Toxicity reduction, industrial discharges

Numerous practices have been developed to eliminate or minimize discharges of pollutants from the metal finishing industry. Successful source reduction measures have been implemented to eliminate cyanide plating baths, as well as substitute more toxic solvents with less toxic cleaners. 

Wong and Maroney [49] reported on a pilot plant comparison of PACT and extended aeration (activated sludge) for treating petroleum rehnery wastewater. Results indicated that although both processes performed similarly in COD removal, only the PACT system yielded an effluent meeting the discharge requirements for whole effluent toxicity reduction. Similar results in toxicity reduction have been reported for wastewaters from other industries [50]. 

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... 

In Estonia the monitoring of effluents is based on chemical analysis. The list of controlled water quahty parameters depends on the type of industry. Bioassays are not used as a monitoring tool. However, according to HELCOM Recommendations No. 16/5, Requirement for discharging of waste water from the chemical industry, and No. 16/10, Reduction of discharges and emission from production of textiles, the toxicity effect of discharges into water bodies should be determined by (at least) two toxicity tests, which could be chosen out of the following four toxicity tests [203] ... 

Similarly, in the case of industrial effluents control maybe based on limitation of the discharge of another toxic metal, say copper or zinc, with a reduction in lead discharge occurring as an added bonus. In this chapter it is necessary, therefore, to consider both control methods specifically designed to limit the discharge of lead, as well as those more general methods which also affect concentrations of lead in effluents. 

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