No description available.

Fluoride concentrations in the Montreal Urban Community's untreated wastewater were analyzed in an attempt to evaluate their levels and seasonal variations. Continual hourly monitoring of the raw sewage, between June 1992 and May 1993. yielded average monthly fluoride concentrations between 0.072 mg/L and 1.984 mg/L, with an annual mean of 0.45 mg/L. Daily variations and frequency distributions showed a wider range of fluoride levels, with the maximum values possibly reaching as high as 4-fold the mean and well over 2 orders of magnitude higher than the minimum values. This suggests that significant massive point discharges occur in the sewer network. Daily monitoring of the precipitation showed that the mean fluoride concentration in liquid precipitation generally fluctuates between 0.030 mg/L and 0.741 mg/L, whereas the average fluoride specific mass in dry precipitation ranges between 0.096 kg/km$ sp2$ and 2.775 kg/km$ sp2$. Seasonal trends have been depicted for fluoride levels in both the raw wastewater and the precipitation. Groundwater sampling yielded an average fluoride concentration of 0.13 mg/L, and analysis of the melting salts used by the City revealed that these do not contain any fluoride. Data from the City's water treatment plants showed that the average fluoride concentration in their raw water is 0.20 mg/L. This is in contrast to the value of 0.13 mg/L used in the literature. Mass balance analyses have shown that the mass of fluoride resulting from infiltration and non-fluoridated waters, as well as that due to the domestic habits of the population constitute, among the identified sources, the major input of fluoride mass into the wastewater. Nevertheless, unidentified sources of fluoride, consisting essentially of industrial discharges, still account for the largest portion (${ approx50 %}$ of the total) and contribute, as an annual average, 375 kg/day.

The first objective of this research was to evaluate oxidation-reduction potential (ORP) as an indicator of effective iron removal in a biological process and to determine its relationship to dissolved oxygen (DO) and residual iron in the filtered water. Biological removal of iron to produce drinking water was established on one full-scale and two pilot-scale plants at two sites in France. Results show that below a minimum DO concentration of approximately 0.3 mg/L, residual iron concentration was related to ORP in the filtered water. Above the minimum DO requirement, ORP on the order of approximately 500 mV consistently reflected effective iron treatment and residual iron concentrations less than the French norm for potable water of 0.2 mg/L. / Secondly, two catalytic materials of filtration known as Ferrolite MC2 and Purolite were investigated on pilot-scale for their capacity to oxidize iron and manganese. Results showed that both materials eliminated dissolved iron to below detection levels regardless of DO or filtration rates up to 15 m/h (Ferrolite MC2) and 20 m/h (Purolite). During the trial period where no filter regeneration was carried out, the elimination of dissolved iron and dissolved manganese, respectively, were 100% and 77% for Purolite and 100% and 65% for Ferrolite MC2 for a raw water with 3.47 mg/L of dissolved iron and 0.317 of dissolved manganese. Purolite filtered a total volume of 1127 L or 137 L/kg of catalytic material and Ferrolite MC2 filtered a total of 1457 L or 217 L/kg.

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

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 40-42). Also available via the Internet.

Thesis (M.S.)--Ohio University, August, 1992. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, March, 1995. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, August, 1994. / Title from PDF t.p.

Thesis (M.S.)--University of Wisconsin. / eContent provider-neutral record in process. Description based on print version record. "References": p. 150.

This thesis deals with- various aspects of broadband horizontal solar irradiance. Quality control of measured datasets are identified and analysed. It was found that solar irradiance datasets may contain significant errors. These sources of errors were divided in two categories, the inherent instrument errors and operation related errors. Methods of assessing the quality of the datasets were evaluated and found to be unsatisfactory. A new method was hence developed to quality control the solar irradiance data. The quality control procedure consists of two tiers of tests. The first tests are physical tests that identify and remove data points that are physical impossibilities. The second tier tests consist of the creation of a mathematical envelope of acceptance in a sky clarity index domain. This envelope of acceptance is based on multiples of standard deviations of the weighted mean of clearness index to diffuse ratio. The available datasets in this study were thus quality controlled to remove any obvious outliers. Modelling the solar resource is an important tool for engineers and scientists. Such models have been developed since the second half of the 20th century. Some models rely on one or two meteorological parameters to estimate the solar irradiance, while other models are more complex and require a far greater number of points. Two of these models have been analysed and evaluated. The two models are all-sky, broadband solar irradiance models. The first model analysed is the Meteorological Radiation Model, or MRM. This model is in fact a sunshine based model, with atmospheric turbidity taken into account as well. The beam irradiance component was found to be acceptable given the number of inputs required by the model. Any extra parameters would increase the complexity of the model, without noticeable improvements. The regressions were modified to take into account sunshine fraction banding. However the diffuse irradiance was identified as one which had the potential III for improvement. Thus, in the present work an attempt has been made to develop improved models. The new model was found to be far superior to the older, original model, thus the name Improved Meteorological Radiation Model, IMRM. The second type of model investigated is the cloud based radiation model. This type of model is simple to use and rely on regressions between irradiation, solar altitude angle and the cloud cover. Careful analysis of the cloud distribution reveals certain flaws in the current regressions. New regressions were formulated and the result was a model superior to all its predecessors. Clear-sky modelling is important for maximum load calculations; however, there is no method of extracting with accuracy clear-sky broadband data. Clear-sky identification techniques were evaluated and a new method was devised. These new datasets were used on four clear-sky models, MRM, Page's Radiation Model, PRM, Yang's radiation model and Gueymard's REST2 model. It was found that using this new method of extracting extremeclear- sky data, the models performed better than when using quasi-clear-sky data. Solar radiation modelling is not an end by-itself, it must serve a purpose for engineers in their applications. Napier University has installed a 160m2 photovoltaic facility in 2003. A 27 -year solar radiation dataset was available for Edinburgh, to do feasibility calculations for the project; however this dataset contained gaps in the data. The cloud radiation model developed in this study was utilised to this end. In addition a complete life cycle analysis was performed on the project, and it was found that with an average efficiency at around 12%, the facility will payback its embodied energy in eight years, and based on a relatively conservative forecast of energy prices, the financial payback is set at under 100 years.