Szabolcs Kertész

Biogas Production of Ozone and/or Microwave-Pretreated Canned Maize Production Sludge

The production of canned maize is accompanied by formation of large volumes of waste water, with high contents of starch, and high chemical- and biochemical oxygen demand. In our work the effects of acidic, microwave and ozone pretreatment on the biogas production and aerobic biodegradability of canned maize production sludge were examined and the energy balance of the processes were determined when different sludge pretreatments were used. It was found that ozone treatment decreased the chemical oxygen demand, while the biochemical oxygen demand and the aerobic biodegradability increased. The combination of microwave and ozone treatment increased the biodegradability relative to ozone treatment alone.

Dairy Waste Water Treatment by Combining Ozonation and Nanofiltration

Abstract The aim of this investigation was to examine the applicability of the membrane technique and the effect of preozonation in dairy waste water treatment technology. The best degree of surfactant removal from model anionic surfactant solution by nanofiltration was achieved at 20°C and 40 bar. Investigations on the effects of ozone treatment of the waste water indicated that preozonation decreased the flux and increased the chemical oxygen demand and surfactant removal efficiency. Ozone treatment enhanced the biodegradability of the retentate from 68.8% to 96.4%.

Comparison of the Effects of Ozone, UV and Combined Ozone/UV Treatment on the Color and Microbial Counts of Wheat Flour

The effects of direct ozone treatment, UV treatment and combined ozone/UV treatment on the color and microbiological count of milled wheat flour were compared. The changes in color and microbiological properties during a 19-week storage period were also examined. Each of the treatments significantly reduced the microbial count of the flour and resulted in whiter flour. The results showed that only the combined treatment furnished flour suitable for consumption. The effect of the combined treatment was similar to, but more pronounced than that of ozone treatment. Changes in the quality of the dough were observable, similar by as in response to other oxidizing agents.

Investigation of parameters affecting the ultrafiltration of oil-in-water emulsion wastewater

Abstract The ultrafiltration (UF) of model oily wastewater containing an emulsifier was investigated in order to determine the main parameters affecting the flux, retention and membrane fouling. The experiments were carried out with a laboratory UF device, using regenerated cellulose UF membranes. The finding that the fall in flux with time correlated best with the cake formation model is in accordance with the result that increasing resistance during filtration is caused predominantly by the concentration polarization, while the participation of membrane fouling in the total resistance is negligible. Analysis of the parameters affecting the UF of oily wastewater demonstrated that the flux is mainly influenced by temperature and concentration (besides the membrane pore size), while the concentration and the stirring speed are the parameters affecting the resistance. The retention increased slightly with concentration, but this was mainly determined by the membrane pore size.

Investigation of module vibration in ultrafiltration

AbstractMembrane fouling is still a critical issue which limits the application of industrial membrane utilizations. Membrane processes operating at a high shear rate are frequently used to control flux decline by reducing the deposition of particles on the membrane surface. In this work, ultrafiltration (UF) of a dairy model and industrial wastewaters was investigated. Membrane module vibration and no-vibration mode were compared by a laboratory mode vibratory shear enhanced processing device during membrane filtration with the same operational parameters. Membrane fluxes, rejections, and energy consumption were measured and calculated for comparison of the vibration effectiveness. Turbidity, chemical oxygen demand, and total organic carbon were measured. The UF experiments were carried out with constant parameters at a temperature of 50°C and recirculation flow rate of 910 L h−1 at 0.8 MPa. Furthermore, to understand the fouling mechanisms in depth, contact angles of the clean, prewetted, and fouled mem...

Investigation of surface and filtration properties of TiO2 coated ultrafiltration polyacrylonitrile membranes

In the present work, the surface and filtration properties of TiO2 coated polyacrylonitrile ultrafiltration membranes were investigated. The membranes were coated using the physical deposition method. The appropriate TiO2 coverage proved to be 0.3 mg/cm2, which formed a hydrophilic cake layer on the membrane surface. The cleanability without chemicals and the retention of the coated membranes was compared to the neat membrane after model oily wastewater filtration. The cleaning sustained of rinsing with distilled water and ultraviolet (UV) irradiation of the fouled membranes. The coated membranes have better antifouling properties; higher flux values during oily water filtration and by the mentioned cleaning process a significantly better flux recovery can be achieved. The amount of the catalyst and the irradiation time are limiting factors to the effectiveness of the cleaning process. The UV irradiation increases the wettability of the fouled membrane surface by degrading the oil layer. The coating, the continuous use, and the cleaning process do not significantly affect the membrane retention expressed in chemical oxygen demand.

The effect of the implementation of ultrasound in enzyme separation

Enzymes are biological catalysts that generally are designed to do one job well, but to do one job only. Therefore, the enzymes that catalyze the hydrolysis of cellulose to sugar do not break down the sugars. Enzymatic hydrolysis processes have been under development for only 10 years. The important research issues include understanding the processes necessary to render the crystalline cellulose easily digestible, understanding and improving the basic mechanisms in the hydrolysis step, and developing better and less expensive enzymes. The other way to make a process less expensive may be the recycling of enzymes. The essential unit operation in the bioethanol production is the cellulose enzymatic degradation, so the question of recycling is very important. In our work the sonication assisted ultrafiltration was investigated as a potential method for enzyme recycling. The results showed the ultrasound effects the permeate flux since the resistance is reduced by the sonication. The sonicated enzyme keeps its activity so the recycling mechanism might be used for bioethanol production.

Treatment of waste thermal waters by ozonation and nanofiltraton

After their use for heating, e.g. in greenhouses, waste thermal waters may cause environmental problems due to their high contents of ions, and in some cases organic matter (associated with an oxygen demand) or toxic compounds. The aims of this work were to decrease the high organic content of waste thermal water by a combination of ozone treatment and membrane separation, and to investigate the accompanying membrane fouling. The results demonstrated that the chemical oxygen demand and the total organic content can be effectively decreased by a combination of ozone pretreatment and membrane filtration. Ozone treatment is more effective for phenol elimination than nanofiltration alone: with a combination of the two processes, 100% elimination efficiency can be achieved. The fouling index b proved to correlate well with the fouling and polarization layer resistances.