A critical review of ammonia recovery from anaerobic digestate of organic wastes via stripping. (June 2021)

• Record Type: Journal Article
• Authors: Palakodeti, Advait; Azman, Samet; Rossi, Barbara; Dewil, Raf; Appels, Lise
• Is Part Of: Renewable & sustainable energy reviews. Volume 143(2021)
• Publication Date: 2021-06
• Subjects: Stripping -- Ammonia -- Anaerobic digestion -- Digestate -- Organic waste -- Modelling -- Ammonia recovery; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2021.110903
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: Anaerobic digestion is a well-established technology that valorises organic wastes to produce renewable energy as biogas. The ammonia released during this process can be inhibitory if it exceeds a threshold concentration. Additionally, ammonia is a harmful environmental pollutant and also a renewable source of energy, thus establishing a need for the recovery of ammonia. Gas-liquid stripping is one such widely researched technology to recover ammonia from wastewater. However, there have not been any reviews focusing solely on the application of stripping to recover ammonia from the anaerobic digestate of organic wastes. This study reviews the current state of research in this field, focusing on the factors affecting the ammonia recovery, stripping column designs and linking of an anaerobic digester to a stripping column. An overview of the work done on the modelling of the ammonia stripping from digestate is also included. This review offers a direction for further research in this field; i.e., experimental and modelling studies on i) the effect of digestate composition on ammonia recovery and ii) the effect of stripping gas on ammonia removal. Highlights: Process conditions and the %CO2 in the stripping gas influence ammonia recovery. Stripping columns designs are not a limiting factor determining ammonia removal. Stripping can alleviate ammonia inhibition in anaerobic digesters. Activity coefficients are used to estimate ammonia speciation in the digestate.