| A/O reactor was used for the treatment of simulated high salinity wastewater in this paper.An experiment was conducted to study the effect of temperature(18～30℃) on shortcut nitrification-denitrification in the high salinity condition.Especially,the way to realize shortcut nitrification-denitrification and mechanism analysis under low temperature(4～15℃) condition.The effect of different salinity,pH value,free ammonia, dissolved oxygen,sludge age on nitrogen removal efficiency.This experiment was conducted to study the phenomenon of simultaneous nitrification denitrification in the system possibly appears as well as.The experimental results indicated that the influences of only the change temperature on accumulation of nitrite was little under 30%seawater salinity condition,in the normal temperature(18～22℃) scope.When the temperature exceeded 25℃,the temperature was higher more favors the nitrite the accumulation.The temperature 25℃,28℃,30℃,the rate of nitrosation respectively was 50%,90%,above 95%.The system of shortcut nitrification-denitrification had stable operation.Under the low temperature condition,along with temperature decreasing,the ammonia nitrogen removal rate dropped gradually.When the temperature from 15℃reduced to 10℃about,the ammonia nitrogen removal rate from 70%to 55%about.The nitrifying bacteria compares the nitrosation fungus activeness to come under a more serious suppression,through the extension sludge age,the experiment appears certain degree the nitrosation phenomenon.Short-cut nitrogen removal could be achieved at 26±1℃by controlling the pH at 7.5～8.5.In the reactor,the nitrite accumulation rate was more than 90%when pH was 8.5.When the free ammonia of influent was 0.799～3.65mg/L,the nitrite accumulation rate could be 93%.Improving pH value in influent was favorable to achieve shortcut nitrification-denitrification with controlling concentration of free ammonia.The inhibition of salinity to the activity of nitrate bacteria was higher than the growth of nitrosomonas. When the proportion of seawater exceed 30%,in the system of activity sludge biofacies was rich and short-cutnitrification and denitrification had stable operation.Short-cut nitrogen removal could be realized under the low oxygen level of the dissolved oxygen DO(0.6～1.0mg/L).After enhancing the DO density(1.5～1.8mg/L) 10 days,the nitrite accumulation ratio was decreased from 75.36%to 25.75%.Even if keeping the DO density in low level once more,the nitrosation rate increased slowly.The experiment indicated if short-cut nitrification was destroied,it would take long time to recovery.The serious sludge bulking did not necessarily occurred under the low DO concentration.The nitrosomonas had used the limited dissolved oxygen fully for a long time of the low DO density,and prevailed in competition with filamentous bacteria. Simultaneously certain seawater proportion(30%) could enhance the sludge settling property,therefore,it did not have the serious sludge bulking.When salinity certain,along with the increasing of sludge age,the structure of sludge floc became looser in the system and sedimentation of sludge decreased.In systerm the nitrite accumulation obviously occurred,when sludge age was 15d,seawater proportion,30%.The accumulation rate achieved about 90%,when sludge age was 18d. When the seawater proportion respectively was 30%,50%,the system best sludge age was 18d,20d.Simultaneous nitrification denitrification appeared in the beginning of controlling dissolved oxygen.The total nitrogen loss was sensitive to the change of dissolved oxygen. In the system the dissolved oxygen was lower(0.6～1.1mg/L),the sludge floc sludge grain size was large(150～250pm),it could infered the simultaneous nitrification denitrification was caused by the restriction of dissolved oxygen diffusion,production the dissolved oxygen gradient in the sludge floc. |
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