Drip irrigation biofouling with treated wastewater: bacterial selection revealed by high-throughput sequencing

Clogging of drippers due to the development of biofilms weakens the advantages and impedes the implementation of drip irrigation technology. The objective of this study was to characterise the bacterial community of biofilms that develop in a drip irrigation system supplied with treated wastewater. High-throughput sequencing of 16S rRNA gene amplicons indicated that the bacterial community composition differed between drippers and pipes, mainly due to changes in the abundance of the genus Aquabacterium. Cyanobacteria were found to be involved in the biological fouling of drippers. Moreover, bacterial genera including opportunistic pathogenic bacteria such as Legionella and Pseudomonas were more abundant in dripper and pipe biofilms than in the incoming water. Some genera such as Pseudomonas were mostly recovered from drippers, while others (ie Bacillus, Brevundimonas) mainly occurred in pipes. Variations in the hydraulic conditions and properties of the materials likely explain the shift in bacterial communities observed between pipes and drippers.滴头因生物膜形成发生堵塞，削弱了滴灌技术的应用优势，同时阻碍了该技术的推广实施。本研究旨在对以再生水（treated wastewater）为供水水源的滴灌系统中形成的生物膜细菌群落进行表征分析。通过对16S rRNA基因扩增子（16S rRNA gene amplicons）开展高通量测序（High-throughput sequencing），结果显示滴头与管道内的细菌群落组成存在差异，该差异主要源于水杆菌属（Aquabacterium）的丰度变化。研究发现蓝藻（Cyanobacteria）参与了滴头的生物结垢过程。此外，军团菌属（Legionella）、假单胞菌属（Pseudomonas）等条件致病菌类群，在滴头与管道生物膜中的丰度均高于进水样本。部分菌属（如假单胞菌属）主要从滴头中分离得到，而另一些菌属（即芽孢杆菌属（Bacillus）、短波单胞菌属（Brevundimonas））则多定植于管道内。水力条件与材料属性的差异，或可解释管道与滴头间观测到的细菌群落结构偏移现象。