Nitrogen removal

The second step is the reduction of nitrate to nitrogen gas. This reaction is also bacterially catalyzed, in this case by denitrifying bacteria, and requires a carbon source and a reducing agent such as methanol, CH3OH, or an organic carbon source, CH2O  

Typically, denitrification is carried out in an anoxic column with added methanol as a food source (microbial reducing agent). Methanol is a synthetic chemical that poses some toxicity and flammability hazards. A greener option is the use of biomass, such as carbohydrates from plants as the microbial reducing agent. One of the best organic reductants for this purpose is high-fructose com syrup. 

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Denitrification of wastewater in treatment plants offers another potential use for methanol. There are a few such plants in the world however, this use is not expected to grow appreciably, as there are more proven methods for nitrogen removal commercially available. 

Excess Nitrogen Removal. A number of low energy processes use excess air in the secondary reformer in order to reduce the primary reformer duty. The surplus nitrogen so introduced has to be removed later in the process. 

The oxidation ditch process is usually considered when nitrogen removal is required. 

Cryogenic distillation has been used extensively ia the processiag of natural gas for nitrogen removal and for helium recovery (22—23). Two basic processes are now used for nitrogen rejection from natural gas— the single-column heat-pumped process and the double-column process. Eadier processes utilized multistage flash columns for helium recovery from natural gas (24). 

To maintain high recycling ratios between the nitrification and denitrification units. This recommendation is also useful to increase the efficiency of nitrogen removal. 

As the adhesive factory will consume a large amount of methanol in its processes, the addition of this compound to carry out nitrogen removal would have a low cost, and is one of the most feasible options. 

Wang, L.K., Investigation of Nitrogen Removal Processes for a Compact Wastewater Treatment Plant at Lake Como, Italy, Lenox Institute of Water Technology, Lenox, MA, Report No. LIR/1280/1, December 1980. 

Puig, S., et al., An on-line optimisation of a SBR cycle for carbon and nitrogen removal based on on-line pH and OUR The role of dissolved oxygen control, Water Sci. Tech., 53,171, 2006. 

The kinetics of hydrocracking reactions has been studied with real feedstocks and apparent kinetic equations have been proposed. First-order kinetics with activation energy close to 50 kcal/gmol was derived for VGO. The reactions declines as metal removal > olefin saturation > sulfur removal > nitrogen removal > saturation of rings > cracking of naphthenes > cracking of paraffins [102],... 

Kinetics studies of the hydrotreatment (and hydrocracking) of VR has led to the conclusion that most of the metals, sulfur and nitrogen removal takes place during the first 50% of the whole VR conversion [119-123], More than one reactor was needed for HDM and HDS of a Maya VR, when HDT is used as feed pretreatment [119,120], Although vanadium removal appears easier and faster than nickel removal, their kinetics results showed very similar values of the activation energy for the demetallization reactions [122],... 

C. tetosteroni 63 [320,349] Susanne Fetzner Quinoline 2-oxidoreductase (360 kDa) Nitrogen removal (hydroxycoumarin pathway). Reactivity demonstrated with heterocyclic-N... 

QN 2-oxidoreductase (OR), lH-2-Oxol, 2-dihydroQN-8monooxygenase. 35% OR yield Nitrogen removal (hydroxycoumarin pathway). OR Activity 19 units (33 times the extract activity)... 

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