Enhancement of claus tail gas treatment with membrane and reducing step

A method for removing sulfur-containing compounds from a sulfur recovery unit (SRU) tail gas stream includes the steps of introducing the SRU tail gas stream to a reducing unit to produce a membrane feed, the reducing unit configured to reduce the sulfur-containing compounds to hydrogen sulfide, introducing the membrane feed to a hydrogen sulfide membrane unit, the hydrogen sulfide membrane unit comprising a membrane, wherein the membrane feed comprises hydrogen sulfide, allowing the membrane feed to contact a feed side of the membrane such that hydrogen sulfide permeates through the membrane to a permeate side, and collecting the retentate gases that fail to permeate through the membrane to produce a stack feed, wherein the stack feed comprises retentate gases.