LAUSR

Abstract The carbon release behaviour of polylactic acid (PLA)/starch blends and the correlation between solid-phase denitrification (SPD) performance and solid-carbon decomposition were investigated by both batch experiments and numerical simulations. The results showed that the mass ratio of PLA to starch is a key parameter in determining the total organic carbon (TOC) release rate of the blends. Hydrolysis of the blends contributed more markedly to the fraction of TOC released during denitrification compared with physicochemical leaching. The maximum denitrification rate of the blend-supported SPD system (PLA/starch mass ratio = 5:5) was 0.008 kg-N/(m3 h). Simulation results suggested that the denitrification performance of the SPD system was strongly affected by the fraction of its bioavailable solid carbon and also suggested that little TOC (mean value of 0.003 kg/m3) would be accumulated in the effluent. Therefore, the PLA/starch blend is a suitable solid-carbon source for nitrate removal because of its adaptability to environmental changes, stability of effluent quality and renewability.