The　application　of　ammonia-oxidizing　archaea　(AOA)-based　partial　nitrification-anammox　(PN-A)　for　mainstream　wastewater　treatment　has　attracted　research　interest　because　AOA　can　maintain　higher　activity　in　low-temperature　environments　and　they　have　higher　affinity　for　oxygen　and　ammonia–nitrogen　compared　with　ammonia-oxidizing　bacteria　(AOB),　thus　facilitating　stabilized　nitrite　production,　deep　removal　of　low-ammonia,　and　nitrite-oxidizing　bacteria　suppression.　Moreover,　the　low　affinity　of　AOA　for　ammonia　makes　them　more　tolerant　to　N-shock　loading　and　more　efficiently　integrated　with　anaerobic　ammonium　oxidation　(anammox).　Based　on　the　limitations　of　the　AOB-based　PN-A　process,　this　review　comprehensively　summarizes　the　potential　and　significance　of　AOA　for　nitrite　supply,　then　gives　strategies　and　influencing　factors　for　replacing　AOB　with　AOA.　Additionally,　the　methods　and　key　influences　on　the　coupling　of　AOA　and　anammox　are　explored.　Finally,　this　review　proposes　four　AOA-based　oxygen-　or　ammonia-limited　autotrophic　nitritation/denitrification　processes　to　address　the　low　effluent　quality　and　instability　of　mainstream　PN-A　processes.　©　2024　Elsevier　Ltd