Activated sludge processes are often inhibited by nickel, cadmium, and cobalt. The inhibitory effect of these heavy metals on a synthetic wastewater treatment process was tested through pulse microrespirometry; i.e., pulse of substrate injected in a microreactor system. The inhibitory effect was tested under different conditions including the heavy metals, substrate and biomass concentrations, and exposure time. The inhibitory effect was quantified by the percentage of inhibition, half saturation constant (K_S), inhibition constant (K_I), and maximum oxygen uptake rate (OUR_max). The results indicated that, in a range of concentration from 0 to 40 mg L^-1, the three heavy metals exerted an uncompetitive and incomplete inhibitory effect, with a maximum inhibition of 67, 57, and 53% for Ni, Co, and Cd, respectively. An increase of the biomass concentration by 620% resulted in a decrease of the inhibition by 47 and 69% for Co and Cd, respectively, while no effect was observed on Ni inhibition. An increase of the substrate concentration by 87% resulted in an increase of the inhibition by 24, 70, and 47% for Ni, Co and Cd, respectively. In the case of nickel and cadmium, an increase in the exposure time to the heavy metals also increased the inhibition.

活性污泥工艺通常受到镍，镉和钴的抑制。通过脉冲微呼吸法测试了这些重金属对合成废水处理过程的抑制作用。即，在微反应器系统中注入的底物的脉冲。在不同条件下测试了抑制作用，包括重金属，底物和生物质浓度以及暴露时间。通过抑制百分比，半饱和常数（K _S），抑制常数（K _I）和最大摄氧速率（OUR _max）来量化抑制作用。结果表明，在0至40 mg L ^-1的浓度范围内，这三种重金属发挥了无竞争性和不完全的抑制作用，对Ni，Co和Cd的最大抑制作用分别为67％，57％和53％。生物质浓度增加620％导致对Co和Cd的抑制作用分别降低47％和69％，而对Ni的抑制作用没有观察到。底物浓度增加87％，Ni，Co和Cd的抑制作用分别增加24％，70％和47％。在镍和镉的情况下，重金属暴露时间的增加也增加了抑制作用。