Denitrification behavior in a woodchip-packed bioreactor with gradient filling for nitrate-contaminated water treatment

Woodchip solid-phase denitrification bioreactors (SPDRs) are widely applied to remove NO3− from water. In this study, two SPDRs with different woodchip filling patterns, namely a gradient filling bioreactor (G-SPDR) and a uniform filling bioreactor (U-SPDR), were constructed and their denitrification performances were investigated. Analysis of the NO3− removal pathway along the water flow path showed that NO3− removal rates could be enhanced...