Designing and Constructing a Novel Hybrid Photobioreactor (HPBR) For Carbon Dioxide (CO2) Mitigation via Chlorella Vulgaris Microalgae
-
Sina Zalbegi,1 Farshid Pajoum Shariati,2,*
1. Department of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
2. Department of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
- Introduction: The Rio de Janeiro Climate Change Agenda Agreement, signed in 1992, addresses global warming and has since emphasized the importance of developing technologies to reduce or absorb greenhouse gases emissions, so much so that the final document expressed concern about rising greenhouse gas levels and the need to prevent them 20 years later. Several studies have recently assessed the ability of specific algae species to reduce CO2 emissions from industrial plants. These microalgae must be able to withstand not only high levels of CO2 but also sulfur dioxide, nitrogen oxides, and volatile organic compounds (VOCs) in waste gases.
- Methods: CO2 removal was investigated in this study after designing and building the novel hybrid photobioreactor (HPBR). The amount of CO2 removal is measured and analyzed in terms of time during each period of microalgae culture. The pH, OD, dry weight (DW), and fluid retention time in the photobioreactor were determined after examining the CO2 removal process. The effect of a long retention time on CO2 removal was observed in a photobioreactor. This study had been divided into three stages; stage1: Algae culture in Erlenmeyer, CO2 removal investigation, and determination of appropriate optical cycle parameters. Stage2: Design and manufacturing of HPBR. Stage3: Investigations in the HPBR system, which all divided into two categories: (A) The effect of reactor design type on CO2 removal rate (in this experiment, three design models were considered; Bubble Colum, Air Lift, and the Novel HPBR) and (B) The effect of microalgae concentration on removal efficiency.
- Results: During 14 days of cultivation within the systems, the photosynthetic performance of Chlorella Vulgaris species was investigated. The Novel HPBR achieved the highest CO2 bio-fixation rate and biomass productivities compared to the control group (Bubble Colum) and Airlift Photobioreactors. The rate of CO2 bio-fixation was 280 mg L-1 d-1, and the biomass productivity was 0.15 g L-1 d-1. The separability of this "Novel HPBR" enabled efficient cleaning and maintenance intending to increase industrialization potential. Furthermore, an additional feature of this novel HPBR enabled its application on wastewater treatment bioprocesses by taking biomass productivity into account.
- Conclusion: Microalgae research for greenhouse gas removal and wastewater treatment has resulted in newly designed close systems such as photobioreactors. These are significantly efficient on both bench-scale and industrialized applications. Considering design indices and microalgae mechanical fluid stimulated the development of the novel HMBR, which provided a higher rate of greenhouse gas removal (specifically CO2), a single construction with multiple applications, and a significantly higher rate of nitrate and phosphate removal from manciple wastewater. Furthermore, higher biomass productivity resulted in greater sustainability.
- Keywords: CO2 Capture, Microalgae, Greenhouse Gas, Sustainability, Wastewater Treatment
