Phosphorus and nitrogen in waste water from sewerage systems contribute to excessive nutrient enrichment of surface waters, presenting a threat to nature conservation, domestic and industrial water supplies, and recreation. The general objective of this research was to investigate phosphate and ammonium removal from waste water by constructed wetland systems (CWS), which are increasingly being used for low-cost water treatment. Phosphate (P) adsorption capacity and other properties of potential CWS substrate materials (bauxite, shale, burnt oil shale, limestone, zeolite, light expanded clay aggregates (LECA) and fly ash) were investigated. Fly ash and shale had the highest P adsorption values, which were significantly correlated with porosity and hydraulic conductivity. Longer - term experiments with shale and bauxite gave maximum P uptake values of 730 and 355 mg P kg- I, respectively. Phragmites australis (common reed) seedlings grew satisfactorily in shale, bauxite, LECA and fly ash. Shale was selected as the most suitable substrate, and used in a pilot-scale CWS in plastic tanks in a greenhouse, with and without P. australis, at two input nutrient concentrations and a loading rate of 0.02 m3 m-2 d-1. Both planted and unplanted systems removed 98 - I 00% of P from a synthetic sewage over ll months. Removal of ammonium N was also complete in the planted tanks, but only 40 - 75% was removed in the unplanted ones. Corresponding nitrate N removal was 85 - 95% and 45 - 75%. The systems performed as well at high as at low concentration for both phosphate and ammonium. The variations in P and N removal could not be attributed to differences in pH, Eh and temperature, which did not differ significantly between planted and unplanted tanks. During the experiment, P and N concentrations were determined at 3 depths and 4 positions along the length of the tanks. H2P04- - P and NH/ - N concentrations were low ( < I. 0 g m-3) at all locations in the planted systems, whereas the P concentrations were sometimes twice as high in the unplanted ones. NH4 + -N in the unplanted systems was relatively high (l 0 - 30 g m"3) throughout the experiment. N03--N concentrations were very low by comparison. P. precipitation on shale and P. australis root and rhizome surfaces was examined by X-ray fluorescence analysis, and by chemical extraction with ammonium acetate, 0.1 M HCI and 2%> citric acid. This showed that P, Fe and Al had precipitated on all these surfaces. However. it was not possible to quantify the surface deposits, and further research is necessary. The hydraulic residence time. flow characteristics and permeability of the shale was investigated by a bromide tracer. The tracer breakthrough curves showed a similar pattern in all tanks, with ca 66% of the flow occurring through the bottom zone. However, the actual hydraulic residence time (6 days) was slightly higher than the theoretical one Although there was a significant difference (p < 0.02) between the distribution of flow in planted and unplanted tanks. there was no reduction in the reactive pore volume observed in any of the tanks. This confirmed that shale has good permeability properties. Monitoring of the full-scale systems was carried out during June - September 1995. Although P removal in a planted bed was between 50-75%, the overall performance of the full-scale systems was disappointing, especially for ammonium removal. This was attributed to high loading rates, visibly non-uniform flow and clogged gabions. A bromide tracer study carried out on these systems confirmed the short hydraulic retention times and heterogeneous flow mechanisms in both the unplanted and planted systems. Results obtained from the pilot scale study do not necessarily provide a quantitative prediction of the performance of larger-scale systems. However, the potential value of a shale-based system has been demonstrated, and this opens a new direction in the design of CWS; most systems built to date in the UK use gravel as a substrate. Shale has proved to have superior properties for P removal and is cheap and readily available in Scotland. Its application as a substrate in a full-scale system remains a subject for further investigation.

In this study, we discussed the treatment efficiencies of different types of industrial wastewaters by several lab-scale constructed wetlands. The purpose this study is to decrease certain pollutants in the effluents from the industrial wastewaters treatment plants investivate the feasibility of water reuse and recovering. We divided the experiment into two stages, and three types of industry wastewaters ,including paper, steel and refiring, are in this study. In the first stage, the treatment efficiencies of controlling the flow rate at 6 mL/min higher that those controlling at 4 mL/min. However, sinece the amounts of phosphur were smalls in the industrial weatewaters, the removal efficiencies are not high enough. Thus, we added sewage and phousphate into the wastewaters in second stage of experiments with the best ratio of N : P of 4 : 1. The performance work of these two stage experiments did help to clean the nutrient of nitrogenous in the industrial wastewater, especially the refining industry comparing to the other two types of industries.

Thesis (M. S. - Soil, Water and Environmental Science)--University of Arizona, 2001. / Includes bibliographical references (leaves 48-50).

Thesis (M. Sc.) (Hons)--University of Western Sydney, Hawkesbury, 1994.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xii, 191 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references (p. 117-119).

Report (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 87-91). Also available via the Internet.

Treating elevated nutrients, suspended solids, oxygen demanding materials, heavy metals and chemical fertilizers and pesticides in agricultural wastewaters is necessary to protect surface and ground waters. Constructed wetlands (CWs) are an increasingly important technology to remediate wastewaters and reduce negative impacts on water quality in agricultural settings. Treatment of high strength effluents typical of agricultural operations results in the production of methane (CH4), a potent greenhouse trace gas. The objective of this study was to evaluate CH4 emissions from two subsurface flow (SSF) CWs (223 m2 each) treating dairy wastewater. The CWs were implemented at the University of Vermont Paul Miller Dairy Farm in 2003 as an alternative nutrient management approach for treating mixed dairy farm effluent (barnyard runoff and milk parlor waste) in a cold, northern climate. In 2006, static collars were installed throughout the inlet, mid and outlet zones of two CWs (aerated (CW1) and a non-aerated (CW2)) connected in-series, and gas samples were collected via non-steady state chambers (19.75 L) over a nine-month period (Feb-Oct 2007). Methane flux densities were variable throughout the nine-month study period, ranging from 0.026 to 339 and 0.008 to 165 mg m-2 h-1 in CW1 and CW2, respectively. The average daily CH4 flux of CW1 and CW2 were 1475 and 552 mg m-2 d-1, respectively. Average CH4 flux of CW1 was nearly threefold greater than that of CW2 (p = .0387) across all three seasons. The in-series design may have confounded differences in CH4 flux between CWs by limiting differences in dissolved oxygen and by accentuating differences in carbon loading. Methane flux densities revealed strong spatial and seasonal variation within CWs. Emissions generally decreased from inlet to outlet in both CWs. Average CW1 CH4 flux of the inlet zone was nearly threefold greater than mid zone and over tenfold greater than flux at the outlet, while fluxes for CW2 zones were not statistically different. Methane flux of CW1 was nearly fifteen fold greater than CW2 during the fall, representing the only season during which flux was statistically different (p = .0082) between CWs. Fluxes differed significantly between seasons for both CW1 (p = .0034) and CW2 (p = .0002). CH4 emissions were greatest during the spring season in both CWs, attributed to a consistently high water table observed during this season. Vegetation was excluded from chambers during GHG monitoring, and considering that the presence of vascular plants is an important factor influencing CH4 flux, the potential CH4 emissions reported in our study could be greatly underestimated. However, our reported average CH4 fluxes are comparable to published data from SSF dairy treatment CWs. We estimate average and maximum daily emissions from the entire CW system (892 m2) at approximately 1.11 and 6.33 kg CH4 d-1, respectively, yielding an annual average and maximum flux of 8.51 and 48.5 MtCO2-e y-1, respectively.

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

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

Thesis (M.S.)--Ohio University, November, 1997. / Title from PDF t.p.