Research on mechanism of utilizing agricultural waste to strengthen constructed wetland to treat tailwater of a sewage treatment plant
To investigate the feasibility of utilizing three typical agricultural waste materials(i.e.,corn cobs,corn stalks,and wheat straw)as external carbon sources for denitrification in constructed wetlands,the enhancement mechanism of plant carbon sources in promoting nitrogen removal from wastewater was analyzed using three-dimensional fluorescence and high-throughput sequencing.The results showed that agricultural waste materials can release organic carbon effectively,with an accumulated carbon release of 119.78-172.84 mg·g-1.The dissolved organic matter(DOMs)decomposed and released mainly consisted of humic acid and fulvic acid.In the constructed wetlands with added agricultural waste materials,the removal efficiency of TN increased by 30.8%-41.2%,and the relative abundance of denitrifying bacteria genera such as Pseudomonas and Thauera increased by 16.38%-22.02%.The constructed wetland with added corn stalks represented better denitrification performance.Utilizing agricultural waste materials as external carbon sources in constructed wetlands for treating tailwater from sewage treatment plants can significantly reduce the TN concentration in the effluent,providing a new avenue for agricultural waste treatment.