Biological Engineering Commons^™

Analysis On Modifications To An Outdoor Field-Scale Rotating Algal Biofilm Reactor With A Focus On Biomass Productivity And Power Usage, Davis R. Haag

All Graduate Theses and Dissertations, Fall 2023 to Present

A rotating algal biofilm reactor (RABR) was operated outdoors for one calendar year to see how the microalgae grown were affected. The algae are grown in wastewater that contains nitrogen and phosphorous, which are elements found in fertilizer. The design used was modified from a previous design, and this project tested the modifications to see if they improved how much microalgae were grown. In February 2025, the objectives of the field study were updated to focus on growing as much microalgae as possible instead of removing as much nitrogen and phosphorous as possible. This updated design increased the fluid flow …

Modeling The Production Of Microalgal Biomass In Large Water Resource Recovery Facilities And Its Processing Into Various Commodity Bioproducts, James Pierson, Gopi Raju Makkena, Sandeep Kumar, Vinod Kumar, Vivekanand Vivekanand, Hasan Husain, Muhammad Ayser, Venkatesh Balan

Civil & Environmental Engineering Faculty Publications

Algae are capable of sequestering nutrients such as nitrates and phosphates from wastewater in the presence of sunlight and carbon dioxide (CO₂) to build up their body mass and help combat climate change. In the current study, we carried out different case studies to estimate the volume of algal biomass that could be produced annually using the rotating algal biofilm (RAB) method in three large-scale water resource recovery facilities (WRRFs) in Texas: Fort Worth, Dallas, and Houston. We calculated the total amount of lipids, carbohydrates, and proteins that could be fractionated from the algal biomass while using the …

Investigating The Feasibility Of Using Mesoporous Silica Particles To Deliver Glucose During Anaerobic Fermentation, Megan E. Walz

Theses and Dissertations--Biosystems and Agricultural Engineering

The study presented herein investigated a potential low-energy method to separate and concentrate glucose from a lignocellulosic hydrolysate. The motivation for this method was twofold: 1) to provide the fermentation microorganism an optimal glucose concentration and 2) to supply a fermentation media free of inhibitory compounds. Two sizes of porous silica particles (with 7 nm and 2.3 nm pores) were synthesized and their ability to adsorb glucose from solution confirmed. Next, the ability of two different microorganisms, Saccharomyces cerevisiae and Streptococcus bovis, to utilize sugars adsorbed to the porous silica particles was investigated.

Both the 7 nm and 2.3 …

Non-Catalytic Co-Gasification Of Sub-Bituminous Coal And Biomass, Guevara Che Nyendu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Utilization of coal as a low-cost domestic energy source is becoming a subject of utmost importance due to fluctuating crude oil prices. However, coal use emits pollutants such as nitrous oxides (NO_x), sulfur oxides (SO_x), carbon dioxide (CO₂), and particulates that have negative environmental impact and significant issues on health. To minimize the harmful effects of coal use, renewable and sustainable biological or green materials called biomass are processed with coal to produce synthetic gas (syngas) that can be processed into clean energy fuels and value-added products.

Currently, coal is converted using combustion technology; …

Conventional And Catalytic Pyrolysis Of Pinyon Juniper Biomass, Bhuvanesh Kumar Yathavan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pinyon and juniper are invasive woody species which has occupied more than 47 million acres of land in Western United States. Pinyon juniper woodlands domination decreases the herbaceous vegetation, increase bare lands which in turn increases soil erosion and nutrition loss. Thus, The US Bureau of Land Management (BLM) has focused on harvesting these woody species to make room for herbaceous vegetation. The major application of harvested pinyon-juniper (PJ) is low value firewood. Thus, there is a need to develop new high value products from this woody biomass to reduce the cost of harvesting. In this study pyrolysis was carried …

The Economics And Logistics Of The Dual Harvest Of Grain And Biomass In A Single-Pass, Matthew T. Wold

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Significant interest has developed in using cellulosic resources, especially crop residues, to create biofuels. Collecting these residues in a single-pass of the harvester across the field has the potential to be a low cost option. Two models have been developed; the first characterizes the in-field logistics of single-pass crop residue collection, the second the economics. These models allow the user to easily examine a wide variety of both grain-only and single-pass residue collection harvest cases. A variety of possible residue collection cases have been examined, and their effects both on harvester field capacity and harvest cost compared to grain-only harvest …

Mutant Alcohol Dehydrogenase Leads To Improved Ethanol Tolerance In Clostridium Thermocellum, Steven D. Brown, Adam M. Guss, Tatiana V. Karpinets, Jerry M. Parks

Dartmouth Scholarship

Clostridium thermocellum is a thermophilic, obligately anaerobic, Gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. …

Thermal Degradation Kinetics Of Distillers Grains And Solubles In Nitrogen And Air, Lijun Wang, Ajay Kumar, Milford Hanna, Curtis L. Weller, D. D. Jones

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The pyrolysis and oxidation kinetics of distillers grains and solubles were determined using thermogravimetric analysis. The starting temperature of pyrolysis and oxidation of distillers grains and solubles increased with the increase of heating rate and initial moisture content. The pyrolysis and oxidation of distillers grains and solubles were completed at 650°C and 850°C, respectively, which were independent of the heating rate and the initial moisture content. The residual weights of distillers grains and solubles after pyrolysis and oxidation were 27.15% and 5.49% of the original dry mass of distillers grains and solubles. Thermogravimetrical analysis data was used to determine kinetic …

Co-Production Of Chemical And Energy Products From Distillers Grains Using Supercritical Fluid Extraction And Thermochemical Conversion Technologies, Lijun Wang, Ajay Kumar, Curtis L. Weller, David D. Jones, Milford A. Hanna

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Dry-grind technology has become the dominant method for ethanol production. During drygrind ethanol production, roughly one-third of the dry grain mass resides in the dried distillers grains with solubles (DDGS) as by-products (i.e., ∼0.8 kg/L ethanol). The energy content residing in the 0.8 kg DDGS is about 20 MJ, compared to the consumption of 1 MJ electricity and 10 MJ thermal energy for production of each liter of ethanol. A sequential supercritical fluid process with solvents including carbon dioxide, water and ethanol was used to recover high-value chemicals from DDGS. Thermochemical conversion methods were used to convert the DDGS residue …