Using porous ceramic media in the upflow packed-bed reactor (UPBR) system for nitrogen removal via autotrophic nitrification and denitrification

In this study, the feasibility of an innovative upflow packed-bed reactor (UPBR) system using porous sulfur and lime ceramic media (CERAMED-L and CERAMED-SL) to remove nitrogen for wastewater treatment was evaluated. The specific lime dissolution rates for CERAMEDs in the UPBRs show an inverse proportion to pH and resulted in 2.32 g as CaCO3 kg−1 CERAMED-L d−1 and 1.64 g as CaCO3 kg−1 CERAMED-SL d−1 at a pH 6.7. The calculated specific nitrification rate resulted 1.73–2.29 kg NH4 +-N m−3 CERAMED-L d−1, with a F/M ratio in the range 0.08–0.31 g NH4 +-N g−1 VS d−1. The alkalinity shortage in the feed solution seemed to be overcome by supplying specific alkalinity of 3.88 kg as CaCO3 m−3 CERAMED-L d−1 through the dissolution of lime from CERAMED-L. Autotrophic denitrification efficiencies were in the range of 83–96% during the test period, and the average specific denitrification rates of 0.97–1.92 kg NO3 −N m−3 CERAMED-SL d−1 and 0.19–0.36 g NO3 −-N g−1 VS d−1 were obtained.