P T Five Star is a textile factory located in the city of Bandung. The production processes carried out by PT Five Star are spinning, weaving, dyeing, printing, and border. The wastewater generated by these activities has an average Ph value of 8, TSS 129 mg / l, BOD5 495.33 mg / l, and COD of 995 mg / l. The average discharge of waste water was 69.01 m3 / day. Discharge fluctuation and wastewater characteristics are very high.Before being discharged into the environment, the wastewater is treated in a wastewater treatment plant (IPAL). The main processing in WWTP is sedimentation and stabilization. The sedimentation process is assisted by ferrous sulfate and lime coagulants. Wastewater from IPAL processing still does not meet quality standards.The main problems of PT Five Star WWTP are insufficient biological treatment capacity, the dimensions of the mixing unit are too large, the flocculation unit is not available, and the dimensions of the equalization basin are not sufficient.To improve the performance of WWTP, the authors recommend enlarging the volume of the equalization bath to 150 m3, converting the mixing basin into two new mixing tanks with a volume of 0.216 m3 and three flocculation tanks with a volume of 0.648 m3, controlling the pH with the addition of acid, and expanding the stabilization bath to 703 m2 and perayaam depth. stabilization bath to 1.5 m.