Targeted external donor dosing in single-stage partial nitritation-anammox: A carbon-efficient control framework sustaining ultrahigh total nitrogen removal - Chengcheng Lin; Yanxiao Wei; Sha Wu; Jiao Jin; Yangkai Liu; Hong Chen; Hanbo Yu; Mohd Fadhil Md Din; Eli Hendrik Sanjaya; Binquan Wang (Process Safety and Environmental Protection, 2026)