Distinctive Microbial Ecology and Biokinetics of Autotrophic Ammonia and Nitrite Oxidation in a Partial Nitrification Bioreactor
Lead Inventors: Kartik ChandranProblem or Unmet Need:Biological nitrogen removal from waste water is a costly process. Traditionally it is achieved by complete oxidation of ammonia present in the waste to a mixture of nitrite (NO2-) and nitrate (NO32-) through ammonia oxidizing bacteria (AOB), the process is called nitrification. The second stage involves the reduction of nitrite/nitrate to nitrogen gas. However, through achieving partial oxidation of ammonia it is possible to solely produce nitrite (NO2-), which can then directly be converted to nitrogen. This can save appreciable amount of aeration and electron donor costs. Successful partial nitrification of ammonia can be achieved through an optimized population of AOB and NOB (Nitrite oxidizing bacteria) in the bioreactor. This requires a thorough understanding of the constituent dynamics of the molecular diversity and their biokinetics in terms of partial nitrification stability. However, most biokinetic estimation studies are based on mathematically approximated concentrations of the nitrifying communities in mixed culture which tends to give erroneous results in real scenarios. This suggests a clear need for studies which can describe the biokinetics of nitrifying bacteria on the basis of direct measures of AOB or NOB abundance in the mixed culture.The present invention applies various techniques to understand the dynamics of AOB and NOB populations, biokinetics and performance in a partial nitrification bio-reactor under steady state and transient operations. Ammonia and nitrite oxidation rates are studied along with the direct measures of AOB and NOB concentrations. The quantification of bacterial concentrations (AOB and NOB) is done through real time PCR. Biokinetics of ammonia and nitrite oxidation were estimated through extant respirometric technique. Estimation of biomass yield and decay coefficient is also achieved. These key reactor biokinetic and stoichiometric parameters are shown to be important for an optimal reactor performance.
Optimized reactor parameters could result in 25% savings in aeration costs by achieving partial nitrification solely to nitrite Subsequently, a 40% savings in electron donor costs can be achieved by direct denitrification of nitrite rather than nitrate to nitrogen Allows industry to comply with stringent total N-effluent concentration limits in a cost effective and sustainable fashionOpportunities: Sponsored research funding in efficient waste denitrification techniques Licensing
Efficient nitrogen removal from municipal waste water and sewage Removal of nitrogen from animal wastes, land fill leachate, and farm fertilizer wastes A better understanding of the dynamics of bacterial populations and its effect on reactor performance will help in optimizing performances of conventional bioreactors Research tool for understanding reactor kinetics
The present invention applies various techniques to understand the dynamics of AOB and NOB populations, biokinetics and performance in a partial nitrification bio-reactor under steady state and transient operations. Ammonia and nitrite oxidation rate...
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