Engineering Application And Debugging Operation Of Enhanced Biological Nitrogen Removal Process

This research briefly described the characteristics and working principle of BNRenhanced biological nitrogen removal process. The original process of sewagetreatment plant was Anaerobic/Oxic (A/O) Phosphorus Removal Process. Afterimprovement, channel No.1maintained original anaerobic treatment unit, channelNo.2and No.3were modified as “Vertical Oxidation Ditch”unit, and channel No.4to9were anoxic units. Enhanced Biological Nitrogen Removal (BNR) Process wasmore effective with high treatment efficiency and low energy consumption, comparedwith A/O Phosphorus Removal Process.During process modification, the “Verticel”unit was always in anoxic state bycontrolling the Oxidation Reduction Potential (ORP) which was related to theadjustment of mixers and plate-spinning opening number and time of the vertical ringoxidation ditch unit. The total nitrogen (TN) removal efficiency of "Verticel" unit wasthus improved. By adjusting dissolved oxygen (DO) of the anoxic unit, ORP, sludgeconcentration, carbon contents of sewage flowing into the aeration tank. And theamount of returning activated sludge, for the anoxic unit occurred shortcutnitrification/denitrification. The carbon sources required by denitrification of thesystem were reduced. The capacity of nitrification and denitrification has beenincreased. By keeping DO of the end of aeration tank with2-3mg/L, the removal ofCOD and NH4+-N in anoxic unit was much more efficient. The BNR process in ourplant could be operated stably.After modification, maximum nitrogen removal was observed in our plant, abideby the principle of scientific, reasonable, economic, safety, and steady. All effluentsmet level B requirements of "The Urban Sewage Treatment Plant Pollutant DischargeStandard "(GB18918-2002). At the same time, we found the optimum balance point ofdenitrification and phosphorus removal was obtained.