Microbial diversity and the implications of sulfide levels in an anaerobic reactor used to remove an anionic surfactant from laundry wastewater

The objective of this study was to evaluate the removal of linear alkylbenzene sulfonate (LAS) from commercial laundry wastewater using an expanded granular sludge bed (EGSB) reactor with two specific LAS loading rates (SLLRs), 1.0 and 2.7 mg LAS gVS ?1 d ?1. The biomass was characterized using denaturing gradient gel electrophoresis (DGGE) and 16S Ion Tag sequencing. Higher LAS removal (92.9%) was observed in association with an SLLR of 1.0 mg LAS gVS ?1 d ?1 than with an SLLR of 2.7 mg LAS gVS ?1 d ?1 (58.6%). A relationship between the S ?2 concentration in the effluent and the surfactant removal efficiency was observed. This result is indicative of the inhibition of LAS-removing microbiota at S ?2 concentrations greater than 20 mg S L?1. By using DGGE, microbial stratification was observed in the reactor in association with granule size, even though the reactor is considered to be a completely mixed regime. The RDP-classifier identified 175 genera, 33 of which were related to LAS degradation.

本研究旨在评估采用膨胀颗粒污泥床（expanded granular sludge bed, EGSB）反应器，以两种特定直链烷基苯磺酸盐（linear alkylbenzene sulfonate, LAS）负荷速率（SLLRs，即1.0 mg LAS·gVS⁻¹·d⁻¹与2.7 mg LAS·gVS⁻¹·d⁻¹），从商业洗衣废水中去除直链烷基苯磺酸盐的效果。研究采用变性梯度凝胶电泳（denaturing gradient gel electrophoresis, DGGE）与16S离子标签测序对反应器内的微生物生物质进行表征。结果显示，当直链烷基苯磺酸盐负荷速率为1.0 mg LAS·gVS⁻¹·d⁻¹时，直链烷基苯磺酸盐去除率可达92.9%，高于负荷速率为2.7 mg LAS·gVS⁻¹·d⁻¹时的58.6%。研究观察到出水中的硫化物（S²⁻）浓度与表面活性剂去除效率存在关联，该结果表明，当硫化物浓度高于20 mg S·L⁻¹时，降解直链烷基苯磺酸盐的微生物菌群会受到抑制。通过变性梯度凝胶电泳分析发现，尽管该反应器被认为是完全混合式运行体系，但其内部仍出现了与颗粒粒径相关的微生物分层现象。核糖体数据库项目分类器（RDP-classifier）共鉴定出175个菌属，其中33个菌属与直链烷基苯磺酸盐降解相关。