The impact of cationic polymer dosage on aerobic granular sludge formation and system performance

Aerobic granular sludge technology faces a significant challenge regarding slow startup time when dealing with real wastewater. The present study introduces an innovative approach to decrease the granulation time while maintaining a substantial degree of organic and inorganic pollutant extraction. With this new strategy, aerobic granulation in an SBR is improved and accelerated by adding a cationic polymer. Hydrofloc cationic polymers were used to augment granule formation. Results show that adding a cationic polymer dosage of 15 ppm accelerated the formation of granules, reducing the reactor startup time. In the initial days, COD efficiency fluctuated due to the reactor's instability because of biomass discharge in the effluent. However, the COD removal efficiency reached 97 ± 1.5% after 15 days of operation of the reactor. NH₄⁺–N, total phosphorus (TP), and total nitrogen (TN) removal efficiencies were 97%, 63%, and 76% on average throughout the 16–50 day stable operating stage. The findings suggest that using a cationic polymer can enhance the granulation process in an aerobic granular system.