Towards biomass production and wastewater treatment by enhancing the microalgae-based nutrients recovery from liquid digestate in an innovative photobioreactor integrated with dialysis bag. (1st September 2022)

• Record Type: Journal Article
• Authors: Shao, Han; Sun, Yahui; Jiang, Xiaoxiang; Hu, Jun; Guo, Chenglong; Lu, Chenjia; Guo, Feihong; Sun, Chihe; Wang, Yunjun; Dai, Chuanchao
• Is Part Of: Journal of environmental management. Volume 317(2022)
• Publication Date: 2022-09-01
• Subjects: Liquid digestate -- Microalgae -- Photobioreactor -- Light availability -- Nutrients removal; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.115337
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Microalgae-based nutrients recovery from liquid anaerobic digestate of swine manure has been a hotspot in recent decades. Nevertheless, in consideration of the high NH4 + -N content and poor light penetrability exhibited by the original liquid digestate, uneconomical pretreatment on liquid digestate including centrifugation and dilution are indispensable before microalgae cells inoculation. Herein, aiming at eliminating the energy-intensive and freshwater-consuming pretreatment on liquid digestate and enhancing microalgae growth, the dialysis bag which permits nutrients transferring across its wall surface whereas retains almost all matters characterized by impeding light transmission within the raw liquid digestate was integrated into a column photobioreactor (DB-PBR). Consequently, light availability of microalgae cells in DB-PBR was elevated remarkably and thus contributed to a 357.58% improvement on microalgae biomass concentration in DB-PBR than the conventional PBR under 80 μmol m −2 s −1 . Likewise, superior nutrients removal efficiencies from liquid digestate were obtained in DB-PBR (NH4 + -N: 74.84%, TP: 63.75%) over the conventional PBR (NH4 + -N: 30.27%, TP: 16.86%). Furthermore, higher microalgae biomass concentration (1.87 g L −1 ) and nutrients removal efficiencies (NH4 + -N: 95.12%, TP: 76.87%) were achieved in the DB-PBR by increasing the light intensity to 140 μmol m −2 s −1 . More importantly, the DB-PBR may provide a simple and greener solution to purify other kinds of wastewater. Graphical abstract: Image 1 Highlights: A dialysis bag based photobioreactor was proposed for liquid digestate treatment. Liquid digestate without pretreatment can be directly employed in the DB-PBR. The dialysis bag contributed to better light availability of microalgae cells. A 357.58% increase in microalgae biomass concentration was realized. The removal efficiencies of NH4 + -N and TP reached 95.12% and 76.87%.