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Allelopathy between algae is an ecological strategy that can facilitate or inhibit the occurrence of algal blooms. The role of allelopathic effects of marine microalgae Cylindrotheca closterium in other phytoplankton population dynamics are still limited. In the current study, the effects of cell-free filtrates of diatom Cylindrotheca closterium on two common dinoflagellate s (Prorocentrum donghaiense and Prorocentrum cordatum), a chrysophyceae (Isochrysis galbana) and a diatom (Chaetoceros curvisetus) were investigated within controlled laboratory experiments. It was observed that the growth of P. donghaiense was significantly suppressed and approximately 80% cells disappeared after 8-d exposure, while the other three algae was less sensitive. P. donghaiense was very sensitive to the exudates of C. closterium from the stationary phase by comparing various percentage (10, 30, 50, 70 and 100%) of filtrates. In addition, the allelopathic effects of extracellular compounds of C. closterium extracted by three different organic solvents (ethyl acetate, chloroform and petroleum ether) on P. donghaiense were explored by determining cell density, chlorophyll content and maximum photosystem II (PSII) quantum yield (F v /F m). It was found that the compounds extracted by ethyl acetate and chloroform appeared to exhibit less toxicity on P. donghaiense than that of petroleum ether. The present results indicated that the allelochemicals released by C. closterium might be concentrated effectively in the petroleum ether extraction phase, which provided a new perspective for controlling the red tides of P. donghaiense in the East China Sea by means of the ecological inhibitors extracted. • The effects of C. closterium filtrates on P. donghaiense , P. cordatum , I. galbana and C. curvisetus were investigated. • P. donghaiense was more sensitive to C. closterium filtrates than other three algae. • Extracellular compounds of C. closterium were concentrated effectively in petroleum ether extraction phase. • Petroleum ether extracts of C. closterium filtrates decreased the chlorophyll content and F v /F m of P. donghaiense. [ABSTRACT FROM AUTHOR]

The cheapest and also the most unsophisticated way to attain potable water from the brackish water normally available at the taps is reverse osmosis process. Today there is strong need for appropriately treated wastewater to protect the environment and to ensure that freshwater is available for all applications. Semi permeable membranes allow the passage of water or other small molecules through them but block the passage of large solute Molecules. As a consequence of osmosis, the concentration on the solution side decreases, because the amount of liquid on this side increases considerably over the passage of time. The study involved testing the performance of the Reverse Osmosis treatment plant. Conventional tests (temp, pH, TDS, turbidity, alkalinity, hardness, chlorine residual), and special tests (Fe, Mn, Zn, Cu, Pb, Cr, F, TOC) were conducted at different sampling locations within the distribution system, over a period of about eight months to evaluate the quality of drinking water. Samples were also collected after different stages of treatment from the main R.O. treatment plant, to determine the nature of treatment provided. The main objective of the research paper is to present fundamental model for brackish water desalination system for domestic purpose and their preliminary findings using prospective design. [ABSTRACT FROM AUTHOR]

Chemical processes often produce filtrate fractions with different chemical and physical properties. Typically filtrate fractions differ in the concentration of dissolved reaction products, reagents, and salts, but they may also differ in pH and temperature. In fractional filtrate configurations these fractions are used separately in earlier stages of the process in a way that ensures the best possible responses for the process.The purpose of this paper is to make a theoretical and systematic evaluation of the possibilities of different fractional filtrate configurations, i.e. fractional washing concepts, in connection with the improvement of wood pulp fibre bleaching. A washing model was used to simulate dissolved organic and residual chemical material balances in eight different process configurations. Each process configuration represents one single bleaching stage, consisting of a filter washer, a reactor, and a second filter washer in series.The results demonstrate that fractional filtrate configurations have the potential either to increase washing efficiency for dissolved reaction products, or to increase the recycling ability of the active process chemicals. However, these two goals are contradictory. The results encourage the creation of process machinery and configurations where different filtrate fractions are used differently for specific aims. The idea of fractional filtrate configuration should also be applicable to and beneficial for other branches of the chemical and mineral processing industries. [Copyright &y& Elsevier]