典型微塑料对异养硝化-好氧反硝化菌的影响特性研究

Influence of common microplastics on heterotrophic nitrification and aerobic denitrification bacteria

以HN-AD中的不动杆菌属Acinetobacter sp.TAC-1为对象,探究了不同种类、粒径和浓度的典型微塑料对其生长活性及脱氮性能的影响。经研究发现:聚丙烯(PP)与聚氯乙烯(PVC)对TAC-1的生长和脱氮性能表现出轻微促进作用,最大分别提高了6.99%和5.7%,而PS对其有一定的抑制作用,最高减小了13.22%,PE则对菌株的影响不显著;在粒径控制条件下,PS组中,100 nm粒径促进了菌株生长但抑制了脱氮效果,30μm粒径抑制了生长但对脱氮无影响。在PP影响下,几乎所有粒径都促进了菌株的生长和脱氮能力;在5μm条件下菌株生长最好,但对脱氮能力促进最强的是100 nm和30μm,其TN去除率分别达到80.61%和77.72%;PE和PVC粒径对菌株生长和脱氮效果均有微弱的促进作用,但不受粒径大小影响。浓度控制实验中,PS浓度为1.0~2.0 g/L时会抑制菌株生长和脱氮效果,浓度增大为2.5 g/L时促进菌体生长和强化脱氮作用,增加了2.3%;PP、PE、PVC浓度对菌株生长和脱氮效果影响不显著。研究结果可为理解微塑料与高氨氮废水共污染环境中的脱氮过程提供参考,对相关污染水体的治理与处理具有指导意义。

Microplastics are widely present in high-ammonia nitrogen wastewater,but their impact on heterotrophic denitrifying aerobic bacteria(HN-AD)remains unclear.In this study,Acinetobacter sp.TAC-1,a bacterium in HN-AD,is investigated to explore the effects of different types,sizes,and concentrations of typical microplastics on its growth activity and denitrification performance.Our study finds polypropylene(PP)and polyvinyl chloride(PVC)exhibits a slight promoting effect on TAC-1’s growth and denitrification performance,with a maximum increase of 6.99%and 5.7%respectively,while polystyrene(PS)has some inhibitory effect,with the highest decrease being 13.22%.Polyethylene(PE)exerts no obvious impact on the bacteria.Under controlled particle size conditions,in the PS group,a particle size of 100 nm promotes bacterial growth but inhibits denitrification,while 30μm inhibits growth but has no effect on denitrification.Under the influence of PP,almost all particle sizes promote both bacterial growth and denitrification capacity.Among these,the best growth occurs at 5μm,but the strongest promotion of denitrification capacity is observed at 100 nm and 30μm,with TN removal rates reaching 80.61%and 77.72%respectively.PE and PVC particle sizes both have a slight promoting effect on bacterial growth and denitrification,independent of particle size.In concentration-controlled experiments,PS concentrations of 1.0~2.0 g/L inhibit bacterial growth and denitrification,but at a concentration of 2.5 g/L,they promote bacterial growth and enhance denitrification,increasing by 2.3%.PP,PE,and PVC concentrations have no significant impact on bacterial growth and denitrification.Our study deepens our understanding of the denitrification process in environments co-polluted by microplastics and high-ammonia nitrogen wastewater and may provide some insights for the treatment and management of some polluted waters.