Suchergebnisse

Fluoride in drinking water above permissible levels is responsible for human dental and skeletal fluorosis. Adsorptive based defluoridation is the most popular technique with several end-user applications. Consequently, this paper describes the fluoride removal potential of a novel sorbent, limestone-derived apatite from drinking water. The adsorbent was prepared by calcining limestone followed by reacting with orthophosphoric acid. Batch sorption studies were performed as a function of contact time, pH, initial fluoride concentration, temperature and adsorbent dose. Sorption of fluoride was found to be pH dependent with a maximum occurring in the pH range of 5-9. The authors also observed that the material had a buffering effect on the same pH range. Meanwhile, the adsorption capacity was found to increase with temperature, depicting the endothermic nature of the adsorption process and decreases with adsorbent mass. The equilibrium data was well described by the conventional Langmuir isotherm, from which isotherm the maximum adsorption capacity was determined as 22.2 mg/g. From the kinetic perspective, the fluoride adsorptive reaction followed the pseudo-second order mechanism.

The kinematic approach to water monitoring of rivers and lakes was by Archimedes Logica under the EU initiatives (LIFE1996) for the monitoring of the Lagoon of Venice. These systems were limited to the measurement of typical basic parameters: pH, Eh, salinity, turbidity, dissolved oxygen, electrical conductivity, temperature and immersion depth. However, this earlier system was unable to help against pollution from hydrocarbons. In this paper, the authors present a new kinematic monitoring system named AQUARIUS, which integrates a new generation of automatic chemical and biological analyzers. Automatic sampling and measurement equipment for micro-organism discrimination and counting are present, especially for detecting dangerous species like toxic algae. This article describes the wide spectrum of applications of the new AQUARIUS system: safety control of freshwater reservoirs, detection of urban and agriculture impacts on inland waters and early warning detection of man-made accidents, which are aided by the adoption of new mobile measurement equipment and broadband data channels offered by the modern 3G network.

Milwaukee is the largest city in Wisconsin and home to approximately one million people. Lake Michigan waters in Milwaukee's coastal area are mainly used for recreational purposes and drinking water. These coastal waters are impacted by many sources of pollution, from which the presence of sewage is a main concern, as this sewage contains numerous harmful pathogens. In this paper, the authors examine and analyze the beaches of Milwaukee for pollutants to serve as an impetus for future action.