Section 5. Tables of Suggested Water Chemistry Targets

Consensus water chemistry controls for the six types of steam generator systems are presented in Tables 1 through 7. The tabulated information is categorized according to operating pressure ranges because this is the prime factor that dictates the type of internal water chemistry employed, the normal cycles of feedwater concentration, the silica volatility, and the carryover tendency. The difference between steam and water densities decreases with increasing pressure and temperature; therefore, separating the steam/water phases completely in the boiler drum becomes increasingly difficult to achieve. Since the tendency to carryover is greater at higher operating pressures, it is necessary to maintain lower boiler water contaminant concentrations to meet the same steam purity target.

The Effect of High Selenite and Selenate Concentrations on Ferric Oxyhydroxides Transformation under Alkaline Conditions

Iron-based nanomaterials have high technological impacts on various pro-environmental applications, including wastewater treatment using the co-precipitation method. The purpose of this research was to identify the changes of iron nanomaterial’s structure caused by the presence of selenium, a typical water contaminant, which might affect the removal when the iron co-precipitation method is used. Therefore, we have investigated the maturation of co-precipitated nanosized ferric oxyhydroxides under alkaline conditions and their thermal transformation into hematite in the presence of selenite and selenate with high concentrations. Since the association of selenium with precipitates surfaces has been proven to be weak, the mineralogy of the system was affected insignificantly, and the goethite was identified as an only ferric phase in all treatments. However, the morphology and the crystallinity of ferric oxyhydroxides was slightly altered. Selenium affected the structural order of precipitates, especially at the initial phase of co-precipitation. Still, the crystal integrity and homogeneity increased with time almost constantly, regardless of the treatment. The thermal transformation into well crystalized hematite was more pronounced in the presence of selenite, while selenate-treated and selenium-free samples indicated the presence of highly disordered fraction. This highlights that the aftermath of selenium release does not result in destabilization of ferric phases; however, since weak interactions of selenium are dominant at alkaline conditions with goethite’s surfaces, it still poses a high risk for the environment. The findings of this study should be applicable in waters affected by mining and metallurgical operations.

Spectroscopic and computational studies on a Dansyl based luminescent probe : Detection of water contaminant in hygroscopic deuterated solvents

: A Dansyl functionalized fluorescent probe (DFFP) has been intended, synthesized, and well-characterized (NMR, IR, Mass, SEM, SCXRD), capable of sensing trace amounts of water contaminant in hygroscopic deuterated solvents by providing color change under UV irradiation. A distinct bathochromic shift in emission spectra of probe DFFP, as well as the visual color change (Green to Yellow) under UV lamp, are the key evidence of the presence of water. To prove the potentiality of the probe while detecting the remnant water, we did some experimental studies along with exhaustive theoretical evaluation. DFT (Energy optimization and other calculations) helped in better understanding the sensing mechanism and the mode of interactions among probe-water-solvent. Total electron density mapped over Electrostatic Potential Surface and calculation of ESP charges helped in locating more electron-dense regions in the ground state. The involvement of TD-DFT studies helped in finding the possible electronic transitions and corresponding absorption bands. Moreover, the probe is capable of sensing ethanolic water vapour in the gaseous phase. Due to high fluorescence and being nontoxic to cells, probe DFFP could be used as a potential cell imaging dye. It has been employed to human cancer cell line (A549), and fluorescent confocal microscopic images were obtained.

Toxicity Assessment Of The Antimicrobial Triclocarban Using Sub-Lethal Behaviour And Reproduction Endpoints

Aquatic environments have long been used as disposal sites for domestic and industrial wastes, resulting in increasing chemical contamination, decreased water quality, and concern for ecosystem health and drinking water sources. This study utilized bioassays, the "golden standard" method to measure biological impact, to assess the toxicity of the widely found surface water contaminant, the antimicrobial triclocarban. Culturing protocols were implemented to provide healthy, age-synchronized organisms for bioassays. Behaviour and reproduction were demonstrated as useful endpoints while refining these methods using 4-chlorophenol and were successfully implemented in the toxicity assessment of triclocarban. While no sub-lethal behavioural impact was seen, 10.0 ppb triclocarban was found to delay reproduction in

Toxicity Assessment Of The Antimicrobial Triclocarban Using Sub-Lethal Behaviour And Reproduction Endpoints

Aquatic environments have long been used as disposal sites for domestic and industrial wastes, resulting in increasing chemical contamination, decreased water quality, and concern for ecosystem health and drinking water sources. This study utilized bioassays, the "golden standard" method to measure biological impact, to assess the toxicity of the widely found surface water contaminant, the antimicrobial triclocarban. Culturing protocols were implemented to provide healthy, age-synchronized organisms for bioassays. Behaviour and reproduction were demonstrated as useful endpoints while refining these methods using 4-chlorophenol and were successfully implemented in the toxicity assessment of triclocarban. While no sub-lethal behavioural impact was seen, 10.0 ppb triclocarban was found to delay reproduction in