New ways of managing hop sediments from brewing and fermentation of beer are constantly being sought and the existing ones improved as part of the circular economy. These wastes are not generated in large amounts, but the absence of their proper characteristics may lead to further processing errors. The study analyses the composting of hop waste under laboratory conditions and the effects of the biological activity of composts introduced into the soil. The study was carried out on two-hop sediments from two different technological stages of beer production: hot trub (HT) and spent hops (SH). Chemical, microbiological and biochemical analyses, as well as the assessment of phytotoxicity to Lepidium sativum L., were performed in the materials. The results proved that, due to their formation technology, the tested feedstocks are safe from an epidemiological point of view and are not a source of microbial contamination. Inhibitory properties for plant development were found for HT and it most likely results from the organic compound content. The mineral composition of hot trub does not exclude composting if its share in biomass is low. Spent hops (SH) were characterised by a significant total nitrogen content, which affected the composting process. Composting this sediment required the selection of substrates with a wide C:N ratio. The number of microorganisms inhabiting the analysed material was very diverse and varied depending on the type of sediments. The sample that contained the composted SH from dry hopping had a much larger number of microorganisms than the sample with HT from wet hopping.
Waste fly ash, with both low (with the addition of vermiculite) and high contents of unburned coal, were subjected to hydrothermal syntheses aiming to obtain zeolite composite materials—zeolite + vermiculite (NaX–Ver) and zeolite + unburned carbon (NaX–C). The composites were compared with parent zeolite obtained from waste fly ash with a low content of unburned carbon (NaX–FA). In this study, the physicochemical characteristics of the obtained materials were evaluated. The potential application of the investigated zeolites for the adsorption of ammonium ions from aqueous solutions was determined. Composite NaX–Ver and parent zeolite NaX–FA were characterized by comparable adsorption capacities toward ammonium ions of 38.46 and 40.00 mg (NH4+) g−1, respectively. The nearly 2-fold lower adsorption capacity of composite NaX–C (21.05 mg (NH4+) g−1) was probably a result of the lower availability of ion exchange sites within the material. Adsorbents were also regenerated using 1 M NaCl solution at a pH of 10 and subjected to 3 cycles of adsorption–desorption experiments, which proved only a small reduction in adsorption properties. This study follows the current trend of waste utilization (fly ash) and the removal of pollutants from aqueous solutions with respect to their reuse, which remains in line with the goals of the circular economy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.