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Ortíz-Sánchez E, Guillén-Garcés RA, Morales-Arrieta S, Ugochukwu Okoye P, Olvera-Vargas H, Sebastian PJ, Arias DM. Cultivation of carbohydrate-rich microalgae with great settling properties using cooling tower wastewater. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:38999-39014. [PMID: 37410327 PMCID: PMC11186883 DOI: 10.1007/s11356-023-28432-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 06/21/2023] [Indexed: 07/07/2023]
Abstract
Wastewater treatment and simultaneous production of value-added products with microalgae represent a sustainable alternative. Industrial wastewater, characterized by high C/N molar ratios, can naturally improve the carbohydrate content in microalgae without the need for any external source of carbon while degrading the organic matter, macro-nutrients, and micro-nutrients. This study aimed to understand the treatment, reuse, and valorization mechanisms of real cooling tower wastewater (CWW) from a cement-processing industry mixed with domestic wastewater (DW) to produce microalgal biomass with potential for synthesis of biofuels or other value-added products. For this purpose, three photobioreactors with different hydraulic retention times (HRT) were inoculated simultaneously using the CWW-DW mixture. Macro- and micro-nutrient consumption and accumulation, organic matter removal, algae growth, and carbohydrate content were monitored for 55 days. High COD (> 80%) and macronutrient removals (> 80% of N and P) were achieved in all the photoreactors, with heavy metals below the limits established by local standards. The best results showed maximum algal growth of 1.02 g SSV L-1 and 54% carbohydrate accumulation with a C/N ratio of 31.24 mol mol-1. Additionally, the harvested biomass presented a high Ca and Si content, ranging from 11 to 26% and 2 to 4%, respectively. Remarkably, big flocs were produced during microalgae growth, which enhanced natural settling for easy biomass harvesting. Overall, this process represents a sustainable alternative for CWW treatment and valorization, as well as a green tool for generating carbohydrate-rich biomass with the potential to produce biofuels and fertilizers.
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Affiliation(s)
- Edwin Ortíz-Sánchez
- Universidad Politécnica del Estado de Morelos, Boulevard Cuauhnáhuac No. 566 Col. Lomas del Texcal, 62550, Jiutepec, Morelos, CP, Mexico
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México (IER-UNAM), Priv. Xochicalco s/n, Col. Centro, 62580, Temixco, Morelos, CP, Mexico
| | - Rosa Angélica Guillén-Garcés
- Universidad Politécnica del Estado de Morelos, Boulevard Cuauhnáhuac No. 566 Col. Lomas del Texcal, 62550, Jiutepec, Morelos, CP, Mexico
| | - Sandra Morales-Arrieta
- Universidad Politécnica del Estado de Morelos, Boulevard Cuauhnáhuac No. 566 Col. Lomas del Texcal, 62550, Jiutepec, Morelos, CP, Mexico
| | - Patrick Ugochukwu Okoye
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México (IER-UNAM), Priv. Xochicalco s/n, Col. Centro, 62580, Temixco, Morelos, CP, Mexico
| | - Hugo Olvera-Vargas
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México (IER-UNAM), Priv. Xochicalco s/n, Col. Centro, 62580, Temixco, Morelos, CP, Mexico
| | - P J Sebastian
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México (IER-UNAM), Priv. Xochicalco s/n, Col. Centro, 62580, Temixco, Morelos, CP, Mexico
| | - Dulce María Arias
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México (IER-UNAM), Priv. Xochicalco s/n, Col. Centro, 62580, Temixco, Morelos, CP, Mexico.
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