Poly(glycerol succinate) – PGSu – is one of glycerol polyesters which has focused nowadays the interest of scientists developing new biomaterials. Probably the polyester could be used as a drug carrier or as a cell scaffold in tissue engineering. Due to its potential use in medicine, it is extremely important to develop a synthesis and then optimize it to obtain a material with desired properties. In this work one flask two-step polycondensation of glycerol and succinic anhydride to PGSu is presented. Synthesis was optimized with the simplex method and also described using a second-degree equation with two variables (temperature and time) to better find the optimum conditions. PGSu was characterized by FTIR spectroscopy, NMR spectroscopy, degree of esterification was determined, and also molecular weight was calculated for each experiment using Carothers equation. A new synthesis route was developed and optimized. Temperature and time influence on molecular weight and esterification degree of obtained polyester are presented. Based on experiments conducted in this work, it was possible to obtain poly(glycerol succinate) with molecular weight of 6.7 kDa.
The paper presents microbiological characteristic of sewage sludge composted in controlled conditions together with biowastes (wheat, maize and rapeseed straw, sawdust and refined glycerol). An experiment was carried out in which the material was mixed at appropriate weight proportions and then placed in bioreactor chambers of constant air flow (4 lźmin-1). The performed composting process aimed at determining the developmental dynamics of heterotrophic bacteria, molds, actinomycetes as well as bacteria from Salmonella genus and Enterobacteriaceae family. Microbiological analyses were performed on selective substrates using Koch's plate method. Moreover, using the floatation method, the presence of live eggs of ATT (Ascaris spp., Trichuris spp., Toxocara spp.) intestinal parasites was assessed and levels of dehydrogenase activity were determined using 1% triphenylotetrazole chloride as a substrate. It was concluded, on the basis of the obtained research results, that the composting process reduced bacterial counts of heterotrophic bacteria, molds and the activity of dehydrogenases activity in all experimental treatments. On the other hand, no reduction was observed in quantities of actinomycetes in the composted materials whose changes in numbers were found to correlate positively most strongly with levels of dehydrogenases activity. In addition, it was found that changes in numbers of the analysed groups of microorganisms depended, primarily, on the pH value and concentrations of ammonia released from the composted materials. Furthermore, the obtained research results also revealed that the sewage sludge used in the experiment did not contain Salmonella spp. bacteria and live eggs of ATT intestinal parasites, and that the composting process reduced completely numbers of bacteria from the Enterobacteriaceae family in all compost treatments. The obtained composts fulfilled all sanitary standards complying with the requirements issued by the Minister of Agriculture and Rural Development (2008) as well as with the EU regulation (EC) No. 185/2007 from February 2007 changing EEC regulations No. 809/2003 and No. 810/2003 connected with the extension of the period of transitional requirements for composting and biogas plants as provided by the EU regulation No. 1774/2002 of the European Parliament and Council.
In this study, the environmental impacts of the organic fraction of municipal solid waste (OFMSW) treatment and its conversion in anaerobic digestion to glycerol tertiary butyl ether (GTBE) were assessed. The production process is a part of the innovative project of a municipal waste treatment plant. The BioRen project is funded by the EU’s research and innovation program H2020. A consortium has been set up to implement the project and to undertake specific activities to achieve the expected results. The project develops the production of GTBE which is a promising fuel additive for both diesel and gasoline. It improves engine performance and reduces harmful exhaust emissions. At the same time, the project focuses on using non-recyclable residual organic waste to produce this ether additive.
The aim of this paper is the evaluation through Life Cycle Assessment of the environmental impact GTBE production in comparison with a production of other fuels. To quantify the environmental impacts of GTBE production, the ILCD 2011 Midpoint+ v.1.10 method was considered. The study models the production of GTBE, including the sorting and separation of municipal solid waste (MSW), pre-treatment of organic content, anaerobic fermentation, distillation, catalytic dehydration of isobutanol to isobutene, etherification of GTBE with isobutene and hydrothermal carbonization (HTC).
The results indicate that unit processes: sorting and hydrothermal carbonization mostly affect the environment. Moreover, GTBE production resulted in higher environmental impact than the production of conventional fuels.
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