The amount of waste activated sludge (WAS) is increasing annually, and since it presents potential environmental and health-related risks, an appropriate treatment and stabilization process is needed. It has been shown in numerous studies in the past few decades that amongst the advanced treatment methods of sludge, microwave and ultrasound-based processes offer promising and effective alternatives. The main advantage of these physical methods is that they are energy-efficient, easy to implement and can be combined with other types of treatment procedures without major difficulties. In this review article we would like to present the recent scientific results of the microwave, ultrasound and combined (microwave-alkaline, microwave-H₂O₂, ultrasound-alkaline and ultrasound-H₂O₂) treatment of wastewater sludge, in terms of different process-efficiency indicators. Although the obtained results somewhat vary between the different scientific papers, it can be undoubtedly stated that both MW and US—either individually or in combination with chemical treatments—can enhance several aspects of sludge processing, like increasing the SCOD/TCOD rate, disintegration degree (DD), or the anaerobic digestibility (AD), but the extent of these increments clearly depends on the treatment conditions or parameters.

Our study aimed to investigate the applicability of dielectric measurements across three key stages of plant-based biomass utilization: enzymatic hydrolysis of native and microwave pre-processed corn-cob residues, ethanol fermentation of the hydrolysates, and anaerobic co-digestion with meat-industry wastewater sludge. Our major findings reveal that microwave pre-treatment not only accelerates enzymatic hydrolysis but also improves sugar yield. A strong linear correlation (r = 0.987–0.979; R² = 0.974–0.978) was observed between the dielectric constant and sugar concentrations, offering a reliable monitoring mechanism. During ethanol fermentation, microwave pre-treated samples resulted in higher yields; however, the overall bioconversion efficiency was lower. Dielectric measurements also exhibited a strong linear correlation (r = 0.989–0.997; R² = 0.979–0.993) with ethanol concentration. Finally, anaerobic co-digestion could be effectively monitored through the measurement of the dielectric constants (r = 0.981–0.996; R² = 0.963–0.993), with microwave-treated samples showing higher biogas yields. These results demonstrate that dielectric measurements provide a promising alternative for monitoring and controlling biomass utilization processes.

In Hungary, viticulture and winemaking have a very long tradition and culture. Nowadays, more and more consumers are paying attention to the nutritional properties of the food they consume, in addition to their enjoyment value. Wines can have an outstanding antioxidant content. The amount of antioxidants can be influenced by a number of parameters (wine-making technology, grape variety, area under vines, etc.). Antioxidants play an important role in the preservation of health, as well as inhibiting oxidation processes in food. Dielectric material analysis methods are also increasingly used in the food industry. The great advantages of dielectric testing include its chemical-free nature and the speed of the test. In our studies, we have investigated the food properties, i.e. alcohol, acid and antioxidant content and dielectric properties of different wine samples

The focus of our research was on two different grape and wine varieties from the Csongrád Wine Region. In the first part of our research, we examined wines of various strains and vintages made using oxidative and reductive techniques. Based on our results, differences in content were identifiable between vintages and between oxidative and reductive techniques, even samples were from the same cultivation site. In the second part of our research, we monitored the fermentation of wines in progress, applying various examination methods. The aim of our research was to gather information on the changes occurring during the fermentation. As the fermentation period progressed, the value of the dielectric constant continuously increased, which was related to the change in alcohol content. Based on our findings, fermentation monitoring based on the dielectric constant could be a well-applicable, chemical-free, and quickly executable method.

Anaerobic digestion is a complex process, and the right quality of feedstock is essential for its proper completion. Although, meat industry wastewater is not ideal feedstock for biogas production, its properties can be improved by pre-treatments. In our chosen pre-treatments, we added magnetite nanoparticles to the sludge and then irradiated it with microwaves at different power levels. Monitoring the fermentation is crucial, especially in industrial practice. We monitored the progress by measuring the dielectric properties of the sludge samples. Our results show that dielectric measurements are a promising alternative for monitoring the anaerobic fermentation because there is a clear correlation between the changes in the value of the dielectric constant and the progression of the fermentation. Our results also clearly support the positive effect of the chosen pretreatments on the amount of biogas produced during fermentation. While the amount of gas increased, the methane content of the biogas produced did not change as verified by gas analysis.