In the paper titled, "Efficient autotrophic
denitrification performance through Integrating the bio-oxidation of Fe(II) and Mn(II)," according to Junfeng and the team, high concentrations of Fe(II) and Mn(II) which co-existed in the natural groundwater body, could be easily oxidized as the electron donor.
Important terrestrial processes in the N cycle include biological N fixation (BNF), mineralization (conversion of organic N to inorganic N during the processes of organic matter decomposition), immobilization (transformation of soil inorganic N to organic N), volatilization (transformation of soil ammonium N to ammonia gas), nitrification (transformation of ammonium N to nitrate and nitrite N),
denitrification (the process of nitrate/nitrite reduction by microbial activities), plant uptake from soil, resorption by living plant organs, adsorption and desorption by soil mineral particles, and N leaching from soil to aquatic systems.
After
denitrification through the addition of carbon, the TN removal rate was 80%-90%.
At the early and late rice main growth stages, the numbers of soil nitrifying and
denitrification bacteria decreased as follows: HOM>LOM>RF>MF>CK.
On the other hand, the concentration of the feed and the dissolved oxygen concentration appeared to be the key to simultaneous nitrification and
denitrification efficiency.
Putida Y-9 exhibited an excellent performance of
denitrification with a low concentration of nitrite at low temperature.
In this studies was reported that low temperatures slow down the nitrification process since the activity of ammonia oxidizing bacteria decrease and also the
denitrification is limited.
Measurements have relied on the use of inhibitors or strictly aerobic conditions to prevent
denitrification, and isotopic labels, but rarely has it been clearly stated whether the calculations were based on net or gross rates, which may account for some of the variance in observed product ratios.
The stabilization reactor was a unique unit with different compartments that could be described as follows: i) SR: an aerated zone of suspended growth with a high presence of organic carbon; ii) SR an anoxic zone which favored
denitrification; iii) SR an attached-suspended growth zone which favored nitrification and
denitrification; and finally, iv) SR, an additional aerated zone of suspended growth with a high ammonia concentrations measured as total ammonia nitrogen (TAN) for favored nitrification.
Hence, the present study aims to achieve the nitrogen removal from MCW which contains a low C/N ratio via SND without external carbon sources for
denitrification using a biofilm filtration system which was optimized with respect to i) nitrogen loading rate (NLR), ii) an appropriate position of air-diffuser, and iii) an aeration rate for SND.
By simultaneously achieving higher efficiency, increased output and low level of emissions of nitrogen oxides (NOx)(2) that enables elimination of
denitrification equipment, the new gas cogeneration system reduces initial costs and increases running cost merits.
Nitrogen losses due to leaching surface volatilization and
denitrification can be minimized by controlling the dissolution rate.
