published_or_final_version / Civil Engineering / Master / Master of Philosophy

Use-oriented benefits and treatment cost analysis have been incorporated into a water quality index to derive economically optimized pollutant concentrations for use in the development of waste water treatment programs. This multi-criteria water quality index can be used in decision-making at federal and local governmental levels. Five major pollutants (coliforms, nitrogen, phosphorus, suspended solids, and detergent) were considered in the treatment of municipal wastewater. With each higher level of improvement, the treatment costs increase proportionally, but the benefits associated with the reuse of this treated wastewater also increase in all cases except that of nutrient removal for agricultural use. Listed in descending order of their general utility, possible uses of reclaimed water include water supply, recreation, irrigation, industrial use, waste disposal, transportation, and commercial fishery. The optimal concentration of a pollutant was defined as that point at which the marginal costs of its removal equal the marginal benefits thereby obtained. The optimum net benefits associated with each kind of reclamation are derived simultaneously. The multicriteria water quality index is a combination of the maximum net benefits and the water quality index of the optimal individual concentrations. Walski and Parker's water quality index was used in rating water quality. This methodology was applied to the Tucson region for the expediency of acquiring data. Possible uses considered for the reclaimed municipal wastewater included agricultural irrigation and recreational lakes in the Tucson metropolitan area. Results from this study indicate that the multi-criteria water quality index is zero dollars, or (NB = $1.83•10⁶, WQI = 0). Similar evaluations for other cities, made in the same way, would permit ranking of this index. This ranking would be useful for making decisions concerning the allocation of regional funds for treating municipal wastewater. This approach could also be used on a local level for determining optimal concentrations of pollutants and for optimal allocation of the treated water.

Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on February 2, 2010. Major professor: Michael M. Cirovic, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Electrical Engineering." "November 2009." Includes bibliographical references (p. 28).

Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Science and Engineering. Includes bibliographical references (leaves 148-163)

Although Texas is a water reclamation leader in the country for quantity of water reclaimed, it falls behind both California and Florida in residential applications. The concept of residential reuse has some barriers to overcome prior to implementation on a broad scale in Texas. The two case studies, St. Petersburg, Florida, and the El Dorado Irrigation District of El Dorado County, California, describe extensive reuse programs in response not only to impending water shortages but also to effluent disposal limitation requirements. Major factors that limit residential reuse in Texas include the following: cost, expediency and negative public perception. Two other considerations exist when determining the feasibility of implementing residential reuse: income level and irrigation needs. Most of the successful reuse programs examined were for higher income areas. Also, irrigation expectations and needs of the residences play a major factor in the success of the program. In arid environments planted with drought-tolerant plants, landscape irrigation becomes less of a priority. Further limitations that specifically affect Texas’ expanding its water reclamation programs include the legal issues of existing water rights and direct versus indirect reuse. / text

A comprehensive Ultrapure Water (UPW) simulator program has been developed to model each unit process in UPW systems, including the entire dynamic system in real time. The program estimates the removal efficiencies for contaminants generated in semiconductor processes and in municipal water supplies. Calculations are performed using flow balance and concentration profile determinations at each unit process throughout the system. Simulator validation occurred using existing industrial facilities. Spent rinsewater (SRW) recycling in semiconductor facilities has been shown to provide significant UPW quality improvements. Contrary to many perceptions, this recycling is not a compromise to the quality, but an improvement. Benefits to the cost, reliability, and environmental improvements have also been identified. Processing risks have also been identified as the use of UPW with even minute quantities of contaminants, in particular the organic contaminants, could cause process problems. The simulator has been shown to be quite capable of predicting the impact on UPW quality due to excursions in SRW quality from semiconductor processes. Photolithography is a primary semiconductor process where organic photoresist is removed from wafers with corrosive chemistries. SRW is contaminated with both organic residues and corrosive chemicals. Ozonated UPW has recently become an alternative chemical for photoresist removal. A single-wafer tool was fabricated out of quartz designed for various processes. With direct observation of the wafer possible. Ultraviolet light experiments were also performed, directing light through the quartz, process solution, and onto the wafer. Experimental procedures were developed to study the effects of turbulence, wafer pretreatment, in-situ process treatments, and vibration on the kinetics and mechanism of photoresist removal by ozonated UPW. Data was obtained to determine which oxidation pathway was dominant; direct ozone, or indirect oxidation through radical formation. Intermediate products were determined using Fourier Transform Infrared Spectroscopy. Two distinct mechanisms were observed: film dissolution via a uniform sheeting method, and a non-uniform vapor-phase bubble mechanism where film dissolution occurred underneath the bubble. Models were developed that describe the film removal under both mechanisms. The uniform sheeting model describes typical process conditions in current tools. This model was validated and found in good agreement with experimental data.

Project Completion Report, OWRT Project No. A-050-ARIZ. / Agreement No. 14-31-0001-5003 / Project Dates: July 1974 - June 1976. / The work upon which this publication was based was supported in part by funds provided by the Office of Water Research and Technology (A-050-ARIZ), U.S. Department of the Interior, Washington, D.C., as authorized by the Water Research and Development Act of 1978. / INTRODUCTION: The use of treated sewage effluent by the Buckeye Irrigation Company began with 800 acre -feet in 1962 and had increased to 40,000 a.f. by 1968. The effluent was diverted by the Buckeye Irrigation Company from the Gila River approximately seven miles below the City of Phoenix 91st Avenue treatment plant, as it became available at their diversion point. Natural streamflow, used in earlier years, had virtually stopped due to upstream development except in heavy runoff years such as 1941. The ground water in the district of the Buckeye Irrigation Company is relatively high in dissolved solids. The quality of the treated effluent is better. In 1971 the company signed a 40 -year contract with Phoenix to assure its use of 30,000 a.f. of effluent per year. The effluent is mixed with native ground water to bring the total water applied on the 18,000-acre district up to approximately 90,000 a.f. (Halpenny, 1973). The treated effluent use by the Buckeye Irrigation Company is the largest in the State of Arizona and one of the largest land applications of treated effluent in the United States. It is unique in that it is being utilized by an irrigation district. Most other uses have been by city operated farms or private farms under a single ownership. In spite of its uniqueness the effects of effluent use by the Buckeye Irrigation District had not, prior to this research, been well documented. This documentation was made in order to improve the general knowledge needed to extend this type of use to other areas in the state and nation. "Widespread consideration and utilization of land application cannot be made until such time as adequate information concerning the technique involved is made available. The experience gained by those who have successfully utilized this wastewater management should be used... specific evaluation of established systems in the various climatic zones would appear to be more fruitful than new research installations for determining long term effects on soils, vegetation, ground water and the indigenous ecology..." (Sullivan, et al., 1973). During the two year research period most of the initial objectives were achieved. The original specific objectives were: 1. To identify changes during an extended period of application of treated wastewater to irrigated fields in: a. irrigation practices b. cropping patterns c. fertilization practices d. crop yield response and quality e. quality of irrigation water, and f. soil properties. 2. To make a preliminary evaluation of the effects of the use of effluent on ground-water conditions. 3. To make a preliminary evaluation of changes in water costs and farm profits.

Project Completion Report, OWRR Project No. A-011-ARIZ / Agreement No. 1071 / Project Dates: July 1967 - June 1969. / Acknowledgment - The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Research Act of 1964. / The purpose of this investigation was to characterize salvageable water resources in the semi-arid Tucson basin and to evaluate appropriate treatment and control methods and management procedures for reuse of these salvageable waters. A preliminary inventory of salvageable water resources in the Tucson basin indicated a conservatively estimated annual total of 30,000 acre-feet available, as follows: municipal system effluents, 25,000 acre-feet; industrial cooling effluents, 1,000 acre-feet; urban runoff, 2,000 acre-feet; and industrial processing waters and other minor sources, 2,000 acre-feet per year. The City water utility has ample information on hand regarding quality of municipal effluents; data collected during this study are sufficient to define representative quality of industrial effluents; and presently developed processes evidently are adequate for the control and treatment of salvageable waters. However, little was known of the quality of urban runoff in this semi-arid environment, and efforts were directed toward exploratory sampling and analysis as indicators of potential problem areas in runoff quality. A ground-water recharge investigation at the Rillito Creek recharge site near Tucson produced a mathematical model which can be used to represent fluctuations of ground-water levels resulting from line-source recharge. Findings can be applied to alternative management schemes in the utilization or storage of salvaged waters. Initial formulation of management alternatives by examination of local salvaged-water subsystems appeared not to require elegant mathematical solution but rather an improved system framework defining community objectives and criteria for salvaged water allocation.

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