Sustainable algae biofuel production is rising in demand, and the need to establish an efficient and proper algae harvesting method is extremely essential. Membrane filtration technology seems to be the most promising as a solid-liquid separation process. However, fouling seems to be the major problem for membranes. There is limited research on how to solve the problem of fouling, and cake buildup inside the membranes. A novel membrane design is required to solve the problem of fouling and cake buildup inside the membranes. The objective of this research is to construct a novel two way membrane design for algae biomass harvesting and water recycling. The methods used include culturing algae species, filtering them through the membrane module, and sample analysis for determining the water quality. The results show that the present filtration model had no fouling, or cake buildup as opposed to the previous filtration model. The present model permeate has a very low optical density of 0.007 absorbance at 750 nanometers. This result shows that permeate is completely devoid of algae.

Utilization of woody biomass for energy is expected to increase rapidly and logging residues are a likely feedstock to meet increased demands. Potentials for increased biomass utilization have created concerns regarding possible impacts of using logging residues for energy. The overall goals of this project were to characterize biomass harvesting operations and to evaluate potential impacts on soil erosion and implementation of Best Management Practices (BMPs) for water quality on biomass harvesting sites. Results indicate that biomass harvesting was integrated into a wide range of logging businesses. Existing biomass harvesting businesses reported total production levels ranging from 6 to 250 loads per week. The majority (98%) of biomass harvesting operations utilized integrated harvesting techniques where roundwood and fuel chips were produced concurrently. Potential erosion rates and BMP implementation scores were evaluated on ten biomass and ten conventional harvest sites in the Piedmont of Virginia. This study of 20 sites found no significant differences in overall estimated erosion rates between biomass harvests (0.7 tons ac-1 yr-1) and conventional harvests (0.8 tons ac-1 yr-1) (p=0.8282). Additionally, there were no significant differences observed in overall BMP implementation scores for biomass (85.2%) and conventional (81.3%) harvests (p=0.5930). A separate, but related study evaluated BMP implementation over a three year period on 88 biomass and 284 conventional harvests in the Piedmont of Virginia. Within the seven logging related BMP categories, only the Streamside Management Zones (SMZs) category had significant differences between biomass (83.1%) and conventional harvests (91.4%) (p=0.0010). Implementation score differences were not caused by insufficient residues for stabilization of bare soil but were apparently the result of operational decisions which resulted in lower implementation of BMPs related to SMZs. Overall, these findings indicate that existing BMPs appear adequate to protect water quality on biomass harvesting operations in the Virginia Piedmont when appropriately implemented. / Ph. D.

Increased costs of fossil fuels, regulatory policies, and investments by federal and state governments have caused increased interest and incentive for the use of wood as a renewable form of energy. As a result, landowners and forest managers are considering chipping whole trees and harvesting residues as a means to meet increased demand of wood chips as a renewable source of energy. However, the profitability, productivity gains, and sustainability of these alternative harvesting methods continue to be an area of research. The objective of this study was to compare two biomass harvesting treatments with regard to the characteristics of the chips they produced, chipper productivity, nutrient removals, and site disturbance. The first biomass harvesting treatment was an integrated harvest where roundwood was merchandized and hauled to the appropriate mill and limbs, tops, and small stems (residues) were chipped for hog fuel. The second biomass harvesting treatment simulated a scenario where biomass markets were competing with pulpwood markets and landowners could choose to sell wood for energy or pulp wood. In this treatment whole trees and small stems were chipped for hog fuel. A third harvesting treatment was a conventional roundwood harvest where no wood was chipped, and this treatment was used as a control for comparison of nutrient removals and site disturbance. The chips produced from both harvesting treatments were very similar, but those produced from whole trees tended to be slightly smaller than those produced from residues. Chipper productivity was significantly higher when chipping whole trees and it was also much more efficient in terms of fuel use. Estimations of nutrient removals showed that there was very little difference in the amount of nutrient removed from the biomass harvesting treatments, but both treatments removed significantly more N and Ca than the conventional roundwood harvesting treatment. There was significantly more downed and standing material left on the site after harvesting in the conventional treatment, but this did not translate into a large amount of additional nutrients left on the site. There was little difference in soil disturbance between all three treatments, and due to the dry soil conditions during harvesting, there was very little visual soil disturbance at all during harvesting. / Master of Science

This thesis explored the impacts of forest harvesting on gaseous elemental mercury emissions from forest soils in both field and laboratory studies, through novel use of enriched mercury isotope tracers. Forest floor Hg emissions, sourced from legacy deposition, increased proportionally to the vegetation quantity removed, with biomass harvesting most exacerbating emissions. Contemporary Hg deposition did not appear to be influenced by harvesting. Some of the tracer was rapidly lost to the atmosphere (~8%), but most was sequestered within the soil. Two regimes facilitating Hg emissions were observed in low-light conditions. Under extremely dry conditions deeper Hg sources (> 2cm depth) were as equally susceptible to emission as shallower sources. Following wetting to field capacity, emissions were elevated only from shallow sources, likely as a result of upward capillary transport. Impacts of vegetation removal and dry fluxes are previously uncharacterized and may constitute large additional sources to regional atmospheric Hg cycling.

This thesis explored the impacts of forest harvesting on gaseous elemental mercury emissions from forest soils in both field and laboratory studies, through novel use of enriched mercury isotope tracers. Forest floor Hg emissions, sourced from legacy deposition, increased proportionally to the vegetation quantity removed, with biomass harvesting most exacerbating emissions. Contemporary Hg deposition did not appear to be influenced by harvesting. Some of the tracer was rapidly lost to the atmosphere (~8%), but most was sequestered within the soil. Two regimes facilitating Hg emissions were observed in low-light conditions. Under extremely dry conditions deeper Hg sources (> 2cm depth) were as equally susceptible to emission as shallower sources. Following wetting to field capacity, emissions were elevated only from shallow sources, likely as a result of upward capillary transport. Impacts of vegetation removal and dry fluxes are previously uncharacterized and may constitute large additional sources to regional atmospheric Hg cycling.