Ammonia removal form municipal wastewater by air stripping process: An experimental study

Abstract

This study was aimed to evaluate ammonia removal efficiency (ARE) in the air stripping process in different operating conditions for wastewater with a low concentration of ammonia such as municipal wastewater treatment plants (WWTPs) on the laboratory scale. The experiments were performed at different pH (9.7 ± 0.26, 10.93±0.16 and 11.94±0.32), temperature (34.25±0.44, 38.57±3.4 and 40.5 ± 7.68 in °C), initial concentration (26.98 -47.34, 19.49 -47.48 and 41–98 in mg/L) and air-water (G/L) ratio (60:1, 70:1 and 80:1). The results showed that ARE in the operating conditions (initial NH4+concentration 26.98 -98 mg/L, pH 9.4–12.38, temperature 34–45.8 °C and G/L 60:1–80:1) was increased from 6.6% to 98% with the range of 1 to 14 h. Based on the results, ARE with 1 standard deviation (SD) increase per unit of pH, temperature and initial NH4+concentration was 13.03%, 3.99% and 2.3%, respectively. Also, based on multivariate regression model at high and low G/L, temperature and pH had the most significant effect on ARE for a synthetic solution as well as a municipal WWTPs stream, respectively. ARE (91%) was obtained during the stripping process of synthetic and actual municipal wastewater.