Microalgal Media Research Articles

Development of a new sterilization method for microalgae media using calcium hypochlorite as the sterilant.

Calcium hypochlorite (Ca(ClO)2), which can be stably stored in powder form for a long period, is widely used as a disinfectant in various fields. A new sterilization process was developed in the present study, where a microalgal medium was sterilized using 0.02% Ca(ClO)2, followed by complete neutralization of the Ca(ClO)2 within 8h through catalytic reaction of an MnCl2-Na2EDTA complex and a synergistic effect of glucose. When comparing the growth of Chlorella vulgaris in the autoclaved medium, a 2.65 times greater maximum cell growth was observed in cells grown in the medium prepared by treatment of Ca(ClO)2. This result indicates that denaturation of the medium by heat can hinder the growth of some microorganisms. In the case of cultivation of Euglena gracilis, successful culture growth was achieved without growth inhibition or contamination on a medium prepared in the same manner.

Effect of hydrodynamic aeration on bioelectricity generation from photoautotrophic Spirulina platensis in biophotovoltaic devices

A biophotovoltaic (BPV) device is a type of bioelectrochemical cell that shows potential for renewable energy production using photosynthetic exoelectrogenic microorganisms. However, the technology currently has limitations due to its relatively low power output and high dependence on biofilm attachment. Thus, this paper examines the effect of hydrodynamic aeration on the bioelectricity generation of BPV devices. Aeration is widely applied in microalgae cultivation to improve the mixing effect between microalgae cells, culture medium, and air bubbles. The methodology involves the cultivation of Spirulina platensis, device fabrication, voltage measurement in both non-aeration and aeration modes, and the use of polarization curves to determine the device performance under a gradually rising external load. The BPV devices are affected by abnormal voltage drop under high external loads, which is called power overshoot. The use of aeration successfully solved the power overshoot issues over time, but it also resulted in a gradual reduction in the voltage output and power density of the BPV devices. During aeration, the BPV devices produced a peak power density of 0.121 ± 0.056 mWm−2 on Day 1, which declined to 0.048 ± 0.025 mWm−2 on Day 13. The blowing of air bubbles had some side effects on BPV devices, including causing the attachment of Spirulina cells to the container walls and accelerating the evaporation of the culture medium. This study emphasizes the role of hydrodynamic aeration in the bioelectricity generation process and opens up possibilities for wider application of BPV devices in renewable energy production.

Cultivation of Chlorella for biomass production and nutrient removal from unsterilized human urine containing washing powder wastewater

ABSTRACT Human urine accounts for less than 1% of domestic sewage while contributes about 80% of nitrogen and 50% of phosphorous. The source-separated human urine featuring high nutrients and low impurities, turbidity, and pathogenic bacteria is a high-quality microalgae culture medium whereas frequently mixed with flush water containing washing powder and usually overdiluted or sterilized before culturing microalgae. The work presented here aimed to assess the Chlorella pyrenoidsa (FACHB-5) and Chlorella sp. (FACHB-1554) cultivation in unsterilized human urine containing washing powder wastewater in terms of the biomass and protein production and the removals of nitrogen, phosphorus, and chemical oxygen demand. FACHB-5 and FACHB-1554 could eliminate 84.79% and 96.33% ammonium nitrogen, 83.66% and 95.18% total nitrogen, 85.77% and 96.32% total phosphorus, and 38.53% and 86.86% chemical oxygen demand from human urine under 40% of human urine wastewater addition ratio and no washing powder wastewater addition and achieved 0.5 and 1.01 g/L biomass yields and 60% and 50% protein contents. The washing powder wastewater significantly inhibited the growths of FACHB-5 and FACHB-1554. As the washing powder wastewater addition ratio increased, the yield of FACHB-5 decreased while the production of FACHB-1554 followed a tendency to rise and then fall. FACHB-1554 was more tolerant to human urine and washing powder wastewater than FACHB-5, and 1% and 2% of washing powder wastewater addition ratios were relatively optimal for FACHB-5 and FACHB-1554 to reach 0.32 and 0.45 g/L of yields and alike 53% of protein contents. Under the conditions, the removals of ammonium nitrogen, total nitrogen, total phosphorus, and chemical oxygen demand reached 66.25%, 64.33%, 65.31%, and 32.53% for FACHB-5 and 76.16%, 74.36%, 75.15%, and 42.31% for FACHB-1554, respectively. Studies revealed the feasibility of cultivating microalgae in a high concentration of unsterilized source-separated human urine wastewater, which might be a promising low-cost approach for realizing the scale production of microalgae, purifying domestic wastewater, and promoting the development of value-added biofuels, microalgae protein, and other industries.

Boron bio-mining by high boron-tolerant native microalgae in Turkey and boron toxicity in the aquatic environment.

Boron (B) is one of the most important trace elements. Turkey has the largest B reserves in the world with 3 billion tons of B. Therefore, the toxicity of B is more important in Turkey. In this study, effective B removal was provided by different types of microalgae and then B recovery in culture media by bio-mining was detected. The water of Lake Mogan in Gölbaşı/Ankara/Turkey was used as the microalgae culture medium as a cost-reducing factor. The effects of light, temperature, NaNO3 and K2HPO4 stresses on B removal were determined. The highest B removal was 17.19% at 25 μmol/m2s light intensity and 25 °C for Phormidium animale in Lake Mogan culture medium. Boron removal of Scenedesmus sp. was 36.42% at 25 μmol/m2s light intensity, at 25 °C, at 1.5 g/L NaNO3 and 40 mg/L K2HPO4 concentrations in BG11 medium on the 15th day. The chl (a + b) concentration of Scenedesmus sp. was 1.63 μg/mL at 75 μmol/m2s light intensity and the chl (a) concentration of P. animale was 2.01 μg/mL at 25 μmol/m2s light intensity. Considering all parameters, Scenedesmus sp. and P. animale are recommended as effective biomaterials for the B removal process.

Carbon dioxide capture from combustion gases in residential building by microalgae cultivation

Introduction: Global warming and the need to reduce greenhouse gas emissions from various emission sectors are not hidden from anyone. The aim of this study was to determine Carbon dioxide (CO2)capture from combustion gases of methane for cultivation of microalgae spirulina platensis.
 Materials and methods: Microalgae culture medium was added in two photobioreactor. Air and combustion gas was injected into control and test reactors respectively. Artificial light with 10 Klux intensity was used and operated in continuous and intermittent (14 h ON and 8 h OFF) modes. Inlet concentration of carbon dioxide in to the test photobiorector was set in the range of 2000 to 6000 ppm and was measured in the inlet and outlet of photo-bioreactor by ND-IR CO2 analyzer.
 Results: In the control photo-bioreactor, the average removal of CO2 from the air was 42%. In the test reactor with an inlet CO2 concentration of 4100 ppm, the average removal of CO2 from the combustion gas was 23%. After 9 days of cultivation, the amount of carbon dioxide stabilized by microalgae was 0.528 and 1.14 g/L (dry weight) in the control and experimental photo- bioreactors respectively. The CO2 bio-fixation rate was in the range of 2.2% and 4.0% at different runs. After 9.0 days of cultivation concentration of microalgae was 0.25 and 1.0 g/L in the control and test reactors respectively. Algae productivity with intermittent light was 35% less than continuous light exposure.
 Conclusion: It is possible to use CO2 capture from combustion gases of commercial heater for cultivation of microalgae spirulina.

Integration of pre-precipitation optimizing performance of culture medium prepared from salvaged cyanobacterial slurry

Cyanobacterial slurry is a waste biomass produced in the remediation of eutrophic lakes; it is obtained in large volume and is difficult to treat, but it has the potential to be used as raw material for culture medium for oil-producing microalgae. In this study, three kinds of oil-producing microalgae were tested, including Chlorella vulgaris, Scenedesmus obliquus, and Nannochloropsis oculate. On the basis of the medium preparation method “hydrothermal oxidation + ultrafiltration,” the pre-precipitation phenomenon induced by pH adjustment was implemented to modify the culture medium and improve its performance. Ammonia nitrogen and macromolecules (mainly humic substances) were found to possibly have a joint-influence mechanism upon microalgae. Pre-precipitation changed the nitrogen species distribution in the medium and lowered the concentration of macromolecules, which improved the ability of microalgae to use different forms of nitrogen. This promoted the growth of, and oil production by, the microalgae.

The potential impact of replacing nitrate with ammonium hydroxide in microalgae production on the biomass productivity and CO2 utilization efficiency

Ammonium hydroxide has many advantages as a CO 2 absorbent compared with other amine solutions in Carbon Capture, Utilization and Storage. In this work, the use of ammonium hydroxide was suggested to replace the nitrate as an alternative nitrogen source and to enhance the CO 2 utilization and biomass production during microalgae cultivation. Abiotic absorption experiments showed that the CO 2 absorption capacity of culture medium increased with the increase of ammonium hydroxide concentration, and it kept consistent with different kind of CO 2 absorbents. Consumption curves for sodium nitrate and ammonium hydroxide were built from batch cultivation experimental data and it was found that the microalgal cells had faster growth rates when these nutrients concentrations were kept at low levels (2 mmol/L and 4 mmol/L, respectively). In the fed-batch cultures under both indoor and outdoor operations, the maximum biomass concentration and carbon utilization efficiency using ammonium hydroxide as a nitrogen source was much higher than that of using sodium nitrate as a nitrogen source. By using pH-regulated CO 2 supplementation, the pH of the microalgae culture medium was maintained within the neutral or slightly alkaline range. Thus, the volatilization of ammonium hydroxide was negligible. These results indicated that replacing nitrate with ammonium hydroxide could be a promising approach to increase CO 2 utilization efficiency and to reduce production costs in microalgae cultivation. • Replacing sodium nitrate with ammonium hydroxide as the nitrogen source was first proposed in microalgal cultivation. • Biomass concentration and carbon utilization efficiency using ammonium hydroxide as nitrogen sources were achieved by 2.35 g/L, and 114.93%. • A 32.8 % increase in the biomass productivity using ammonium hydroxide compared to that of sodium nitrate under outdoor conditions. • Ammonium hydroxide could be a cheaper source of nitrogen that can enhance CO 2 utilization by microalgae.

Kultivasi mikroalga Nannochloropsis sp dalam pupuk kotoran ayam untuk meningkatkan biomassa dan lipid sebagai preliminari produksi biodesel

Microalgae is one of the natural resources that has the potential to make biodiesel because it contains a fairly high amount of oil. The content of fat (lipid) and fatty acid (fatty acid) in microalgae is a source of energy and is used as raw material for biodiesel. In lipids there are elements of saturated fatty acids that play a role in the process of making biodiesel. The addition of growth nutrients into microalgae culture media is considered the most influential aspect on the quantity of biomass produced by microalgae cultivation. This study aims to determine the effect of chicken manure on the growth rate of Nannochloropsis sp. and to get the best treatment the lipid content of Nannochloropsis sp. of dry weight. The method used in this study was to use a non-factorial Complete RandomIzed Design (RAL) with 3 repeat treatments. The treatments in this study were A: 0 mg/L, B: 250 mg/L, C: 300 mg/L, D: 350 mgL. The results showed that the effect of giving chicken manure with different doses had a very real effect on the density of Nannochloropsis sp, and population peaks. Treatment B with a dose of 250 mg/L of showed the best results with an average density value of 4713 x 104 cells/ml and a population peak of 9415 x 104 cells/ml and the highest lipid levels found in treatment B, which is 12.73. Water quality during the study was conditioned standard. Temperature 26 - 27 oC, pH 7.1 - 7.7, DO 5.2 - 6.3 and salinity 31 - 34 ppt. Based on the results of the study found that lipid results are high, so it is possible to try biodiesel testing.Keywords: Biodesel; Biomass; Lipid; Microalgae; Nannochloropsis sp

Cultivation of microalgae Nannochloropsis sp in chicken manure to increase biomass and lipids as an introduction to biodiesel production

Microalgae is one of the natural resources that has the potential to make biodiesel because it contains a fairly high amount of oil. The content of fat (lipid) and fatty acid (fatty acid) in microalgae is a source of energy and is used as raw material for biodiesel. In lipids there are elements of saturated fatty acids that play a role in the process of making biodiesel. The addition of growth nutrients into microalgae culture media is considered the most influential aspect on the quantity of biomass produced by microalgae cultivation. This study aims to determine the effect of chicken manure on the growth rate of Nannochloropsis sp. and to get the best treatment the lipid content of Nannochloropsis sp. of dry weight. The method used in this study was to use a non-factorial Complete RandomIzed Design (RAL) with 3 repeat treatments. The treatments in this study were A: 0 mg/L, B: 250 mg/L, C: 300 mg/L, D: 350 mgL. The results showed that the effect of giving chicken manure with different doses had a very real effect on the density of Nannochloropsis sp, and population peaks. Treatment B with a dose of 250 mg/L of showed the best results with an average density value of 4713 x 104 cells/ml and a population peak of 9415 x 104 cells/ml and the highest lipid levels found in treatment B, which is 12.73. Water quality during the study was conditioned standard. Temperature 26 - 27 oC, pH 7.1 - 7.7, DO 5.2 - 6.3 and salinity 31 - 34 ppt. Based on the results of the study found that lipid results are high, so it is possible to try biodiesel testing.Keywords: Biodesel; Biomass; Lipid; Microalgae; Nannochloropsis sp

Winery waste valorisation as microalgae culture medium: A step forward for food circular economy

Wastewater is one of the critical environmental problems worldwide. In this study, the circular economy concept was applied to winery wastewater that has been considered as a rich source of nutrients for growing edible microalgae to produce a high value protein product. To this end, Chlorella vulgaris and Arthrospira platensis were co-cultured. The effects of processing parameters on the microalgae yield and protein recovery were examined. Different microalgae growth systems: open pond, column and tubular photobioreactor were used for obtaining more than two grams of dry weight biomass per liter. The protein fraction was extracted and recovered by ultrasound-assisted extraction. The image analysis shows that wastewater strongly affected the intracellular components concentration, cell morphology, and resistivity to cell rupture. The results of our study demonstrate that it is viable to use microalgae to substantially reduce the pollutant impact of the wastewater and produce high value products such as proteins.

Комбінована дія Chlorella vulgaris Beijer. (Chlorophyta) та кремнієвмістного органічного добрива на продуктивність болгарського перцю, мікробіоценоз, алелопатичні та агрономічні характеристики ґрунту

The combined effect of green microalgae Chlorella vulgaris and siliceous organo-mineral fertilizer (analcite + peat (pH 5.8) in a ratio of 1 : 3) on the characteristics of growth, development, photosynthetic productivity, yield and fruit quality of sweet pepper (Capsicum annuum L., variety "Bieloziorka"), as well as microbiocenosis, allelopathic and agronomic characteristics of the soil was studied in pot experiments. The microalgae culture medium was applied in a volume of 10 mL per a pot (0.7 L) with sifted and sterilized gray podzolic soil. Plants were grown in a phytochamber under controlled conditions of light, temperature and soil moisture. The vitality of the pepper plants was assessed by morphometric growth characteristics (shoot height, stem diameter, leaf surface area, length of roots, shoot and root dry weights, quantity and weight of fruits), content of photosynthetic pigments in leaves, protective antioxidants (carotenoids, flavonoids and anthocyanins) in fruits. At the end of the experiment, the content of phenolics, electric conductivity, redox potential, pH, the content of NH4+, NO3- and HCO3- in the soil solution were determined. A synergistic enhancement of the positive effect of microalgae and siliceous organo-mineral fertilizer on the growth, development, productivity and yield quality of sweet peppers has been established. The combined application of chlorella culture medium with siliceous organo-mineral fertilizer more effectively improved agronomic and allelopathic characteristics of the soil, stimulated the development of agronomically useful ecological and trophic groups of microorganisms, the intensity of mineralization and transformation of organic matter compared to control and treatments in which microalgae or fertilizer were applied separately.

Microalgae Culture Medium Recycling: Improved Production of Biomass and Lipids, Biodiesel Properties and Cost Reduction

Microalgae Culture Medium Recycling: Improved Production of Biomass and Lipids, Biodiesel Properties and Cost Reduction

Enhancement of PVDF/LiCl membrane performance by modifying the membrane surface using zeolite NaY and ZCC spray coating method for Dunaliella salina microalgae dewatering

Utilization of Dunaliella salina microalgae as a raw material for bioethanol production encountered problems in terms of harvesting microalgae. The dilute solution and the size of the microalgae are too small to be a challenge in harvesting microalgae. In this study, the surface modification of PVDF/LiCl membrane with Zeolite NaY and Zeolite-Carbon Composite (ZCC) was carried out by spray coating for harvesting Dunaliella salina microalgae. Zeolite NaY was synthesized by hydrothermal method at 100 °C for 7 h and ZCC was synthesized by sucrose impregnation on zeolite. All membranes were characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infra Red (FTIR) instruments, as well as Water Contact Angle (WCA) test and membrane performance test for harvesting Dunaliella salina microalgae The results showed that Zeolite NaY and ZCC coatings have been shown to increase the hydrophilicity and performance of PVDF/LiCl membranes for harvesting Dunaliella salina microalgae. The increase in the hydrophilicity of the membrane was indicated by decreasing the contact angle of the PVDF/LiCl membrane from 84.14° to 69.2° for 0.10% PVDF/LiCl/ZCC membrane. The coating of zeolite NaY 0.15% into PVDF/LiCl membrane enhanced the permeability from 148.53 ± 32.98 L/m2h to 173.40 ± 8.42 L/m2h, while the coating of 0.10% ZCC into PVDF/LiCl membrane enhanced the water permeability into 208.48 ± 27.99 L/m2h. Furthermore, the selectivity also increased from 97.64% to 100% rejection in microalgae dewatering process. This shows that selectively modified zeolite NaY and ZCC membranes are only able to pass seawater as a microalgae culture medium.

Mixotrophic Cultivation of Microalgae in Cassava Processing Wastewater for Simultaneous Treatment and Production of Lipid-Rich Biomass

Cassava processing wastewater (CPW) is a highly polluting, liquid residue of cassava processing, usually discarded or treated anaerobically. However, it can serve as a low-cost culture medium for microalgae. After a preliminary evaluation of the growth of 10 microalgal strains in diluted CPW, the microalgae Haematococcus pluvialis SAG 34−1b and Neochloris (Ettlia) oleoabundans UTEX 1185 were selected for cultivation in CPW without a supply of additional nutrients and evaluated for their growth, lipid production, and nutrients removal. Maximal biomass concentrations of 1.79 g·L−1 for H. pluvialis and 3.18 g·L−1 for N. oleoabundans were achieved with 25% CPW medium on the 13th day of growth. The algae H. pluvialis and N. oleoabundans removed 60.80 and 69.16% of the chemical oxygen demand, 51.06 and 58.19% of total nitrate, and 54.68 and 69.84% of phosphate, respectively. On average, lipid productivities reached 0.018 and 0.041 g·L−1 day−1 for H. pluvialis and N. oleoabundans, respectively. Therefore, cultivating these microalgae in diluted CPW is a promising treatment for cassava wastewater with simultaneous valuable biomass production.

Evaluation of Microalgae Culture in PA and Commercial Urea Media

This work aimed to evaluate the growth and cost cultivation of Chlorella sp microalgae in PA and commercial urea medium solutions compared to BBM standard medium. We cultivated the microalgae Chlorella sp in BBM, PA urea, and commercial urea media, evaluating their growth for 8 days. In addition, we appraised the cost of the culture media considering the quotation of the reagents and the mass used for pilot-scale cultivation (100l). It was possible to observe the similar growth of microalgae with urea PA and BBM. The use of urea PA as a culture media for microalgae has the potential to reduce the cost of the medium by 68%. Thus, the cultivation of Chlorella in urea medium represents an alternative to reduce the production costs of biomass from this microorganism.

Cultivation of Chlorella sp. for biodiesel production using two farming wastewaters in eastern Colombia

The production of biofuels using wastewater as a microalgae culture medium is a little explored technology, but with potential for success. In order to contribute to the knowledge of these technologies and their technical feasibility for microalgae growth, in this work the Chlorella sp. strain was cultivated in two types of effluents generated in an experimental farm located in eastern Colombia, before and after a biological treatment process. The consumption of the main nutrients that regulate growth and lipid production was evaluated, in order to extract, quantify, characterize and convert them into biodiesel. The results showed that Chlorella sp. growth and lipid production is more favourable in R2 medium of treated water than in R1 medium of raw water, mainly due to phosphorus limitation and higher N-NO3 concentration in R2 compared to R1. In the R2 medium culture, a percentage of 42.54% of long-chain fatty acids was found, which is necessary to obtain a high quality biodiesel. Finally, the best transesterification experiment allowed reaching a fatty acid methyl esters (FAME) percentage of 90.1 ± 2.7%. In general, the results demonstrated the potential viability of using the wastewater generated in the San Pablo farm to produce biomass with lipid content to obtain biodiesel, finding that where the concentration of nutrients, mainly nitrogen, has a great influence on the microalgal metabolism for lipid accumulation.

Evaluate the Effect of Using Source of Nitrogen (Soaked Brown Lentils) on Chemical Composition for Marine Microalgae Nannochlorpsis oceanica

Microalgae culture media must be efficient, give high growth, meet micro-requirement, and be available. The effect of different levels of brown lentil infusion and use at [25, 50 and 75%] levels on the chemical composition (protein, carbohydrates, fatty acids, and amino acids) in N. oceanic was evaluated. Compared to the standard F/2 Guillard. The obtained results indicated that the chemical components of N. oceanica were affected by these levels. The highest protein and carbohydrate content and the highest EAA content (55.92%) were obtained using OB3 medium (75% SBL) compared to the control group (100% F/2). The highest biomass production was obtained in OB3 medium. The highest TSFA and USFA were recorded for N. oceanica by the OB3 mean.
 The present study recommended that it is possible to use microalgae grown on OB3 and OB2 medium as a lipid and protein inducer in aquaculture.

Алелопатичний вплив мікроводоростей на пшеницю озиму

The results of the study of the allelopathic activity of the culture medium of two species of green and charophyte microalgae (Chlorella vulgaris Beijer. and Interfillum terricola (J.B.Petersen) Mikhailyuk et al.) to winter wheat (Triticum aestivum L.) in model pot experiments with the aim to discover of physiological mechanisms of allelopathy and finding effective and safe compounds with growth-promoting effects. The microalgae culture medium was applied in a rate of 1; 3 and 10 mL per a pot (250 mL) filled with sifted and sterilized gray podzolic soil, before sowing wheat seeds. Test plants were grown in a phytochamber under controlled conditions of light intensity, temperature and soil moisture. The number of germinated seeds was recorded from the 2nd to the 8th day after sowing. The vitality of winter wheat was evaluated at the end of the experiments using morphometric characteristics of growth (height of aboveground parts, leaf surface area, length of root system, number of lateral roots; dry matter mass of aboveground parts and roots) and content of photosynthetic pigments in leaves. At the end of the experiment, the indicators of electrical conductivity, redox potential, pH and content of nutrients in the soil were determined. The positive effect of microalgae on seed germination, growth and photosynthetic apparatus of T. aestivum plants was established. Culture medium of C. vulgaris showed a higher stimulating effect on seed germination and growth of wheat seedlings than I. terricola. The positive effect of microalgae on the photosynthetic activity of wheat and the content of organic carbon in the soil indicates the possibility of developing of biofertilizers based on them in order to improve the structural and functional organization of agroecosystems. The obtained results confirmed the prospects of C. vulgaris as a biofertilizer in crops. The allelopathic effect of I. terricola on vascular plants has been studied for the first time. The important role of indirect allelopathic mechanisms in the interactions between the studied species of microalgae and vascular plants has been established.

Insights into the technology utilized to cultivate microalgae in dairy effluents

The population increase has brought a number of consequences, such as greater demands for food, fossil fuels, and freshwater. The cultivation of microalgae appears to be an alternative source of food and energy because the biomass of microalgae can yield several products with applications in the fields of bioenergy, agriculture, and human and animal food. However, growing microalgae requires high concentrations of nutrients and water, making it an expensive process for large-scale production. The use of some effluents as culture media for microalgae has become a promising solution to reduce process costs and to obtain effluent treatment. The organic residues present in dairy effluent are considered harmful to the environment due to the high chemical and biochemical oxygen demand. Another problem is the high concentrations of nitrogen and phosphorus. However, these two nutrients are among the main nutrients used to grow microalgae. The ability of microalgae to effectively absorb nutrients from dairy effluent and the concomitant generation of value-added products make this effluent a potential medium for biomass production at a reduced cost. Therefore, this review aims to present recent advances in microalgae biotechnology for the treatment of dairy effluents. In addition, the review contributes to the existing literature by expanding knowledge about replacing drinking water and synthetic nutrients with dairy effluents in the cultivation of microalgae. This review shows the efficiency of the treatment of this effluent by microalgae and the possible applications of microalgae biomass cultivated in dairy effluents.

Effect of Dilution on Nitrogen Removal from Ammonia Plant Effluent using Chlorella vulgaris and Spirulina platensis

In this study, the removal of nitrogen from effluent of ammonia plant by Chlorella vulgaris and Spirulina platensis was investigated. For this purpose, microalgae were cultivated in three diluting percentage of the wastewater (1, 3, and 5%) at 29±1 ◦C and light intensity at surface of culture were adjusted to 150 µmol photon / (m2. s). The results showed that Spirulina platensis is more capable than Chlorella vulgaris to grow in high levels of total nitrogen concentration. Also, maximum biomass production rate happened in 1% diluted samples for Chlorella vulgaris and 3% for Spirulina platensis. Furthermore, Chlorella vulgaris reduce total nitrogen concentration up to 55%. This value for Spirulina platensis was about 96%. However, for both species the removal of nitrogen in 1% diluted wastewater was maximum. According to the results of diluted wastewater of ammonia plant, it is a suitable culture medium for microalgae and it can be used to remove the nitrogen before entering the wastewater in nature.