A Dimensionality-Reducible Operational Optimal Control for Wastewater Treatment Process.

Operational optimal control (OOC) is an essential component of wastewater treatment process (WWTP). The control variables usually are high-dimensional, nonlinear, and strongly coupled, which can easily fail traditional optimization control methods. Mathematically, these operational variables usually are in the unknown low-dimensional space embedded in the high-dimensional space.

Response of activity and community composition of nitrite-oxidizing bacteria to partial substitution of chemical fertilizer by organic fertilizer.

Nitrite oxidation as the second step of nitrification can become the determining step in disturbed soil systems. As a beneficial fertilization practice to maintain high crop yield and soil fertility, partial substitution of chemical fertilizer (CF) by organic fertilizer (OF) may exert a notable disturbance to soil systems. However, how nitrite oxidation responds to different proportions of CF to OF is still unclear.