Effect of Nutrients on Biological Nitrification.

Biological nitrification is the most commonly used process for nitrogen removal from wastewater. Nitrification is carried out in two steps. First ammonia is converted to nitrite by ammonia oxidizing bacteria. In the second step nitrite oxidizing bacteria convert nitrite to nitrate. The study involves the effect of nutrients (both organic and inorganic components) on biological nitrification and the optimum concentrations of di-sodium hydrogen phosphate, potassium di-hydrogen phosphate, sodium hydrogen phosphate, sucrose and ferric chloride were observed over ammonium ion removal. The effect of dissolved oxygen also was studied and maximum percentage removal of ammonium ion was found to be 89.2%.

Biological Nitrification of Waste Water.

Nitrification has been studied extensively as a result of its significance within the biological process and at intervals the necessity for treatment of waste water. In the last decade, the treatment of high ammonical concentration effluents has become a matter of nice interest. Many effluents will contain some hundred milligrams of nitrogen per liter (supernatants from anaerobic digestion, lechates from municipal water, etc.) may have specific treatment before utilization them to the plant recycling process. Sometimes this reaction is applied by maintaining robust ammonical concentrations which have the role of inhibiting the nitrite – oxidizing population responsible for the reaction of nitrites into nitrates (final stage of nitrification). However the nitrification methods served as a very important basis for the development of today understands and mathematical models for several waste treatment processes (activated sludge process using biofilm reactors) and self – purification in rivers. Often nitrogen removal from sea wastewater is problematic due to the low rate of bacteria concerned. Immobilization is an economical technique to retain slow growing organisms in continuous flow reactors. Immobilized cells can be classified into “naturally” attached cells (biofilms) and “artificially” immobilized cells. The simultaneous nitrification and denitrification within the step feeding biological nitrogen removal method were investigated below different inflowing substrate and aeration flow rates. The experimental results showed that there was additionally linear relationship between simultaneous nitrification and denitrification and DO concentration below the conditions of low and high aeration rate.

Effect of nitrogen sources on microbial production of xylitol.

Experimental investigation on batch fermentation of xylose to xylitol using Candida parapsilosis NCIM-3323 has been carried out and the effect of different nitrogen sources on xylitol production has been investigated. It is noticed that Ammonium sulfate is best suitable compared to other sources used. The present work utilized five nitrogen sources namely Potassium Nitrate, Ammonium Chloride, Ammonium Sulfate, Ammonium Nitrate and Urea in the experiments for a fermentation period of 144 h at 30 0C at pH of 3.5 with initial xylose concentration of 60 g/l. The work was also carried out varying concentration of Ammonium sulfate, wherein it was found that 4 g/l of ammonium sulfate gives highest yield.

Isolation and characterization of naphthalene degrading bacteria from soils in warangal.

Bacteria capable of utilizing naphthalene, as their sole source of carbon and energy for growth were isolated from three different sites in warangal,Andhra Pradesh. By standard bacteriological methods, these bacteria were characterized taxonomically as belonging to the genus Pseudomonas, Burkholderia or Actinomycetes. Two of the isolates, which showed the highest growth during screening as demonstrated by an increase in their optical densities at 600 nm and named as NITWDBT1 and NITWDBT3.In isolate NITWDBT1, the lowest optimum growth of 0.189 at 600 nm was observed when the level of anthracene was lowest (50 ppm); while the highest optimum growth of 0.578 was recorded when the level of anthracene was highest (300 ppm). Similarly, the lowest optimum growth in isolate NITWDBT3 was 0.173 at anthracene level of 50ppm, while the highest was 0.380 when the level of anthracene was 250 ppm (OD600). These two isolates were identified as Pseudomonas aeruginosa and Burkholderia cepacia respectively, were also able to grow in anthracene and carbazole, but not very much so in 2,4-dichlorophenol and D-camphor. The isolates showed a concentration-dependent growth in all the compounds they were grown. There were visible changes in the colour of the growth medium of the isolates during their incubation, suggesting the production of different metabolites. There were also changes in their medium pH during growth. These studies demonstrate the possession by the bacterial species of novel degradative systems.