effluent from ro (reverse osmosis) systems during recovery gradually becomes concentrated and supersaturated with soluble salts such as calcium carbonate (caco3), calcium sulfate (caso4), barium sulfate (baso4) and silica (sio2). thus we were looking for procedures to prevent precipitation of soluble salts on the membrane surface and decrease membrane permeability. therefore, recovery could be ...

H activities have caused dramatic and unprecedented changes in the global chemical and physical environment, including well-documented increases in atmospheric carbon dioxide (CO2) concentration and mean annual temperature (Karl and Knight 1998, New et al. 2001, IPCC 2007). If greenhouse gas emissions continue to increase at present rates, atmospheric CO2 concentrations will more than double pr...

In January and February 2009, a series of water samples were collected from streams on Byers Peninsula. These samples were analysed for major elements and dO to determine the role of lithology and landscape position on stream geochemistry, and to understand better the hydrology (i.e. residence time of water) of these systems. Precipitation chemistry is enriched in Na, as are the streams located...

7-Aminocephalosporanic acid wastewater usually contains high concentrations of ammonium (NH₄⁺-N), which is known to inhibit nitrification during biological treatment processes. Chemical precipitation is a useful technology to remove ammonium from wastewater. In this paper, the removal of ammonium from 7-aminocephalosporanic acid wastewater was studied. The optimum pH, molar ratio, and various c...

A novel chemical absorption-biological reduction (CABR) integrated process, employing ferrous ethylenediaminetetraacetate (Fe(II)EDTA) as a solvent, is deemed as a potential option for NOx removal from the flue gas. Previous work showed that the Fe(II)EDTA concentration was critical for the NOx removal in the CABR process. In this work, the pathway of FeEDTA (Fe(III)/Fe(II)-EDTA) transformation...

A study on the connection between the state of the atmosphere, as represented by cluster-mean trajectories, and the chemical composition of precipitation at the Croatian GAW regional station of Zail,art is presented. The trajectory cluster analysis has been done on the basis ofdaily backward trajectories calculated for 1996, using the IIYSPLIT_4 trajectory model. The seasonal cluster analysis i...

The eastern part of the Adelaide Geosyncline contains well preserved glaciomarine sequences of the Sturtian glaciation (:750–700 Ma) including calcareous or dolomitic siltstone, manganiferous siltstone, dolostone and diamictite units and the associated Braemar ironstone facies. The ironstone facies occurs as matrix to diamictites and as massive to laminated ironstones and comprises abundant Fe ...

The removal of phosphorus and nitrogen compounds from biochemically treated wastewater effluents by alum flocculation and lime precipitation was investigated. Samples of secondary effluent were flocculated or precipitated in accord with conventional Jar Test procedures. The phosphorus removal was found to be highly pH dependent with an optimum pH of 5.57 ± 0.25. At this pH an alum dose of 250 m...

electroplating industry wastewater (eiw) characterized by high chemical oxygen demand (cod) is a big source of water and air contamination with heavy metals. the formation of cyanide complex with heavy metals is responsible for its elevated cod. the concentration of heavy metals in eiw can be removed by the use of different precipitating agents (sulfide and hydroxide). but the major bottleneck ...