Energy recovery by anaerobic digestion of algal biomass from integrated microalgae/constructed wetland wastewater treatment

Abstract

The present study evaluated the potential for biogas generation from microalgae (MA) biomass and macrophytes used in vertical flow constructed wetlands (VFCW). The samples were obtained by separation and collection of MA after a hydraulic retention time of 14 days, frozen and taken to the laboratory, while the macrophytes of VFCW were obtained, by pruning, every 6 months. The obtained results presented reductions of 63.22% and 61.18% for COD and BOD 5 , respectively, and removal efficiencies of 53.91% for TP and 99.98% de N-NH 3 . Average biogas generation was 2322.51 NmL-gSV −1 with 54.61% CH 4 (winter/2019), 4491.47 Nml-gSV −1 with 57.17% CH 4 (spring/2019), 680.78 NmL-gSV −1 with 16.04% CH 4 (summer/2020), and 681.0 NmL-gSV −1 with 19.86% CH 4 (autumn/2020) for MA biomass and generation of biogas of 3826.70 NmL-gSV −1 with 44.26% CH 4 for VFCW biomass in winter and spring/2019 and of 829.68 NmL-gSV −1 with 17.06% CH 4 in summer and autumn/2020. Regarding electricity generation, the present work obtained 1.50 kWh/m 3 , therefore reaching similar values to other studies that used more traditional biomass sources.

Current trends and future directions of global research on wastewater to energy: a bibliometric analysis and review

“…Energy recovery from wastewater is an essential part of the circular economy model (EEA 2022 ). Energy recovery can be achieved by anaerobic digestion of algal biomass from integrated microalgae/constructed wetland wastewater treatment (Silveira et al 2023 ). The concept of circular economy can serve as the main impetus for WWTPs in the development of technologies towards energy and carbon neutrality (Zhang and Liu 2022 ) through resource recovery and carbon reduction (Preisner et al 2022 ) allowing better management and utilisation of wastewater treatment processes towards energy self-sufficiency and resource efficiency.…”

Bibliometric analysis of wastewater treatment with microalgae in the period 1985–2023

“…Nandini et al (2023) In turn, Satheesh et al (2023) experimented with the production of biohydrogen from the culture of Chlorella pyrenoidosa, Scenedesmus obliquus and Chlorella sorokiniana; Scenedesmus obliquus was able to produce 45.5 mL of H 2 g 1 VS, from the accumulation of 25.34% lipids in 710 mg L 1 of biomass. While Oliveira et al (2023) produced 8175.7 N mL 1 Gsv 1 with a Chlorophycea-class microalgae.…”