M.Sc. (Chemistry) / In this study the stability as well as the fate and behavior of ZnO engineered nanoparticles (ENPs) in municipal wastewater systems were investigated. The first part of the study examined the influence of pH and ionic strength on the stability of ZnO ENPs in domestic wastewater to elucidate the dynamic changes on the ENPs physicochemical characteristics (e.g. aggregation or dissolution). The ZnO ENPs obtained commercially were characterized using transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), dynamic light scattering (DLS), BET surface area determination, and energy dispersive X-ray spectrometry (EDS). Results derived from inductively coupled plasma optical emission spectrometry (ICP-OES) for zinc analysis indicated a decrease on the released zinc concentration from wastewater as the pH and ionic strength increased. Conversely, an increase on zinc concentration from the sludge was observed. The findings suggest the removal of ZnO ENPs from the influent wastewater as the sludge settled out, and the removal efficiency was directly proportional to ionic strength and pH. In addition, the ZnO ENPs suspension in the wastewater was used to monitor the particle size distribution using the dynamic light scattering analysis (DLS). The formation of agglomerates was observed which the TEM and EDS analysis confirmed to be ZnO aggregates. The distribution of zinc in the sludge was investigated using XRD analysis and the findings indicated partial sedimentation of ZnO ENPs as the sludge settled out. The second part of the study assessed the fate and behavior of ZnO ENPs in wastewater treatment systems. This study was carried out in a simulated activated sludge wastewater treatment plant (AS WWTP), constructed in accordance to the Organization for Economic Co-operation and Development (OECD 303 A) guidelines. Results from the ICP-OES analysis for zinc indicated 50 – 200 μgL-1 and about 3 000 mgkg-1 were released into the effluent and sludge, respectively, after spiking the influent wastewater with 5 mgL-1 ZnO ENPs. Moreover, we noted that increasing the ZnO ENPs concentration up to 20 mgL-1 resulted in a linear increase in the zinc releases into effluent wastewater. However, the increase was insignificant in comparison to the zinc found in the control unit. Therefore, the findings indicated that ZnO ENPs had stronger affinity for the suspended bio-solids during wastewater treatment, and postulated that the ENPs removal from the influent wastewater was due to bio-sorption, and bio-solid settling mechanisms. These were confirmed by results from XRD and diffuse reflectance spectroscopy (DRS) analysis of the sludge as they showed the presence of ZnO in the sludge. The dissolved organic carbon (DOC) and chemical oxygen demand (COD) were concurrently monitored during the ENPs exposure studies to indirectly assess the ZnO ENPs impact to the bacterial degradation of the organic matter. An average of 43 and 91 % for DOC and COD removal efficiencies, respectively, were observed throughout the study. Overall, from results obtained indicated the suitability of the OECD 303 A method to assess the fate and behavior of ZnO ENPs in WWTPs. Secondly, in light of low concentrations of ZnO ENPs found in the treated effluent due to their removal with the waste activated sludge (WAS), suggest low likelihood of ZnO ENPs release and dispersion into the aquatic systems from WWTPs as point sources. Finally, the elevated concentrations of ZnO ENPs in the sludge therefore necessitates additional treatment steps to ensure mitigation of possible dispersion of ENPs from various disposal mechanisms such as landfilling, incineration, and agricultural applications.

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This research involves design and implementation of computer program for simulation of a wastewater treatment plant. The program has the capability to be interfaced with an existing analog wastewater plant process flow training board which is equipped with meter readouts of key process variables and adjustable control valves. It is planned that the total system simulator could be used to train wastewater treatment plant operators to afford them hands-on dynamic experience in plant operations. The wastewater treatment process modeled is the activated sludge process. Beginning with the known plant design stead-state equations for this particular process an algorithm was developed to simulate the treatment process through probable system dynamics. All assumptions are presented in a logical manner and used to develop the necessary transient equations. The success of this project demonstrates that a simulation program which emulates a waste treatment process is possible; however, it is suggested that further research is needed to provide deeper insight into variable changes during system transients.

The report describes an alternative to the use of septic tanks for invidual dwellings. The major problems confronting the larger wastewater treatment plants (0.012 to 10 million gallons per day) in central Florida are also discussed. Solutions in this report are for individual and multi-unit dwelling treatment systems (to 0.06 MGD). these units can provide 90% biochemical oxygen demand (BOD) and suspended solids (SS) removal in accord with new state and county regulations. A comparison of the large versus the small plants reveals that small innovative plants, though more expensive, are more environmentally sound than the poorly operated large facilities. Flexibility of modularized (using multiple small plant equipment) wastewater systems appear to be a major advantage in expanding areas. finally, proper control of individually owned and operated units is discussed with some practical solutions offered.

The basic objectives of this study were to determine: (1) the extent of water pollution contributed by our communities in the form of municipal and industrial wastes, (2) an investigation of the extent of use, performance characteristics, and costs or the sewage lagoon, (3) the planning aspects of the sewage lagoon, (4) the extent of anti-pollution law enforcement, and (5) the existing financial aid available to communities tor the construction of' sewage lagoons. The findings of this study indicate that: 1. The extensive contribution to the water pollution problem by municipalities and industry is serious. The projection of future water use based upon present standards of use and recovery indicates a very serious water problem in the near future. A need exists for an inexpensive method or sewage treatment. 2. Sewage lagoons are relatively new but are widely used. They have proved to be relatively inexpensive and are achieving a high standard of purification. 3. Possible secondary benefits resulting from the use of sewage lagoons may prove to be of substantial value to municipalities in terms of efficient land use and the preservation of open land for alternate future uses. 4. The enforcement of the existing anti-pollution laws have been ineffectively enforced; however, new emphasis is being placed upon legal proceedings I rather than the voluntary compliance that has been practiced in the past. 5. With proper planning, a community can conceivably use several governmental programs for financial assistance both in grants-in-aid and long term loans for the construction or a sewage lagoon. / Master of Science

Research was undertaken in order to simulate and optimize an Aquatair Model P-3 package sewage treatment plant for which operating data from the National Sanitation Foundation was available. The treatment plant consists essentially of a plastic medium trickling filter mounted overtop of a complete-mix activated sludge (CMAS) tank; the unit also has a primary sludge holding tank and a secondary clarifier. From consideration of reaction kinetics, reactor type, and geometry, a mechanistic model was developed to explain the phenomena of substrate removal in the Aquatair Model P-3. The two-factor SIMPLEX optimization procedure was used to determine the best set of biological reaction constants K1 and K2 which would characterize the substrate removal behavior of the Aquatair biological oxidation tower and recirculation chamber, respectively, based on actual plant data. Once the behavior of the plant was accurately simulated, cost functions were developed in order to relate the various design variables to cost. An n-factor PERPLEX optimization routine was then used to optimize the various plant variables for a given flow, organic load, and efficiency. PERPLEX, a modification of the Box COMPLEX method, was shown to be a useful tool for evaluating the factor space defined by a set of mathematical assumptions. The cost benefit of aerobic digestion occurring in the Aquatair bio-oxidation tower was predicted by the model and confirmed by nitrification data and sludge production calculations. / Master of Science

no abstract provided by author / Master of Science

The current Environmental Protection Agency (EPA) method utilized for analysis of trace organic chemicals and heavy metals leached from solid waste is the Extraction Procedure (EP) Toxicity Test. Because of various operational problems and limitations of the EP, the EPA has developed and plans to implement the Toxicity Characteristic Leaching Procedure (TCLP), which is an expanded version of the EP capable of analyzing more organic components, in particular volatile organic chemicals. The purpose of this research was to investigate and compare the ability of the EP and TCLP test procedures to quantitatively recover added surrogate standards (1,2-dibromoethane, bromoform, 1â chlorooctane, fusarex, heptachlor, and DDT) and also qualitatively identify and evaluate unknown trace organic chemicals in domestic wastewater sludges. In order to meet the research objectives established, three small (approximately 1 MGD or less) municipal wastewater treatment plants that land applied their sludges were analyzed. / Master of Science

Master of Science