Laboratory simulation of Jar-test for drinking water treatment. Copyright: Institute of Hydrodynamics of the CAS, v.v.i.

Computational fluid dynamics (CFD) simulations applied to photocatalytic systems are reviewed. Simulations of three models for simulating radiation distribution in 3D annular photoreactors and 2D rectangular enclosures with black walls are covered. The discrete ordinates model is selected to find the radiation distribution inside the reactor. CFD models agree excellently with literature results.

A systematic overview of published life cycle assessment (LCA) studies on water and wastewater treatment in Africa is presented. Unitary estimates for energy use, global warming potential (GWP), and eutrophication potential (EP) are provided for geographical locations and water sources. The meta regression model is fit to predict how these factors influence energy use, GWP, and EP.

Waste rendering fat (WRF), a solid residuum from rendering plants, consists of a mixture of lipids with a high content of mono-, di-, and triglycerol esters and free fatty acids. Catalytic liquefaction and deoxygenation of WRF with four different iron-based catalysts are proposed, with the aim to prepare new catalysts and use them for upgrading WRF for application in current refineries.

The effects of the flapper valve for particle discharging in an industrial cyclone separator on the flow field, static pressure drop, cut size, and slope of the grade efficiency curve have been investigated using the Reynolds stress model simulation. The cyclone was simulated in three operation regimes, namely, when the flapper valve is open, closed, and without the flapper valve.

Acinetobacter venetianus isolated from samples of oil spilled on the Brazilian coast was able to produce a biosurfactant with high emulsification potential and stability against variations in temperature, pH, and presence of NaCl. The bioproduct obtained was capable to disperse oil residues present in stones contaminated by oil spills, evidencing its potential for bioremediation.

This paper demonstrates how the nontoxic isocyanate hexamethylene diisocyanate biuret low viscosity (HDB-LV) allows the fabrication of polyurea microcapsules for cosmetic applications at decent reaction rates. A theoretical model is presented to fit the experimental data and obtain key parameters of the reaction. Three different amines and various temperatures were tested.

A pilot-scale reactor was set up to determine the feasibility of single-cell protein (SCP) recovery from fuel synthesis process water (FSPW), a zero-nitrogen feedstock, via anaerobic purple non-sulfur bacteria treatment under various light intensities. FSPW treatment efficiency, biomass yield and content were dependent on light intensity. Substantial SCP recovery was achieved at low light intensity.

Non-isothermal mass transfer to dispersed fluid drops was studied using the computational fluid dynamics simulation tool ANSYS FLUENT. The temperature-dependent diffusion coefficient was employed with the help of the User-Defined Function. Mass transfer is faster for drop heating than for drop cooling and significant solute transfer occurs at the final higher temperature.

Industrial cooling circuits are strongly susceptible to fouling and particularly biofouling. This work proposes a compartmental model built from a full hydrodynamic characterization of an industrial cooling circuit and implemented with a biofilm growth model which considers kinetic (temperature, concentrations) as well as hydrodynamic (internal and external transfer) limitations.

Scaling algorithms for planetary roller extruders on laboratory and production scale are developed in this contribution. In systematic studies, different operating conditions are analyzed with regard to process temperatures, pressure build-up capacity, and residence time distribution. Machine learning models are applied to make predictions of process variables with high accuracy.

The effect of an electromagnetic equipment to prevent incrustations in pipes is evaluated. An immediate technique of forced precipitation of calcium carbonate to verify this effect is applied to distinguish between electromagnetically treated and untreated tap water, by means of temporal evolution of turbidity, absorbance, and the final size of the particles formed, with temperature control.

A systematic experimental investigation of the distance between the catalysts for CO₂ to dimethyl ether tandem reaction system is presented. The distance mainly causes external mass transfer limitations which affect the overall performance of the catalysts, whereas, if the catalysts are very close to each other, poisoning of the acid catalyst due to high local concentration of water may occur.

Composite materials based on epoxy resins with microspheres additives were tested for resistance to alternating temperatures, corrosive media like acid, alkali, and gasoline, and to abrasion. The improved chemical resistance, wear capacity, and resistance to temperature drops by adding microspheres allows the application as corrosion-resistant coatings for metal structures and during machine maintenance.

A catalytic technology to produce H₂ from biogas was investigated. Since biogas is a wet mixture of methane and CO₂, the process currently studied takes advantage of the presence of the two common oxidants used to convert CH₄, an approach often known as bi-reforming of methane. The effect of sulfur, a common poison found in biogas streams, was evaluated by adding dimethyl sulfide to the catalysts.

In the reactor proposed for treating wastewater containing refractory organic substances, the roles of ultraviolet (UV) irradiation, ultrasound, ultrasonic mist, and photocatalyst were investigated by comparing the pollutant removal performance under different operating conditions. The results show that the use of UV, ultrasound, and photocatalyst is necessary to utilize mist as a reaction field.

The local values of gas holdup together with the liquid mixing time were investigated with the specific purpose of assessing the difference in gas-liquid mixing performances obtained with the standard Rushton turbine and the asymmetric concave blade design, namely, the Bakker turbine, in single and multiple impeller configurations. The latter was more energetically efficient for gas-liquid mixing.

A hydrogen concentration measurement device for nuclear power plants is under development. The experience on the device preparation complexity is shared by the Mass Transfer Laboratory at UCT Prague. The amperometric hydrogen sensor tests illustrate how to enhance the sensor durability. A successful improvement is confirmed by the operational test at the Dukovany nuclear power plant.

The role of biomass considering the occurrence of pollution remains still understudied. The deposition flux of different ionic compounds to fine particulate matter for urban, agricultural, and forest regions was determined. Possible sources, concentrations, and ionic composition of atmospheric particulate matter present in the atmosphere of Araraquara were analyzed and related to emission sources.

Pyrolysis liquids obtained by fast pyrolysis of birch wood pretreated with diluted sulfuric acid have been separated by solid-phase extraction to valorize the aromatic by-products which arise during levoglucosan production. Solid-phase extraction offers good separation between sugars and phenols, also allowing further selective extraction of different aromatic species.

Intensification work is carried out using a thin-gap bubble column intended as a photobioreactor, with high confinement ratio and cell concentration. Consequences of this geometrical condition and rheological properties of the liquid phase on the gas holdup and flow regimes are studied for different model fluids, having the same rheological properties as microalgae suspensions at high concentrations.

An innovative separation microdevice based on a Brownian sieving effect coupled with hydrodynamic chromatography is proposed to investigate and optimize a modified geometry suitable for obtaining the simultaneous separation of a three-size diluted suspension. The results prove a significant improvement of up to 3000 % over the standard hydrodynamic chromatography.

Quantification of water flow in natural low-cost adsorbents employed as multilayer filters for wastewater treatment by the infiltration-percolation technology was investigated. Laboratory tracer experiments and mathematical modeling were performed for such adsorbents. The choice of the appropriate adsorbent is crucial to improve flow uniformity, which in turn will impact the treatment efficiency.

Stereolithography (SLA) and fused deposition modeling were used to additively manufacture ChannelCOMB, a consecutive flow distributor. The SLA ChannelCOMB shows a smaller flow deviation, because SLA promotes better flow uniformity due to the lower fabrication tolerance and material impermeability. The flow distribution can be well predicted by CFD simulations and the resistance analog model.

The significant impact of screw configuration on the final granule size distribution was investigated by means of gPROMS FormulatedProduct software to perform optimization, estimation of complex processes, and analyses. Twin-screw granulation modeling was applied to evaluate the contribution of screw configuration and liquid-to-solid ratio on granule size distribution.

Measurements of dynamic and steady-state drop size distributions were performed in silicone oil-in-water systems with rising dispersed phase viscosity using an in situ endoscope technique in a stirred tank. The predictive power of a population balance model for partly mobile interfaces is evaluated critically. The fitting procedure and impact of daughter drop size distribution shape are discussed.

The rate of nucleation of (poly)glycine molecules increases with the number of glycine residues added. This may be attributed to more interactions between the (poly)glycine molecule and the heterosurface. Molecular dynamics simulations confirmed the existence of more interaction sites, resulting in an increase in hydrogen bond interaction lifetime of (poly)glycine with heterosurfaces.

Bunno's Fabulous Soap-Making Challenge is a resource-managing game in which players plan, organize, and execute the production of soap. The game concept, educational theory, design, educational content, and projected learning outcomes are described and discussed. A first mixed-method evaluation collects and identifies players' game-playing experiences. Results indicate that players enjoyed playing it.

Chemical recycling allows for the transformation of waste polyolefins into valuable products which can be employed as secondary feedstocks for chemical and petrochemical industries. The acid site density of HZSM-5 catalysts can be used as a tool for tuning the product selectivity during thermocatalytic pyrolysis of polyolefins.

The design of continuous simulated moving-bed chromatography and its optimization for the separation of mannose from natural sources are described. The results are compared based on the purities of mannose in the extract stream and galactose in the raffinate stream. The developed method can be extended to more feed compounds and separation of aqueous solutions not only in carbohydrate technologies.

Bioremediation of Cr(VI)-contaminated effluents is an economical and environment-friendly treatment method. Cr(VI) removal in a bench-scale bioreactor was investigated using municipal dried sludge as a permeable bioreactive barrier. The indigenous bacteria obtained from a wastewater treatment plant were able to effectively remove Cr(VI) with or without any biostimulation.