Comparison of the MBBR denitrification carriers for advanced nitrogen removal of wastewater treatment plant effluent

The moving bed biofilm reactors( MBBRs) were used to remove the high concentration NO-3-N of wastewater treatment plant( WWTP)effluent,and the MBBRs carriers were compared for denitrification. The results showed that good denitrification efficiency can be achieved with polyethylene,polypropylene,polyurethane foams and haydite carriers under the following conditions: 7. 2 to 8. 0 p H,24 ℃ to 26 ℃ temperature,12 h HRT,25. 5 mg·L- 1external methanol,WWTP effluent TN between 7. 5 mg·L- 1and 13. 3 mg·L- 1,and NO-3-N between 2. 2 mg·L- 1and 12. 4 mg·L- 1. The MBBR filled with polypropylene carriers had higher TN and NO-3-N removal rate( 45. 3% and 76. 3%,respectively) than those with other kinds of carriers. The minimum effluent TN and NO-3-N of MBBR were 2. 4 mg·L- 1and 0. 2 mg·L- 1,and the maximum denitrification rate reached10. 6 g·m- 2·d- 1. The three-dimensional excitation-emission matrix analysis showed that the influent and effluent of MBBRs mainly contained SMP and BOD5,which can be removed better by MBBRs with haydite and polypropylene carriers.