Tubular Photobioreactor Research Articles

Model-driven design and validation of glucose supply control in a tubular photobioreactor operated under oxygen-balanced mixotrophy

Scaling up bioprocesses remains challenging due to the partially unpredictable and suboptimal behavior of microbes during scale transition. Mathematical modelling serves as a valuable tool in navigating these challenges. In this study, we developed and validated a kinetic model based on the tank-in-series approach for a novel bioprocess known as oxygen-balanced mixotrophy with the microalga Galdieria sulphuraria. This model aims to facilitate the design of an effective glucose feeding control strategy tailored for two-phase tubular photobioreactors (TPBRs). The residence time distribution of our reference reactor was investigated by means of a tracer experiment. Qualitative analysis of the results indicated that our system was optimally represented by simulations with a 100 stirred-tank reactors (STRs).The controlled variable, oxygen concentration in the gas phase, showed a downward trend in simulations with simplified conditions: fixed oxygen production and balanced glucose supply. The decrease was caused by dominant net heterotrophic activity and accumulation of CO2 in the gas phase. Different configurations of a proportional-integral-derivative (PID) controller were designed by means of the ultimate gain method and compared under these simplified conditions. The most effective PID controller was implemented and refined in simulations with outdoor weather conditions. The model was validated successfully by simulating over time in a lab-scale STR the spatial fluctuations happening in a TPBR. The empirical oxygen consumption and production were faster and steeper than in the model, probably due to inaccuracies in parameter estimation or biomass adaptation.

Tubular photobioreactor design based on mixing intensity

A novel design methodology for tubular photobioreactors (TPBRs) for the mass culture of microalgae that can account for mixing intensity is presented. To date, TPBRs have been mainly designed and operated under the assumption of perfect mixing with regard to photosynthesis performance (light integration regime). In this work we show that this simplification has been leads to significant errors in the prediction of the optimal dilution rate and biomass productivity. To this end, computational fluid dynamics and light distribution model have been employed to calculate the trajectories and light histories I(t) of a microalgal cell population represented by 50 particles of 5 μm diameter. The density of the microalgal cells was set at 1000 kg m−3 and the tube diameters (D) were 14, 24, 44, 64 and 84 mm, with the circulation velocities (v) ranging from 0.4 to 1 m s-1. This has been coupled to a dynamic photosynthesis model in order to calculate the average photosynthetic response and hence the integration factors in TPBRs. It has been demonstrated that for a generic microalgal strain, the use of the light integration simplification (Γ = 1) would result in the prediction of an optimal dilution rate of 0.0315 h−1 (for D = 14 mm and v = 0.4 m/s as an example), which would lead to an actual biomass productivity of 182.5 g biomass m−3h−1 if the predicted integration factor (Γ = 0.578) is used whereas the newly proposed method predicts an optimal dilution rate of 0.0125 h−1 and a biomass productivity of 362.3 g biomass m−3h−1. This demonstrates that simplifying the light integration regime is inadequate for TPBRs design and operation, resulting in significant inaccuracies. The estimation charts and regressions proposed in this work to estimate actual integration factors will enable the development of an optimization method for TPBRs based on mixing intensity.

Analysis of suitable regions for microalgae cultivation and harvesting potential for carbon capture: A global feasibility study

Microalgae, have the ability to capture CO2 and the potential for biofuel production. However, scaling up capturing carbon by microalgae is not feasible worldwide because of difference in weather conditions. Hence, identifying favorable regions for capturing carbon by microalgae is the initial step in commercializing this industry. In this research, a global feasibility study has been conducted to analyse the potential of microalgae cultivation and harvesting to capture CO2, based on carbon emissions, weather conditions, and the boundary of countries. A total of 454 cities were selected for this research, and the amount of microalgae productivity and carbon capture rate in each area was calculated according to the optimal environmental conditions for microalgae growth. Methodology and results have been illustrated using Geographical Information System (ArcGIS 10.8) to provide better visual insight for researchers. The results showed that the average microalgae productivity in Open Ponds (OP) and Tubular Photobioreactors (TPBR) is 132.63 T/ha/y and 78.26 kg/m3/y, respectively. Additionally, the average carbon capture rate by microalgae in OP and TPBR is 37.60 T/ha/y and 40.83 kg/m3/y, respectively. The study also revealed that microalgae will have a higher productivity in OP than in TPBR for 158 regions according to the first scenario, while the number of these areas will decrease to 58 and 29 under the second and third scenarios, respectively. Moreover, the global average potential energy content resulting from microalgae cultivation in OP is 4.854*106 MJ/ha/y. Therefore, selecting suitable regions regarding weather condition and type of cultivation system, is the most significant factors in outdoor commercial scaling up of carbon capture by microalgae.

Outdoor tubular photobioreactor microalgae-microorganisms biofilm treatment of municipal wastewater: Enhanced heterotrophic assimilation and synergistic aerobic denitrogenation

This research evaluated a microalgae consortium (MC) in a pilot-scale tubular photobioreactor for municipal wastewater (MWW) treatment, compared with an aeration column photobioreactor. Transitioning from suspended MC to a microalgae-microbial biofilm (MMBF) maintained treatment performance despite increasing influent from 50 L to 150 L in a 260 L system. Carbon and nitrogen removal were effective, but phosphorus removal varied due to biofilm shading and the absence of phosphorus-accumulating organisms. High influent flow caused MMBF detachment due to shear stress. Stabilizing and re-establishing the MMBF showed that a stable phycosphere influenced microbial diversity and interactions, potentially destabilizing the MMBF. Heterotrophic nitrification-aerobic denitrification bacteria were crucial for MC equilibrium. Elevated gene expression related to nitrogen fixation, organic nitrogen metabolism, and nitrate reduction confirmed strong microalgal symbiosis, highlighting MMBF’s treatment potential. This study supports the practical application of microalgae in wastewater treatment.

Unveiling potential of promising filamentous microalga Klebsormidium cf. nitens: Shear stress resilience and carotenoid-fatty acid dynamics in tubular photobioreactor

In this study, the effects of shear stress and different culture media on the growth of the filamentous microalga Klebsormidium cf. nitens were studied. The microalga’s growth, carotenoids and fatty acids were further evaluated in a pump-driven tubular photobioreactor. The results show that this microalga had the ability to withstand high shear stress and the adaptability to grow in a culture medium that lacks certain trace elements. K. cf. nitens grew consistently in the tubular photobioreactor at different average light intensities although it did not grow well in a tall bubble column. The carotenoid analysis revealed that the xanthophyll cycle was activated to protect the cell photosynthetic system. The fatty acids increased with irradiance, with linoleic acid (C18:2n6) making up over 50 % of the total fatty acids. This study supports the potential of employing pump-driven tubular photobioreactors to produce the filamentous microalga K. cf nitens at the large scale.

Development of a Greenhouse Wastewater Stream Utilization System for On-Site Microalgae-Based Biostimulant Production

The challenges to feed the world in 2050 are becoming more and more apparent. This calls for producing more with fewer inputs (most of them under scarcity), higher resource efficiency, minimum or zero effect on the environment, and higher sustainability. Therefore, increasing the circularity of production systems is highly significant for their sustainability. This study investigates the utilization of waste streams from greenhouse hydroponic drainage nutrient solutions for the cultivation of the microalgae Desmodesmus sp. The cultivation was done in an automatically controlled container-scale closed tubular Photo Bio-Reactor (PBR). The study included lab-scale open-pond system experiments and in situ container-scale experiments in the greenhouse wastewater system to assess biomass growth, optical density, nitrogen consumption, and the influence of enzymatic complexes on microalgae cell breakdown. A batch-harvesting process was followed, and the harvested microalgae biomass was pre-concentrated using FeCl3 as a flocculant that has demonstrated efficient sedimentation and biomass recovery. Following microalgae sedimentation, the produced biomass was used for biostimulant production by means of a biocatalysis process. The enzymatic complexes, “EnzProt”, “EnzCell”, and “EnzMix” were tested for cell breakdown, with “EnzMix” at a dosage of 10% showing the most promising results. The results demonstrate successful biomass production and nitrogen uptake in the lab-scale open-pond system, with promising upscaling results within container-scale cultivation. The findings contribute to a better assessment of the needs of Desmodesmus sp. culture and highlight the importance in optimizing culture conditions and enzymatic processes for the production of biostimulants.

Myo-inositol as a carbon source in Chlorella sp. production

The study aimed to investigate the possible use of myo-inositol as a carbon source in Chlorella sp. culture. Firstly, experiments were conducted with different myo-inositol concentrations and glycerol in flasks. Secondly, a laboratory-scale tubular photobioreactor (PBR) was operated with CO2 and myo-inositol to determine performance under industrial production conditions. The highest dry weight of the experiments with flasks was 1.62 ± 0.02 g.L−1 and was obtained with 1 g.L−1 myo-inositol concentration. Myo-inositol yielded two times higher lipid accumulation compared to glycerol in the experiment with flasks and 12 % compared to CO2 in the PBR experiment. The results revealed that myo-inositol is one of the most efficient carbon sources with 0.86 CBCR (carbon to biomass conversion rate). Even if myo-inositol is more expensive than many carbon sources such as CO2, high efficiency and less light energy expenses make it a competitive carbon source in Chlorella sp. production.

Multiscale effects of radial mixing on mixotrophic microalgal growth and macromolecular synthesis in tubular bubble-column photobioreactors

Extremophillic microalga Chlorella sorokiniana is grown mixotrophically in a 5 L externally-illuminated tubular bubble-column photobioreactor with an external light intensity of 10,500 lx (≈195 μmol-photons.m−2.s−1) at atmospheric (0.04 %), 1 %, 2 %, 3 %, 4 %, and 5 % CO2 concentrations, with acetic acid and urea as the organic carbon and nitrogen sources, respectively, for 6–8 days. Two different setups are employed: one permits axial air flow, and another promotes radial mixing of algal particles, dissolved CO2 and nutrients along with axial sparging. We show that radial mixing increases biomass yields by reducing both photo-limitation and photo-inhibition up to CO2 concentrations <3 %, above which substrate (CO2) inhibition necessitates lower reactor mixing. Radial mixing increases the lipid yield from 1.06 and 1.61 g/L to 1.27 and 1.78 g/L at 2 % and 3 % CO2, respectively, in nitrogen-limited cases, resulting in a 10–20 % increase. We show that complete reactor mixing, facilitated by the dual effects of branched (radial) and axial sparger, is preferred only in the absence of substrate (CO2) inhibition. Subsequently, we stratify the tubular photobioreactor design strategy into two regimes based on CO2 inlet concentrations. In one regime (for inlet CO2 < 3 %), we recommend the deployment of branched sparger to facilitate both radial and axial mixing simultaneously, thereby creating a well-mixed reactor at lower CO2 concentrations. In the other regime (for inlet CO2 > 3 %), axial sparging alone is recommended since complete mixing of CO2 increases substrate inhibition by reducing the reactor pH below 7.5.

Pilot composite tubular bioreactor for outdoor photo-fermentation hydrogen production: From batch to continuous operation

A novel 70 L composite tubular photo-bioreactor was constructed, and its photo-fermentation hydrogen production characteristics of batch and continuous modes were investigated with glucose as the substrate in an outdoor environment. In the batch fermentation stage, the hydrogen production rate peaked at 37.6 mL H2/(L·h) accompanied by a high hydrogen yield of 7 mol H2/mol glucose. The daytime light conversion efficiency is 4 %, with 37 % of light energy from the sun. An optimal hydraulic retention time of 5 d was identified during continuous photo-fermentation. Under this condition, the stability of the cell concentration is maintained and more electrons can be driven to the hydrogen generation pathway while attaining a hydrogen production rate of 20.7 ± 0.9 mL H2/(L·h). The changes of biomass, volatile fatty acids concentration and ion concentration during fermentation were analyzed. Continuous hydrogen production by composite tubular photo-bioreactor offers new ideas for the large-scale deployment of photobiological hydrogen production.

Production of techno-functional proteins and plant biostimulants from Nannochloropsis gaditana

Nannochloropsis gaditana is produced mainly for its lipid content and fatty acid profile. However, its protein content is comparable to or even higher than that of most conventional protein sources. In this work, the microalga N. gaditana BEA 1202B purchased from the Spanish Bank of Algae (BEA) was produced using 3.4 m3 tubular photobioreactors achieving a biomass productivity of 0.1 g L−1·day−1 and a protein content of 29.2 ± 4.5 % (d.w.). The biomass produced was used as a source of proteins; the protein recovery was optimised following a response surface methodology. Under optimal conditions, which were solubilisation at pH = 10.2 and precipitation at pH = 3.1, the protein recovery yield was 17.5 g·100 g−1. The extract exhibited a water-holding and an oil-holding capacity of 2.1 and 3.0 g g−1, respectively. The leftovers from protein extraction were assessed as plant biostimulants and demonstrated a positive effect on root development, weight gain, and chlorophyll retention. The process described in this work presents a sustainable and environmentally friendly approach to harness the potential of the microalga N. gaditana in producing high-value food proteins and plant biostimulants. The integration of this microalgal-based biorefinery concept could contribute to more sustainable agriculture and address the growing global demand for protein-rich products and plant promoters.

Optimizing cultivation strategies and scaling up for fucoxanthin production using Pavlova sp.

The microalgal-based production of fucoxanthin has emerged as an imperative research endeavor due to its antioxidant, and anticancer properties. In this study, three brown marine microalgae, namely Skeletonema costatum, Chaetoceros gracilis, and Pavlova sp., were screened for fucoxanthin production. All strains displayed promising results, with Pavlova sp. exhibiting the highest fucoxanthin content (27.91 mg/g) and productivity (1.16 mg/L·day). Moreover, the influence of various cultivation parameters, such as culture media, salinity, sodium nitrate concentration, inoculum size, light intensity, and iron concentration, were investigated and optimized, resulting in a maximum fucoxanthin productivity of 7.89 mg/L·day. The investigation was further expanded to large-scale outdoor cultivation using 50 L tubular photobioreactors, illustrating the potential of Pavlova sp. and the cultivation process for future commercialization. The biomass and fucoxanthin productivity for the large-scale cultivation were 70.7 mg/L·day and 4.78 mg/L·day, respectively. Overall, the findings demonstrated considerable opportunities for fucoxanthin synthesis via microalgae cultivation and processing.

A comprehensive review on effective parameters on microalgae productivity and carbon capture rate

Rising carbon emissions caused by population growth and industrialization is a significant environmental challenge in various countries. To combat this issue, Renewable Energy (RE) and Carbon Capture and Storage (CCS) technologies should be commercialized to reduce Greenhouse Gas (GHG) emissions and generate carbon-free energy. One such technology is the use of microalgae, which can directly capture CO2 from the air through photosynthesis and potentially produce biofuels due to their high energy content. However, the carbon capture rate of microalgae varies globally due to numerous parameters and variables affecting microalgae productivity. Additionally, microalgae productivity and carbon capture formulas yield different results worldwide, especially in outdoor industrial-scale cultivation. This research aims to comprehensively review the effective variables and parameters in carbon capture by microalgae based on microalgae productivity and carbon capture formulas. The research also ranked countries based on CO2 production in four different categories to determine whether the biggest carbon producer countries could exhibit suitable weather conditions for microalgae cultivation. Findings reveal optimal ranges of critical variables in the microalgae growth formula, including temperature, solar radiation intensity, Photon Flux Density (PFD), and sunlight duration. The study also analyzes microalgae cultivation, carbon capture, and oxygen production formula in different systems such as Open Ponds (OP), Tubular Photobioreactors (TPBR), and Flat Plate Photobioreactors (FPPBR), while discussing other influential parameters. In conclusion, emphasizing the adjustment and utilization of optimal values of effective parameters in microalgae cultivation not only holds promise for future carbon capture by microalgae but also pushes human beings toward sustainable development goals.

Estimation of design parameters of the Fibonacci-type photobioreactor 5000 L

The presented Fibonacci-type tubular photobioreactor represents a significant advancement over classical tubular photobioreactors. It exhibits notable flexibility in its geometric design with the ability to adapt its parameters to meet the specific photosynthetic requirements of microalgae, thereby achieving maximum efficiency. As a result, it emerges as a viable alternative to conventional tubular systems. Furthermore, the strategy utilized for optimizing the design of Fibonacci-type photobioreactors is also described. This strategy is applied to design a 5000 L reactor, serving as a potential approach to harnessing these reactors for the industrial-scale production of high-value microalgae with commercial significance.

Biomass productivity and characterization of Tetradesmus obliquus grown in a hybrid photobioreactor.

In this study, the effects of CO2 addition on the growth performance and biochemical composition of the green microalga Tetradesmus obliquus cultured in a hybrid algal production system (HAPS) were investigated. The HAPS combines the characteristics of tubular photobioreactors (towards a better carbon dioxide dissolution coefficient) with thin-layer cascade system (with a higher surface-to-volume ratio). Experimental batches were conducted with and without CO2 addition, and evaluated in terms of productivity and biomass characteristics (elemental composition, protein and lipid contents, pigments and fatty acids profiles). CO2 enrichment positively influenced productivity, and proteins, lipids, pigments and unsaturated fatty acids contents in biomass. The HAPS herein presented contributes to the optimization of microalgae cultures in open systems, since it allows, with a simple adaptation-a transit of the cultivation through a tubular portion where injection and dissolution of CO2 is efficient-to obtain in TLC systems, greater productivity and better-quality biomass.

Study of Chlorella sorokiniana Cultivation in an Airlift Tubular Photobioreactor Using Anaerobic Digestate Substrate

Microalgae offer a promising solution for efficiently treating high-nitrogen wastewater and recovering valuable nutrients. To optimize microalgae growth and nutrient assimilation, case-dependent studies are essential to demonstrate the process’s potential. This study aimed to evaluate the treatment capacity of high-nitrogen anaerobic digestion effluent as a nutrient source for a C. sorokiniana microalgal culture in a tubular photobioreactor. The study had two primary objectives: to assess how the concentration and composition of the digestate influence microalgae growth, and to identify the preferred nitrogen forms assimilated by the microalgae during long-term, continuous operation. A 20 L tubular airlift bioreactor was constructed and used in batch mode; various digestate concentrations were examined with ammonia nitrogen levels reaching to 160 mg/L. These experiments revealed a biomass growth rate of up to 130 mg/L/d and an ammonia nitrogen assimilation rate ranging from 8.3 to 12.5 mg/L/d. The presence of phosphorous proved essential for microalgae growth, and the growth entered a stationary phase when the initial phosphorous was fully assimilated. A nitrogen-to-phosphorous (N/P) ratio of 10 supported efficient species growth. While ammonia was the preferred nitrogen form for microalgae, they could also utilize alternative forms such as organic and nitrate nitrogen, depending on the specific digestate properties. The results from the continuous photobioreactor operation confirmed the findings from the batch mode, especially regarding the initial nitrogen and phosphorous content. An important condition for nearly complete ammonia removal was the influent dilution rate, to balance the nitrogen assimilation rate. Moreover, treated effluent was employed as dilution medium, contributing to a more environmentally sustainable water management approach for the entire process, at no cost to the culture growth rate.

Sustainable microalgae cultivation: A comprehensive review of open and enclosed systems for biofuel and high value compound production

Microalgae have emerged as a promising feedstock for biofuels and high-value compounds, offering potential solutions to global energy and resource challenges. This comprehensive review examines the latest advancements in microalgae cultivation technologies, focusing on both open systems and enclosed photobioreactors (PBRs). We analyze various configurations including open raceway ponds, tubular PBRs, flat panel PBRs, and novel designs such as the Light Exchange Bubble-column (LEB). The review encompasses key performance indicators such as biomass productivity, energy efficiency, and water usage, as well as life cycle assessment (LCA) results for different cultivation systems. We also discuss the challenges and opportunities in scaling up microalgae production, the potential for integrating wastewater treatment and CO2 mitigation, and the prospects of biorefinery approaches. By synthesizing recent research findings and identifying knowledge gaps, this review aims to provide a comprehensive understanding of the current state and future directions in sustainable microalgae cultivation for researchers, engineers, and policymakers in the field of renewable energy and biotechnology.

Study of the Influence of the Temperature and Time of Microalgae Cultivation on the Reproduction Rate of Chlorella and Scenedesmus Microalgae When Cultured in a Tubular Photobioreactor

The use of algae for carbon dioxide fixation is based on their natural ability to photosynthesize. Dynamic experiments make it possible to calculate the short-term photosynthetic activity of microalgae strains in photobioreactors. In this study, the effect of temperature and culture time on the intensity of reproduction and on CO2 absorption by some microalgae was evaluated. It was found that the maximum increase in biomass occurred during algae cultivation at 29–32 °C and pH = 8.4. A ratio of ~2.0 was observed between CO2 absorption and the increase in biomass for different microalgae. When using the Chlorella genus, the increase in biomass under comparable conditions was greater than when cultivating microalgae of the Scenedesmus genus.

Removal of Nitrogen and Phosphorous from Synthetic Wastewater by Oscillatoria sp. Cultivated in Vertical Tubular Photobioreactor under Natural Environmental Conditions

A newly isolated cyanobacterium Oscillatoria sp. from the Sub-Himalayan region of India was assessed for nutrient removal efficiencies. It was cultivated in synthetic wastewater under uncontrolled natural environmental conditions. The filaments of cyanobacterium formed entangled mats which easily floated on the surface of the medium. This characteristic feature was exploited for easy harvesting of the biomass that is hitherto a bottleneck for the industrial scale oil production from microalgae. The cultures of Oscillatoria sp. grown in synthetic wastewater removed 93.02% of 76 mg/L nitrate and 94.11% of 51 mg/L phosphate. The fatty acid profiling of 10-day-old cultures showed the dominance of saturated and monounsaturated fatty acids. The percentages of predominant fatty acids found in Oscillatoria sp. were 25.25% myristoleic acid (14:1w5c), 23.3% myristic acid (14:0), 16.81% palmitoleic acid (16:1w7c), 14.88% palmitic acid (16:0) and 4.765% hexadecanoic acid (16:1 w5c). The biomass productivities of 0.065 g/L/day and 0.05 g/L/day were attained by the cultures grown in synthetic wastewater and control BG-11 growth media respectively. This mesocosm study was conducted under the influence of natural sunlight, uncontrolled temperatures and the presence of biological contaminants namely, bacteria and small ciliates. The main objective of the study was to mimic the outdoor conditions, which is the way forward for achieving economic and environmental sustainability in microalgae biomass production.

Computational fluid dynamics coupled to biokinetic models: Numerical methodology for microalgae cultivation optimization

Mixing of the algal culture medium in a photobioreactor (PBR) is a crucial factor to enhance microalgae cultivation and production, since it ensures microalgae cells can homogeneously access nutrients and light radiation. Hydrodynamic conditions in an industrially applicable PBR cannot be tested in laboratory cultivation systems since the scale-up methodology is not specified; hence requiring complex tests at a demonstrative scale or the application of mathematical models. In this study, a three-dimensional numerical model of the hydrodynamic conditions in a hybrid horizontal tubular PBR was developed to investigate the mixing of the culture medium under various operating conditions, in order to optimize biomass production in this type of system. The PBR consists of two open tanks connected through sixteen polyethylene transparent tubes, at a demonstrative scale (total volume 11.7 m3). Microalgae cells movement inside the tubes was simulated. Cell trajectory prediction allows to simulate the intensity of mixing of the culture medium. Subsequent coupling with the biokinetic BIO_ALGAE model allows to monitor the influence of hydrodynamic conditions on the distribution of light in the culture medium and the yield of microalgae. The simulations were experimentally validated. The more intense mixing of the culture medium caused by increasing flow rate (Re = 23,700–46,200) allows more frequent exposure of the microalgae cells to the light source, which according to the results obtained can increase the microalgal yield by 14% in the summer cultivation period and by 151% in the winter period.

Progressive pollution abatement in raw dairy wastewater induced by the algae Poterioochromonas malhamensis with a high-value biomass yield

This work aimed to systematically abate in batch mode organic pollutants from raw dairy wastewater (DW) with high values of chemical oxygen demand (COD, ∼10.3 g L−1), total organic carbon (TOC, ∼2.4 g L−1), and total nitrogen (TN, ∼0.28 g L−1) by using the Poterioochromonas malhamensis algae strains. In this regard, variables such as fractions of DW (40–100%, v/v), mineral nutritional inoculum addition (0–100%, w/v) and CO2-enriched air (2–8%) were proposed to address a study in optimizing conditions with new insights on algae production. As controlled photobioreactors (PBR), a set of tubular PBRs and a pair of flat-plate PBRs (FP-PBR) surrounded by fluorescent lamps and pumped by CO2-enriched air at a flow rate of 1.4 L min− 1 per litre were used. A Box-Behnken design (BBD) for algal growing was applied using the set of tubular PBRs to get a better reduction in TOC, TN and COD, defining an optimized condition. On the best tubular PBRs-based outcome and including a holed baffles system for hydrodynamically providing a flashing light state, 9-day kinetic experiments based on a pair of FP-PBRs were performed to provide more insights on how to enhance the algal yield and COD, TN and TOC reduction. A biomass yield rate of 1.1 g L−1 per day was attained using FP-PBRs, being comparatively 10% better than tubular PBRs. Additionally, the organic pollution abatement in DW was highly significant, with a decrease of about 98%, 95%, and 92% in COD, TN and TOC, respectively, besides changing the initial bacteria diversity to another less harmful one.