In this study, a proportional – integral feedback control system was implemented on a lab-scale differential biofilter to control the gas phase toluene concentration in the soil bed through online manipulation of the inlet toluene concentration. The feedback control system was based on a cascade controller that manipulated the setpoint of an air bath diffusion system to manipulate the inlet toluene concentration. The controller performed well for toluene concentrations in the reactor of 10 – 300 ppm for both setpoint changes and disturbance rejections; however, the system was nonlinear requiring different tuning parameters at different outlet concentrations. Feedback control of the toluene concentration in the differential reactor was used to explore the impact of concentration on start-up and long-term biofilter operation in a rigorous fashion. Starting at an reactor concentration of 20 ppm and then increasing to 65 ppm increased the toluene removal rate (33 ± 1.6 g m⁻³h⁻¹) compared to starting the reactor at an outlet concentration of 81 ppm before settling at 65 ppm (42 ± 0.9 g m^{− 3}h⁻¹). The toluene removal rate increased with increasing outlet toluene concentration and then eventually decreased when reaching the inhibitory toluene concentration (ranged from 80 to 250 ppm).

在这项研究中，在实验室规模的差分生物滤池上实施了比例积分反馈控制系统，以通过在线控制进口甲苯浓度来控制土壤床中的气相甲苯浓度。反馈控制系统基于级联控制器，该级联控制器控制空气浴扩散系统的设定值以控制进口甲苯浓度。对于设定值变化和干扰抑制，控制器在反应器中的甲苯浓度为10 – 300 ppm时表现良好。但是，系统是非线性的，需要在不同的出口浓度下使用不同的调整参数。差分反应器中甲苯浓度的反馈控制用于严格控制浓度对启动和长期生物滤池运行的影响。^-3 h ^-1），而出口反应器在出口浓度为81 ppm之前启动，然后以65 ppm（42±0.9 gm ^-3 h ^-1）沉淀。甲苯去除率随出口甲苯浓度的增加而增加，然后在达到抑制性甲苯浓度（范围为80至250 ppm）时最终降低。