Eshetu Bekele

Alkaliphilic Bacterial Mixed Cultures: for Removal of Cyanide from Synthetic Wastewater Eshetu Bekele

The Alkaliphilic sludge sampled from Lake Chitu and acclimated on SWW having 200 mg CN-/l for 48 days in oxic-anoxic bioprocess, contained cyanide degrading, ammonia oxidizing and denitrifying bacterial isolates that considered necessary in biotransformation of cyanide to CO2 and N2. Some isolates of them found to tolerant as high as 1000 mg CN- /l in the SWW. Inflow SWW with 200, 400, 600, 800, and 1000 mg CN-/l the corresponding cyanide removal efficiency were 99.9, 100, 99.9, 99.5 and 95.5%. The removal efficiency for feed of 200, 400, 600 and 800 mg CN-/ml was indicating nearly complete removal of cyanide. Corresponding effluent amounts of NH4+and NO3- was less than 1.6 and 9.5 mg/l respectively and below the standard of discharging set by several agencies. In this study, the alkaliphilic bacterial mixed cultures showed remarkable potential for simultaneous removal of cyanide, ammonium and nitrate from wastewaters having cyanide as primary contaminant.