Development of a Process for Biodetoxification of Metal Cyanides from Wastewaters
Patil Y.B. and Paknikar K.M. (2000) Development of a process for biodetoxification of metal cyanides from wastewaters. Process Biochemistry 35: 1139-1151 (Elsevier, Scopus; ISSN: 1359-5113)
Posted: 13 Nov 2014
Date Written: November 13, 2014
A bacterial consortium capable of utilising metal cyanides as a source of nitrogen was used to develop a microbiological process for the detoxification of metal cyanides (viz. copper cyanide and zinc cyanide) from electroplating waste water. Optimal conditions biodegradation of both the metal-cyanide compounds were pH 7.5, temperature 35°C, inoculum size 109 cells per ml and glucose or sugarcane molasses requirement of 5 mM or 0.6 ml/l, respectively. Metal precipitates obtained during metal-cyanide biodegradation were identified as metal-hydroxides. When the treatment was carried out in a 27 l rotating biological contactor (RBC) in continuous mode, the system could achieve >99.9% removal of 0.5 mM metal cyanide (ca. 52 mg/l cyanide and 30-40 mg/l copper/zinc) in 15 h with sugarcane molasses as carbon source. The RBC treated effluent was found to be safe for discharge in the environment as confirmed by chemical analysis and fish bioassay studies.
Keywords: Biodegradation, Biodetoxification, Citrobacter sp., Metal cyanides, Poecilia reticulata, Pseudomonas sp.
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