Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment.

Publisher Summary This chapter highlights the physiology of autotrophic ammonia- and nitrite-oxidizing bacteria. Several aspects of the physiology of nitrifiers of relevance to their growth and activity in natural environments are considered. The chapter describes the basic features of the biochemistry of ammonia and nitrite oxidation and discusses the growth limiting factors and activity of these organisms. The influence of oxygen concentration, pH value, and inhibitors on their physiology is also described. Nitrification plays a central role in the nitrogen cycle of terrestrial and aquatic ecosystems, converting the most reduced form of nitrogen, NH3, to the most oxidized form, NO3. Nitrifying bacteria occupy niches in many ecosystems and compete successfully with faster and more efficiently growing organisms for oxygen, ammonia, and carbon dioxide. Nitrifiers are capable of reversing the nitrification process, carrying out denitrification and producing nitrite, ammonia, nitrous and nitric oxides, and gaseous nitrogen. Ammonia oxidizers can metabolize urea and can assimilate carbon from methane while nitrite oxidizers can grow anaerobically in the presence of organic compounds and nitrate.

Autotrophic nitrification in bacteria

https://www.waterboards.ca.gov/water_issues/programs/tmdl/records/region_2/2008/ref2426.pdf

Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates.

A review of the research on the kinetics of nitrification and denitrification is presented including an explanation of reaction engineering models. The results of laboratory scale experiments with high rate nitrification processes are discussed using kinetic results for oxygen limitation as well as for substrate limitation and inhibition. It can be demonstrated that reaction engineering models are helpful for a better understanding of the processes and for the design of reactors. Pilot scale investigations from the last 15 years show remarkable advances in the increase in nitrification efficiency and in the stabilization of the process. The time is ripe for nitrogen removal from industrial effluents in full scale processes!

Biological Nitrogen Removal from Wastewater.

The biofloc technology (BFT) in indoor tanks: Water quality, biofloc composition, and growth and welfare of Nile tilapia (Oreochromis niloticus)

Nitrification and nitrogen removal

Experimental and thermodynamic evidence is presented to show that nitrate‐N can be reduced beyond nitrite‐N in a cadmium reductor. The studies are made in a batch system and include the effect of sample to reductor ratio. Data presented show that aqueous ammonium‐N can be oxidized to nitrite‐N at a rate of about 0.0.‐0.04 percent per day in the presence of air and cadmium‐copper or cadmium‐mercury complex. The rate of this oxidation, unaffected by absence of light, is reduced to the order of 0.001 percent per day or less in a nitrogen atmosphere and cadmium‐mercury complex. Hence a requirement for air is suggested for the oxidation reaction.

Bhavender Sharma

Papers

Nitrification and nitrogen removal

Oxidation‐reduction chemistry and aqueous ammonium oxidation in the estimation of nitrate by the cadmium reduction method