Nitrogen　(N)　and　phosphorus　(P)　species　in　wastewater　treatment　plants　(WWTPs)　effluents　are　important　sources　of　nutrient　input　to　water　bodies,　resulting　in　deteriorated　eutrophication.　The　combination　of　electrochemical　technology　and　constructed　wetland　provides　emerging　prospects　for　tertiary　treatment　of　WWTPs　effluents.　In　this　work,　three　bench-scale　electrochemically　integrated　vertical　flow　constructed　wetlands　(E-VFCWs)　were　established　in　parallel　with　different　inoculated　sources.　Among　them,　the　E-VFCW　inoculated　with　anaerobic　sludge　(AN)　of　a　swine　wastewater　treatment　plant　exhibited　significantly　shorter　start-up　period　(9　d),　followed　by　anoxic　sludge　(A)　from　a　municipal　WWTP　(18　d),　and　no　inoculum　(NI)　exhibited　the　longest　start-up　duration　(30　d).　In　addition,　AN　group　allowed　the　highest　removal　efficiencies　(NO3--N　(97.0　±　1.6　%),　TN　(83.3　±　4.6　%),　and　PO43--P　(93.3　±　3.3　%))　in　tertiary　wastewater　treatment,　and　lower　concentrations　of　SO42--S　and　total　Fe　in　effluents.　Results　of　microbial　structure　and　Tax4Fun　suggested　that　multi-path　metabolisms　including　H2-,　Fe(II)-,　and　FemSn-dependent　denitrification　might　facilitate　NO3--N　reduction　in　E-VFCWs.　The　microbial　mechanisms　that　AN　exhibited　the　highest　denitrification　efficiency　in　the　E-VFCWs　may　include　the　highest　bacterial　copies　number　and　the　more　abundant　denitrifying　genes.　Moreover,　it　should　be　noted　that　electron　transfers　mediated　by　sulfur　(S)　cycle　might　significantly　enhance　NO3--N　reduction　in　E-VFCWs,　especially　in　AN　group.　To　conclude,　the　study　offers　new　microbial　insights　into　N　conversion　and　S　cycling　patterns　in　electrochemically　integrated　systems　in　response　to　inoculated　source.　©　2022　The　Institution　of　Chemical　Engineers