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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.

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.

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.

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.

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.