Effect of Recirculation Frequency in Anaerobic-semiaerobic Bioreactor Landfill

Anaerobic bioreactor landfill with a semi-aerobic aged refuse bioreactor was studied for reducing high concentration ammonia nitrogen cumulated in anaerobic bioreactor landfill,in order to accelerate the stabilization of landfill.ANBL1#,a simulated anaerobic bioreactor,as the reference group and two simulated anaerobic-semiaerobic bioreactors(AN-SABL2#,AN-SABL3#)as control groups were devised,for studying the stabilization of AN-SABL operated at different leachate recirculation frequencies.Results indicated that leachate pH value in ANBL1# remained less than 7 until the 100th week.By contrast,the pH value of leachate in AN-SABL2# and AN-SABL3# both rose to more than 7 after 94 weeks and 98 weeks respectively,which demonstrated that AN-SABL could make acidification phase shorter.COD concentration of leachate was reduced in AN-SABL more effectively.COD concentration in the simulated anaerobic bioreactor(D2)of AN-SABL2# was 40.63% of that in the simulated anaerobic bioreactor(D1)of ANBL1#,and that in the simulated anaerobic bioreactor(D3)of ANSABL3# was only 12.5%.The removal rates of COD in the simulated anaerobic-semiaerobic bioreactors were mostly more than 95%.AN-SABL can reduce high concentration ammonia nitrogen accumulated in anaerobic bioreactors,which depends on strong nitrogen removal ability of semi-aerobic aged refuse bioreactor.The overall trend of NH3-N concentration in the simulated anaerobic bioreactors is as NH3-ND1 NH3-ND3,NH3-ND1 NH3-ND2.The removal rates of ammonia nitrogen in simulated anaerobic-semiaerobic bioreactors(d2,d3)were almost more than 90%.In the acidification phase,the lower leachate recirculation frequency(once 3 d) was better for ammonia nitrogen removal,in contrast that higher leachate recirculation frequency(once a day)was more favorable in the anaphase.