Nannochloropsis oceanica harvested using electrocoagulation with alternative electrodes – An innovative approach on potential biomass applications

Figueiredo, Daniel; Ferreira, Alice; Quelhas, Pedro; Schulze, Peter S.C.; Gouveia, Luísa

doi:10.1016/j.biortech.2021.126222

Cited by 9 publications

(4 citation statements)

References 40 publications

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“…Ammonium concentration was then calculated using equation ( 2) [22]. Removal efficiency was calculated using equation (3). A spectrophotometer (Spectroquant®Prove 100, Merck KGaA, Darmstadt, Germany) adjusted to a wavelength of 442 nm was used to measure the optical density (OD) of D. salina culture, which allowed for the calculation of the percentage of harvesting efficiency (%).…”

Section: Sample Analysis and Concentration Calculationmentioning

confidence: 99%

“…Currently, the focus of efforts to reduce climatealtering CO2 emissions is shifting from fossil fuels to ones based on biological materials [2]. Microalgae are a biological resource that can be used for many things, such as making food, medicine, animal feed, biofertilizers, cosmetics, fuels, treating wastewater, and making bioplastics [3].…”

Section: Introductionmentioning

confidence: 99%

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Equilibrium of Ammonia (NH3) and Ammonium (NH4+) during Microalgae Harvesting using Electrocoagulation

Purwono

Hadiyanto

Budihardjo

2023

IJE

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Harvesting microalgae is an important process in gaining biomass while the remaining water is still rich in nutrients. These nutrients, mainly nitrogen and phosphorous, could cause eutrophication of water bodies (rivers, lakes, and oceans) and ecosystem degradation if discharged directly without proper treatment. Electrocoagulation (EC) is one of the harvesting methods and has several advantages: ease of operation, fast harvesting, adaptability, environmental friendliness, and low footprint. However, EC method for harvesting microalgae has the potential in producing ammonia, which is undesirable due to its threat to the environment. The purpose of this study is to establish the equilibrium of ammonium (NH4 + ) and ammonia (NH3) during Dunaliella salina harvesting. The harvesting was conducted using EC with a variation of 20 volts, 30 min, and 400 rpm. The result shows that the harvesting efficiency can reach 93.72% after 5 min of processing, decreasing the concentration of inorganic nitrogen compounds in total ammonia nitrogen (TAN) to 98.80%.

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Section: Sample Analysis and Concentration Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Equilibrium of Ammonia (NH3) and Ammonium (NH4+) during Microalgae Harvesting using Electrocoagulation

Purwono

Hadiyanto

Budihardjo

2023

IJE

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“…Microalgae have a microscopic size (2-30 µm), and the cultures present low biomass concentrations with densities close to water, making sedimentation difficult [8,10]. Usually, the biomass concentration ranges from 0.2 to 6 g L −1 , being about 0.5 g L −1 in a typical 20 cm deep raceway pond [8,11].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Microalgal Harvesting with Inorganic and Organic Flocculants Using Factorial Design of Experiments

2022

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Microalgae have a lot of potential as a source of several compounds of interest to various industries. However, developing a sustainable and efficient harvesting process on a large scale is still a major challenge. This is particularly a problem when the production of low-value products is intended. Chemical flocculation, followed by sedimentation, is seen as an alternative method to improve the energetic and economic balance of the harvesting step. In this study, inorganic (aluminum sulfate, ferric sulfate, ferric chloride) and organic (Zetag 8185, chitosan, Tanfloc SG) flocculants were tested to harvest Chlorella vulgaris in batch mode. Preliminary assays were conducted to determine the minimum dosages of each flocculant that generates primary flocs at different pH. Except for chitosan, the organic flocculants required small dosages to initiate floc formation. Additional studies were performed for the flocculants with a better performance in the preliminary assays. Zetag 8185 had the best results, reaching 98.8% and 97.9% efficiencies with dosages of 50 and 100 mg L−1, respectively. Lastly, a 24 full factorial design experiment was performed to determine the effects of the flocculant dosage, settling time, and mixing time on the Zetag 8185 harvesting efficiency. The harvesting efficiency of C. vulgaris was optimal at a dosage of 100 mg L−1 and 3 min of rapid mixing.

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“…The reason is that all of the reactions given in Equations (1-7) will take place depending on the physicochemical properties of the electrode material (Liu et al, 2018). Although several metals such as zinc (Safwat, 2020), steel (Santhosh et al, 2015), magnesium (Figueiredo et al, 2022) are used as electrode materials, aluminum and iron are the most widely used due to their various advantages such as abundance on the earth and low price, their non-toxicity, and high valence that leads to efficient removal of pollutants (Hakizimana et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Treatment of vegetable oil wastewater by a conventional activated sludge process coupled with electrocoagulation process

Akarsu

Bilici

Dizge

2022

Water Environment Research

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The present work aims to study chemical oxygen demand (COD), oil-grease, and color removal from vegetable oil wastewater by combined electrocoagulation and activated sludge processes. For this purpose, the sample was pretreated using electrocoagulation by various optimization parameters such as electrode type (Al-Al and Fe-Fe), current density (100-400 A/m 2 ), pH (2-8), and electrolysis time (15-180 min). The results showed that 89.3% of COD, 100% of oil-grease, and 66.2% of color were removed by electrocoagulation under the conditions of 300-A/m 2 current density, pH 2, and 180-min reaction time with Al-Al electrode pairs. Then, the effluent of electrocoagulation was treated by an activated sludge process. The results depicted that the activated sludge process was also effective for vegetable oil wastewater treatment and it enhanced 98.9% COD and 79.2% color removal efficiency. The effluent of the combined process was very clear, and its quality exceeded the direct discharge standard of the water pollution control regulation. The laboratory-scale test results indicate that the combined electrocoagulation and activated sludge process is feasible for the treatment of vegetable oil wastewater. Practitioner points• Vegetable oil wastewater was treated by combination of electrocoagulation and activated sludge processes.• The combined electrocoagulation and activated sludge processes supplied 99.9% COD, 100% oil-grease, and 93.0% color removal efficiency.• The laboratory-scale test results indicate that the combined EC-SBR processes were feasible for the treatment of vegetable oil wastewater.

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Nannochloropsis oceanica harvested using electrocoagulation with alternative electrodes – An innovative approach on potential biomass applications

Cited by 9 publications

References 40 publications

Equilibrium of Ammonia (NH3) and Ammonium (NH4+) during Microalgae Harvesting using Electrocoagulation

Equilibrium of Ammonia (NH3) and Ammonium (NH4+) during Microalgae Harvesting using Electrocoagulation

Optimization of Microalgal Harvesting with Inorganic and Organic Flocculants Using Factorial Design of Experiments

Treatment of vegetable oil wastewater by a conventional activated sludge process coupled with electrocoagulation process

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