Velásquez-Orta SB, Yáñez-Noguez I, Ramírez IM, Ledesma MTO. Pilot-scale microalgae cultivation and wastewater treatment using high-rate ponds: a meta-analysis.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024;
31:46994-47021. [PMID:
38985422 PMCID:
PMC11297075 DOI:
10.1007/s11356-024-34000-7]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 06/11/2024] [Indexed: 07/11/2024]
Abstract
Microalgae cultivation in wastewater has been widely researched under laboratory conditions as per its potential to couple treatment with biomass production. Currently, only a limited number of published articles consider outdoor and long-term microalgae-bacteria cultivations in real wastewater environmental systems. The scope of this work is to describe microalgal cultivation steps towards high-rate algal pond (HRAP) scalability and identify key parameters that play a major role for biomass productivity under outdoor conditions and long-term cultivations. Reviewed pilot-scale HRAP literature is analysed using multivariate analysis to highlight key productivity parameters within environmental and operational factors. Wastewater treatment analysis indicated that HRAP can effectively remove 90% of NH4+, 70% of COD, and 50% of PO43-. Mean reference values of 210 W m-2 for irradiation, 18 °C for temperature, pH of 8.2, and HRT of 7.7 are derived from pilot-scale cultivations. Microalgae biomass productivity at a large scale is governed by solar radiation and NH4+ concentration, which are more important than retention time variations within investigated studies. Hence, selecting the correct type of location and a minimum of 70 mg L-1 of NH4+ in wastewater will have the greatest effect in microalgae productivity. A high nutrient wastewater content increases final biomass concentrations but not necessarily biomass productivity. Pilot-scale growth rates (~ 0.54 day-1) are half those observed in lab experiments, indicating a scaling-up bottleneck. Microalgae cultivation in wastewater enables a circular bioeconomy framework by unlocking microalgal biomass for the delivery of an array of products.
Collapse