Study On Treating Of High Strength Ammonia Wastewater In A Submerged Membrane Bioreactor

On the basis of summarizing the related references home and abroad, a great deal of experiments had been done to study the basic characteristics,the characteristic of the activated sludge and the influencing factor of a submerged membrane bioreactor (SMBR) treating synthetic high strength ammonia organic wastewater .The results indicated that,with the reactor operating at a hydraulic retention time (HRT) of 24h,the pH at 7.06～7.89,the DO at 2.1～3.8mg/L , the ORP at 435mv～557mv , the free ammonia below 0.3mg/L , the ammonia volumetric loading rate below 2.80kgNH₄⁺-N/(m³Â·d), the ammonia concentration of the effluent was constantly under 5.0mg/L, the NH+4-N removal rate was constantly above 95.8%, the TN removal rate varied from7.5% to 22.6%, the COD concentration of the influent keep under 30.0mg/L in most time,and the COD removal rate was above 91.5% in most time. The pH , DO ,ORP and free ammonia concentration are all important influencing factor of the SMBR.When the ammonia volumetric loading rate of the influent increase to 2.99kgNH₄⁺-N/(m³Â·d),the system become unsteady acutely,the nitrogen and nitrite accumulated easily in the SMBR in a shot time.The nitrification ability of the SMBR can resume in a week,with decreasing the ammonia volumetric loading rate of the influent to 2.40kgNH₄⁺-N/(m³Â·d).The activated sludge has a good nitrification activity,and the specific nitrification rate can increase to 0.1052/d and the INTF value of unit activated sludge can increase to 0.382×10^-3.The sludge concentration increasing continuancly,and the MLVSS/MLSS ratio decreasing from 0.71 to 0.62.The concentration of the heterotrophic bacteria, ammonia oxidizing bacteria, and nitrite oxidizing bacteria increase all the while over the operation period. The proportion of ammonia oxidizing bacteria, and nitrite oxidizing bacteria increase all the while over the operation period. An increasing occurrence of extracellular polymeric substances (EPS) with operation time. The SMBR has strong anti-shock loading capability and can resume in a short time. The SMBR can run steadily when increasing the ammonia concentration of the influent from787.0mg/L to 874.9mg/L and from 1173.4mg/L to 1574.3mg/L.