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Among the current environmental challenges facing humanity is the protection of water in quantity and quality. The objective of reduce to zero the generation of waste in productive activities by applying the concept of circular economy has led to the emergence of proposals for the production of biomaterials capable of contributing to environmental protection and that do not imply huge investments of money. As a good example of these proposals, biochar had to be mentioned which is a material with excellent adsorbent properties, with low production costs and that is made with any type of organic matter such as agricultural waste. In this work a nanoparticle-modified ultrafiltration membrane was used as a pre-treatment method prior to ammonium adsorption. As adsorbent for ammonium removal alkaline modified biochar produced from banana leaves were used. The characterization of biochar and the research about kinetics models obtained after batch experiments. The general results obtained after the combination of membrane filtration and adsorption are promising and reflect a satisfactory ammonium removal percentage, and these results prove that biochar would be a good adsorbent for nutrient recovery from wastewaters.

Microwave irradiation is a promising pre-treatment method for sludge stabilisation, but there are few studies focusing its effect on organic matter solubility and biodegradability of wastewater and sludge originated from the food industry. In our research, microwave irradiation was applied standalone and in combination with alkaline treatment to enhance the solubilisation and biodegradation of organic matter content of meat industry wastewater and municipal sludge, respectively. The energy efficiency was investigated, as well. Dielectric measurement is a suitable method to detect physicochemical changes, therefore our research work covered the determination of dielectric properties of the investigated materials. Our experimental results have revealed that the lower power and energy intensity microwave-alkaline treatments were the most efficient pre-treatment process from energetically aspects to increase the organic matter solubility and biodegradability of wastewater and sludge. Furthermore, a strong linear correlation was found between the dielectric constant and the indicators of the solubility of organic matter (SCOD/TCOD) and aerobic biodegradability (BOD/COD) in both treated materials, respectively. Our results show that the dielectric measurements can be applied for detection of physicochemical changes, predict the improvement of biodegradability, and considered as a promising method to estimate the efficiency of sludge pre-treatment methods.

This study investigates the enhancement of dairy wastewater treatment using chemical and physical pre-treatments coupled with membrane separation techniques to reduce membrane fouling. Two mathematical models, namely the Hermia and resistance-in-series module, were utilized to comprehend the mechanisms of ultrafiltration (UF) membrane fouling. The predominant fouling mechanism was identified by fitting experimental data into four models. The study calculated and compared permeate flux, membrane rejection, and membrane reversible and irreversible resistance values. The gas formation was also evaluated as a post-treatment. The results showed that the pre-treatments improved UF efficiency for flux, retention, and resistance values compared to the control. Chemical pre-treatment was identified as the most effective approach to improve filtration efficiency. Physical treatments after microfiltration (MF) and UF showed better fluxes, retention, and resistance results than ultrasonic pre-treatment followed by UF. The efficacy of a three-dimensionally printed (3DP) turbulence promoter was also examined to mitigate membrane fouling. The integration of the 3DP turbulence promoter enhanced hydrodynamic conditions and increased the shear rate on the membrane surface, shortening filtration time and increasing permeate flux values. This study provides valuable insights into optimizing dairy wastewater treatment and membrane separation techniques, which can have significant implications for sustainable water resource management. The present outcomes clearly recommend the application of hybrid pre-, main- and post-treatments coupled with module-integrated turbulence promoters in dairy wastewater ultrafiltration membrane modules to increase membrane separation efficiencies.

Industrial wastewater is a growing environmental challenge due to its high concentrations of organics and its limited biological degradability. Up to date, however, no published work discussed industrial wastewater characterization, which is the focus of this study. Moreover, the effect of hydrothermal treatment on the chemical oxygen demand (COD) removal and the soluble chemical oxygen demand (SCOD) release was investigated in this work. Wastewater samples were collected from different industrial sites and characterized in order to determine their initial properties. It was summarized that the salinity of wastewater estimated by EC was relatively low, and its pH values were in the acceptable range. On the other hand, however, high values of sodium absorption ratio (SAR) were obtained in all samples post to hydrothermal treatment. Nonetheless, our results revealed higher SCOD release post to hydrothermal treatment suggesting better efficiency of COD removal obtained by this treatment technique.

A bio-motorhajtóanyagok előállításával és energetikai célú hasznosításával kapcsolatos kutatások fontosságát egyrészt Magyarország Megújuló Energia Hasznosítási Cselekvési Tervében foglaltak, másrészt az Európa 2020 által is hangsúlyozott intelligens és fenntartható növekedés elősegítése indokolja. Közleményünkben közölt kutatási program közvetlen célja a mikrohullámú előkezelés bio-energetikai célú felhasználási lehetőségének vizsgálata, közvetett cél az energiaellátás biztonságának megteremtése. Az eddigi tapasztalatok alapján a mikrohullámú energiaközlés előnyösen használható egyes kémiai reakciók intenzifikálása területén. Előkísérleti tapasztalataink azt mutatt ák, hogy a növényi olajok mikrohullámú térben történő átészterezése (metanolos átészterezés NaOH katalizátorral) az eljárás idejének és energiafelhasználásának csökkentését eredményezi. A mikrohullámú energiaközléssel végzett növényi alapú hajtóanyagok előállítása eltérő műveleti -, eljárás- és folyamatparaméterek mellett történt. A kísérletek eredményeként megállapítható, hogy a hagyományos átészterezés reakcióidejéhez viszonyítva a mikrohullámmal történt átészterezési reakcióidők jelentősen lecsökkentek, azonban az eljárásenergeti kai szempontú opti málásához a kezelt reakcióelegy összetételének és az összetevők dielektromos jellemzőinek további vizsgálata, illetve meghatározása is szükséges.

Nowadays, the development of rapid and non-destructive measurement methods have high importance. The dielectric measurement is a promising technique to detect the chemical and physicho-chemical change of different materials. The dielectric behavior of pure water is widely investigated for decades, but there is very few information available related to the dielectric parameters of wastewater. Our study aims to investigate the applicability of dielectric measurements for the detection of the change of biodegradability of wastewater. In the experiments the change of organic matter solubility and biodegradability of sugar beet processing wastewater, meat processing wastewater, dairy industry wastewater and municipal wastewater was examined. Our results show that dielectric constant - measured at the frequency of 2400 MHz - has a strong linear correlation with the soluble chemical oxygen demand (SCOD), which makes possible the fast detection of disintegration efficiency of different wastewater and sludge treatment processes, or the organic matter removal efficiency of wastewater purification technologies. Furthermore, our results verified that the change of aerobic biodegradability (expressed in BOD5/SCOD ratio) show also good linear correlation with the dielectric constant. These preliminary results enable to develop a dielectric behavior based detection method for the estimation of the efficiency of wastewater treatment processes.

A significant representative of the third generation of raw materials is waste containing hemicellulose. Agriculture and the food industry generate a great deal of this type of waste, which has many potential opportunities for processing. Our research group investigated the pre-treatments for the enzymatic saccharification of the cellulose content of the two fractions of corn cob meal. Microwave energy communication was performed in both acidic and alkaline media. It was found that the pH of the medium influences the amount of reducing sugars, but to an almost equal extent. The yield is also significantly dependent on the starting material and the concentration of the suspension.

The anaerobic digestion (AD) of wastewater sludge presents a promising and efficient method of wastewater and sludge treatment, as it can lower the organic content of sludge while producing a renewable source of energy—biogas—at the same time. However, using native, non-treated industrial wastewater sludge as a substrate for AD may present difficulties, hence we focused our research primarily on the applicability of measuring techniques—viscosity and dielectric measurement. One of our research goals was to investigate the presence of any connection between the aforementioned properties and the overall biogas production, in order to prove whether these measurement techniques were capable of monitoring the process of AD. Our other aim was to investigate how microwave (MW) pre-treatment affected the anaerobic fermentation. Our results revealed that in terms of total biogas yield, microwave irradiation could enhance fermentation by 14%, and also reduced the viscosity of the fermentation media by 13%. However, microwave irradiation did not change the overall tendencies of the AD process regarding these aspects. Moreover, it was discovered that dielectric and absolute viscosity measurements were effective methods for monitoring the fermentation. Additionally, a correlation was found between the accumulating biogas yield, the dielectric constant and loss factor, and the absolute viscosity of the digested media—each of these share a similarity in tendency and can indicate the occurrence of different phases during batch anaerobic fermentation.

Non-solvent induced phase-inversion is one of the most used methods to fabricate membranes. However, there are only a few studies supported by statistical analysis on how the different fabrication conditions affect the formation and performance of membranes. In this paper, a central composite design was employed to analyze how different fabrication conditions affect the pure water flux, pore size, and photocatalytic activity of polyvinylidene fluoride (PVDF) membranes. Polyvinylpyrrolidone (PVP) was used to form pores, and titanium dioxide (TiO2) to ensure the photocatalytic activity of the membranes. The studied bath temperatures (15 to 25 °C) and evaporation times (0 to 60 s) did not significantly affect the pore size and pure water flux of the membranes. The concentration of PVDF (12.5 to 17.5%) affected the viscosity, formation capability, and pore sizes. PVDF at high concentrations resulted in membranes with small pore sizes. PVP affected the pore size and should be used to a limited extent to avoid possible hole formation. TiO2 contents were responsible for the decolorization of a methyl orange solution (10−5 M) up to 90% over the period studied (30 h). A higher content of TiO2 did not increase the decolorization rate. Acidic conditions increased the photocatalytic activity of the TiO2-membranes.

Microbial number reduction in spices through various treatments represents a necessity considering possible changes which may occur during spices’ storage and application in food resulting in public health risk. The present study was conducted in order to examine the effects of sterilisation and microwave irradiation treatments on total mesophilic aerobic bacteria (TMAB) and bacterial spore content reduction in black pepper. Treatments applied were: sterilisation at 130 °C during 30, 60 and 90 min; and microwave irradiation at a power level of 600 W during 1.5, 3, and 5 min. Prolongation of the sterilisation treatment expressed positive influence on TMAB and bacterial spore reduction in black pepper. Compared to the sterilisation, microwave irradiation treatment exhibited better results in terms of black pepper decontamination. Maximal decontamination regarding TMAB and bacterial spore was achieved in black pepper samples treated with microwave irradiation during 3 min. The present results suggest that microwave irradiation could be applied in black pepper decontamination considering better effectiveness compared to the sterilisation treatment.

Emulsified oily contaminants of wastewaters cannot be eliminated effectively by conventional treatments, but they pose significant risks both to the environment and to human health, therefore their...

Kutatasunk soran a mikrohullammal intenzifikalt Fenton-reakcio alkalmazhatosagat vizsgaltuk husipari szennyviz kezelese eseten. A kiserletek soran figyeltuk a Fenton-reakciohoz szukseges reagens (Fe2+ es H2O2) adagolasi dozisanak es a kozolt mikrohullamu energianak a kemiai oxigenigeny (KOI) csokkentesere (es igy a szervesanyag-tartalom csokkentesere) gyakorolt hatasat. A kutatasi eredmenyeink igazoltak, hogy a szervesanyag-eltavolitasi hatekonysag az alkalmazott Fe2+/H2O2 aranytol es az osszes kozolt MW energiatol is fugg. Magasabb dozisu Fenton-reagens nagyobb mertekű KOI-csokkenest eredmenyezett, a mikrohullamu energiakozles pedig kepes az oxidacios reakcio hatekonysagat novelni – magas kozolt MW energia eseten adott KOI-ertek csokkeneshez joval kevesebb reagens is elegendő volt. A kiserletek soran azt is igazoltuk, hogy a dielektromos vesztesegi szogtangens meresevel a szervesanyag-eltavolitas pontosan es konnyen nyomon kovethető. Abstract: Our experimental work focused on the applicability of microwave-assisted Fenton-reaction for wastewater treatment. We investigated the effects of Fenton’s reagent dosage and irradiated MW energy on the removal efficiency of chemical oxygen demand (COD). The results verified that organic matter removal efficiency is influenced by the Fe2+/H2O2 ratio and the microwave energy as well. Higher reagent dosage caused higher COD-removal, and it was proved that the microwave irradiation can enhance the efficiency of the oxidation process; the higher the MW energy was, the less reagent concentration was needed for reaching a given organic compound removal effectiveness. The experimental results also showed that measuring the dielectric loss tangent can be used to monitor the change in organic matter removal, i.e. the change in chemical oxygen demand.

Membrane-based methods of filtering are becoming increasingly popular in the food industry, but membrane fouling significantly affects filtration performance, making the characterisation of fouling mechanisms critical. This study examined the applicability of three mathematical models. The resistance-in-series model divides the total resistance into membrane resistance, reversible resistance and irreversible resistance. The Hermia models distinguish four basic blocking mechanisms, namely complete blocking, standard blocking, intermediate blocking and cake filtration. The Makardij model analyses the flux-reducing or -enhancing effects. In the experiments, different models were investigated and compared. The feed solution was two milk substitute drinks (soy and oat) that were ultrafiltered under different operating parameters (transmembrane pressures: 0.05–0.1 MPa, stirring rate: 100–400 min(−1)). By fitting the data to the models, the most characteristic blocking mechanism and the rate constant that most influenced flux could be determined.

In this study, ultrasound disruption was employed to enhance the efficiency of microwave disintegration of dairy sludge. Results revealed that ultrasound specific energy input of 1,500 kJ/kg TS was found to be optimum with limited cell lysis at the end of the disruption phase. Biodegradability study suggested an enhancement in suspended solids reduction (16%) and biogas production (180 mL/gVS) in floc disrupted (deflocculated) samples when compared to sole microwave pretreatment (8.3% and 140 mL/gVS, respectively). Energy assessment to attain the 15% optimum solubilization revealed a positive net production of 26 kWh per kg sludge in deflocculated samples compared to 18 kWh in flocculated (sole microwave) samples. Thus, ultrasound disruption prior to microwave disintegration of dairy sludge was considered to be a feasible pretreatment technique.

Our experimental work focused on the applicability of a quite novel process for wastewater treatment, i.e. a microwave (MW) irradiation-enhanced Fenton-like method. The aim of our research was to detect and evaluate the efficiency of this oxidation process, during the treatment of meat industry wastewater containing a high concentration of organic material. The efficiency was defined by the measurement of the change in COD (chemical oxygen demand, with an initial COD value of 1,568 mg L−1), and with the determination of dielectric parameters during the process. It can be summarized that MW irradiation could assist in a Fenton-like oxidation process to achieve higher organic matter removal. Furthermore, our experimental results and statistical analysis show that there can be found a correlation between the effects of applied MW energy and the dosage of H2O2/FeSO4. If the intensity of MW irradiation and the amount of FeSO4 were set higher, the decrease of COD and the increase of tanδ (the dielectric loss tangent) were definitely more significant. With the application of 60 kJ MWE and a 0.14 mgFe2+/mgCOD dosage, the COD removal efficiency was more than 40%, and the increment of tanδ was nearly threefold. Considering the effects of MW-specific process parameters, it can be concluded that the power intensity of MW–oxidation treatment has a significant effect on COD decrease, if the irradiated MW energy was set at lower (30–45 kJ) levels.

For the effective purification of emulsified oil contaminated waters advanced treatment methods have to be applied, such as membrane filtration, which is able to eliminate macro-, and even nanoscale oil droplets, however, membrane fouling is still a major problem, which prevents economic utilization. Therefore, fouling mitigation is one of the most important aspects in the field of membrane separation developments. In the present study, solely TiO2 and TiO2/carbon nanotubes (CNT) composite modified PVDF membranes were prepared and used to purify oil-in-water emulsions. Achievable fluxes, reversible and irreversible filtration resistances, fouling models, filtration efficiencies and photocatalytic activities were compared in case of different nanomaterial covered and unmodified PVDF membranes. Applying either solely TiO2 or solely CNT coating resulted in the significant reduction of total filtration resistance in both cases, but the combination of the two components (TiO2 with 1 wt% CNT) resulted in by far the highest flux and lowest resistance, meanwhile, the enhanced photocatalytic efficiency of the composite was also achieved. To the best of our knowledge, this study demonstrates the beneficial effects of the combination of TiO2 and CNT nanomaterials for the first time in the field of membrane separation of oil-in-water emulsions.

It has been numerously verified that microwave radiation could be advantageous as a pre-treatment for enhanced disintegration of sludge. Very few data related to the dielectric parameters of wastewater of different origins are available; therefore, the objective of our work was to measure the dielectric constant of municipal and meat industrial wastewater during a continuous flow operating microwave process. Determination of the dielectric constant and its change during wastewater and sludge processing make it possible to decide on the applicability of dielectric measurements for detecting the organic matter removal efficiency of wastewater purification process or disintegration degree of sludge. With the measurement of dielectric constant as a function of temperature, total solids (TS) content and microwave specific process parameters regression models were developed. Our results verified that in the case of municipal wastewater sludge, the TS content has a significant effect on the dielectric constant and disintegration degree (DD), as does the temperature. The dielectric constant has a decreasing tendency with increasing temperature for wastewater sludge of low TS content, but an adverse effect was found for samples with high TS and organic matter contents. DD of meat processing wastewater sludge was influenced significantly by the volumetric flow rate and power level, as process parameters of continuously flow microwave pre-treatments. It can be concluded that the disintegration process of food industry sludge can be detected by dielectric constant measurements. From technical purposes the applicability of dielectric measurements was tested in the purification process of municipal wastewater, as well. Determination of dielectric behaviour was a sensitive method to detect the purification degree of municipal wastewater.

This study investigated the adsorption of phosphate from aqueous solutions using pomegranate peel (PP) as a bio-adsorbent. For this purpose, PP was activated via saponification using sodium hydroxide (NaOH) followed by cationization using iron chloride (FeCl3). The iron-loaded PP (IL-PP) was characterized using zeta potential measurement, scanning electron microscopy, and Fourier transform infrared analysis. The batch adsorption method was followed to determine the equilibrium time and effect of pH on the adsorption process. The full factorial design methodology was used to analyze the effects of influencing parameters and their interactions. The effective removal of phosphate up to 90% was achieved within 60 min, at pH 9 and 25 °C temperature using a 150 mg dose of IL-PP. A non-linear method was used for the modeling of isotherm and kinetics. The results showed that the kinetics is best fitted to the Elovich model (R2 = 0.97), which assumes the dominance of the chemisorption mechanism, whereas the isotherm obeys both Langmuir (R2 = 0.98) and Freundlich (R2 = 0.94) models with a maximum phosphate uptake of 49.12 mg·g−1. Investigation of thermodynamic parameters indicated the spontaneity and endothermic nature of the process. These results introduce IL-PP as an efficient bio-adsorbent of phosphate.

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.

A mikrohullámú energiaközléses műveletek az élelmiszeripar, a vegyipar, a biotechnológia és a környezetvédelmi eljárások gyakorlatában is egyre inkább elterjednek. A mikrohullámú kezelési eljárások hatékonyságának részletesebb elemzése és a léptéknövelés azonban szükségessé tenné a folytonos anyagáramú kezelőrendszerekben végzett kísérletek végrehajtását. A kutatási munkánk során szennyvizek és iszapok biológiai hasznosíthatóságát befolyásoló szerkezeti és biológiai lebonthatósági változásokat vizsgáltuk folytonos anyagáramú mikrohullámú kezelések esetében. A vizsgálataink emellett kiterjedtek a mikrohullámú sugárzás hőkeltési hatékonyságát meghatározó dielektromos jellemzők mérésére is.

Absztrakt: 2017-ben beszerzesre kerult egy DAK-3.5 merőrendszer, mely alkalmas folyadekok, szilard halmazallapotu es gel allagu anyagok dielektromos parametereinek meghatarozasara. Mivel a merőrendszerrel kapcsolatban csak csekely tapasztalat all rendelkezesre, a probameresek soran kulonboző folyadek halmazallapotu anyagokat vizsgaltunk, a mintatarto geometriajanak, anyaganak, es a merőszonda elhelyezesenek valtoztatasa mellett. A kulonboző beallitasok soran kapott eredmenyeket osszehasonlitottuk a gyarto altal megadott kalibracios ertekekkel, illetve megvizsgaltuk, hogy a meresi korulmenyek milyen hatassal vannak a mert dielektromos jellemzőkre. Abstract: DAK-3.5 measuring system was purchased in 2017. This system is suitable for determining the dielectric parameters of liquids, solid and gel-like materials. During test measurements various liquid substances were studied varying the geometry and the material of sample holder and the placement of the measuring probe. The results obtained at various settings were compared with the calibration values provided by the manufacturer and the effects of the measurement conditions on the measured dielectric characteristics were examined.

The ultrafiltration of whey solutions is a common feature of dairy processes. However, the frequent fouling of ultrafiltration membranes and the subsequent cleaning cycle significantly affects the economics of the process. In this work, we investigated the effect of ultrasonically assisted ultrafiltration. The ultrafiltration of whey solution was investigated in order to determine the main parameters affecting the flux, retention and membrane fouling. The experiments were carried out with an ultrasonic combined laboratory ultrafiltration device, using regenerated cellulose ultrafiltration membranes. The results showed that increasing resistance during filtration is predominantly caused by the concentration polarization, while the participation of membrane fouling in the total resistance is negligible. The ultrasonically assisted ultrafiltration actively reduces the concentration polarization layer resistance. The retention changed slightly with ultrasound power. Practical Applications Combination of ultrasound and ultrafiltration processes in dairy industry may enhance the efficiency of whey separation processes during ultrafiltration of why solutions. The given model for describing the filtration mechanism and modified Reynolds number for ultrasonically assisted batch reactor allow the scale up of coupled ultrafiltration process for dairy industry.

One possible solution for the production of wood for energy or industrial purposes is the planting of energy wood plantations. In this type of target plantation, a large amount of dendromass can be produced in a short time. Before the afforestation the site survey is highly important. Based on the results the tree species can be chosen and the corresponding cultivation technologies can be planned. Energy plantations are generally man-made forests with fast-growing species and the rotation period is short. Therefore it is necessary to determine the method of harvesting and the corresponding machine system already at the planning phase. After harvesting the timber should be transported in a short period of time in order not to prevent the development of the next tree stand. At the transport large amount of wood chip must be moved for shorter or longer distance. Thus the applied logistic plays very important role in the whole process, by making the operation of timber utilizing power plants as profitable as possible.

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.

This paper reports on the process optimization study of anthocyanin extraction from black currant marc by microwave-assisted extraction (MAE) using acidic solvents. Maximum yields of anthocyanins were achieved at pH 2 with an extraction time of 10 min with a microwave power of 700 W. The anthocyanin yields in MAE were compared with those obtained by conventional solvent extraction (CE) using citric or hydrochloric acids, and citric acid and water with a sulfur concentration of 50 ppm. A significant reduction of extraction time was achieved using MAE; maximum anthocyanin yield was obtained after 10 min using MAE, while using CE only after 300 min. Furthermore, the amount of solvent used halved; the mass ratio of marc to solvent was 1:40 in CE and 1:20 in MAE. Additionally, the final anthocyanin concentration in the solvent phase of MAE increased by 20 % compared to the conventional extraction with hydrochloric acid at pH 2 and temperature of 80 °C. The results suggest that microwave-assisted extraction is a more efficient technique for the extraction of valuable compounds from black currant residue.

Microwave (MW) irradiation is a relatively new possibility of conditioning and pretreating for wastewater sludge. Following its application in the telecommunications and food-industries, the environmental use of this technique has come into the limelight in recent years, and has become increasingly popular. Various publications have dealt with the examination of the effects of MW irradiation in municipal sludge-handling processes. We focused on the effects of MW irradiation at different power levels on solubilization (sCOD/tCOD), biodegradation and anaerobic digestion of sludge from the food-industry. For evaluating the efficiency of MW pre-treatment, the changes in the soluble fraction of the organic matter, the VS/TS ratio, the biogas yield, the methane content in the biogas, and the rate of batch mesophilic digestion were used as control parameters. Additionally, the energetic efficiency of MW pre-treatment was also examined. The results were compared with those of conventional heat (CH) treatments of the same sludge. The MW treatment proved to increase both the sCOD/tCOD and the VS/TS ratio. Furthermore, the biogas and methane yields increased during the digestion of the MW-pretreated food-industry sludge. A higher MW power level generally enhanced the biogas and methane production. Energetically, the most economic pre-treatment of sludge from dairy and meat processing was at a power level of 1.5 Wg(-1) and 2.5 Wg(-1) MW respectively; the surplus energy content of the enhanced biogas product could not compensate the extra energy demand of the stronger MW pre-treatments.

Extraction of pectic substances from solid agro-wastes and the application of recovered pectin in the food, pharmaceutical and cosmetic industry can significantly contribute to a more economic and environmentally sound agro-industrial production. Thus investigation of the physicochemical properties of extracted pectic substances seems important not only from human health preservation considerations, but their advantageous properties can be confirmed for the possible manufacturers, potential processing, as well. Therefore, in this work pectic substances were extracted from red currant, black currant, raspberry, blackberry and elderberry press residues by hot water and the composition, antioxidant activity, total phenol, anthocyanin content and the color coordinates of pectins were determined. The results show that the pectin colors fall in the range between reddish purple (black currant and elderberry) and yellow (citrus and apple). Moreover some of the pectins in a powder form have different color coordinates than in the form of aqueous solutions or gels. This might be very important when the pectins are selected for different production processes. The anthocyanin content of pectin preparations is lower than the values of fruit juices. It can be concluded that the colorants found in pectin preparations belong to the group of phenolics and have adequate antioxidant capacity, which is extremely beneficial for human health. As a summary it was concluded that the investigated pectins can be easily extracted and successfully used as natural colorants or antioxidants since they have adequate antioxidant activity, total phenol and anthocyanin content and suitable color coordinates.

Microwave irradiation is a novel and very promising technology for sludge conditioning. As pretreatment, it has a verified beneficial effect on the microbial degradation and anaerobic digestion of sewage sludge, but in present work we dealt with the applicability of microwave pretreatments for food industrial sludge. However, studies cannot be found that specialize on the effects of the MW treatments with different intensities on the anaerobic digestion of sludge. In our work we focused on the examination of the effect of MW pretreatment for 0.5, 2.5, and 5 W/g on the carbonaceous biochemical oxygen demand (CBOD5), solubilization of organic matters (sCOD/tCOD), and the mesophilic anaerobic digestion of dairy sewage sludge. It can be concluded that the MW pretreatments were appropriate to enhance the efficiency of anaerobic digestion. With MW pretreatments the specific biogas product could be increased from 220 mL g−1 to more than 600 mL g−1 because of the increased solubility (from 9.7% to more than 40%), and the enhanced accessibility of organic compounds for decomposing bacteria. © 2010 American Institute of Chemical Engineers Environ Prog, 2011

The aim of this study was to examine the applicability of reverse osmosis (RO) for the concentration of blackcurrant juice by AFC-80 polyamide tubular membrane that has a salt rejection greater than 80%. The fresh juice had a total soluble solids content of about 16.5°Brix. The effect of centrifugation followed by depectinization with two commercially available pectinase enzyme preparations (Panzym Super E and Trenolin Rot DF) on the permeate flux has been evaluated. For the description of the concentration process, the resistance-in-series model has been used. It was concluded that the applied RO membrane is suitable for concentration of blackcurrant juice up to 28.6°Brix, which was achieved with the juice that had been treated with Panzym Super E. The total resistances were calculated and compared, taking into account membrane fouling and polarization layer resistance.

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.

Production rate of technologies applied in the food industry can only be economical if energy consumption is specifically reduced simultaneously with increasing the capacities and/or utilization of alternative energy sources gains higher ratio during production. A high proportion of waste forms is produced in food processing technologies. Fiscal and environmental cost of waste handling i.e. transportation, recovery and disposal is often significant. Brewing industry’s most important by-product is the brewers' spent grains (BSG) formed during mashing. Utilization of this product is theoretically solved, it is most frequently sold as animal fodder, however utilization in the energy sector can and should be considered and has promising possibilities. Seeking economic and environmental benefits, this paper analyses the possibilities of energy recovery from brewers’ spent grains through aerobic digestion and anaerobic fermentation.

Microfiltration membranes made from polytetrafluorethylene (PTFE) have been successfully used for the separation of oily waste waters by membrane coalescence, but filtration of the oily waste waters with high emulsifier content have not yet been investigated. Our aim was to examine the effect of emulsifier content on membrane coalescence on this type of membrane, and to investigate the effect of surfactant addition on oil retention and filtration parameters. It was found that the oil content of the emulsion can be separated with MF PTFE membranes. Efficiency of the retention depends on the concentration of emulsion: increasing concentrations resulted in an increased retention. The addition of coagulant also affected filtration parameters: higher coagulant concentrations resulted in a significant increase of the flux, while the retention marginally decreased.