Sander Kutti

Presence of fluoroquinolones and sulfonamides in urban sewage sludge and their degradation as a result of composting

The concentrations of some widely used pharmaceuticals, namely fluoroquinolones (ciprofloxacin C17 H18FN3O3, norfloxacin C17 H18FN3O3 and ofloxacin C18 H20FN3O4 and sulfonamides (sulfadimethoxine C12 H14N4O4s and sulfamethoxazole C10 H11N3O3S were determined in urban sewage sludge utilized for making compost. The levels of degradation of these pharmaceuticals resulting from sludge treatment were assessed. The concentrations of the studied pharmaceuticals sufficiently varied both in sewage sludge and in compost and due to this phenomenon the possible danger resulting from the presence of pharmaceuticals in sewage sludge, used for composting, can not be ignored. The concentrations of the studied pharmaceuticals were lower in compost, if compared to the relevant concentrations in sewage sludge. The highest pharmaceutical concentration in sewage sludge — 426 μg/kg — was detected in the case of ciprofloxacin. The highest concentrations present in compost were 22 μg/kg of norfloxacin and 20 μg/kg of ciprofloxacin. Results show that before using the sewage sludge for making compost or before using the compost a fertilizer for food plants, they should be carefully tested against the content of commonly used pharmaceuticals.

Biocidal properties study of silver nanoparticles used for application in green housing

We report on the study of surfactant-free silver nanoparticles synthesized using non-hydrolytic sol–gel methods for applications in straw bale constructions. Micro-organism infestation in green constructions is of concern as their proliferation tends to induce health problems. We demonstrate the biocidal properties of these Ag nanoparticles and their efficacy against fungi. Outdoor tests with Ag nanoparticles have demonstrated the effective protection of straw against micro-organisms. Indoor tests using broth liquid are compared with a method of testing we recently developed where the possible nature of the biocidal properties of the silver nanoparticles are further probed. In contrast to the commonly reported results, this study shows that Ag nanoparticles synthesized using non-hydrolytic sol–gel methods have antifungal properties against common fungi in outdoor conditions which demonstrate high potential in related applications.

New Methodology for the Antifungal Testing of Surfactant-Free Silver Metal Nanoparticles for Applications in Green Housing

This work presents a method that enables the cheap production of surfactant-free stable metal nanoparticles in air. The silver nanoparticles are good candidates for new applications in green housing. Recently, we demonstrated usage of air-stable silver MNPs as biocidal coatings instead of chemical agents for protection of straw bales used in a green housing construction. Application of the silver nanoparticles as antifungal agents needs a method that does not neutralize their biocidal properties as a result of the testing method. In this study, we discuss the usual methods that are used for the antibacterial property testing and the development of a method that allows demonstrating the antifungal properties of metal nanoparticles.