A comparison of aerobic granular sludge with conventional and compact biological treatment technologies

ABSTRACT

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.

KEYWORDS:

• Aerobic granular sludge
• chemicals’ consumption
• electricity demand
• integrated fixed-film activated sludge
• membrane bioreactor
• footprint

Acknowledgements

The authors are grateful to Jonatan Flodin (H2OLAND), Jesper Olsson (Uppsala Vatten och Avfall), Maria Jonstrup (VA SYD), Karin Myring (Strömstads kommun) and Jerry Johansson (Strömstads kommun) for support and fruitful discussions during the project.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Britt-Marie Wilén http://orcid.org/0000-0001-6155-7759

Additional information

Funding

This work was supported by the Swedish Water & Wastewater Association under project number 16-121 and Sweden Water Research.