Indirect assessment of biomass accumulation in a wastewater-based Chlorella vulgaris photobioreactor by pH variation
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Abstract:
Algae bloom in coastal waters is partly supported by residual nutrients in treated wastewater (WW) released from coastally located treatment plants. In response, a Chlorella vulgaris-based photobioreactor was recently proposed for lowering nutrient levels in WW prior to release. However, the solution requires maintaining biomass accumulation to within a photobioreactor capacity for optimum operation. For high density Chlorella vulgaris suspensions, this is easily done by monitoring turbidity increase, a property directly related to biomass accumulation. For low density suspensions however, direct turbidity measurement would require a cumbersome process of concentrating large volumes of Chlorella vulgaris suspensions. Here, we demonstrate that by measuring pH of the suspensions, turbidity (T) can be estimated indirectly by the following wastewater-dependent expression: pH = aT + pH0, hence avoiding the need to concentrate large volumes. The term pH0 is the initial pH of the suspensions and a, a wastewater-dependent constant, can be computed independently from a = - 0.0061*pH0 + 0.052. In the event %WW is unknown, the following wastewater-independent Gaussian expression can be used to estimate T: pH = 8.71*exp(- [(T - 250)2]/[2*1.26E05]). These three equations should offer an avenue for monitoring the turbidity of dilute Chlorella vulgaris suspensions in large, stagnant municipal Chlorella vulgaris-based wastewater treatment system via pH measurements.Keywords:
Photobioreactor
Chlorella vulgaris
Turbidity
To reduce the level of CO2 content in air, effort on converting CO2 to useful products is required. One of the alternatives includes CO2 fixation to produce biomass using Chlorella vulgaris Buitenzorg. Chlorella vulgaris Buitenzorg is applied for production of food supplement. Chlorella vulgaris Buitenzorg is also easy to handle due to its superior adaptation. Currently, Chlorella vulgaris Buitenzorg has been analyzed by some experts for its cellular composition, its ability to produce high quality biomass and the content of essential nutrition. A series of experiments was conducted by culturing Chlorella vulgaris Buitenzorg using Beneck medium in bubbling column photobioreactor. The main variation in this experiment was photoperiodicity, where growth of Chlorella vulgaris Buitenzorg was examined during photoperiodicity condition. The difference between CO2 gas concentration of inlet and outlet of the reactor during operational period, was compared to the same experiment under continuous illumination. Under photoperiodicity of 8 and 9 h/d, the culture cell densities (N) were approximately 40 % higher than under continuous illumination. Final biomass density of Chlorella vulgaris Buitenzorg at 9 h/d illumination was 1.43 g/dm3, around 46% higher than under continuous illumination. Specific carbon dioxide transfer rate (qCO2) in photoperiodicity was 50-80% higher than under continuous illumination. These experiments showed that photoperiodicity affects the growth of Chlorella vulgaris Buitenzorg The specific growth rate (μ) by photoperiodicity was higher than that by continuous ilumination while the growth period was two times longer. Based on the experiments, it can be concluded that photoperiodicity might save light energy consumption. The prediction of kinetic model under continuous illumination as well as under photoperiodicity illumination showed that Haldane model became the fitted kinetic model.
Chlorella vulgaris
Photobioreactor
Carbon fixation
Light intensity
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The aim of this study was to investigate the efficiency of optical panel (OP) on the growth rate of Chlorella vulgaris (C.vulgaris).The size of C. vulgaris (FC-16) was 3~8 µm, having round in shape.The cells of C. vulgaris was cultured in the Jaworski's Medium with deionized water at 22℃ for 15 days.For this experiment, three light samples were prepared to evaluate the efficiency of OP on the growth rate of C. vulgaris; OP with LED (Light Emitting Diode) (Run 1), Fluorescent light (Run 2) and LED (Run 3).The specific growth rate of C. vulgaris for Run 1 was found to be 14 times and 5 times faster than Run 2 and Run 3, respectively.In addition, the average biomass of C. vulgaris for Run 1 was measured 11.79 g/L in 11 days.This means that the biomass for Run 1 was reached 30 times and 6.5 times higher than Run 2 and Run 3, respectively.This may be due to the fact the OP was increased the light uniformity and hindered the shading effects in photobioreactor.Therefore, the growth rate of biomass in photobioreactor with OP is compared better than the without OP used other photobioreactor.
Photobioreactor
Chlorella vulgaris
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Аннотация: Представлено накопительное и непрерывное культивирование микроводоросли Chlorella vulgaris в трубчатом фотобиореакторе.Проведена оценка прироста биомассы по показаниям оптической плотности
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Chlorella vulgaris
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Photobioreactor
Chlorella vulgaris
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Algae bloom in coastal waters is partly supported by residual nutrients in treated wastewater (WW) released from coastally located treatment plants. In response, a Chlorella vulgaris-based photobioreactor was recently proposed for lowering nutrient levels in WW prior to release. However, the solution requires maintaining biomass accumulation to within a photobioreactor capacity for optimum operation. For high density Chlorella vulgaris suspensions, this is easily done by monitoring turbidity increase, a property directly related to biomass accumulation. For low density suspensions however, direct turbidity measurement would require a cumbersome process of concentrating large volumes of Chlorella vulgaris suspensions. Here, we demonstrate that by measuring pH of the suspensions, turbidity (T) can be estimated indirectly by the following wastewater-dependent expression: pH = aT + pH0, hence avoiding the need to concentrate large volumes. The term pH0 is the initial pH of the suspensions and a, a wastewater-dependent constant, can be computed independently from a = - 0.0061*pH0 + 0.052. In the event %WW is unknown, the following wastewater-independent Gaussian expression can be used to estimate T: pH = 8.71*exp(- [(T - 250)2]/[2*1.26E05]). These three equations should offer an avenue for monitoring the turbidity of dilute Chlorella vulgaris suspensions in large, stagnant municipal Chlorella vulgaris-based wastewater treatment system via pH measurements.
Photobioreactor
Chlorella vulgaris
Turbidity
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Photobioreactor
Chlorella vulgaris
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Solid-state cultivation is a promising technology for algal biomass production, achieving high productivities without the need for dewatering. However, such systems have suffered from high evaporation, and capital costs. Here we describe a hydrogel photobioreactor (hPBR) with the aim of reducing water demand in solid-state cultivations. Two designs are described with "Design A" offering better control over growth conditions. A biomass productivity of 2.4 g m-2 d-1, and 3.2 g m-2 d-1 when using physically crosslinked poly(vinyl) alcohol (pPVA) and chemically crosslinked PVA (cPVA) respectively were achieved with Chlorella vulgaris with a water demand around 0.44 kg g-1 of biomass. Over the 23 days of growth, the lipid content increased from 18.9% to 56.6% and 13.8% to 43.2% for pPVA and cPVA respectively, and the chlorophyll content also decreased. However, cell viability stayed high at over 98% and surface coverage analysis showed good coverage of the gel surface.
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Chlorella vulgaris
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Photobioreactor
Chlorella vulgaris
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Photobioreactor
Chlorella vulgaris
Carbon fixation
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Lipid productivity of Chlorella vulgaris and Nannochloropsis oculata was evaluated in a 5 L lab scale externally illuminated photobioreactor. The effect of operating conditions such as pH, temperature, light intensity and photoperiod on biomass productivity, lipid content and lipid productivity was evaluated. At optimum conditions, a maximum lipid productivity of 69.46 and 192.3 mg lipid. L -1 .day- 1 was observed for C.vulgaris and
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Chlorella vulgaris
Light intensity
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