Chlorophenols are inhibitory compounds that can be biodegraded by aerobic granules in discontinuous processes. Many industrial wastewaters are characterized by transient pH variation over time. These pH changes could affect the overall granule structure and microbial activity during the chlorophenol biodegradation. The objective of this research was to evaluate the effects of transient pH variation on the specific degradation rate (q), granule integrity coefficient (IC), and size in sequencing batch reactors treating 4-chlorophenol (4-CP). First, aerobic granules were acclimated for efficient 4-CP degradation (>99%). The acclimated granules consisted of 55.7% of the phyla Proteobacteria and 40.6% of Bacteroidetes. The main bacteria belong to the order Sphingobacteriales (24%), as well as Amaricoccus, Acidovorax, Shinella, Rhizobium, and Flavobacterium, some of which are new genera reported in acclimated granules degrading 4-CP. Then, pH changes were applied to the acclimated aerobic granules, observing that acid pHs decreased to a greater extent the specific degradation rate (67% to 99%) than basic pHs (34% to 80%). These pH changes caused the granule disaggregation but with lower effects on the IC. The effects of pH change were mainly on the microbial activity more than the physical characteristics of aerobic granules degrading 4-CP.

氯酚是抑制性化合物，可在不连续过程中被好氧颗粒生物降解。许多工业废水的特征在于pH随时间变化。这些pH变化可能会影响氯酚生物降解过程中的总体颗粒结构和微生物活性。这项研究的目的是评估在处理4-氯苯酚（4-CP）的分批反应器中，瞬时pH变化对比降解率（q），颗粒完整性系数（IC）和尺寸的影响。首先，使好氧颗粒适应有效的4-CP降解（> 99％）。适应的颗粒由55.5％的门菌属细菌和40.6％的拟杆菌属组成。主要细菌属于Sphingobacteriales（24％）以及Amaricoccus，Acidovorax，Shinella，Rhizobium和Flavobacterium，其中一些是新的属，它们在降解4-CP的适应颗粒中有报道。然后，将pH变化应用于已适应的好氧颗粒，观察到酸性pH值比基本pH值（34％至80％）在更大程度上降低了比降解率（67％至99％）。这些pH值变化导致颗粒解体，但对IC的影响较小。pH变化的影响主要是对微生物活性的影响，而不是好氧颗粒降解4-CP的物理特性。