The　successful　application　of　bio-electrocatalyzed　system　(BES)　to　wastewater　treatment　inevitably　depends　on　the　improvement　of　performance　and　the　reduction　of　costs　at　a　scale-up　level.　One　efficient　way　to　achieve　these　goals　is　to　couple　BES　with　traditional　anaerobic　processes　to　industrial　wastewater　treatment.　Here　we　developed　a　hybrid　anaerobic　system　built-in　with　electrode　modules　(HAR-BES,　30　L)　as　an　inexpensive　but　high-performance　process　for　azo　dye　containing　wastewater　treatment.　HAR-BES　showed　faster　start-up,　10%　higher　azo　dye　decolorization　efficiency,　and　20%　higher　COD　removal　efficiency　than　an　anaerobic　reactor　(AR)　without　electrode　modules.　Microbial　community　analysis　showed　functional　diversity　in　electrode　biofilm　and　sludge　samples.　Geobacter　and　Syntrophus,　which　would　account　for　electrode　respiration　and　reduction　of　azo　dye,　respectively,　were　dominant　in　electrode　biofilms.　Tracer　experiments　and　modeling　of　residence　time　distribution　indicated　that　the　fluid　pattern　in　HAR-BES　was　close　to　plug　flow.　Simulation　of　computational　fluid　dynamics　showed　faster　water　velocity　near　electrode　modules　and　better　sludge　expansion　in　HAR-BES　than　AR.　This　study　proved　that　HAR-BES　improved　anaerobic　wastewater　treatment　comprehensively　through　the　analysis　of　chemicals,　microbial　community,　and　modeling　of　fluid　pattern.