<p> This study was performed to investigate the effects of humid air on nitrogen oxide (NOx) and particulate matter (PM) emissions of a compressed natural gas (CNG) engine. A 50 horse-power, 4 cylinder, naturally aspirated CNG engine was used for this study at a research facility in the College of Engineering at California State University Long Beach. The experiments were carried out at different relative humidity levels of 30%, 45%, and 60% at different power outputs of 5 HP, 12.5 HP, 25 HP, and 37.5 HP. At each test condition, the NOx and PM emissions are collected and analyzed through a dilution tunnel, the Horiba gas analyzer, and a cyclone with Teflon air filters. For PM measurements, the Teflon filters are weighed using a micro-balance at University of California, Irvine&rsquo;s biology lab, in prior and after running the experiments. Results show a decrease in NOx emission up to 91 percent and increase in PM emission by 7.4 mg with the increase in intake air humidity level.</p><p>

<p> Local, national and regional water supplies needed for energy production, meet the irrigation demands, industrial and domestic usage have come under sever degradation hence decreased the piezo metric water table level in the groundwater resources which finally results in negative environmental impacts. Silver Creek basin (area 154.8 mile2 equals to approximately 400.930 km²) locates in southern part of Illinois State, is connected to highland lake (which has a huge impact in the area and specifically Highland City) with east fork tributary. In this research watershed modeled in a hydrological model called SWAT (Soil and Water Assessment Tool) which is an extension of ArcGIS software, then watershed area is divided into 75 sub watersheds. Different parameters and variables are considered for sensitivity analysis in order to figuring out the most sensitive parameters and their ranges for flow rate calibration within different hydrological response units (HRUs). The flow rate quantified at sub basin level with daily time intervals. The model inputs are precipitations and meteorological data such as Solar Radiation, Wind speed and direction, Temperature and Relative Humidity, then model was calibrated with two sets of real data for Troy and Freeburg Stations in the middle and pouring point of watershed respectively. The main object was to test the performance of SWAT and the feasibility of using this model as a simulator of flow rate at a watershed scale. Model calibration and uncertainty analysis performed with SUFI-2 (sequential Uncertainty Fitting) which is interfaced with SWAT applying iSWAT generic program.</p><p>

<p> Tools for predicting rain garden performance are limited, particularly for predicting seasonal performance. Changes in temperature cause changes in the viscosity of water, infiltration rates, and evapotranspiration rates. A variably-saturated soil model, HYDRUS-1D, was calibrated and validated using observed ponding depth and soil moisture data for the Philadelphia Zoo Rain Garden, owned and operated by the Philadelphia Water Department (PWD). Warm and cold seasons were simulated with typical meteorological data and temperature-adjusted saturated hydraulic conductivity values. Design-storm simulations confirmed that the rain garden is over-performing. Maximum capacity of the system was simulated by increasing the loading ratio until overtopping occurred or ponding remained longer than 24 hours. This study will demonstrate how modeling of an operational urban rain garden offers a realistic picture of performance and could be used as a tool for informing regulations and design. </p><p>

<p> Heavy duty on-road vehicles represent one of the largest sources of NO_x emissions and fuel consumption in North America. Heavy duty vehicles are predominantly fueled with diesel, with the recent interest in natural gas (NG) systems. As emissions and greenhouse gas regulations continue to tighten new opportunities for advanced fleet specific heavy duty vehicles are becoming available with improved fuel economy. NO_x emissions have dropped 90% for heavy duty vehicles with the recent 2010 certification limit. Additional NO_x reductions of another 90% are desired for the South Coast Air basin to meet its 2023 NO_x inventory requirements and the California optional low NO_x standard in 2015.</p><p> One of the difficulties in quantifying NO_x emissions at the levels proposed in this research (90% of the 2010 certification level ~ 0.02 g/bhp-hr) is the measurement methods are approaching their detection limit to sufficiently quantify NO_x emissions. Three upgraded NO_x measurement methods were considered which include a raw NO_x measurement integrated with real time exhaust flow, a real-time ambient correction approach, and a trace level ambient analyzer for accurate bag analysis. In summary the improved methods varied in their success where the raw sampling approach showed to be the most accurate and precise over the rage of conditions tested. </p><p> The ISL G NZ 8.9 liter NG engine met and exceeded the target NO_x emissions of 0.02 g/bhp-hr. This engine significantly reduced 97%&ndash;100% of NO_x emissions compared with previous ISL G 8.9 engines. The NO_x emissions decreased as the duty cycle was decreased which was the opposite trend for the diesel vehicles. It is expected NG vehicles could play a role in the reduction of the south coast NO_x inventory problem given their near zero emission factors demonstrated.</p>

During the last few decades governments all around the world have increased concerns about water shortages and pollution. Consequently, they issued a multitude of environmental legislations and regulations, land and water-use planning measures, and other environmentally related procedures. The objective of this work was to contribute in developing efficient adsorbent for heavy metal ions from wastewater. Two different kinds of adsorbents were studied: MCM-41 (Mobil Catalytic Material number 41) mesoporous silica whose pores have been expanded by a post-synthesis hydrothermal treatment in the presence of N,N-dimethyldecylamine (DMDA), and 3-aminopropyltrimethoxysilane (AMP) grafted MCM-41 after being pore expanded and calcined. The pore-expanded MCM-41, (PE)MCM-41, (i.e., containing DMDA) has been tested as adsorbent for Cu2+ cations. Regeneration ability and factors affecting the stability of this material such as pH and stirring time have been investigated. The results showed that (PE)MCM-41 is fast, sensitive, and high capacity adsorbent. However, it is not an appropriate material for environmental applications due to its poor stability in aqueous solutions. Further studies using calcined and pore-expanded MCM-41, (CPE)MCM-41, silica as support for grafting AMP have been carried out. A systematic investigation of the amine loading as a function of the relative amount of AMP and water used during the grafting procedure was carried out. The surface characteristics, AMP loading, Cu2+ adsorption capacity, CO2 adsorption capacity, and rate of CO2 adsorption were determined for all materials. Surface area, pore size and pore volume decreased significantly from 950 m 2/g, 11.3 nm and 2.16 mL/g for unmodified (CPE)MCM-41 to 783 m 2/g, 7.4 nm and 1.54 mL/g for the materials grafted under dry conditions in the presence of 1.0 mL AMP/g silica, and to 730 m2/g, 6.34 nm and 0.77 mL/g for the materials grafted under wet conditions in the presence of 2.0 mL AMP/g silica and 0.4 mL water/g silica. The maximum amine loading, CO2 adsorption capacity and Cu2+ adsorption capacity suggested that the optimum grafting conditions are 2 mL AMP/g silica and 0.4 mL of water/g silica, and that any excess of water or amine added to the grafting mixture has negative effect on the adsorption performance of the material. Two approaches have been investigated to recycle the copper loaded adsorbent: treatment with acidic solution and treatment with complexing agent, ethylenediamine-tetra acetic acid tetra sodium salt (EDTA). The results showed a significant drop in the adsorption capacity after the first regeneration cycle. With further testing of the material, it was concluded that the (CPE)MCM-41 is not stable when being in contact with water and thus, even the material was still loaded with amine, structural changes of the material caused the amine to become inaccessible for Cu2+ or CO2 molecules. So, further work is still required to improve the stability of this material in water or to use more robust material.

First order trends in the strontium isotopic (87Sr/86Sr) composition of seawater are controlled by radiogenic inputs from the continent and non-radiogenic inputs from exchange at mid-ocean ridges. Carbonates precipitated in seawater preserve trace amounts of strontium that record this isotope ratio and therefore record the relative importance of mid-ocean ridge and weathering chemical inputs to sea water composition. It has been proposed that environmental changes during the Ediacaran-Cambrian transition may have enabled the rapid diversification of life commonly named the “Cambrian explosion.” Proposed environmental changes include 2.5x increase in mid-ocean ridge spreading at the Ediacaran-Cambrian boundary and large continental fluxes sediment into oceans. These hypotheses rely on a poorly resolved strontium isotope curve to interpret Ediacran-Cambrian seawater chemistry. A refined strontium isotope curve through this time period may offer insight into the environmental conditions of the early Cambrian. New age models and detailed mapping in the Zavkhan terrane in west-central Mongolia provide the context necessary for robust geochemical analysis. This study aims to better resolve the coarse strontium isotope curve for the early Cambrian period by analyzing carbonate sequences in the Zavkhan basin. These carbonate sections are rapidly deposited, have undergone little diagenesis, and are likely to preserve a primary seawater signal. Strontium isotope analysis of these sequences was carried out to determine changes in hydrothermal activity and weathering fluxes during this time period. Recompiling these data with a global dataset of strontium isotopes through this time period indicates a stable strontium isotope signal through much of the early Cambrian. These data do not support previous hypotheses attributing the driving mechanism for the early Cambrian transition from Mg-dominated to Ca-dominated seas to increased sea floor spreading rates.

Membrane systems are being used increasingly throughout the western world to treat landfill leachate as environmental regulations tighten. This work examined leachate filtration using a bench-scale MF/UF membrane system, focussing on surface fouling and constituent reductions at the Trail Road Landfill in Ottawa, Ontario. The study found that ultrafiltration membranes with a molecular weight cut-off of 10 KDa and below gave the best overall leachate treatment. A 1 KDa ultrafiltration membrane gave the highest percent removals overall of all the membranes tested, but had one of the lowest steady state fluxes ranging from 2 to 5 L/m2h. Carbonates such as calcite and dolomite were determined to be one of the main foulants/scalants. Iron sulphides or iron oxides tended to form a general coating over the membrane surface and may have been the base for a surface coating of mixed-element origins observed in spring 2003. The fouling type was generally thought to be cake filtration based on flux results and basic fouling determination equations. (Abstract shortened by UMI.)

Solution gas is commonly evolved in the production of oil and bitumen. When crude ail in the reservoir is exposed to atmospheric pressure, the gaseous stream dissolved in the liquid phase comes out of solution. Flaring or venting directly to the atmosphere are two common means to dispose of solution gas at oil and bitumen batteries where it cannot be conserved. Although the trend for conservation continues to grow, there were still 408 million m 3 of solution gas flared and 435 million m3 vented in 2003 at crude oil and bitumen batteries in Alberta, Canada. Our project aims at the partial recovery of the heat that is currently lost to the atmosphere when solution gas burns in an open-air flame. The ultimate objective of the recovery system is the generation of electricity to inject enough air for the complete combustion of solution gas that is flared in order to reduce greenhouse gas emissions and smoke formation. (Abstract shortened by UMI.)

The objective of this thesis was to study the adsorption and desorption characteristics of natural organic matter (NOM) adsorbed on granular activated carbon (GAC). Five different natural waters (Ottawa River, ON; St. Lawrence River, ON; Vars Ground Water, ON; Buffalo Pound Lake, SK; Ohio River, OH) were studied to see if the characteristic of irreversible adsorption was a universal phenomenon. This was studied by comparing desorption isotherms to adsorption isotherms. Preliminary long-term kinetic studies were used to ensure that the contact time was sufficient for equilibrium. The waters were also fractionated to further study the differences in adsorption and desorption properties of various surface waters. The fractionation techniques used were; ultrafiltration by membrane separation, extraction of humic acids using a methylmethacrylate resin (XAD8) and size exclusion chromatography using a sephadex gel in a glass column. (Abstract shortened by UMI.)

Wastewater treatment generates large quantities of sewage sludge whose disposal is expensive. Mainly because anaerobic digestion produces methane, which can be beneficially used as an energy source, this process has become the most popular means of stabilizing sewage sludge prior to spreading on agricultural land or disposal to landfills. Several pretreatment technologies have recently been developed to render sludge more degradable during anaerobic digestion. The purpose of this study is to investigate whether microwave irradiation can enhance the anaerobic degradability of aerobic sequencing batch reactor sludge. Relationships relating microwave irradiation duration, microwave intensity, sludge concentration and the temperature reached by the sludge were developed. Sludge concentration in the 1.2-4.3% total solids range was found not to impact the temperature reached by the sludge. Three techniques were used to assess the impact of microwave irradiation on the size of the particles: visual analysis of sludge settling, microscopic analysis and particle size distribution analysis. (Abstract shortened by UMI.)