Chemical process industries waste reduction

Many wastewaters from the chemical process industry contain organo-chlorine compounds which are, amongst others, responsible for the toxicity of such wastes. The electrochemical reduction of chlorine atoms from organic molecules prior to their discharge may greatly facilitate the subsequent biological treatment of toxic wastewater [290]. Schmal et al. of TNO Delft (the Netherlands) have examined the electrochemical dechlorination of eight priority... 

The chemical process industries are under increasing pressure to develop environmentally friendly products and processes, with the key being a reduction in waste. This timely new series will introduce different clean technology concepts to academics and industrialists, presenting current research and addressing problem-solving issues. 

The first equation is an example of hydrolysis and is commonly referred to as chemical precipitation. The separation is effective because of the differences in solubiUty products of the copper(II) and iron(III) hydroxides. The second equation is known as reductive precipitation and is an example of an electrochemical reaction. The use of more electropositive metals to effect reductive precipitation is known as cementation. Precipitation is used to separate impurities from a metal in solution such as iron from copper (eq. 1), or it can be used to remove the primary metal, copper, from solution (eq. 2). Precipitation is commonly practiced for the separation of small quantities of metals from large volumes of water, such as from industrial waste processes. 

Compared to conventional chemical processes, the use of microbial systems offers the advantages of reduction of wastes as well as minimization of costs and pollutant gas emissions. In addition, the ability of utilizing renewable sources instead of non-renewable ones, turned industrial biotechnology into a key technology for the development of a sustainable chemical industry [9, 10],... 

The importance of waste reduction through the use of a chemical catalyst can be exemplified by the use of yV-methylimidazole as a catalyst in the leaching step of gold extraction from ores in the mining industry. Cyanide, a toxic substance that poses a major health threat, has traditionally been used for these processes. A sample case is the 1999 leak in a Rumanian facility from a cyanide storage tank into the Rhine River that killed thousands of fish. 

Mercury salts have been known for a long time to be toxic to human health. This problem has been stressed during the two past decades, leading various countries to develop research programs aimed to remove mercury salts from industrial waste water. Available methods are either chemical, involving ion exchange resins and various oxidation or reduction processes, or physical, using ultrafiltration techniques, evaporation of solutions or electrochemical treatments. 

Under the auspices of the SITE Program, and in cooperation with the City of Bay City, Michigan Environment Canada and the Ontario Ministry of the Environment and Energy US EPA conducted the demonstration of the gas-phase chemical reduction process at Bay City s Middleground Landfill. The landfill accepted municipal and industrial wastes for approx 40 yr. A 1991 remedial investigation indicated elevated... 

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