Sludge　dewatering　is　one　of　the　keys　for　sludge　disposal　and　treatment　of　municipal　wastewater　treatment　plants.　In　this　study,　the　sludge　dewaterability,　flocculant　consumption　and　costs　of　sludge　dewatering　for　different　wastewater　treatment　processes　including　A2/O　and　A2/O-MBR　processes　were　analyzed,　as　well　as　the　factors　of　sludge　dewatering　were　analyzed　by　redundancy　analysis　(RDA)　method,　based　on　the　data　of　one　municipal　wastewater　treatment　plant　of　Beijing　in　2013.　Results　showed　that　both　sludge　dewaterability　and　flocculant　consumption　presented　the　seasonal　variation,　which　means　sludge　dewatering　was　harder　and　coupled　with　higher　flocculant　consumption　in　the　winter.　Although　the　lower　moisture　content　of　dewatered　sludge　was　obtained　in　the　A2/O-MBR　process　(81.92%±1.64%)　compared　with　that　in　the　A2/O　process　(82.56%±1.35%),　the　consumptions　of　flocculant　[(8.70±7.25)　kg·t-1　DS]　and　electric　energy　(331.82　kW·h·t-1　DS)　in　the　A2/O-MBR　process　were　higher　than　those　in　the　A2/O　process　[(7.42±2.96)　kg·t-1　DS,　121.57　kW·h·t-1　DS　for　flocculant　consumption　and　electric　energy　respectively],　resulting　in　higher　operation　costs　(RMB　204.76　yuan·t-1　DS　of　flocculant　consumption　and　RMB　231.61　yuan·t-1　DS　of　energy　consumption　for　the　A2/O-MBR,　RMB　175.00　yuan·t-1　DS　of　flocculant　consumption　and　RMB　84.86　yuan·t-1　DS　of　energy　consumption　for　the　A2/O,　respectively).　Results　of　RDA　showed　that　the　seasonal　variation　of　sludge　dewaterability　mainly　depended　on　the　content　of　organic　matter　in　sludge　which　was　related　to　the　seasonal　factors　such　as　temperature,　and　was　also　impacted　by　the　operating　parameters　such　as　SRT　in　wastewater　treatment.　©,　2015,　Science　Press.　All　right　reserved.