Experimental Study On Denitrification Treatment Of Cracking Catalyst Production Wastewater

Cracking catalyst production wastewater is a kind of high ammonia nitrogen wastewater,with high temperature,low C/N ratio,pH fluctuation,biodegradability and other characteristics.Anaerobic Ammonia Oxidation（ANAMMOX）technology is a new type of biological denitrification technology,withing low oxygen demand,less mud production,no external carbon source,suitable for low C/N wastewater and other advantages.The ANAMMOX biological nitrogen removal process is the object of study,discussing the feasibility of applying ANAMMOX technology to the cracking catalyst production wastewater from the small test to the pilot test.The small tests cultivate anaerobic ammonia bacteria by water distribution,to evaluate the activity of the flora.Long term stable operation data show that the removal rate of NH₄⁺-N and NO₂^--N in ANAMMOX biofilter is both above 80%,the nitrogen stoichiometric ratio of△（NH₄⁺-N）:△（NO₂^--N）:△（NO₃^--N）is 1:1.29:0.23,and the pH difference between inlet and outlet is stable at 1.0¹.08.The bioactivity of anaerobic ammonia bacteria in the filter is good.In the pilot test,the ANAMMOX biofilter was successfully started after 30 days of operation in the start-up phase to recover activity and achieve proliferation of the anaerobic ammonia bacteria by water distribution.After80 days,the removal rate of NH₄⁺-N and NO₂^--N in ANAMMOX biofilter is above 75%and 70%,Stable operation data show that the nitrogen stoichiometric ratio of△（NH₄⁺-N）:△（NO₂^--N）:△（NO₃^--N）is 1:1.30:0.25,the pH difference between inlet and outlet is stable at 0.80¹.07,and the total nitrogen removal load is 3.5KgTN/（m³·d）,the denitrification performance is good.Using the cracking catalyst production wastewater to domesticate the anaerobic ammonia bacteria,the distribute radio is 30%,50%,80%and 100%.The experimental results show that it takes 50 days to domesticate the anaerobic ammonia bacteria by using the cracking catalyst production wastewater.At the stage of treatment for cracking catalyst wastewater by shortcut nitrification-anaerobic ammonia oxidation process,the influent NH₄⁺-N is 86¹27mg/L,TN is 115¹50mg/L,the removal of NH₄⁺-N and TN in ANAMMOX biofilter is upto90%and 83%,and the final effluent NH₄⁺-N≤6 mg/L,TN≤20mg/L.The treatment of cracking catalyst production wastewater by the shortcut nitrification-anaerobic ammonia oxidation process has a certain feasibility.