A novel pattern of coupling sulfur-based autotrophic disproportionation and denitrification processes for achieving high-rate and precisely adjustable nitrogen removal

•SADP process was independently and controllably maintained in sulfur PBR.•SAD2 system achieved 2.38 times higher of SADN rate by the assist of SADP.•SADP-S2− had higher biocompatibility than chemical-S2− (Na2S).•Bioaugmentation and polysulfuration by SADP-S2− stimulated S0 utilization rate.•An applicable pattern of SAD2 system was supposed.