The aerobic granular sludge (AGS) technology is growing towards becoming a mature option for new municipal wastewater treatment plants and capacity extensions. A process based on AGS was compared to conventional activated sludge processes (with and without enhanced biological phosphorus removal), an integrated fixed-film activated sludge (IFAS) process and a membrane bioreactor (MBR) by estimating the land area demand (footprint), electricity demand and chemicals' consumption. The process alternatives compared included pre-settling, sludge digestion and necessary post-treatment to achieve effluent concentrations of 8 mg/L nitrogen and 0.2 mg/L phosphorus at 7°C. The alternative based on AGS was estimated to have a 40-50% smaller footprint and 23% less electricity requirement than conventional activated sludge. In relation to the other compact treatment options IFAS and MBR, the AGS process had an estimated electricity usage that was 35-70% lower. This suggests a favourable potential for processes based on AGS although more available experience of AGS operation and performance at full scale is desired.

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Aerobic granular sludge (AGS) plants have gained growing interest and application due to their low energy demand, small footprint, and low operational costs. However, the fulfilment of strict discharge limits...

This study demonstrates a comparison of energy usage, land footprint and volumetric requirements of municipal wastewater treatment with aerobic granular sludge (AGS) and conventional activated sludge (CAS) at a full‐scale wastewater treatment plant characterized by large fluctuations in nutrient loadings and temperature. The concentration of organic matter in the influent to the AGS was increased by means of hydrolysis and bypassing the pre‐settler. Both treatment lines produced effluent concentrations below 5 mg BOD7 L‐1, 10 mg TN L‐1, and 1 mg TP L‐1, by enhanced biological nitrogen‐ and phosphorus removal. In this case study, the averages of volumetric energy usage over one year were 0.22 ± 0.08 and 0.26 ± 0.07 kWh m‐3 for the AGS and CAS, respectively. A larger difference was observed for the energy usage per reduced P.E., which was on average 0.19 ± 0.08 kWh P.E.‐1 for the AGS and 0.30 ± 0.08 kWh P.E.‐1 for the CAS. However, both processes had the potential for decreased energy usage. Over one year, both processes showed similar fluctuations in energy usage, related to variations in loading, temperature, and DO. The AGS had a lower specific area, 0.3 m2 m‐3 d‐1, compared to 0.6 m2 m‐3 d‐1 of the CAS, and also a lower specific volume, 1.3 m3 m‐3 d‐1 compared to 2.0 m3 m‐3 d‐1. This study confirms that AGS at full‐scale can be compact and still have comparable energy usage as CAS.