RESUMEN
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%.
RESUMEN
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.
RESUMEN
Objective To amplify and sequence the distinctive norB gene of Nitrobacterium. Methods The norB gene was amplified by PCR and was cloned into T-vector and then transformed into E.coli JM109. After white-and-blue selection, positive colonies were sequenced with T7 sequencing primers by Takara Company. Spliced with Vector NTI Suite software, the homologous analysis of sequences were conducted in Genbank through Internet. Results The results showed that all of norB genes obtained from the nitrite-oxidizing bacteria were homologous with the norB gene of Nitrobacterium hamburgensis in Genbank. The homology ranged from 96% to 98%, and there were no frameshift mutations, which guaranteed the correct ORF. Conclusion The obtained genes are norB genes indeed.
RESUMEN
Objective To screen and seperate nitrobacteria that could be used to treat nitrogenous compound pollution.Methods Autotrophic nitrite-oxidizing microorganisms were screened by enrichment culture from soil.After morphological and biological detection,primers were designed to detect the distinctive gene norB of nitrobacteria.The PCR production was se-quenced,and the homology was identified according to the sequence in Genbank.Results One strain of bacterium was screened that could oxidize nitrite.This bacterium was small,light-yellow bacilli.The expected-size DNA fragments could be amplicated by PCR.The sequence of a PCR production was blasted in Genbank and showed99%consistent with norB gene of N hamburgensis.Conclusion It was preliminarily confirmed that the microorganism screened in this study might be nitrobac-terium.
RESUMEN
ve To control and minimize the water pollution by nitrogen. Methods The autotrophic amino-oxidizing bacteria in soil were screened by enrichment and incubation. After bacterio-morphological identifica-tion their nitrifying rates were determined. Results All of the 12 screened strains were gram-negative and in the shape of brevi-rod dorminantly. The colonies with a dorminant form of short diameter in round shape, light yellow and smooth formed after 7-day incubation at 28℃ . The nitrifring rates ranged 0.40 mg/ (L?d)~1. 15 mg/ (L?d) . Conclusion The screened 12 strains all presented nitrifying function, some of them could be used to control water environment pollution by nitrogen.