Thesis (M.S. in environmental engineering)--Washington State University, May 2010. / Title from PDF title page (viewed on June 18, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 28-29).

Urea finds common use at most airports in Canada where it is used as an anti-icer or de-icer. Urea contains up to 46% nitrogen which finds its way to the environment around the airport. Of the potential environmental problems, eutro-phication of lakes is of the most concern in British Columbia. Several methods for minimizing the impact of urea de-icer were considered. Urea can be hydrolyzed to ammonia by the common soil enzyme urease on an airport runway and this ammonia can volatilize to the atmosphere. The natural enzymatic activity on runway test sections was found to cause less than 0.5% of the applied urea to hydrolyze with no volatilization after 90 minutes, at room temperature. Supplemental urease was added to pyrex models to test the effect of various conditions on hydrolysis and volatilization. Thirty-two tests were performed at various temperatures (-4, 0, 4, 120C), urease additions (100, 200, 500, 750 mg/model), ice thicknesses (3, 5, 8 mm), urea applications (0.45, 0.9, 1.8 kg/70m2), urea types (Cominco Industrial and Forestry Grade, Sherritt Gordon Mines Industrial Grade) and solar radiations (50 and 100 BTU/h-ft2). An addition of 500 mg urease to the model cuased hydrolysis of 65% of the applied urea and volatilization of 1% at 12°C. Lower temperatures produced poorer results. Relative to the high costs and low efficiency, control of urea through hydrolysis and volatilization on an airport runway is impractical. Biological nitrification-dentrification, breakpoint chiorination, selective ion exchange, and air stripping have high nitrogen removal efficiencies under normal conditions, but are not suitable for winter airport operation. Passage of urea through soil can be an effective method for removal of this de-icing agent if the quantity of nitrate and urea leached to surface waters is low. Published data indicates that soil could be 75-90% efficient in controlling nitrogen loss to surface and ground waters. A reduction in the quantity of urea used on a runway would decrease the environmental impact. The yellow aura produced by the urea-Ehrlich reagent reaction, was used to monitor the movement of urea in 5 mm thick ice at -4°C. After 90 minutes from placement on the ice, the Cominco Forestry Grade aura covered the largest area. On a weight basis, however, the Sherritt Gordon Mines covered the largest area. This greater aura coverage is due to the smaller particle size of the Sherritt Gordon Mines pellets. If the size of the aura can be correlated with the ease of removal of ice from an airport runway, then the Sherritt Gordon Mines-Industrial Grade urea is more effective as a de-icer than either of the two Cominco grades under the conditions tested. Further research is recommended in optimizing the use of urea and soil treatment. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Thesis (M.S.)--Ohio University, March, 2004. / Title from PDF t.p. Includes bibliographical references (leaves 226-232).

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Master of Science / Department of Civil Engineering / Kyle Riding / Some limestone coarse aggregate in concrete pavement can break down under repeated freeze-thaw cycles. Application of rock salt may increase the severity of exposure conditions because of trace compounds, such as calcium sulfate, in rock salt. Subsequently, limestone aggregate in concrete was subjected to freeze-thaw cycling in two methods: salt-treating the aggregate before batching concrete, and half-immersing concrete specimens in rock salt solution during freeze-thaw cycling. Concrete and saw-cut limestone specimens were also subjected to wet-dry cycles in varying salt solutions to examine the influence of trace compounds in rock salt. Freeze-thaw test results indicate that the test methods used were not severe enough to determine if a limestone aggregate was durable or not. The wet-dry testing was also not severe enough to determine the effects of trace compounds in salt solution.

Shallow geothermal energy (SGE) systems are becoming increasingly popular due to both their environmental and economic value. By using the ground as a source and sink for thermal energy, SGE systems are able to more efficiently heat and cool structures. However, their utility beyond structural heating and cooling is being realized as their applications now extend to slab and pavement heating, grain and agricultural drying, and swimming pool temperature control. Relatively recently, SGE systems have been combined with deep foundations to create a dual purpose element that can provide both structural support as well as thermal energy exchange with the subsurface. These thermo-active foundations provide the benefits of SGE systems without the additional installation costs. One of the novel applications of thermo-active foundations is in bridge deck deicing. Bridge decks experience two main winter weather related problems. The first of which is preferential icing, where the bridge freezes before the adjacent roadway because the bridge undergoes hastened energy loss due to its exposed nature. The second problem is the accelerated deterioration of concrete bridge decks resulting from the application of salts and other chemicals that are used to prevent accumulation and/or melt the frozen precipitation on roads and bridges. By utilizing the foundation of a bridge as a mechanism by which to access the shallow geothermal energy of the subsurface, energy can be supplied to the deck during the winter to melt and/or prevent frozen precipitation. An experimental ground-source bridge deck deicing system was constructed and the performance is discussed. Numerical models simulating the bridge deck and subsurface system components were also created and validated using the results from the numerical tests. Furthermore, the observed loads that result in a foundation from bridge deck deicing tests are shown. In order to better design for these loads, tools were developed that can predict the temperature change in the subsurface and foundation components during operation. Mechanisms by which to improve the efficiency of these systems without increasing the size of the borehole field were explored. Ultimately this research shows that SGE can effectively be used for bridge deck deicing. / Ph. D.

No description available.

A road in operation along with its traffic can pose aserious pollutant threat to groundwater and surface water inits vicinity. Examples of pollutants are metals from thecorrosion of vehicles, rails and poles and the wear of roadsurfaces and tyres; hydrocarbons from the wear of roadsurfaces, tyres, exhausts, oils; sodium chloride from roadsalt; and hazardous goods discharged in accidents. Eventuallypollutants that are not degraded or retarded in soil will reachgroundwater and surface water. The chloride ion in deicing saltis a good tracer. It is conservative and highly soluble and notsubject to retardation or degradation. If the chlorideconcentration has increased in groundwater or surface water inthe vicinity of a deiced road, other road-related pollutantsmight also be present in the water. Increased chloride concentrations have been observed inseveral water supplies, in groundwater as well as in surfacewater, since the 1970s. The number of affected water supplieshas also increased. The increase in chloride concentration inwaters is concurrent with the increase in deicing saltapplication and it is clear that most of the increase is due tothe application of deicing salt. The thesis presents a simple tool that quantified theincrease in chloride concentration for water in a catchmentarea, based on a steady-state water balance. The data wereefficiently processed and presented as maps with GIS. At aregional catchment area scale, substantially increased chlorideconcentrations were calculated. The variation between catchmentareas was verified by a national monitoring programme of lakes.Deicing salt application was estimated to account for more thanhalf of the total chloride load for a catchment area in the midsouth of Sweden. A distributed dynamic method was used to evaluate thetemporal and spatial variation of the chloride concentration inan aquifer. The distributed dynamic approach integrated thespreading of deicing salt from the road with the infiltrationin the unsaturated zone in the soil, which in turn wasintegrated with the groundwater flow. The simulation was runfor a 40-year period and showed a potential to describe aspecific system. <b>Keywords:</b>road, deicing salt, monitoring, chloride,catchment area, river basin, simulation, GIS, groundwater,surface water