Nutrient removal from wastewater by corn straw and its fertilization potential

In northern rural China, the uncontrolled disposal of corn straw and domestic wastewater have posed a serious challenge to the ecological environment, whereas studies of their combined and efficient treatment remain relatively limited. In this study, a bucket-scale constructed wetland system was established to jointly treat corn straw and domestic wastewater, aiming to investigate the effects of corn straw on nitrogen and phosphorus removal under different operational conditions and its decomposition and adsorption behaviors during wastewater treatment to assess its potential for fertilizer-oriented resource utilization. We found under the medium-concentration wastewater with crushed corn straw, pollutant removal was highest (≈70%) but declined markedly after day 8; meanwhile, wastewater conditions increased straw decomposition by ~20% and enhanced adsorption of total nitrogen (TN) and total phosphorus (TP). EEM analysis revealed a significant increase in the proportion of biodegradable organic components. And structural characterization showed pronounced disruption of cellulose crystalline regions and their associated functional groups. Therefore, corn straw can effectively remove nitrogen and phosphorus from water while exhibiting considerable potential for fertilizer-oriented resource utilization, providing a scientific basis for the synergistic treatment of agricultural residues and water pollutants in northern rural regions.