In order to investigate the tolerance of endogenous partial denitrification(EPD)system to different types of low molecular weight polycyclic aromatic hydrocarbons(PAHs)and to explore methods to enhance the impact resistance of EPD systems, this study first acclimated EPD systems with 20mg/L PAHs(phenanthrene and anthracene), and then added other types of PAHs(anthracene, phenanthrene, and naphthalene)at concentrations of 0~80mg/L to the EPD system to analyze the mechanisms of PAHs tolerance by batch tests. The results indicated that under the stress of phenanthrene and anthracene, the EPD systems maintained a high accumulation rate of 86% for NO2--N and a removal capacity of 50% for PO43--P. In the anthracene system, the microorganisms secreted more extracellular polymeric substances to protect themselves, while a greater enrichment of PAH-RHD GNF/R and PAH-RHD GPF/R genes was observed to enhance tolerance to PAHs in the phenanthrene system. The introduction of phenanthrene and anthracene significantly enriched denitrifying glycan bacteria and denitrifying phosphorus accumulating bacteria. The denitrifying activity of the EPD system acclimated with phenanthrene was(167.429±2.321)mgN/(gVSS⋅h), and it still maintained a well phosphorus removal capacity under the stress of naphthalene and anthracene. The EPD system acclimated with anthracene maintained high NO2--N accumulation capacity under the stress of naphthalene and phenanthrene, with denitrifying bacterial activity at(220.137±0.575)mgN/(gVSS⋅h). This study provides the theoretical support for the tolerance of EPD systems to low molecular weight PAHs and also proposes insights into enhancing the impact resistance of EPS system through technological interventions, which has significant importance for optimizing the operational effectiveness of EPD in wastewater treatment.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |