This　paper　is　concerned　with　the　dissolved　oxygen　control　problem　in　the　wastewater　treatment　plants　(WWTPs)　based　on　a　dynamic　event-triggered　PID　control　strategy　(D-EPID).　The　aim　of　the　paper　is　to　develop　a　simple　event-triggered　PID　strategy　for　practical　application.　The　developed　strategy　differs　from　existing　PID　controllers　in　that,　it　updates　the　control　input　only　when　certain　triggering　conditions　are　satisfied,　while　existing　controllers　update　the　control　input　at　each　sampling　instant.　The　latter　controller　may　consume　extra　energy　even　there　is　no　need　to　update　the　control　input.　The　triggering　condition　is　designed　based　on　the　deviation　of　tracking　error　and　an　auxiliary　variable.　The　stability　analysis　is　conducted　theoretically　via　designing　an　appropriate　Lyapunov　function,　which　cannot　be　provided　by　existing　PID　control　methods.　The　controller　is　designed　for　improving　the　control　performance　of　WWTPs　by　regulating　one　significant　variable,　i.e.,　oxygen　concentration　at　some　set　points.　Simulations　based　on　the　BSM1　platform　are　conducted　to　verify　the　effectiveness　of　the　proposed　control　strategy.　Simulation　results　show　that　for　our　proposed　control　method,　the　updating　number　of　the　control　input　can　be　decreased　greatly　while　maintaining　the　desired　tracking　performance.