Renewable Energy Revenues, Carbon Credits, and Subsidies in Agricultural Waste Treatment Economic Decisions [abstract]

Only abstract of poster available.Track III: Energy InfrastructureAll environmental waste has societal cost, and mitigation is difficult to transfer into benefits that economically justify action. Current subsidies and carbon credit financing have grown to developed within our society to actually put economic resources that are representative of the benefits, and now advanced waste treatment is viable through new economic possibilities related to methane capture and energy production. An economic model was constructed to evaluate the financial potential of anaerobic digestion for swine waste considering initial investments, the associated costs and new revenue streams of carbon credits, renewable energy credits, electricity sales and current available subsidies. The model was formulated based on case-specific inputs and was applied to three case studies in central Missouri. The model inputs were also evaluated by experienced vendors (who have developed similar projects) for validity. The results revealed that the present prices of carbon credits and electricity are not enough to prove the financial feasibility of applying AD technology in all cases without the availability of subsidies. The endeavor also showed that electricity prices have modest impacts on the corresponding Net Present Value of the projects. On the other hand, the carbon credit market projections affect the NPV to a greater degree. Clearly, carbon credit markets may play a pivotal role in widespread development and implementation of the technology. In all the three scenarios the projects were profitable with the presence of the current state and federal subsidies. However, since the subsidies may not be available for many years, high Carbon Credit and electricity prices are needed for future profitability of the technology

Phytoforensics: Soil and Groundwater Sampling Without Soil or Groundwater!

Plants directly interact with surrounding water, air, and soil, collecting and storing chemicals and elements from the surrounding environment. Tree coring methods have shown that groundwater contamination can be assessed without directly sampling the groundwater. In this work, two new and innovative sampling methods that place sampling devices inside the plant, i.e. “in-planta”, were developed to access this valuable data that can direct and perhaps replace traditional methods for contaminated-site investigations. Traditional site assessments may be limited due to time, site access, and expense, resulting in incomplete understanding of the contaminated plumes and inefficient remedial approaches. The new techniques presented include placing established solid phase microextraction fibers (SPMEs) and newly developed solid phase samplers (SPSs) that have greater sensitivity and reproducibility and can also provide repeated sampling of the same trees with minimal damage, offering new possibilities in using plants to monitor contaminated sites as well as doing initial investigations. These methods are also much faster and can be accomplished with little of no property and ecological damage, and with amazing acceptance by property owners

Phytoremediation: Plant Uptake of Atrazine and Role of Root Exudates

Phytoremediation is an Emerging Technology for Degradation of Organic Chemicals. the Potential of Phytoremediation in the Cleanup of Contaminated Sites and Prevention of Non-Point-Source Pollution Was Examined with the Pesticide Atrazine in Two Experimental Systems. Uptake Was Determined in Batch Experiments with 14C Ring-Labeled Atrazine and Hybrid Poplar Trees Grown in Two Soil Types. Mineralization Was Studied Utilizing Soil Microcosms with the Addition of Root Exudates. Results Indicate that Poplar Cuttings Were Able to Uptake the Majority of Applied Atrazine that Was Not Tightly Sorbed to the Organic Fraction of the Soil, with No Detectable Adverse Effects to the Trees. the Addition of Root Exudate to Microcosms Showed Slight Stimulation and the Addition of Ground-Up Root Biomass Revealed Large Stimulation of Mineralization to 14CO2. from Experimentally Acquired Data, a Mathematical Model Was Developed to Obtain Kinetic Rate Constants. This Research Indicates that Vegetative Uptake and Degradation in the Rhizosphere Can Play a Major Role in Remediation at Hazardous Waste Sites. © ASCE

Phytoforensics: Trees as bioindicators of potential indoor exposure via vapor intrusion

Human exposure to volatile organic compounds (VOCs) via vapor intrusion (VI) is an emerging public health concern with notable detrimental impacts on public health. Phytoforensics, plant sampling to semi-quantitatively delineate subsurface contamination, provides a potential non-invasive screening approach to detect VI potential, and plant sampling is effective and also time- and cost-efficient. Existing VI assessment methods are time- and resourceintensive, invasive, and require access into residential and commercial buildings to drill holes through basement slabs to install sampling ports or require substantial equipment to install groundwater or soil vapor sampling outside the home. Tree-core samples collected in 2 days at the PCE Southeast Contamination Site in York, Nebraska were analyzed for tetrachloroethene (PCE) and results demonstrated positive correlations with groundwater, soil, soil-gas, sub-slab, and indoor-air samples collected over a 2-year period. Because treecore samples were not collocated with other samples, interpolated surfaces of PCE concentrations were estimated so that comparisons could be made between pairs of data. Results indicate moderate to high correlation with average indoor-air and sub-slab PCE concentrations over long periods of time (months to years) to an interpolated tree-core PCE concentration surface, with Spearman\u27s correlation coefficients (ρ) ranging from 0.31 to 0.53 that are comparable to the pairwise correlation between sub-slab and indoor-air PCE concentrations (ρ = 0.55, n = 89). Strong correlations between soil-gas, sub-slab, and indoor-air PCE concentrations and an interpolated tree-core PCE concentration surface indicate that trees are valid indicators of potential VI and human exposure to subsurface environment pollutants. The rapid and non-invasive nature of tree sampling are notable advantages: even with less than 60 trees in the vicinity of the source area, roughly 12 hours of tree-core sampling with minimal equipment at the PCE Southeast Contamination Site was sufficient to delineate vapor intrusion potential in the study area and offered comparable delineation to traditional sub-slab sampling performed at 140 properties over a period of approximately 2 years

Mineralization and Uptake of Triazine Pesticide in Soil-Plant Systems

Deep-Rooted Trees Planted as a Buffer Zone Can Intercept Runoff and Eroded Sediments, Thus Reducing Non-Point-Source Pollution Due to Agricultural Chemicals. in This Study, Populus Sp. Were Grown in Bioreactors with an Agricultural Soil (Silt-Loam) and in a Silica-Sand Media; Both Were Spiked with 14C Uniformly Ring-Labeled Atrazine. the Plants Took Up over 11% of the 14C Labeled Atrazine Applied to the Silt-Loam Soil and over 91% of that Applied to the Silica Sand Media, with the Majority of the 14C Accumulating as Nonphytotoxic Metabolites in the Leaves. Research Suggests that, in Addition to Nutrient Uptake, Poplar Tree Buffer Strips May Be Effective in Removing Atrazine from Agricultural Percolation and Runoff Water. © ASCE

General Report - Session 6

This general report provides a summary of 40 accepted papers submitted to sessions 6a on ground improvement methods and session 6b on geoenvironmental engineering. The papers are contributed by the researchers and professionals from the United States and 15 other countries and they cover a wide range of topics based on laboratory experiments, field design, construction and monitoring, and mathematical modeling. A brief summary of each paper is provided under organized sections and the reader is referred to consult the full paper for details. Finally, the topics for discussion are listed

Joel Burken Podcast

Professor of Architectural and Environmental Engineering Joel Burken discusses environmental effects of the Renewable Fuel Standard, which requires the U.S. to produce 36 billion gallons of biofuels by 2022