Three measures of sludge(mixed liquid) return(pump-lift,impeller-lift and air-lift) about nitrogen and phosphorus removal processes are introduced and analyzed.The measures of impeller-lift and air-lift can not only simplify processes and integrate the devices for nitrogen and phosphorus removal so that the land occupation and investment demand for the plant are reduced,but also can be easily operated with less electricity consumption,which are considered to be promising for application in medium-sized and mini-type plant of wastewater treatment.