Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [118]-130).

Eutrophication, caused by phosphorus and nitrogen overloading, is a global pollution problem for our fresh water lakes and streams. Regulatory bodies have developed treatment guidelines for point-source pollution to address this concern, creating a need for small and remote waste producers to develop low cost solutions for nutrient removal – in particular phosphorus. Constructed wetlands have often been implemented as a low cost alternative to treat various sources of wastewater, however, their efficiency in removing phosphorus has been questioned. Post-treatment blast furnace slag filters (known to have a high phosphorus sorption capacity) have been in operation since 2008 in Haliburton, Ontario, Canada, treating aquaculture wastewater following treatment by a constructed wetland. Phosphorus removal performance of three filters of varying configuration have been assessed: • a random packed filter, packed randomly with unsieved blast furnace slag removed only 26% of phosphorus overall and became severely clogged likely due to the presence of fines, poor flow distribution and formation of calcium carbonate precipitate; • a screen filter, designed as twenty individual filters separated by 3 inches of space to provide more uniform flow throughout removed 55% of the total phosphorus added and maintained a uniform flow throughout the study; and • an anaerobic filter, designed to be sealed from the atmosphere in an effort to prevent the formation of calcium carbonate and subsequent filter clogging, removed 19% of the total phosphorus added and revealed signs of poor flow distribution. Lab-scale flow through cells were designed to parallel the field scale studies and were operated at varying configuration, temperature and residence times to assess these factor effects on phosphorus removal. The results of this research provide a valuable contribution to research involving blast furnace slag filters for phosphorus removal. It has been demonstrated that cold temperatures reduce the slag filter’s efficiency to remove phosphorus (but cold-climate filters can still be effective in removing phosphorus), the removal of slag fines reduces the potential for slag clogging, a screen design is effective in promoting uniform flow and offsetting the effects of clogging and an optimum residence time may exist for phosphorus removal beyond which phosphorus removal is minimal. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-04-23 21:46:44.136

Producing fruits and vegetables in the Intermountain West can be challenging due a short growing season, extreme temperatures, and limited availability of irrigation water. This is particularly true of strawberries, where commercial production is limited due to late fall and early spring frosts that shorten the growing season. With the increasing demand for local produce as urban populations grow and as consumer buying habits change, growers are looking for ways to overcome these climatic challenges. High tunnels are one option growers can use. High tunnels are similar to greenhouses, but less expensive to construct and to maintain. Another way to protect crops against adverse climatic conditions is with low tunnels. As the name implies, they are a smaller version of a high tunnel, usually only tall enough to cover the canopy of the plant. Low tunnels can be used by themselves or in conjunction with (inside) a high tunnel. Adding heat is another option. However, heating can be expensive and may not be profitable. Targeting heat additions in the root zone may decrease cost of heat but still provide protection to the plant.These protection methods were evaluated in Cache Valley, Utah for effectiveness of increasing strawberry yield. High tunnels increased total yield, as did high tunnels used in conjunction with low tunnels. However, low tunnels by themselves were not able to increase yield in comparison to unprotected plants in the field. Targeted root zone heating was evaluated in both high and low tunnel with two target temperatures: 7 and 15 °C. There was no difference in total yield between the two temperatures, but both increased yield above the high tunnel alone and the 15 °C heating treatment moved the harvest season approximately 6.5 weeks earlier than unheated tunnels and approximately 12 weeks earlier than field production. The additional cost associated with using supplemental heat was offset by the increased yields and the higher value of early fruit.Separate experiments were carried out to determine susceptibility of strawberry leaves to damage from cold temperatures, which can then be used to provide guidelines for temperature management in high tunnels. Strawberry leaves were not significantly damaged when exposed to -3 °C, but significant damage occurred once leaves were exposed to -5 °C. To maximize the advantages of protected cultivation, growers should manage tunnels and heating to keep leaf temperatures above -3 °C. These results provide improved guidelines for growers interested in using protected cultivation strategies to provide fruit for local consumption in the Intermountain West.

Diss. (sammanfattning) Luleå : Univ., 2000. / Härtill 10 uppsatser.

Increased urbanization leads to an increasing amount of impervious surfaces and a decrease ofthe natural hydrological function. Urban stormwater does thus risk to create high surface flows which could damage the receiving water bodies (e.g. erosion) or the urban area itself (flooding). Integrating more nature-based systems into the urban area increases the natural hydrological function and the risks for high surface flows are lowered. One way of implementing nature-based systems in the urban environment is to install green roofs. Most of the research and development done on green roofs have been focusing on the conditions of central Europe. Installing green roofs with the same vegetation in the subarctic climate of northern Sweden would expose it to a climate it might not be suited for, and growth would be limited. The vegetation helps increase the retaining and detaining capabilities of the green roofs and therefore the purpose of this thesis was to examine if planting native vegetation would help increase thegreen roofs performance in a subarctic climate. Conventional green roofs vegetated with sedum was hypothesized to have lessened retaining and detaining capabilities when placed in cold climates since the vegetation was exposed to a climate it probably was not suited for. It was examined whether planting more native vegetation could help increase green roofs performance. The vegetation was chosen based on Grime´s “universal adaptive strategy theory”, which describes competitors, stress tolerators and ruderals as three different vegetation groups with different survival strategies. Different species from each strategy were selected and planted on the roofs. There were five roofs per survival strategy and five roofs where all strategies were mixed. Conventional sedum vegetation was planted on five roofs to be able to compare green roofs performance. Five control roofs with substrate only and one reference roof made of steel were installed as well. In total, seven rainfall events were analyzed, and few significant differences could be found between the competitors, stress tolerators, ruderals and the vegetation mix. A conclusion is that stress tolerators may help to increase green roof performance the most, but due to the relatively short study period, continued measurements are recommended to draw further conclusions. The survival strategies did improve retention and detention relatively to using sedum vegetation and substrate only. The extent of vegetation coverage does not affect the retention or detention from the green roofs. The competitors, stress tolerators, ruderals and vegetation mix had larger plant mass than the sedum and the increased plant mass is probably the reason for their improved retention.

Green roofs have, in the past 15 years or so, gained increasing acceptance as a means of replacing or offsetting the lost of green space due to urban development and urban sprawl. Green roof systems can provide numerous potential benefits, both public and private, including improved control of a building’s internal temperatures with reduced power use. The effectiveness of Green roofs at decreasing energy use in buildings in warm climates is well known. However, their thermal performance in cold climate conditions is not well known, but is of particular interest in regions such as in Eastern Ontario where Green roofs are rapidly gaining popularity. This thesis presents an initial step in understanding the thermal behaviour of currently used Green roof systems in cold climate conditions, and quantifying the thermal benefits, if any, to be gained from the installation of these systems in cold regions as compared against a typical conventional roofing system. A review of available literature is presented which discusses the various benefits of Green roofs. A novel hot box has been designed and constructed, and thermal testing of two Green roofs and a conventional flat roof using the new apparatus are presented and discussed. The data are used to estimate the potential energy savings that might be expected with the installation of a Green roof (such as those tested) on a flat roofed commercial building in the Kingston area. The data suggest that Green roofs may provide a marginal (10% to 24%) thermal benefit as compared with a conventional flat roof under cold climate conditions. This benefit could translate into a $0.09 savings per square metre of roof area in total heat energy costs on an annual basis. Recommendations for future work in this research area are provided. / Thesis (Master, Civil Engineering) -- Queen's University, 2007-09-23 21:14:30.381

Thesis (M.S.P.H.)--University of Michigan, 1939.

Thesis (M.S.P.H.)--University of Michigan, 1939.

A field study was conducted to evaluate the influence of a trellis system, Genova double curtain (GDC), Scott Henry (SH), mid-wire that was vertical shoot positioned (VSP), and high wire cordon (HW), on fruit ripening and indirectly its influence on cold hardiness for cold-hardy, red wine grape cultivars, Marquette and Petite Pearl. In 2017, ‘Petite Pearl’ reached higher yields than ‘Marquette’, while VSP and SH trellis systems resulted in higher yields. However, in 2018, ‘Marquette’ had a greater yield than ‘Petite Pearl’. In 2019, 77.34% of ‘Marquette’ and 52.34% of ‘Petite Pearl’ had severe winter injury regardless of the trellis system. Unpredictable climate patterns in terms of growing degree-days, minimum winter air temperature, and rainfall manipulated both cultivars’ phenology during early establishment. Results suggest that under North Dakota climatic conditions, proper cultivar selection is more important than trellis system selection for sustainable grape production.

This comparative study explores the mechanisms of pollutant removal efficiency in cold-climate constructed wetlands (CWs) and investigates the benefits, standing and practicability of using these systems to treat wastewater in Canada and Northern China. Treatment efficiencies defined by the Canadian and Northern China experience vary considerably. Experience in both countries shows that the majority of effluent values are generally better than that required by discharge standards in Canada and China. A review of the available case studies on cold weather treatment in both countries indicates that this technology is feasible in Canada and Northern China, although further monitoring data are needed to optimize CW design and ensure that the effluent quality standards are consistently met. In both of these countries and around the globe, increasingly strict water quality standards and the growing application of treatment wetlands for wastewater treatment is an important motive for the development of better numerical models as predictive process design tools. An investigation of the SubWet 2.0 model, a horizontal subsurface flow modeling program used to predict the level of treatment that can be expected was conducted. It has been shown that SubWet can consider the influence of several factors at one time, where empirical equations are generally not able to consider more than two factors at one time and usually in isolation of the other influential parameters. Three different data sets, two from natural wetlands from the Canadian Arctic and one from a CW in Africa were used to illustrate how SubWet can be calibrated to specific wetlands. Compared to other models, it is suggested that SubWet provides one of the best modeling options available for natural tundra wetlands. Further calibration of SubWet with twelve municipal treatment wetlands in the Canadian Arctic clearly demonstrated its ability to model treatment performance within natural tundra wetlands and thus provide an additional predictive tool to aid northern stakeholders in the treatment of municipal effluents. It is anticipated that increased monitoring and the generation of additional measured data will help to better identify the level of year to year variability and improve the overall predictive capability of the model. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-10-22 17:14:23.322