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High dewatering costs, resulting from the harvesting and separation of microalgae from the cultivation medium, pose a significant challenge to the large-scale commercial production of algae-based products, accounting for 20–60% of total cultivation expenses. This study presents research findings on the recovery of Baltic green microalgae Chlorella vulgaris BA-167 from water under static sedimentation conditions, evaluating its potential as a cost-effective harvesting method. The study investigates the effect of suspension concentration on the kinetics and efficiency of sedimentation under both autoflocculation and targeted flocculation conditions, using the Flokor 1.2A coagulant, which is commonly employed in industrial water treatment processes in Poland. The novelty of this research lies in the application of the new coagulant Flokor 1.2A to explore its potential for harvesting Chlorella vulgaris BA-167 cultivated under laboratory conditions. The results demonstrate a strong correlation between the algae removal rate and their initial concentration in the suspension, within the range of 0.375–2.380 g/L. Under autoflocculation conditions, the final minimum algae concentration in the liquid after sedimentation ranged from 0.078 to 0.148 g/L, corresponding to initial concentrations of 0.960 g/L and 0.615 g/L, respectively. Experimental results indicate that combining sedimentation with targeted flocculation significantly increases microalgae harvesting efficiency. Flokor 1.2A facilitates the coagulation and agglomeration of microalgae cells, promoting the formation of larger aggregates (flocs) ranging from 20 μm to 690 μm, which settle more easily during gravity-driven sedimentation. Within the coagulant concentration range (CF) of 0.01–0.36 g/L, sedimentation time was reduced by 3–7 times, and algae harvesting efficiency exceeded 92%. The greatest reductions in algae concentration occurred with 0.12 g/L of coagulant for 0.615 g/L algae and 0.17 g/L for 0.960 g/L algae, achieving maximum harvesting efficiencies of 83.2% and 92.9%, respectively. These results represent a 2.02–2.53-fold improvement over autoflocculation. [ABSTRACT FROM AUTHOR] more...

This paper summarises a series of large-scale fire suppression tests conducted to simulate a fire in the big surface and/or surface sprinkling. The subject of this paper is the research on water spraying with the use of the Turbo Jet 2011 water-foam nozzle manufactured by Supon Białystok. The results discuss the pressure losses caused by the flow through the discharge hose, spray angle, and the intensity of surface sprinkling. The greatest stream ranges and the highest maximum values of the sprinkling intensity were obtained at the capacity of 400 l/min, and a solid spray angle. The smallest values were obtained at 200 l/min, a pressure of 5 bar, and a solid spray angle. The actual pressures taking into account the losses in the hose section were calculated. As for the highest firefighting effectiveness of the stream, the authors recommended the following parameters: semi spray angle, 200 l/min, and 2.5 bar. more...

This paper reports the results of research into air, water and oil flow through pipes filled with open-cell metal foams, which form a material with a considerable potential for application in the design of process equipment. This study applied three metal foams with various geometrical parameters. The objective of the experiments involved the measurement of pressure drop within a relatively large range of the variability of the flow conditions. On the basis of data from the literature and analysis of the results of experiments, an assessment was undertaken concerned with the influence of the geometrical parameters of the foams as well as velocities and fluid properties on the flow regime and pressure drop. The results demonstrate that the theory concerned with the fluid flow through porous media has a limited application with regard to metal foams due to the considerable turbulence of the flow through such foams. If flow occurs in other conditions than laminar regime, the permeability of metal foams is relative not only to the geometrical structure of the foams but also depends on the properties and velocity of the fluid. The present study demonstrated that the assessment of the flow regime can apply the modified Reynolds number in which the characteristics dimension is defined on the basis of the parameters accounting for the geometrical foam structure. Three flow regimes were distinguished – laminar flow, transient Forchheimer and transient Froud flow. The ranges corresponding to the occurrence of the particular flow regimes were subsequently determined. more...

The paper reports the results of Chlorella vulgaris sedimentation process including description of cultivation condition of microalgal biomass. The process of algae cultivation was carried out in photobioreactor comprising systems of carbon dioxide supply, mixing and artificial LED illumination. The growth of microalgae was determined alternatively in three ways by measuring the amount of dry mass over time, counting the cells and measurement of optical density by use of a spectrophotometer. Algae biomass with different concentration was subjected to the separation process by gravity. This led to the determination of the characteristic of sedimentation process for different concentrations and cell sizes. The experimental results indicate that sedimentation process offers a tool with a potential application for microalgae harvesting. more...

This paper undertakes the description and assessment of various solutions applied for the design of photobioreactors as the type of apparatus, which can provide high output of green algae biomass. The design of such apparatus plays an important role in the context of the concurrent fulfillment of ecological and economic requirements, which are necessary to conduct an efficient and effective technology using cheap and easily accessible resources to produce different goods. Nowadays, algae is seen as one of the most promising sustainable way to produce energy in the future (biofuels, electricity, thermal energy) but technologies of biomass production and processing are still under development particularly to increase biomass and energy output. The cultivation costs in closed systems are still high, limiting their commercial applications to high-valued compounds but they can be reduced by efficient bioreactor designs, which are able to achieve high areal biomass productivities. This paper focuses on the advantages and drawbacks associated with the application of the particular types of bioreactors in algae production, description of their operation parameters and area for practical application, pointing of the constructions (tubular, flat panel, bubble column) that can contribute to improvement the profitability of large-scale production. more...

The study presents the possible use of optoelectronic system for the measurement of the values, which are specific for hydrodynamics of two-phase gas liquid flow in vertical pipes, where a very-high-viscosity liquid forms a falling film in a pipe. The experimental method was provided, and the findings were presented and analysed for selected values, which characterize the two-phase flow. Attempt was also made to evaluate the effects of flow parameters and properties of the liquid on the gas-liquid interface value, which is decisive for the conditions of heat exchange and mass transfer in falling film equipment. The nature and form of created waves at various velocities were also described. more...

Copyright of Ecological Engineering / Inżynieria Ekologiczna is the property of Polish Society of Ecological Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

Copyright of Technical Transactions / Czasopismo Techniczne is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

The paper presents the results of a study concerned with the hydrodynamics of an annular downward multiphase flow of gas and two mutually non-mixing liquids through a vertical pipe with a diameter of 12.5 mm. The air, oil and water were used as working media in this study with changes in superficial velocities in the ranges of jg = 0.34–52.5 m/s for air, jo = 0.000165–0.75 m/s for oil, and jw = 0.02–2.5 m/s for water, respectively. The oil density and viscosity were varied within the ranges of ρo = 859–881 kg/m3 and ηo = 29–2190 mPas, respectively. The research involved the identification of multiphase flow patterns and determination of the void fraction of the individual phases. New flow patterns have been identified and described for the gravitational flow conditions of a two-phase water–oil liquid and a three-phase air–water–oil flow. New flow regime maps and equations for the calculation of air, oil and water void fractions have been developed. A good conformity between the calculated and measured values of void fraction were obtained. The map for the oil–water–air three-phase flow is valid for the following conditions: j3P = 0.35–53.4 m/s (velocity of three-phase mixture) and oil in liquid concentration βo* = 0.48–94% (oil in liquid concentration). In the case of a downward annular oil–water two-phase flow, this map is valid for liquid mixture velocity jl = 0.052–2.14 m/s and βo* = 0.48–94%. [ABSTRACT FROM AUTHOR] more...

This paper reports the results of research involving observations of flow patterns during air-oil-water three-phase flow through a vertical pipe with an internal diameter of 0.03 m and a length of 3 m. The conductometric method based on the measurement of electrical conductivity of the gas-liquid-liquid system was used to evaluate the flow patterns. In the studies, a set of eight probes spaced concentrically in two tube sections (four probes per each) with a spacing of 0.015 m were used. The paper presents a theoretical description of the test method and the analysis of the measurement results for air-oil-water multiphase flow system. Results of this study indicate that the developed method of characterizing the voltage of the gas-liquid-liquid system can be an important tool supporting other methods to identify flow patterns, including visual observation. [ABSTRACT FROM AUTHOR] more...

The European Groundwater Directive could be improved by limiting the scopes of the Annexes I and II to the manmade and natural substances, respectively, and by defining a common monitoring protocol. The changes in the European landuse patterns, in particular the urban sprawl phenomena, obscure the distinction between the point and diffuse sources of contamination. In the future more importance will be given to the household contamination. Moreover, the agricultural environment could be used for developing new conceptual models related to the pharmaceuticals. more...