Optimization for preparation of composite slow-release carbon source filler by response surface methodology and its denitrification characteristics
In response to the prevalent issue of inadequate organic carbon content in the effluent of urban wastewater treatment plants,the composite slow-release carbon source fillers were developed with Acorus calamus,a natural wetland plant,and β-hydroxybutyric acid and β-hydroxyvaleric acid copolymer(PHBV)as primary materials.The Box-Behnken Design model within the response surface methodology was utilized to study the impact of various mass ratios,freezing time,cross-linking time,and other key preparation parameters on the release properties of organic matter(measured in terms of TOC).The results indicated that both freezing time and the mass ratio-crosslinking time combination factors had a significant impact on carbon release properties.The results of the static leaching experiments indicated that the filler could slowly release carbon source with an average organic carbon release rate of(0.88±0.05)mg·(g·d)-1 and a total organic carbon release of(35.27±1.50)mg·g-1.The carbon release behavior followed both second-order kinetic and Ritger-Peppas kinetic models.In denitrification batch experiments with initial NO3-N concentrations ranging from 5 mg·L-1 to 20 mg·L-1,the biological denitrification effect was good with an average NO3--N removal rate of 84.42％to 92.20％.The BET characterization indicated that the optimally prepared filler had a specific surface area of 3.05 m2·g-1 and a pore size of 26.38 nm.The scanning electron microscopy(SEM)and the fluorescence excitation-emission matrix(EEM)analysis results indicated that the surface of the optimally prepared filler was rough and porous,which was conducive to the utilization of microbial growth and their attachment.The leachate organic matter consisted mainly of proteins,and they were available for microbial denitrification.The composite fillers demonstrated the combined effect of continuous carbon release and biological nitrogen removal processes,and can provide a reference for advanced denitrification technology from wastewater based on the carbon source fillers enhancement.
万方数据
维普
