This　study　evaluated　the　performance　of　a　full-scale　upgrade　of　an　existing　wastewater　treatment　plant　(WWTP)　with　the　intermittent　cyclic　extended　aeration　system　(ICEAS),　located　in　Qingdao,　China.　The　ICEAS　system　was　not　able　to　meet　effluent　standards;　therefore,　a　series　of　modifications　and　control　strategies　were　applied　as　follows:　(1)　floating　plastic　carriers　were　added　to　the　tank　to　aid　biofilm　formation;　(2)　operation　parameters　such　as　mixing　and　aeration　time,　feeding　rate,　and　settling　time　were　adjusted　and　controlled　with　a　real-time　control　system;　(3)　a　sludge　return　system　and　submersible　water　impellers　were　added;　(4)　the　aeration　system　was　also　improved　to　circulate　carriers　and　prevent　clogging.　The　modified　ICEAS　system　exhibited　efficient　organic　and　nutrient　removal,　with　high　removal　efficiencies　of　chemical　oxygen　demand　(89.57　+/-　4.10%),　NH4+-N　(95.46　+/-　3.80%),　and　total　phosphorus　(91.90　+/-　4.36%).　Moreover,　an　annual　power　reduction　of　1.04　x　10(7)　kW.h　was　realized　as　a　result　of　these　modifications.