In-situ retrofitting from IFAS-AAO to IFAS-Bardenpho in a wastewater treatment plant for advanced nitrogen removal - Hongyu Wang; Zhihong Zheng; Xiao Rang; Yulong Yang; Zhengran Hao; Xingyu Zheng; Xilin Peng; Jie Yao; Minghua Wei; Shuang Zhang; Jin Xu (Journal of Environmental Chemical Engineering, 2026)