The　nitrite　accumulation　in　handling　nitrate　and　sulfide-laden　wastewater　in　a　continuous-flow　upflow　anaerobic　sludge　blanket　reactor　was　studied.　At　sulfide/nitrate-nitrogen　ratio　of　1:0.76　and　loading　rates　of　1.2　kg-S　m(-3)　d(-1)　and　0.4　kg-N　m(-3)　d(-1),　the　elemental　sulfur　and　nitrite　accumulation　rates　peaked　at　90%　and　70%,　respectively,　with　Acrobacter,　Azoarcus　and　Thauera　presenting　the　functional　strains　in　the　studied　reactor.　The　accumulated　nitrite　was　proposed　a　promising　feedstock　for　anaerobic　ammonia　oxidation　process.　An　integrated　partial　autotrophic　denitrification-anaerobic　ammonia　oxidation-aeration　process　for　handling　the　ammonia　and　sulfide-laden　wastewaters　is　proposed　for　further　studies.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.