Automation of the Treatment of Hexavalent Chromium In Waste Water

Abstract

There has been great demand for development of technologies that remove toxic heavy metal ions from wastewater. Chemical precipitation operation is known to remove heavy metal ions from water. In this Research studying the reduction and separated of hexavalent chromium (which is very toxic heavy metal) from waste water ,and the automation of the process was undertaken. Reduction process is done by adding suitable quantity of sodium bisulfite solution to waste water in pH range 2.0 - 2.5 after acidifying the media with solution of sulfuric acid. The trivalent chromium ions were then precipitated by adding sodium hydroxide which increases the alkalinity of the solution up to the pH value 10.0.The size of chromium hydroxide crystal enlarged by adding flocculent solution. Then the treated waste water solution filtered to separate chromium hydroxide flocculated crystals. The pH of remaining treated waste water is reduced to pH 7.0 and discharged directly to the sewage. Experimental works was carried out to determine the exact value of solution potential in ml volts during treatment process steps. The standard solutions after prepared were treated ideally to determine the end points of the reactions in ml volts. Sepotrrato 100R is one of intelligent systems which were developed for treatment of waste water from electroplating processes. The Electroplating Department,Sudan Currency Printing Press, waste water usually contain many heavy metals ions such chromium, and nickel. This Sepotrrat 100R was recalibrated and programmed according to research finding, for reactions end points.