In this paper, we consider a new Monod type chemostat model with time delay and impulsive input concentration of the nutrient in a polluted environment. Us- ing the discrete dynamical system determined by the stroboscopic map, we obtain a "microorganism-extinction" periodic solution. Further, we establish the sufficient condi- tions for the global attractivity of the microorganismoextinction periodic solution. Using new computational techniques for impulsive and delayed differential equation, we prove that the system is permanent under appropriate conditions. Our results show that time delay is "profitlcss".