Resumen de Effect of various factors to ammonia biodegradation by two stage biofiltration system
Silvija Strikauska, Dzidra Zarina, Olga Mutere, Uldis Viesturs, Andrejs Berzins
An autotrophic ammonia-biodegrading PNNS association was isolated from the biological activated sludge of the fish factory wastewater treatment plant and used in the two-stage biofiltration system with the ammonia load 0.78 g/m3h ensured the total removal efficiency up to 0.69 g/m3h as the result of the denitrification process. Additional investigations were made to study physiological and biochemical properties of individual strains of the PNNS association in order to control their growth under various cultivation conditions with the aim to find out the most optimal conditions for biomass preparation and immobilisation. Individual strains of the association can be revealed and counted because of their different colony morphology using selected medium. Cultivation of individual strains of the PNNS association under aerobic conditions revealed a stimulation effect of (NH4)2SO4 in the concentration range of 0.21 � 4.45 g N/l to their growth. Addition of saccharose, glucose, fructose and/or cabbage leaf extract (CLE) in various combinations to agarized medium resulted in the growth stimulation of individual strains of the PNNS association, i.e. Pseudomonas sp., Nitrosomonas sp., Nitrobacter sp. and Sarcina sp. The whole association was cultivated in the liquid mineral medium with amendments mentioned above. Stimulation of the growth in the presence of CLE and some reducing sugars was observed. The results obtained in these experiments will be used for further optimisation of the two-stage biofiltration system using the PNNS association.
