenge in slums. As most decentralized sanitation technologies fail when applied in these environments, better technologies need to be developed that cater to the specific needs of slum dwellers. One promising technology, the membrane bioreactor (MBR) is routinely used in developed countries when a compact and resilient treatment …


A Life Cycle Assessment Of A Uranium Mine In Namibia, Janine Lambert Jun 2016

A Life Cycle Assessment Of A Uranium Mine In Namibia, Janine Lambert

USF Tampa Graduate Theses and Dissertations

Uranium mining and nuclear power is a controversial topic as of late, especially in light of the recent Fukushima event. Although the actual use of nuclear fuel has minimal environmental impact, its issues come at the very beginning and end of the fuel’s life cycle in both the mining and fuel disposal process. This paper focuses on a life cycle analysis (LCA) of uranium mine in the desert nation of Namibia in Southern Africa. The goal of this LCA is to evaluate the environmental effects of uranium mining. The LCA focuses on water and energy embodiment such that they can …


Sizing An Anaerobic Digester In A Rural Developing World Community: Does Household Fuel Demand Match Greenhouse Gas Production?, Ronald Keelan Greenwade Mar 2016

Sizing An Anaerobic Digester In A Rural Developing World Community: Does Household Fuel Demand Match Greenhouse Gas Production?, Ronald Keelan Greenwade

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion is the process by which organic carbon is converted into biogas in the form of carbon dioxide (CO2) and methane (CH4). Both of these products are greenhouse gases that contribute to global warming. Therefore if anaerobic reactors are improperly maintained and biogas is leaked or intentionally released into the atmosphere because biogas production exceeds household demand, these reactors may become generators of greenhouse gas emissions instead of sustainable energy producers. The objective of this research was to develop a framework to assess if the demand for biogas by a rural adopter of an anaerobic …


Modeling Food Security, Energy, And Climate And Cultural Impacts Of A Process: The Case Study Of Shea Butter In Sub-Saharan Africa, Colleen Claire Naughton Feb 2016

Modeling Food Security, Energy, And Climate And Cultural Impacts Of A Process: The Case Study Of Shea Butter In Sub-Saharan Africa, Colleen Claire Naughton

USF Tampa Graduate Theses and Dissertations

Millions of people in the world, particularly women and people in sub-Saharan Africa, suffer from hunger and poverty. Three of the major 2015-2030 United Nation’s Sustainable Development Goals (SDGs) aim to eliminate hunger through food security and sustainable agriculture, eradicate poverty, and achieve gender equality through women’s empowerment. Shea trees and their associated fruit and butter can play a major role in each of these three SDGs for women and their families throughout sub-Saharan Africa. Shea trees are located over a wide expanse stretching more than 5,000 kilometers across over eighteen countries in sub-Saharan Africa. These trees produce fruit that …


Pathogen Removal In Natural Wastewater Treatment And Resource Recovery Systems: Solutions For Small Cities In An Urbanizing World, Matthew Eric Verbyla Nov 2015

Pathogen Removal In Natural Wastewater Treatment And Resource Recovery Systems: Solutions For Small Cities In An Urbanizing World, Matthew Eric Verbyla

USF Tampa Graduate Theses and Dissertations

Sanitation, renewable energy, and food security are among the most pressing global development needs of the century, especially for small cities with rapid population growth. Currently, 53% of the world’s population either lacks access to improved sanitation or discharges fecal waste to the environment without treatment. Furthermore, 80% of food consumed in developing regions is produced by 500 million small farms, and while many of them are still rain-fed, irrigated agriculture is increasing. The post-2015 Sustainable Development Goals, recently adopted by the United Nations, include targets to address the water-energy-food nexus. Wastewater reuse in agriculture can be an important solution …


Design, Fabrication And Analysis Of A Paver Machine Push Bar Mechanism, Mahendra Palnati Nov 2015

Design, Fabrication And Analysis Of A Paver Machine Push Bar Mechanism, Mahendra Palnati

USF Tampa Graduate Theses and Dissertations

Now-a-days, the major challenge that’s being faced by the concrete industry is the cleaning of concrete handling equipment. Concrete consists of aggregates, which harden with time, and the transportation of concrete mixture within the plant is a significant problem. This will not only increase the overall maintenance cost, but will lead to loss of raw materials, affect the rate of production, and reduce the lifetime of concrete handling equipment.

The present study focuses on the design and implementation of an adaptive cleaning mechanism in the concrete industry and its importance in achieving efficient cleaning, which is tested to verify its …


High-Solids Anaerobic Digestion Of The Organic Fraction Of Municipal Solid Waste State Of The Art, Outlook In Florida, And Enhancing Methane Yields From Lignocellulosic Wastes, Gregory Richard Hinds Oct 2015

High-Solids Anaerobic Digestion Of The Organic Fraction Of Municipal Solid Waste State Of The Art, Outlook In Florida, And Enhancing Methane Yields From Lignocellulosic Wastes, Gregory Richard Hinds

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion (AD) is a biotechnology that employs natural microbial metabolism under oxygen-free conditions to stabilize organic waste. AD has been shown to be the most environmentally sustainable technology for treating the organic fraction of municipal solid waste (OFMSW), as it allows for the recovery of energy and nutrients from the waste. AD of OFMSW also saves landfill space and reduces leachate generation and fugitive methane emissions from landfills. High-solids AD (HS-AD) technologies (those designed to process feedstocks with >15% total solids content) have been shown to yield additional benefits when compared with liquid AD (L-AD) for treating OFMSW, including …


Energy Production And Effluent Quality In Tubular Digesters Treating Livestock Waste In Rural Costa Rica, Maureen Njoki Kinyua Sep 2015

Energy Production And Effluent Quality In Tubular Digesters Treating Livestock Waste In Rural Costa Rica, Maureen Njoki Kinyua

USF Tampa Graduate Theses and Dissertations

Use of tubular anaerobic digesters to treat livestock waste in developing countries has energy, agricultural, health, social and environmental benefits. However, careful use of digester effluent as a soil amendment is required due to the potential presence of protozoan parasites Cryptosporidium parvum and Giardia lamblia. This research investigated the performance of four tubular digesters in the Monteverde region of Costa Rica. High (>75%) volatile solids and BOD5 removal efficiencies were observed, which was attributed to the formation of a biologically active floccular sludge layer. Computational fluid dynamics (CFD) and bioprocess models were developed to evaluate the transport and transformation …