The importance of medical waste management has grown during the COVID-19 pandemic because of the increase in medical waste quantity and the significant dangers of these highly infected wastes for human health and the environment. This innovative review focuses on the possibility of materials, gas/liquid/solid fuels, thermal energy, and electric power production from medical waste fractions. Appropriate and promising treatment/disposal technologies, such as (i) acid hydrolysis, (ii) acid/enzymatic hydrolysis, (iii) anaerobic digestion, (vi) autoclaving, (v) enzymatic oxidation, (vi) hydrothermal carbonization/treatment, (vii) incineration/steam heat recovery system, (viii) pyrolysis/Rankine cycle, (ix) rotary kiln treatment, (x) microwave/steam sterilization, (xi) plasma gasification/melting, (xii) sulfonation, (xiii) batch reactor thermal cracking, and (xiv) torrefaction, were investigated. The medical waste generation data were collected according to numerous researchers from various countries, and divided into gross medical waste and hazardous medical waste. Moreover, the medical wastes were separated into categories and types according to the international literature and the medical waste fractions’ percentages were estimated. The capability of the examined medical waste treatment technologies to produce energy, fuels, and materials, and eliminate the medical waste management problem, was very promising with regard to the near future.

Many recent studies focused on the research of thermal treated biomass in order to replace fossil fuels. These studies improved the knowledge about pretreated lignocellulosics contribution to achieve the goal of renewable energy sources, reducing CO2 emissions and limiting climate change. They participate in renewable energy production so that sustainable consumption and production patterns can by ensured by meeting Goals 7 and 12 of the 2030 Agenda for Sustainable Development. To this end, the subject of the present study relates to the enhancement of the thermal energy content of barley straw through torrefaction. At the same time, the impact of the torrefaction process parameters, i.e., time and temperature, was investigated and kinetic models were applied in order to fit the experimental data using the severity factor, R0, which combines the effect of the temperature and the time of the torrefaction process into a single reaction ordinate. According to the results presented herein, the maximum heating value was achieved at the most severe torrefaction conditions. Consequently, torrefied barley straw could be an alternative renewable energy source as a coal substitute or an activated carbon low cost substitute (with/without activation treatment) within the biorefinery and the circular economy concept.

No abstract

No abstract

The purpose of this study was first to examine and then to maximize, the adsorbency of torrefied barley straw, in order to remove basic dyes like Methylene Blue (MB) from wastewater. On the other hand, the effect of the torrefaction process on the heating value of the material was investigated. Moderate modification conditions (220 ºC, 20 min) were found to maximize adsorbency of modified barley straw. The experimental data were simulated by a pseudo-second order kinetic model. The torrefaction also significantly enhanced the higher heating value of the pretreated barley straw compared to the untreated material. Specifically, the calorific value increased from 16.1 MJ/kg to 19.4 MJ/kg for sample torrefied at 240 ºC during 40 min. Consequently, the torrefaction of barley straw leads to the coproduction of material with enhanced energy content in combination with improved adsorption capacity. The coproduction of energy and adsorbents from lignocellulosic biomass takes into account (i) the biorefinery (more than one product) and (ii) the Industrial Ecology concept (using solid waste to clean wastewater pollution).