Optimization of ammonia removal in an integrated fix-film activated sludge using response surface methodology

In this work, removal of ammonia from synthetic wastewater using integrated fixed-film activated sludge (IFAS) process was optimized using response surface methodology (RSM). The main operating parameters such as ammonia concentration rate (ALR) and hydraulic retention time (HRT) were optimized to acquire the maximum removal efficiency. The linear, 2FI, quadratic, mean, and cubic models were utilized for modeling of the parameters. Residual nitrate and nitrite were determined as the byproducts. The results showed that the actual data fitted well with the predicted results. The maximum ammonia removal achieved using mean, linear, 2FI, quadratic, and cubic models were 59.88, 79.05, 79.32, 77.11, and 78.65%, respectively. Nitrate and nitrite were determined in ammonia concentrations of higher than 100 mg/l. The obtained results showed that RSM is a suitable technique for the optimization of conditions for the maximum removal of ammonia.