Advanced nitrogen removal using pilot-scale SBR with intelligent control system built on three layer network

Since eutrophication has become increasingly severe in China,nitrogen and phosphorous have been the concern of wastewater treatment,especially nitrogen remov-al.The stabilization of the intelligent control system and nitrogen removal efficiency were investigated in a pilot-scale aerobic-anoxic sequencing batch reactor(SBR)with a treat-ment capacity of 60 m3/d.Characteristic points on the profiles of dissolved oxygen(DO),pH,and oxidation reduction potential(ORP)could exactly reflect the process of nitrifica-tion and denitrification.Using the intelligent control system not only could save energy,but also could achieve advanced nitrogen removal.Applying the control strategy water quality of the effluent could stably meet the national first discharge standard during experiment of 10 months.Even at low tem-perature(t=13°C),chemical oxygen demand(COD)and total nitrogen(TN)in the effluent were under 50 and 5 mg/L,respectively.