A PhD thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering. Johannesburg / This study involves the investigation of the paint wastewater treatment using inorganic coagulants such as FeCl3, Fe2(SO4)3, AlCl3 and Al2(SO4)3 in a jar test during rapid and slow mixing for 250 and 100 rpm respectively, settled the samples, measure the pH and turbidity. The pH, turbidity and area covered by the flocs were used as measurements in this study to determine the quality of treated paint wastewater. In the first experiment, 200 mL sample of 169.2 g of paint wastewater dissolved in 1L of potable water was poured into six 500 mL glass beakers sample dosed with FeCl3 only, combined FeCl3 and Ca(OH)2 or Mg(OH)2 as well as FeCl3-Ca(OH)2 and FeCl3-Mg(OH)2 polymers respectively, run through a jar test with rapid and slow mixing. The supernatant was extracted after 1 hour settling to measure the pH and turbidity. The observations showed that combined FeCl3 and Mg(OH)2 as well as FeCl3-Mg(OH)2 polymers yielded identical and slightly higher turbidity removal than combined FeCl3 and Ca(OH)2 and FeCl3-Ca(OH)2 polymers. Another batch of experiments was carried out using the same metal salts with Ca(OH)2 and Mg(OH)2 respectively for pH adjustment. The samples were treated in a jar test using various dosing patterns such as dosages, dosing prior or during mixing, combined dosages interchangeably, retention time. A third batch of experiments was carried out by dosing synthetic polymers of FeCl2-Ca(OH)2 and FeCl2-Mg(OH)2 respectively using similar dosing patterns. The results obtained in first set of experiments, were Fe3+ and Al3+ salts were added in paint wastewater showed that the changing pH correlates with turbidity removal. It was also observed that dosing prior or during mixing do not play any significant role in wastewater treatment. Another observation showed that flocculation of the paint wastewater dosed with FeCl2-Ca(OH)2 or FeCl2-Mg(OH)2 polymers do not show correlation between the pH and turbidity, which indicates that the pH is not an indicator of turbidity removal in a more alkaline solutions such as paint wastewater. A second study was carried out using the same paint wastewater samples (200 mL) and samples dosed with Fe3+ and Al3+ salts treated in a jar test and immediately two drops of supernatant were placed on a microscope slide and view it under a microscope connected to a camera, images were captured after 1, 60 and 90 minutes respectively (Exp A). Samples were prepared from the original paint wastewater and the standard solution of Fe3+ and Al3+ in a small scale using identical metal salt/paint wastewater volume ratios as above. Two drops from the paint wastewater and metal salt solution were place on a microscope slide and images were captured as above using 1, 60 and 90 minutes respectively (Exp B). All the visuals were printed and the visuals obtained in Exp A were compared with their corresponding visuals in Exp B in accordance with time. The results obtained showed that the percentage area covered by flocs treated in a jar test (Exp A) correlates linearly with the percentage area covered by the flocs from a microscope slide (Exp B). The results obtained using this technique also confirm that the reaction between the drops of a sample and the drops of coagulant produces well-developed solid hydrolysis species. A third study was carried out by pouring 200 mL of the same paint wastewater samples into six 500 mL glass beakers and with Fe3+ and Al3+ salts as above, run through a jar test during 30, 45 and 60 seconds rapid mixing (250 rpm) only for 2 minutes respectively. The samples settled for 1 hour, and then pH and turbidity were measured. Another experiment was carried out using the similar method as above with samples run through a jar test at 250 rpm during 30, 45 and 60 seconds rapid mixing (250 rpm) for 2 minutes followed by slow mixing (100 rpm) for 10 minutes (combined rapid and slow mixing). The samples settled for 1 hour, and then pH and turbidity were measured. The results obtained from the jar tests (comparison between flocculation during rapid mixing only and combined rapid and slow mixing) showed that the pH in the samples with rapid mixing shows an insignificant change compared to their corresponding samples with combined rapid and slow mixing; turbidity in the samples with 30, 45 and 60 seconds rapid mixing showed that most of the flocs are formed within 30 seconds. There is a correlation between the pH and turbidity when paint wastewater is dosed with Fe3+ or Al3+ metal ions in their respective metal salts without pH adjustment. The Fe3+ and Al3+ of the same concentration yield a similar pH and turbidity trend.

University of Macau / Faculty of Science and Technology. / Department of Civil and Environmental Engineering

Digitized by Kansas Correctional Industries

No description available.

The prevalence of the cyanobacterial metabolites: MIB, geosmin and microcystin in drinking water is a major concern to the water industry as these metabolites can compromise the quality of drinking water. Consequently, effective removal of these metabolites from drinking water is paramount. The combination of ozone (O3) and granular activated carbon (GAC) has been shown to be effective for the removal of these metabolites from drinking water. In this study, the ozonation of MIB and geosmin was affected by the character of natural organic material (NOM). In particular, NOM containing compounds of high UV absorbing properties and high molecular weight (MW) resulted in greater destruction of MIB and geosmin due to the formation of hydroxyl (OH) radicals. In addition, alkalinity also affected the ozonation process, with waters containing higher alkalinity resulting in decreased destruction of MIB and geosmin. Laboratory scale minicolumn experiments, coupled with the homogenous surface diffusion model (HSDM), were found to be ineffective in predicting the GAC breakthrough behaviour of MIB and microcystin at two different pilot plants. This can be attributed to the biological degradation of the metabolites at the pilot plants which cannot be modelled by the HSDM. In addition, the volume of GAC used in the minicolumn experiments may not have been appropriate for the predictions, rather, larger laboratory scale columns were found to be more applicable in mimicking pilot plant results. Microcystins were shown to be readily degraded by the bacteria attached to the GAC. Furthermore, the lag period prior to the onset of degradation, which is indicative of most biological degradation studies, was effectively eliminated and in one instance abated. This finding suggests that biological filtration of microcystin is practically feasible especially since the occurrence of microcystins in water supplies is seasonal. This study expands on previous research in the area of O3 and GAC for the treatment of MIB, geosmin and microcystin. With the imminent increase of the use of O3 and GAC in Australian water treatment plants (WTPs), this study provides valuable information for the use of these processes both alone and in combination, particularly since minimal research in this area has been conducted in Australia. / thesis (PhDAppliedScience)--University of South Australia, 2004.

Electrocoagulation is an empirical (and largely heuristic) water treatment technology that has had many different applications over the last century. It has proven its viability by removing a wide range of pollutants. The approach to reactor design has been haphazard, however, with little or no reference to previous designs or underlying principles. This thesis reviewed these reactor designs, identifying key commonalities and synthesising a new design hierarchy, summarised by three main decisions: 1. Batch or continuous operation; 2. Coagulation only or coagulation plus flotation reactors, and; 3. Associated separation process if required. This design decision hierarchy thereby provides a consistent basis for future electrocoagulation reactor designs. Electrochemistry, coagulation, and flotation are identified as the key foundation sciences for electrocoagulation, and the relevant mechanisms (and their interactions) are extracted and applied in an electrocoagulation context. This innovative approach was applied to a 7 L batch electrocoagulation reactor treating clay-polluted water. Structured macroscopic experiments identified current (density), time, and mixing as the key operating parameters for electrocoagulation. A dynamic mass balance was conducted over the batch reactor, for the first time, thereby enabling the extraction of a concentration profile. For this batch system, three operating stages were then identifiable: lag, reactive, and stable stages. Each stage was systematically investigated (in contrast to the previous ad hoc approach) with reference to each of the foundation sciences and the key parameters of current and time. Electrochemical behaviour characterised both coagulant and bubble generation. Polarisation experiments were used to determine the rate-limiting step at each electrode�s surface. Consequently the appropriate Tafel parameters were extracted and hence the cell potential. At low currents both electrodes (anode and cathode) operated in the charge-transfer region. As the current increased, the mechanism shifted towards the diffusion-limited region, which increased the required potential. Polarisation experiments also define the operating potential at each electrode thereby enabling aluminium�s dissolution behaviour to be thermodynamically characterised on potential-pH (Pourbaix) diagrams. Active and passive regions were defined and hence the aluminium�s behaviour in an aqueous environment can now be predicted for electrocoagulation. Novel and detailed solution chemistry modelling of the metastable and stable aluminium species revealed the importance of oligomer formation and their rates in electrocoagulation. In particular, formation of the positively trimeric aluminium species increased solution pH (to pH 10.6), beyond the experimentally observed operable pH of 9. Thereby signifying the importance of the formation kinetics to the trimer as the active coagulant specie in electrocoagulation. Further leading insights to the changing coagulation mechanism in electrocoagulation were possible by comparison and contrast with the conventional coagulation method of alum dosing. Initially in the lag stage, little aggregation is observed until the coagulant concentration reaches a critical level. Simultaneously, the measured zeta potential increases with coagulant addition and the isoelectric point is attained in the reactive stage. Here a sorption coagulation mechanism is postulated; probably charge neutralisation, that quickly aggregates pollutant particles forming open structured aggregates as indicated by the low fractal dimension. As time progresses, pollutant concentration decreases and aluminium addition continues hence aluminium hydroxide/oxide precipitates. The bubbles gently sweep the precipitate through the solution, resulting in coagulation by an enmeshment mechanism (sweep coagulation). Consequently compact aggregates are formed, indicating by the high fractal dimension. Flotation is an inherent aspect of the batch electrocoagulation reactor via the production of electrolytic gases. In the reactor, pollutant separation occurs in situ, either by flotation or settling. From the concentration profiles extracted, original kinetic expressions were formulated to quantify these competing removal processes. As current increases, both settling and flotation rate constants increased due to the additional coagulant generation. This faster removal was offset by a decrease in the coagulant efficiency. Consequently a trade-off exists between removal time and coagulant efficiency that can be evaluated economically. A conceptual framework of electrocoagulation is developed from the synthesis of the systematic study to enable a priori prediction. This framework creates predictability for electrocoagulation, which is innovative and original for the technology. Predictability provides insights to knowledge transfer (between batch and continuous), efficient coagulant and separation path, to name just a few examples. This predictability demystifies electrocoagulation by providing a powerful design tool for the future development of scaleable, industrial electrocoagulation water treatment design and operation process.

International disputes over access to water resources can act as a catalyst for conflict or cooperation amongst nations. In the case of Israel and the occupied West Bank, water conflict further exacerbates preexisting political tension, and yet a peaceful and equitable solution between these countries could spark further negotiation. Within this context, the Palestinian Hydrology Group conducted a water questionnaire amongst Palestinian households in the occupied West Bank in 2001. The aim of the PHG’s survey was to investigate which water management system would be the most suitable in terms of equity, cost-recovery, and long-term development of the resource. Ultimately the water pricing system that was recommended was an increasing block-tariff system, which prioritizes the delivery of necessary amounts of water used for basic needs amongst all users before further allocating water to other uses. However, most of the work conducted by the PHG was qualitative and based entirely on descriptive statistics. Analysis regarding the relationships between water pricing, water consumption, and water needs, and how these relationships change over different scales, was not present in the final report. The purpose of this thesis to continue the research conducted by the PHG by analyzing the water questionnaire database as a means to further advise and direct water services within the occupied West Bank. In order to discern relationships between seasonal patterns of water pricing and consumption, an in-depth analysis of that data was conducted. In addition, perceived water needs were also examined. This analysis was performed at a variety of scales, including amongst districts, average monthly income levels, and connection/non-connection to a water network. Results indicate that some districts in the occupied West Bank are comparatively under-serviced. The economically poor district of Jenin seems to be in greatest need of stabilized and equitable water resources, followed by Hebron, Nablus and Ramallah. It was also observed that those within lower income brackets bear a disproportionate share of pricing fluctuations and, not surprisingly, low consumption levels. Connection/non-connection to a water network indicates that not only is consumption amongst non-connected households significantly low, but also that the difference between perceived water needs and water consumption is much greater than amongst connected households. This thesis supports the PHG’s recommendation for an increasing block-tariff system, since regression analysis indicates inequitable distribution and pricing amongst districts and income levels.

Annual rainfall of Taiwan was 2.6 times larger than the average of the world, but the average allocation of rainfall per square meter of everyone in Taiwan was less than the fifth of the average of the world because of severe rainfall and dense population. When the government set into action of water conservation, education and guidance were the most important tools, however, the arduous challenge of the government was how to turn the slogan into the motion. This paper aimed to explore IMC (Integrated Marketing Communication, IMC) applied to public policies of the government and influenced an attitude of water consumption of consumer by literature discussion. Besides A Case Study of Taiwan Water Corporation, this paper analyzed and explored the influence of de-marketing strategies of the government on the south of Taiwan by questionnaire survey. The samples for the quantitative research were the water users from Kaohsiung City and Kaohsiung County , and there were 351 valid data finally. The conclusions were that each aspect of IMC was related to the water conservation, but only ¡§Preference Assessment¡¨ and ¡§Satisfication Assessment¡¨ had predictability. And the bettet preference and satisfication of the water conservation measures of the government consumers had, the better coordinate degree of water consumption.

No description available.

Thesis (M.S.)--University of Nevada, Reno, 2008. / "December 2008." Includes bibliographical references (leaves 66-67). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.