It　is　essential　for　a　full-scale　treatment　plant　processing　saline　wastewater　to　understand　the　effects　of　salt　on　an　activated　sludge　system　and　the　performance　of　pollutant　removal.　For　this　purpose,　a　bench-scale　modified　university　of　cape　town　(MUCT)　process　was　tested　to　treat　real　saline　sewage　with　salt　concentrations　of　5,　8,　10　and　15　g/L.　The　experimental　results　indicated　that　salt　in　sewage　significantly　affected　nutrient　removal　compared　with　organic　removal.　Total　phosphorous　removal　efficiency　in　MUCT　deceased　from　92%　when　treating　freshwater　to　72%　when　treating　8　g/L　saline　wastewater,　while　total　nitrogen　removal　efficiency　decreased　from　75%　to　62%.　Vital　number　of　aerobic　heterotrophic　bacteria　shrunk　when　salt　concentration　in　wastewater　was　over　15　g/L,　resulting　in　decreased　organic　removal　efficiency.　Obvious　nitrite　accumulation　in　the　aerobic　tank　and　denitrifying　nitrite　by　polyphosphate　accumulating　organisms　(PAOs)　in　the　anoxic　tank　occurred　in　the　MUCT　treating　saline　sewage　containing　over　8　g/L　NaCl.　Elevated　salt　level　enhanced　the　carbon　requirement　for　phosphorus　release.　Population　shift　in　biological　community　(aerobic-heterotrophic,　nitrifying,　and　denitrifying　organisms)　in　treatment　system　was　observed　in　response　to　salinity　inhibition,　which　contributed　to　an　insight　into　the　nature　and　the　magnitude　of　the　salt　effects.