Library: Earth and Environmental Sciences

Air streams discharged from industrial sources contain volatile organic compounds (VOCs) for which environmental regulations are being increasingly restrictive. Biofiltration is an environmentally friendly technology for treatment of waste gases containing relatively low concentration of VOCs, because of its simplicity, low cost and non-generating hazardous residues. In this work, three laboratory-scale peat biofilters were operated at 90s empty bed residence time for a continuous period of 7 months. Biodegradation of ethyl acetate, toluene, or a 1:1 mixture were investigated (these compounds ...

This study was conducted in South Africa. South Africa is the first country within the Southern African Development Community to have regulated plastic shopping bags waste through the imposition of both a standard on thickness and a levy. Given this scenario, the Plastic Bags Regulations present an illustrative case for researching complexity, uncertainty and controversies surrounding a new trend in environmental policy making, namely waste product regulation. The thesis focuses on understanding and investigating tensions, debates and responses emerging from the policy process as actors and ac...

The Louisiana timber industry relies on the availability of harvestable trees. In areas affected by Hurricanes Katrina and Rita, the black turpentine beetle (Dendroctonus terebrans) contributed to the mortality of loblolly (Pinus taeda) and slash (Pinus elliottii) pine trees. This timber loss due to natural causes reduces the landowner’s earnings The BTB girdles the cambium layer of pines that are weakened by wind or drought. This study estimated post-Rita beetle damage on a 458-acre slash pine tract consisting of 157 trees per acre on the West Bay Wildlife Management Area, Louisiana. Timber ...

Groundwater represents an important supply source for municipal and irrigation uses in Far West Texas. The City of El Paso receives about 50 percent of its municipal water supply from surface water and 50 percent from local groundwater. Groundwater pumping in El Paso is from the Hueco Bolson and the Mesilla Bolson. Historic groundwater pumping in the Texas portion of the Mesilla Bolson has not resulted in significant changes in groundwater levels or groundwater quality in existing wells. Historic pumping in the Hueco Bolson has resulted in lowered groundwater levels and brackish groundwater ...

Anaerobic digestion is the most widely process used for the stabilisation of wastewater treatment sludge. Organic matter is transformed into CH4 and CO2 by the action of different bacteria groups. The main advantages are the reduction of the volume of waste sludge and the production of methane gas that can be utilized as energy supply for the process. During anaerobic digestion of activated sludge from enhanced biological phosphorus removal process (EBPR-process), most of the phosphorus eliminated during the water treatment, as well as that from cellular lysis, is released. So that, phosphorus...

In recent years, due to expanding populations and industries, regulatory authorities have imposed tighter discharge limits on nutrients from wastewater treatment facilities to avoid eutrophication in water streams. Common methods, such as metal salt precipitation, are being used to lower phosphorus concentrations which are a main contribution. However, alternate phosphorus removal techniques, such as phosphorus crystallisation, can provide further benefits. Precipitated solid can be utilised as a marketable fertiliser. Principles of magnesium and ammonia phosphate precipitation, working with a...

Simulation modeling is arguably the most versatile scientific tool for predicting the future environment. However, the reliability of model-based predictions is limited to the behavior domain defined by the historical data employed for conceptualizing and calibrating the model. Future changes in external inputs and internal structure tend to produce system behavior significantly different from prior predictions. To abate this seeming lack of credibility, it is now customary to qualify model predictions with uncertainty estimates. This dissertation explores the complementary approach of back-ca...

The Agulhas Retroflection transfers heat, salt and vorticity from the Indian Ocean to the South Atlantic. The transfer is accomplished by discrete meso-scale features and by the advection of a water column of mixed Atlantic and Indian Ocean origins. The objectives of this thesis are to measure the strength of the Agulhas-South Atlantic (ASA) exchange and to develop a generalized method for the measurement of mass and thermohaline fluxes. First, ASA mass and energy fluxes are estimated by using sea surface height (SSH) anomalies from satellite altimetry to monitor Agulhas eddies, a signifi...