Study Of Short-cut Nitrification And Denitrification In Normal Temperature

This thesis studies on the regulations of pH variation during organic oxidation, nitrifying and denitrifying in Sequencing Batch Reactor (SBR), and discuses the possibility of pH serving as parameter to judge reactive end. This thesis also studies on achieving short-cut nitrification and denitrification by making use of low DO selective restrain, and discusses that reducing temperature affects on short-cut nitrification and denitrification. The main conclusions are as follows:1.The regulation of pH variation occurs during reaction. The characteristic points of pH curve may judge the close of organic oxidation, nitrifying and denitrifying in SBR on assistant DO variation at DO>lmg/L, while these characteristic points can judge the close of nitrifying and denitrying in SBR at DO lmg/L.2. Through controlling DO=0.35-0.80mg/L at 25 C ,the short-cut nitrification and denitrification is achieved in SBR after thirty-two day's domestication, at this time the accumulation rate of nitrite is 64.29% ( > 50%) .3.Comparing to other study, it increases the accumulation rate of nitrite under the same influent ammonia that making use of characteristic points of pH curve judges to the nitrifying close.4.SND of shortened nitrification occurs at aerobic reaction under low DO.5. When temperature reduces from 25 C to l4 C, the accumulation rate of nitrite also reduces; the critical of temperature of short-cut nitrification at low DO is 16 C.6.Under abundant nutrition in wastewater, anoxic selector and short time aeration after denitrification may efficiency prevent sludge from bulking during reducing temperature in low dissolved oxygen SBR.