A/A/O工艺厌氧缺氧好氧(硝化)二沉池进水出水剩余污泥污泥回流混合液回流改良A/A/O工艺厌氧/缺氧调节厌氧进水10%缺氧好氧(硝化)沉淀池出水污泥回流剩余污泥进水90%混合液回流UCT工艺厌氧缺氧好氧二沉池进水出水剩余污泥外回流R(50~100%)内回流II(100~200%)内回流I(r=100~200%)MUCT工艺厌氧缺氧I好氧二沉池进水出水剩余污泥缺氧II回流R(50~100%)内回流I(r=100~200%)内回流II(100~200%)倒置A/A/O工艺MSBR(改良型SBR)缺氧池进水厌氧池缺氧池污泥浓缩SBRSBR0.5Q1.5Q回流1.0Q好氧池出水1.5Q回流1.0Q1.5Q回流