Browsing by Author "Grübel, Klaudiusz"

Now showing 1 - 4 of 4
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    Disintegration of Wastewater Activated Sludge (WAS) for Improved Biogas Production
    (MDPI, 2019-12-21) Wacławek, Stanisław; Grübel, Klaudiusz; Silvestri, Daniele; Padil, Vinod V. T; Wacławek, Maria; Černík, Miroslav; Varma, Rajender S
    Due to rapid urbanization, the number of wastewater treatment plants (WWTP) has increased, and so has the associated waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas via fermentation processes. This review presents recent advances in the anaerobic digestion processes that have led to greater biogas production. Disintegration techniques for enhancing the fermentation of waste activated sludge can be apportioned into biological, physical and chemical means, which are included in this review; they were mainly compared and contrasted in terms of the ensuing biogas yield. It was found that ultrasonic- and microwave-assisted disintegration provides the highest biogas yield (>500%) although they tend to be the most energy demanding processes (>10,000 kJ kg−1 total solids).
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    Microwave-assisted sustainable co-digestion of sewage sludge and rapeseed cakes
    (Elsevier Ltd, 2019-11-01) Grübel, Klaudiusz; Kuglarz, Mariusz; Wacławek, Stanisław; Vellora Thekkae Padil, Vinod; Černík, Miroslav; Varma, Rajender S.
    The technological concept ensuring highly efficient co-digestion of by-products from the production of biodiesel and sewage sludge was examined. Rapeseed cakes (RC) 1–5% addition to waste activated sludge (WAS) 95–99% in digesters, positively influenced the degree of biodegradation of organic matter and the quantity and quality of the biogas produced. Under the optimal conditions (HRT = 20–22 days), the co-digestion mixtures (WAS + microwave disintegration + RC) generated double the amount of biogas, containing approximately 10–12% more CH4, than the samples which had the sewage sludge only. Under these conditions, the biogas yield increased by approximately 48–82% depending on the co-substrate used and was further improved via the introduction of microwave pre-treatment. After testing at the pilot scale, this method could be considered as a sustainable alternative to conventional methods for WAS and RC treatment.
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    UV-Catalyzed Persulfate Oxidation of an Anthraquinone Based Dye
    (MDPI, 2020-01-01) Krawczyk,Kamil; Wacławek, Stanisław; Kudlek, Edyta; Silvestri, Daniele; Kukulski, Tomasz; Grübel, Klaudiusz; Padil, Vinod V. T.; Černík, Miroslav
    Wastewater from the textile industry has a substantial impact on water quality. Synthetic dyes used in the textile production process are often discharged into water bodies as residues. Highly colored wastewater causes various of problems for the aquatic environment such as: reducing light penetration, inhibiting photosynthesis and being toxic to certain organisms. Since most dyes are resistant to biodegradation and are not completely removed by conventional methods (adsorption, coagulation-flocculation, activated sludge, membrane filtration) they persist in the environment. Advanced oxidation processes (AOPs) based on hydrogen peroxide (H2O2) have been proven to decolorize only some of the dyes from wastewater by photocatalysis. In this article, we compared two very different photocatalytic systems (UV/peroxydisulfate and UV/H2O2). Photocatalyzed activation of peroxydisulfate (PDS) generated sulfate radicals (SO4•−), which reacted with the selected anthraquinone dye of concern, Acid Blue 129 (AB129). Various conditions, such as pH and concentration of PDS were applied, in order to obtain an effective decolorization effect, which was significantly better than in the case of hydroxyl radicals. The kinetics of the reaction followed a pseudo-first order model. The main reaction pathway was also proposed based on quantum chemical analysis. Moreover, the toxicity of the solution after treatment was evaluated using Daphnia magna and Lemna minor, and was found to be significantly lower compared to the toxicity of the initial dye.
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    Waste-activated sludge disruption by dry ice: bench scale study and evaluation of heat phase transformations
    (2019-01-01) Machnicka, Alicja; Grübel, Klaudiusz; Wacławek, Stanisław; Sikora, Krzysztof
    The freezing process consists of dissipating heat from the product until the final temperature is lower than the temperature of crystallisation of that product. Freezing can be used for numerous applications, including for disruption of waste-activated sludge (WAS). The aim of this study was to calculate the estimated amount of heat conveyed between the solidified carbon dioxide and the WAS, in the following ratios: 0.25:1; 0.5:1; 0.75:1 and 1:1. In heat of phase transformations, dry ice sublimation, water solidification, the amount of heat transferred by other substances and heat transferred from the sludge (dry sludge) were taken into account during the process of WAS freezing. Heat changes on the surface of WAS were registered using a thermovision camera. The effectiveness of WAS disintegration was confirmed by several biochemical parameters such as soluble chemical oxygen demand (increase over 14 times), degree of disintegration (48%), proteins (increase over 5 times), carbohydrates (increase almost 7 times), RNA (increase by 2.23 mg L−1), ammonia nitrogen (increase over 23 times), phosphates (increase almost 27 times) and turbidity (increased over 7 times). It was found that dry ice pretreatment of WAS can be an intriguing alternative for the conventional methods used.