Removal of nitrogenous compounds from wastewaters using immobilized cyanobacteria Anabaena CH3

The removal of nitrogenous compounds from wastewaters using calcium-alginate entrapped cyanobacteria Anabaena CH3 was studied in batch as well as semicontinuous cultures. Results of the batch cultivation showed that the removal rates of nitrate and ammonium nitrogen were between 15 - 23 and 17 - 30 mg N L -1 d -1 g -1 Anabaena CH3 while the observed specific growth rates of Anabaena CH3 for different initial nitrate and ammonium concentrations were between 0.35 - 0.65 and 0.2 - 0.56 d -1 , respectively. Results of the semicontinuous cultivation gave the average growth rate of Anabaena CH3 and ammonium removal rate of 83 mg L -1 d -1 and 86 mg N L -1 d -1 g -1 Anabaena CH3. The factors which influence the mass transfer limitations of substrate and the cultivation conditions of immobilized Anabaena CH3 were evaluated and quantitatively determined. The optimal growth conditions for immobilized Anabaena CH3 were derived as : pH 7 - 9, 30 -40°C, 2500 - 4000 lux, above 10 mg L -1 NO 3 -N or 10 - 100 mg L -1 NH 4 -N.