Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. By applying hydrodynamic disintegration the lysis of cells occurs in minutes instead of days. The intracellular and extracellular components are set free and are immediately available for biological degradation which leads to an improvement of the subsequent anaerobic process. Hydrodynamic disintegration of the activated sludge results in organic matter and a polymer transfer from the solid phase to the liquid phase, and an increase in COD value of 284 mg•ℓ-1 was observed, i.e. from 42 mg•ℓ-1 to 326 mg•ℓ-1. In addition the degree of disintegration changed from 14% after 15 min disintegration to 54% after 90 min of disintegration. A disruption of bacterial cells by hydrodynamic cavitation has a positive effect on the degree and rate of excess sludge anaerobic digestion. The cells of the activated sludge microorganisms rupture and addition to the digestion process leads to increased biogas production. The hydrodynamic disintegration of activated sludge leads to a higher degree of degradation and higher biogas production. Adding the disintegrated sludge (10%, 20% and 30% of volume) to fermentation processes resulted in an improvement in biogas production of about 22%, 95% and 131% respectively.

Large amounts of sludge are produced in biological wastewater treatment plants. Since the sludge is highly contaminated, it has to undergo proper stabilization before it is disposed or utilized in an environmentally safe way. On the whole, the aim of bacterial cell disintegration is the release of cell contents in the form of an aqueous extract. Chemical disintegration of surplus activated sludge by alkalization results in destruction and disruption of the flocs and microorganisms as well as increase concentration of organic matter in supernatant. The mesophilic anaerobic sewage sludge digestion is an established process, most often applied at medium and large municipal sewage treatment plants. Four major steps of anaerobic digestion are distinguished. The first hydrolysis step leads to solubilization of insoluble particulate matter and biological decomposition of organic polymers to monomers or dimers. The hydrolysis step is recognized as the rate-limiting step of the following second and third steps, the processes of acidogenesis and acetogenesis. Chemical disintegration activates biological hydrolysis and, therefore, it can significantly increase the stabilization rate of the secondary sludge. It has been shown that when the activated sludge was subjected to alkalization to pH 9.0 value, the COD concentration increased from 101 to 530 mg/dm 3 in sludge supernatant. The paper presents a potential application of chemical disintegration for sewage sludge (mainly activated sludge) to upgrading biogas production.

Hydrodynamic disintegration of activated sludge resulted in organic matter and polymers transfer from the solid phase into the liquid phase. Disintegration by hydrodynamic cavitation had a positive effect on the degree and rate of excess sludge anaerobic digestion. Also, addition of a part of anaerobic digested sludge containing adapted microorganisms resulted in acceleration of the process. The disruption of cells of foam microorganisms and addition to the digestion process led to an increase of biogas production.

Introduction Oxidative tissue damage caused by reactive oxygen species results in a significant decrease in the total antioxidant capacity of the biological system. The aim of this interdisciplinary study was to answer the question of whether active antioxidants modify, at a molecular and supramolecular level, the tissue of pathological amnion and the necrotic eschar degraded in thermal burn. Methods A Nicolet 6700 Fourier-transform spectrophotometer with OMNIC software and the EasiDiff diffusion accessory were used in the FTIR spectroscopic analysis. A NICOLET MAGNA-IR 860 spectrometer with FT-Raman accessory was used to record the Raman spectra of the samples. The samples were exposed to bacteria capable of causing nosocomial infections, ie Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa . Whereas samples of hypotrophic amnion interacted with Staphylococcus aureus, Escherichia coli and Enterococcus faecalis . The obtained flame retardant effect of placentas was evaluated using the method of the limiting oxygen index (LOI). Results The infrared spectroscopy analysis proved that after modification of the amniotic samples in graphene oxide and ortho-silicic acid, the amide II band is split into two components. Incubation of samples in modifier solutions: graphene oxide, sodium ascorbate and L-ascorbic acid results in shifts and changes of intensity within the broadly understood lipid band 1743–1745–1747 cm −1 . The oxidising changes observed within the lipid and amide bands are affected by the incubation effect of graphene oxide as a modifier, possibly adsorbing on the surface of the amniotic membrane. On the basis of microbiological studies, pathogenic bacteria commonly causing amniotic infections and growing in burn wounds were found to have particularly good resistance to stabilized ortho-silicic acid ( E. coli ) and lactoferrin ( S.aureus ). Conclusion This thermogravimetric study found the highest stability of the analysed tissues (hypotrophic amnion and burnt epidermis) after modification with graphene oxide and sodium ascorbate.