Studies On The Nitrification Characteristics Of Nitrifying Bacteria N4-L And Its Application In SBR System

ABSTRACT:Industrial wastewater is one of the largest sources of pollution in water, while monosodium glutamate wastewater is a kind of industrial wastewater with great harmful to the environment. In biological wastewater nitrogen removal process, the nitrifying bacteria plays a major role in bacteria groups, the nitrification rate affects the effect of wastewater treatment and biological denitrification efficiency. In winter conditions, nitrification bacteria is susceptible to temperature effect, then nitration reaction is the key step in the whole process.Therefore it is of great practical significance to research the nitrification characteristics of low temperature resistance nitrifying bacteria and apply it to the actual operation of monosodium glutamate wastewater during the winter.In this study we used a strain of high performance low nitrifying bacteria N4-L, by adding the effect of organic matter on the nitrification rate,we obtained that glucose can effectively improve the rate of nitrification when adding as organic matter,and when the glucose concentration was1g/L, the nitrification rate increase maximum,67.33mg/L·d-1.For nitrification and denitrification capacity test of N4-L, the N4-L has the ability of nitrite, and the ammonia nitrogen removal rate keeps maintain steady growth in a certain range; and N4-L does not have the denitrification ability under aerobic and anaerobic conditions. Based on study of N4-L nitrification ability in the early period, we can get more comprehensive grasp of nitrification characteristics of N4-L, which lays a theoretical foundation for practical application of N4-L in the late of monosodium glutamate wastewater treatment.Applying N4-L to SBR experimental device for monosodium glutamate wastewater treatment,it shows that after joining the N4.L in the reactor in winter conditions, COD and ammonia nitrogen removal rate reaches94.12%and94.35%respectively. In addition the NO2-and NO3-content in water is very low,which also can meet the relevant provisions of national wastewater discharge standard, all these show that adding nitrifying bacteria N4-L significantly promote the treatment effect of monosodium glutamate wastewater. When N4-L is added to the SBR, it can adapt to low temperature treatment effect and can significantly enhance the monosodium glutamate wastewater, which saves the cost of winter wastewater treatment, reduces environmental pollution load. At the same time, the result also establishes the foundation for the further establishment of practical engineering application of monosodium glutamate wastewater treatment enhanced nitrification process.