<p> As highway runoff is one major source of non-point pollution in urban areas, removal of contaminants in runoff should be of great concern. In this paper, the necessity of highway runoff treatment in Shanghai was approved, systemic comparisons between runoff treatments were listed, detailed discussions on treatment approach selection were given based upon the availability of land. Three design models for highway runoff treatment were proposed; one focused on the urban highway, one focused on the suburb highway, and the third focused on the urban-suburb area. A survey among scientists studying runoff in China showed that the use of constructed wetlands was a remedy that was highly approved. They also supported the establishment of an urban runoff database. This paper will assist in the development of suitable treatment strategies for highway runoff in urban areas in China.</p>

Dried cattail and bulrush plant pieces in mesh bags were incubated in the constructed wetland treating Pope & Talbot pulp mill effluent. Two ponds planted with each species and two depth ranges in each pond were chosen, to determine decomposition rates. Bags were withdrawn and analyzed at five time points for the cattail and three for the bulrush. Also a laboratory study was conducted, where ground cattail and bulrush material was incubated aerobically and anaerobically. Both species and control were sampled at five time points. The remaining dry mass and the contents of hemicellulose, cellulose, lignin, and silica was examined. Decomposition rates were determined by fitting the data to the single exponential model with the intercept fixed in 1 (100%). An asymptotic model was used to obtain better fit. The sum of squared errors (SSE) was used as a measure of fit. In the field study the ANOVA revealed no change in decomposition with depth. Neither was there a difference between cattail and bulrush ponds. During the first two days only the cell compounds are drastically reduced. Cellulose and hemicellulose start to decline later. Lignin increased slightly during the first half of the experiment. Decay rates from the single exponential model with the intercept fixed were higher than the ones listed for wetlands by Webster & Benfield (1986). The asymptotic model indicates, that there is a fraction, which does not decompose significantly during the time frame of the experiment. It predicts 36% cattail and 53% bulrush material to be left after one year of decomposition. All samples in the laboratory incubation showed strong leaching during the first day (26.5% for cattail, 23% for bulrush). After this the t-test (95% confidence) showed a significant decay coefficient only for the aerobic cattail samples the model with the best fit. These same samples had an increased cell component, and a very small particle size at the last sampling time (120 days). Neither bulrush nor the anaerobic cattail incubations showed the same effect. Cattail and bulrush plants in the field were labeled to observe the senescence. Their height and in the case of cattail the amount of green and dry leaves was recorded monthly. Plants were harvested once a month until February, and the fiber composition was measured. Cattail was completely dry in January, while bulrush still showed green spots in February. Cattail entered the aquatic system mainly by dropping pieces of leaf tips, less by breaking off and losing the outside leaves. In February the average height of cattail plants was 64.7% of the maximum average height in August. Bulrush plants shortened to 84.1% of the maximum average height from September. Most of the bulrush plants died through nutria, a rodent, which is chopping off the plants. Less material was lost by dropping small pieces off the plant tips. / Graduation date: 1994

As highway runoff is one major source of non-point pollution in urban areas, removal of contaminants in runoff should be of great concern. In this paper, the necessity of highway runoff treatment in Shanghai was approved, systemic comparisons between runoff treatments were listed, detailed discussions on treatment approach selection were given based upon the availability of land. Three design models for highway runoff treatment were proposed; one focused on the urban highway, one focused on the suburb highway, and the third focused on the urban-suburb area. A survey among scientists studying runoff in China showed that the use of constructed wetlands was a remedy that was highly approved. They also supported the establishment of an urban runoff database. This paper will assist in the development of suitable treatment strategies for highway runoff in urban areas in China.

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Constructed wetlands (CWs) utilize the natural mechanisms in wetlands to remove pollutants by physical, chemical and biological processes. CWs are one of the ecological engineering methods to purity water quality and has been experimented to assess their capabilities to remove nutrients from eutrophic water bodies of lakes and reserviors. This study was carried out to compare the removal of nutrients between vegetated and unvegetated CWs. The vertical flow bed was placed in the upstream, while the horizontal subsurface flow bed was set in the downstream. Cannaceae was selected to plant in the vegetated CWs. Two kinds of hydraulic retention time (HRT), 3 days and 7 days, were applied and compared with each other in this study. The experimental results show that no significantly difference between vegetated and unvegetated systems. The removal efficiencies of SS, BOD, NH3-N, TP are measure equal to about 80%, 75%, 80% and 65%, respectively, while the removal efficiencies of TN, OP, and COD were reached about 50% and larger. Both of the two systems show high efficiencies for nutrient removal. In the comparison between the two kinds of HRT¡¦s, the HRT controlled at 3 days presented higher removal efficiencies than that controlled at 7 days.

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Otto Stein. Includes bibliographical references (leaves 41-43).

Thesis (Ph.D.)--Baylor University, 2006. / In abstracts "- and 2" are superscript. In abstracts "3 and 2" are subscript. Includes bibliographical references (p. 105-114).

Thesis (M. Sc.)--University of Western Sydney, Hawkesbury, 1991. / Includes bibliographical references.

Thesis (M. Env. Sc.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1999. / Includes bibliographical references (leaves 104-110).

Thesis (M.Sc.). / Written for the Dept. of Bioresource Engineering. Title from title page of PDF (viewed 2008/05/14). Includes bibliographical references.