Fraction Of Waste Research Articles

Thermo‐economic assessment of a bench‐scale pyrolysis unit through a process simulator

AbstractThis article focuses on the holistic appraisal of a pilot‐scale updraft reactor (E1) powered by the processed residue of forest waste (W1) and hog fuel (W2). The detailed analysis of the up‐draft unit includes the availability of energy, economic evaluation, and the determination of the lignocellulose content of the pine waste. The reformed structure of the pine pellet was used for gas, bio‐oil, and char generation. The Aspen HYSYS process simulator was used for simulation purposes and the results were validated with the solution obtained experimentally. For the measurement of the constituent contents of the pine needles, the National Renewable Energy Laboratory (NREL) procedure was adopted. To investigate the similitude of the packed bed reactor, the Soave–Redlich–Kwong model was considered. For comparison of the given prototype, five different reactor types – conversion (R1), equilibrium (R2), Gibbs (R3), continuous stir tank (CST) (R4) and plug flow (R5) – were juxtaposed and their thermodynamic behavior was evaluated. From structural composition, it was noticed that the cellulose and hemicellulose(s) content dropped by 24.95% and 37.37%, respectively, whereas a rise of 23.33% was seen in the acid‐insoluble lignin (AIL) fraction of forest waste after the torrefaction process. Irrespective of the fuel type, the unconsumed fuel percentage was the same for both wood and processed residue pellets for R5. The relative percentage of methane increased by 1% for processed forest residue. The CO2 emission was estimated to be maximum for reactors R3 and R4. The O2 gain was absent in the R2 reactor. Concomitantly, it gained momentum in R1, R3, and R4. The simulated polytropic equations of state for W1 and W2 were PV1.083 = C and PV1.092 = C, respectively. The levelized cost of energy dropped by 12.50% while scaling up a pyrolysis unit.

Hybrid Prediction-Driven High-Throughput Sustainability Screening for Advancing Waste-to-Dimethyl Ether Valorization.

Assessing the prospective climate preservation potential of novel, innovative, but immature chemical production techniques is limited by the high number of process synthesis options and the lack of reliable, high-throughput quantitative sustainability pre-screening methods. This study presents the sequential use of data-driven hybrid prediction (ANN-RSM-DOM) to streamline waste-to-dimethyl ether (DME) upcycling using a set of sustainability criteria. Artificial neural networks (ANNs) are developed to generate in silico waste valorization experimental results and ex-ante model the operating space of biorefineries applying the organic fraction of municipal solid waste (OFMSW) and sewage sludge (SS). Aspen Plus process flowsheeting and ANN simulations are postprocessed using the response surface methodology (RSM) and desirability optimization method (DOM) to improve the in-depth mechanistic understanding of environmental systems and identify the most benign configurations. The hybrid prediction highlights the importance of targeted waste selection based on elemental composition and the need to design waste-specific DME synthesis to improve techno-economic and environmental performances. The developed framework reveals plant configurations with concurrent climate benefits (-1.241 and -2.128 kg CO2-eq (kg DME)-1) and low DME production costs (0.382 and 0.492 € (kg DME)-1) using OFMSW and SS feedstocks. Overall, the multi-scale explorative hybrid prediction facilitates early stage process synthesis, assists in the design of block units with nonlinear characteristics, resolves the simultaneous analysis of qualitative and quantitative variables, and enables the high-throughput sustainability screening of low technological readiness level processes.

(General Student Poster Award Winner - 2nd Place) Electrochemical Routes for Polymer Upcycling

Approximately 380 million tons of plastic are produced annually, and it is projected to rise to nearly 1.1 billion by 2050 [1]. The largest fraction of such waste consists of polyethylene (PE) and polypropylene (PP), which commonly require energy-intensive methods to achieve depolymerization (such as pyrolysis and hydrogenolysis) due to their remarkable thermodynamic stability. Electrochemical methods are a promising alternative for polymer upcycling as they can utilize renewable energy to create an external potential, overcoming the thermodynamic constraints that the C-C bond cleavage endothermicity imposes on low-temperature polymer conversion. They also offer improved chemical process control by manipulating the electrode potential and minimizing the use and storage of hazardous reagents. Electrochemistry provides a broad range of opportunities for establishing green routes to converting plastic into valuable products.Botte's group is investigating electrochemical approaches to convert polyolefins into valuable products like fuels and fatty acids [2]. Our findings indicate that an electrocatalyst in concert with controlled ionic strength and applied potential enable the selective functionalization of polyolefins and their defragmentation towards target molecules regardless of impurities present in the polymer. In this presentation, we will discuss results of the electrochemical functionalization and deconstruction of low-density polyethylene implementing transition metal electrocatalysts. Acknowledgments: The authors would like to acknowledge the financial support of the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Upcycling of Polymers Program, under Award DE-SC0022307[1] J. E. Rorrer, C. Troyano-Valls, G. T. Beckham, and Y. Román-Leshkov, "Hydrogenolysis of Polypropylene and Mixed Polyolefin Plastic Waste over Ru/C to Produce Liquid Alkanes," ACS Sustainable Chemistry & Engineering, vol. 9, no. 35, pp. 11661-11666, 2021/09/06 2021, doi: 10.1021/acssuschemeng.1c03786.[2] G. G. Botte, "Process for the Electrochemical Up-Cycling of Plastics (US Pending Patent)," U.S. Patent 63040929, 2020.

Plastics and Micro/Nano-Plastics (MNPs) in the Environment: Occurrence, Impact, and Toxicity.

Plastics, due to their varied properties, find use in different sectors such as agriculture, packaging, pharmaceuticals, textiles, and construction, to mention a few. Excessive use of plastics results in a lot of plastic waste buildup. Poorly managed plastic waste (as shown by heaps of plastic waste on dumpsites, in free spaces, along roads, and in marine systems) and the plastic in landfills, are just a fraction of the plastic waste in the environment. A complete picture should include the micro and nano-plastics (MNPs) in the hydrosphere, biosphere, lithosphere, and atmosphere, as the current extreme weather conditions (which are effects of climate change), wear and tear, and other factors promote MNP formation. MNPs pose a threat to the environment more than their pristine counterparts. This review highlights the entry and occurrence of primary and secondary MNPs in the soil, water and air, together with their aging. Furthermore, the uptake and internalization, by plants, animals, and humans are discussed, together with their toxicity effects. Finally, the future perspective and conclusion are given. The material utilized in this work was acquired from published articles and the internet using keywords such as plastic waste, degradation, microplastic, aging, internalization, and toxicity.

A systematic review of country-specific drivers and barriers to household food waste reduction and prevention.

Food waste is a global challenge that threatens the sustainable development of human societies. Although food waste is produced in all stages of the food supply chain, household food waste is the biggest contributor to the food waste fraction. In this research, we systematically reviewed 54 empirical studies to explore drivers and barriers to household food waste reduction and prevention. Key aspects, such as comprehension and perception of food waste issues, practices and lifestyles, were examined. Our findings suggest that a great understanding of the impact of one's food waste on health, environment and economy directly promotes food waste management. Additionally, the food waste issue is not attributed to a single factor, it may differ varies across countries. The majority of the reviewed literature on household food waste comes from European countries, where similar geographical, economic and cultural characteristics may lead to comparable drivers and barriers. This could be the reason for showing optimistic experience to the respective food waste management interventions. However, the applicability of these findings and interventions to regions beyond Europe are uncertain. Future studies should also be expanded to include regions such as Asia, North America, Africa, Oceania, Latin America and the Caribbean. To support the sustainable management of household food waste, mapping country-specific food waste determinants is crucial in developing easy-to-implement food waste interventions that can specifically address the food waste issue in each country.

A REVIEW OF WASTE MANAGEMENT IN THE EU COUNTRIES AND THE EXPERIENCE OF ITS ENERGY USE

The article is devoted to the review of waste management in the EU countries and the study of the practices of their energy use. The amount and sources of waste generation in the EU countries and the current trends in its management are analyzed. Special attention is paid to the analysis of production and collection of organic (food) waste by the population; evaluated the top 5 best European models of their collection (open container; door-to-door collection; open container on the street, accessible only to owners; collection of household waste divided into two streams «wet/dry»; composting directly on the territory of their generation). The door-to-door model has shown the highest efficiency when implemented by the households in most European countries in most cases. Two main directions of organic waste management were analyzed: composting and anaerobic fermentation with biogas production. These directions of waste use correspond to the principles of the circular economy and help to use the available potential of waste. Anaerobic digestion of waste is preferred to the composting because it produces both energy resources (biogas, which can be purified to biomethane and also converted into electrical and thermal energy) and biofertilizers (digestate). The experience of individual European countries in the energy use of the organic fraction of municipal solid waste (hereinafter referred to as MSW) is presented. It is substantiated that the use of waste of various origins (households, enterprises, municipal wastewater, etc.) for the production of biogas is actively developing in European countries; both the number of manufacturing enterprises and their production capacities are growing. A trend towards an increase in the production of biomethane – purified biogas, which has a wider application then biogas – has been noted. The production of biomethane and biogas in relation to the total gas consumption in the sixteen largest European countries is analyzed, the largest percentage of substitution as of 2021 is noted in Denmark – 5% of natural gas was replaced by biogas, 19% – by biomethane. It has been confirmed that European countries are intensifying the production of energy carriers from waste in order to reduce dependence on buying natural gas from russia. An increase in energy independence on russian energy resources is expected to accelerate as a reaction to hostilities in Ukraine.

Anaerobic Co-digestion of sewage sludge and organic fraction of municipal solid waste: Focus on mix ratio optimization and synergistic effects

The utilization of municipal solid waste (MSW) and sewage sludge (SS) as a source of renewable energy is crucial in achieving sustainable and integrated MSW management. SS and organic fraction of municipal solid waste (OFMSW) can be anaerobically digested to produce methane for energy. However, anaerobic digestion of specific substrates is challenging with respect to substrate characteristics. The problem of mono-digestion can be mitigated by co-digestion of these two major organic wastes because of their complementary characteristics. Moreover, there is a lack of studies on optimization of different mix ratios of organic fraction of municipal solid waste (OFMSW) and sewage sludge (SS) based on total solids (TS). The study aims to optimize the mix ratio for anaerobic co-digestion of OFMSW and SS. The study further elucidates synergistic effects associated with the co-digestion process. Different mix ratios of SS and OFMSW (0:100, 20:80, 40:60, 60:40, 80:20, 100:0) at 5, 7.5 and 10% TS were assessed for biomethane potential assessment. The results showed that with an increase in SS in the mix ratio feed the methane yield increased by 91% and 50% as compared to mono digestion of sewage sludge and OFMSW respectively at TS 7.5%. Based on the kinetic analysis, it was observed that the lag phase reduced for 60:40 mix ratio leading to higher rate of biodegradation. Positive synergistic effects were observed for 40:60, 60:40 and 80:20 mix ratio of SS:OFMSW based on co-digestion impact factor value. Response surface modelling was used to get the optimized mix ratio and TS %. The optimum mix ratio with the highest methane yield (388 ml/gVS added) was 70:30 (SS: OFMSW) at TS 7.5% with a desirability value of 0.98. These findings demonstrate that co-digesting SS and OFMSW is a preferable alternative for harnessing renewable energy and managing organic waste in a sustainable manner.

Hydrothermal liquefaction potential of wastewater treatment sludges: Effect of wastewater treatment plant and sludge nature on products distribution

The rapid growth of urban populations necessitates the development of more efficient and environmentally sustainable methods for waste treatment and resource recovery. Hydrothermal liquefaction (HTL) has emerged as a promising technology for converting organic waste into bio-crude oil. In this study, the HTL products of various waste fractions (Fat, oil, and grease (FOG), food waste, primary and secondary sludge, and digestate) produced or handled by four wastewater treatment plants in Denmark were analysed. Additionally, the effect of mixing the produced waste was investigated. The HTL experiments were conducted at temperatures 300, 325, and 350 °C, with a residence time of 20 min and dry matter content of 16.7%. The highest HTL bio-crude yields were obtained at a temperature of 325 °C for all feedstocks except FOG (300 °C). The mixing of wastes resulted in a positive synergistic effect, presenting an energy recovery between 62 and 76% and bio-crude yields higher than expected due to interactions between the feedstock's biochemical composition. Based on the biochemical composition and on the feedstocks fraction, two models are proposed for the prediction of bio-crude yields, with an error between 4 and 5% in absolute terms. In addition, important process water parameters, as well as the nutrient recovery and heavy metal load of the solid residues are analysed and discussed, giving a comprehensive overview of the potential of different wastewater treatment plant sludges.

High-Temperature Rheological Properties of Asphalt Mortar Modified with Spent FCC Catalysts

Spent fluid catalytic cracking catalysts (S-FCC-Cs) constitutes a fraction of the hazardous solid waste generated in the petrochemical industry. The resource application of S-FCC-Cs remains a challenge. This study aims to explore utilizing S-FCC-Cs in asphalt mortar as a means to enhance resource utilization. Five different S-FCC catalysts were used as substitutes for mineral powder in the asphalt slurry at varying proportions. The high-temperature rheology of the resulting spent FCC catalyst-modified asphalt slurry was analyzed using temperature scanning tests and multiple stress creep recovery (MSCR) tests conducted at different temperatures and substitution doping levels. As the proportion of alternative doping increased, both the phase angle and irrecoverable creep flexibility decreased, while the absolute values of the rutting factor, deformation recovery rate, and irrecoverable creep flexibility difference increased. Moreover, as the temperature rose, the phase angle increased while the rutting factor decreased. The inclusion of an alternative admixture significantly improved the high-temperature performance of the asphalt mastic. This improvement was attributed to several factors, including the increase in the elastic component, enhanced deformation resistance, and improved deformation recovery. While the high-temperature performance of spent FCC catalyst-modified asphalt mastic gradually declined with increasing test temperature, all performance indices remained superior to those of limestone mineral powder asphalt mastic. In addition, the asphalt mortar modified by S-FCC-C JX with a surface area and hydrophilic coefficient of 105 m2/g and 1.026, respectively, exhibited the best rutting resistance and resilience performances among the five mortars, suggesting that the two factors co-affected the high-temperature rheological properties of S-FCC-C asphalt mortar. Considering stress sensitivity, it is more advantageous in improving the high-temperature deformation resistance of asphalt slurry at the JX dosage of 20%. These research findings offer valuable guidance for the application of S-FCC catalysts in asphalt pavement.

Evaluation and optimization of hydrothermal carbonization condition for hydrochar and methane yield from anaerobic digestion of organic fraction of municipal solid waste (OFMSW)

Effectively converting and utilizing the organic fraction of municipal solid waste is a critical strategy to combat environmental pollution and optimize resource utilization. Responsible handling of waste by-products in an environmentally sustainable manner is essential. The utilization of hydrothermal carbonization and anaerobic digestion are rising as progressive, environmentally sustainable technologies for handling the organic component of municipal solid waste, with the added benefit of energy recuperation. Given distinct experimental objectives, comprehensively investigating the optimal conditions for both hydrothermal carbonization and anaerobic digestion experiments with hydrochar feed poses significant challenges. As a result, this study centers its attention on the hydrochars generated through the hydrothermal carbonization process and their impact on the anaerobic digestion of the organic fraction of municipal solid waste. In the first, the relationship between proximate analysis, ultimate analysis, fuel properties, fiber composition, and methane yield of hydrochars at different conditions (150 ≤ temperature ≤ 230 °C, 20 ≤ retention time ≤ 60 min, and 0.15 ≤ biomass loading ≤ 0.35 g/ml) was evaluated. The content of carbon and hydrogen was increased while the content of oxygen decreased. The hydrothermal carbonization process resulted in an increase in the carbon and hydrogen content, accompanied by a decrease in oxygen content. Moreover, alterations in temperature and retention time during the hydrothermal pretreatment led to variations in the contents of cellulose, hemicellulose, and lignin in the hydrochars. Upon subjecting the hydrochars to anaerobic digestion, the methane yield exhibited a wide range, varying from −51.3 to 61.69% in comparison to the control sample. These outcomes emphasize the significant influence of hydrothermal carbonization conditions on the subsequent anaerobic digestion process, yielding a diverse spectrum of methane production levels. Subsequently, the Response Surface Method, a statistical methodology, was employed to investigate the influence of three parameters. Through this approach, optimal conditions were determined to achieve the maximum hydrochar yield (HC150-20-0.35) at 68.6%, the maximum methane yield (HC168.52-39.47-0.19) at 251.38 ml/g VS, and the simultaneous maximization of hydrochar yield and methane yield (HC159.9-28.75-0.23) at 63.1% and 237.68 ml/g VS, respectively. Finally, the structural and morphological properties of the optimized hydrochars were subjected to thorough analysis.

Evaluating the potential of pectin de-esterifying bacterial cultures for the production of methanol from fruit waste: Optimization of critical operational parameters

Fruit wastes are a good source of pectin, which can be de-esterified into pectate and methanol by microbial pectinesterases. Methanol is an important fuel substance and thus, this study aimed at developing a scalable process for efficient biological conversion of fruit wastes into methanol. Pectin digesting bacteria were enriched, identified and the consortium was used for methanol production. Experiments were conducted in two phases, where, feasibility of methanol production using the enriched consortium was investigated in phase I and in phase II, the critical operational parameters such as substrate/inoculum (S/I) ratio, fraction of fruit waste, temperature and rpm were optimized. Initial reactor experimental study resulted in the production of 44.13 g/L methanol which was further optimized with respect to substrate fractionation, S/I ratio, temperature and rpm. Maximum methanol was obtained with whole blend fruit wastes as substrate with S/I ratio of 3 at 40 °C and 150 rpm. By further studying the pectin conversion efficiency of the microbe and efforts towards increasing it for higher methanol production this process can be scaled up or integrated into other biomass conversion processes for methanol as another product.

AQUAPONICS IN BRAZIL: REVIEW AND SURVEY ON WASTE MANAGEMENT PRACTICES

Aquaponics is a food production technique that may be applied in the context of urban agriculture to help achieve food security and promote sustainable agriculture and production patterns, among other Sustainable Development Goals. Brazilian population is large and highly concentrated in urban areas and might benefit from this technique. Similar to any other production activity, aquaponic systems generate wastes that must be properly managed, but until now no study focused on waste generated on such systems or on management practices adopted by Brazilian producers; the goal of this article was to address both of these gaps. A systematic review identified waste streams generated on aquaponics, while management practices were seldom mentioned and addressed. A survey on producers located in 17 of the 27 Brazilian federal units helped confirm sludge, packaging waste, dead fish and unusable plant fractions as typical waste streams. It also identified a lack of concern for a more in-depth assessment of such streams to improve management practices, which tended to gravitate toward adequate and inadequate disposal. Finally, the article proposes management practices for each waste stream, drawing from strategies foreseen in Brazilian National Solid Waste Policy.

Valorization of landfill mined plastic waste and soil-like fractions in polymer composites – A comprehensive solution for sustainable landfill mining

Utilization of Landfill-Mined Plastic Waste (LMPW) and LandFill-Mined-Soil like-Fractions (LFMSF), which together contribute to ≈85–90% of the landfill residues, read as Socio-Economic Refuses (SERs), is the need of the hour. Though earlier researchers have tried to utilize LMPW through energy recovery options, the emission of chlorine-based organic compounds and H2S became big concerns. Similarly, LFMSF has been investigated for its suitability as a manmade resource to produce compost, refuse-derived fuel, pH buffering material and for structural filling applications. However, its potential for leaching salts, heavy metals and microplastics remains a primary environmental concern. To overcome these issues, developing innovative solutions by using LMPW and LFSMF, in tandem, which would result in sustainable landfill mining, is necessary. One of the ways to achieve this could be the creation of polymer Composites, designated as CompoSERs, in which LMPW and LFSMF work as binder and filler, respectively. Such a strategy would help in restricting the negative impact of both these constituents on the geoenvironment in terms of leaching and/or fugitive dust in the surrounding. Keeping this in view, the influence of LFMSF (read filler content) on the overall characteristics of CompoSERs, including macro- and micro-mechanical, functional group, morphological, thermal, and leaching, has been investigated. Since the LMPW consists of inherent fillers in the form of additives/fillers used in the original plastics and adhered contaminants, the experimental (read actual) filler content (designated as FCexp) would be higher than LFMSF added in the process of manufacturing. Hence, easy-to-use empirical relationships between FCexp and mechanical properties of the CompoSERs that can be employed for field-scale applications have been proposed. Based on these relationships, the critical FCexp, which defines a change in the trends of the FCexp and mechanical properties of the CompoSERs, has been observed as 30% by weight. Moreover, unlike other existing utilization schemes of LFMSF, this strategy turns out to be an efficient way to avoid the contamination of the geoenvironment owing to the leaching of heavy metals and dissolved organic matter present in it.

Monitoring of a microbial community during bioaugmentation with hydrogenotrophic methanogens to improve methane yield of an anaerobic digestion process

Methane production by microbial fermentation of municipal waste is a challenge for better yield processes. This work describes the characterization of a hydrogenotrophic methanogen microbial community used in a bioaugmentation procedure to improve the methane yield in a thermophilic anaerobic process, digesting the organic fraction of municipal solid waste. The performance of the bioaugmentation was assessed in terms of methane production and changes in the microbial community structure. The results showed that bioaugmentation slightly improved the cumulative methane yield (+ 4%) in comparison to the control, and its use led to an acceleration of the methanogenesis stage. We observed associated significant changes in the relative abundance of taxa and their interactions, using high throughput DNA sequencing of V3-16S rRNA gene libraries, where the abundance of the archaeal hydrogenotrophic genus Methanoculleus (class Methanomicrobia, phylum Euryarchaeota) and the bacterial order MBA08 (class Clostridia, phylum Firmicutes) were dominant. The relevant predicted metabolic pathways agreed with substrate degradation and the anaerobic methanogenic process. The purpose of the study was to evaluate the effect of the addition of hydrogenotrophic methanogens in the generation of methane, while treating organic waste through anaerobic digestion.

Improvement of Biogas Production Using Biochar from Digestate at Different Pyrolysis Temperatures during OFMSW Anaerobic Digestion

Anaerobic digestion (AD) was utilized to treat the ever-growing amount of organic fraction of municipal solid waste (OFMSW) generated due to population growth and the expansion of the global economy. The widespread application of AD has led to a continuous increase in residual solid digestate that necessarily requires further disposal. Improving AD efficiency and reducing the large amount of digestate is necessary. This study investigated the chemical and physical characteristics of biochar derived from digestate at different pyrolysis temperatures (300 °C, 500 °C, and 700 °C), as well as corn stover biochar at 500 °C, and their effects on AD performance. The pH value of the biochar increased with an increase in pyrolysis temperature while the electrical conductivity decreased. Macropores dominated the biochar’s pore size, and decreased with an increased pyrolysis temperature. The biochar preparation temperature significantly influenced the AD efficiency. Biochar prepared at 700 °C outperformed the other groups, improving the biogas production yields by 10.0%, effectively shortening the lag time, and increasing the average chemical oxygen demand (COD) degradation rate by 14.0%. The addition of biochar (700 °C) and corn stover biochar increased the relative abundance of the volatile fatty acid (VFAs)-oxidizing bacteria Syntrophomonadaceae, which expedited the acid conversion in AD systems. Biochar facilitated direct interspecies electron transfer between DMER64 and Trichococcus with Methanosaeta, enhancing the biogas production performance. These findings confirmed that the biochar derived from digestate promoted biogas production and acid conversion in the AD system of OFMSW. Furthermore, biochar has an improved AD stability, which represents a promising approach to recycling digestate.

Model of Residence Time Distribution, Degree of Mixing and Degree of Dispersion in the Biomass Transport Process on Various Grate Systems

Biomass includes diverse raw materials of plant or animal origin that are biodegradable. It also constitutes a significant fraction of municipal waste burned in waste incineration plants. Grate technology is one of the more commonly used technologies in the thermal conversion of biomass. The mass transport of material on the grate is a complex issue. The article presents a model for determining selected mass flow parameters on the grate, primarily the distribution of residence time, degree of mixing, and dispersion. The model is a description of mechanical mass transport on the grates of thermal waste conversion devices and represents the kinetics of the processes occurring on the grate. It allows for the design of the details of the specific movement of the material particles on the grates depending on their size and density. In addition, experimental tests of flow parameters realized on a laboratory stand simulating the operation of the grate are presented. Tests were conducted on different types of grates and with selected types of biomass materials. They included variants of the operating parameters of the grates, such as the speed and pitch of the grates an their inclination, simultaneously with the fulfillment of the 1:1 scale condition of the size of the laboratory stand to the actual size of the industrial grate (its section). A general trend can be seen in the mean residence time of the material on the grate, which is higher in the case of a reciprocating grate. The degree of dispersion is mainly influenced for moving and reciprocating grates by the inclination angle of the grate. The analysis of the test results made it possible to clarify the mechanism of material mass transport on different types of grates. It is also proposed to use the results in modeling the process of biomass combustion in grate chambers as well as their design and operation.

Techno-economic and environmental sustainability assessment of succinic acid production from municipal biowaste using an electrochemical membrane bioreactor

The techno-economic and environmental performance of succinic acid (SA) production by an engineering Yarrowia lipolytica strain has been evaluated in a process using the organic fraction of municipal solid waste (OFMSW) as feedstock and a novel electrochemical membrane bioreactor (EMB) for simultaneous SA production and extraction. The minimum selling price (MSP) of SA ($2.70–3.71/kg) considering 50,000 tSA/year production capacity using the EMB-based process was slightly lower than the conventional bioprocess depending on OFMSW management fees ($0–35/tOFMSW). Life Cycle Assessment was carried out for the EMB-based bioprocess and the conventional bioprocess considering either conventional electricity production mix (grid) or renewable electricity production from photovoltaics. The use of renewable electricity in the EMB-based bioprocess led to lower Global Warming Potential (0.81 kg CO2-eq/kgSA), Abiotic Depletion Potential (15.71 MJ/kgSA), Acidification Potential (1.87 kg SO2-eq/kgSA) and Eutrophication Potential (0.25 kg PO4-eq/kgSA) than the conventional bioprocess when renewable electricity was used, while higher Human Toxicity Potential (0.29 kg DCB-eq/kgSA) was observed due to the raw materials (e.g. heavy metals) and utilities (e.g. electricity) used in photovoltaics production. It has been demonstrated that the EMB-based system could improve the sustainability of SA production.

Recovery of chemical energy from retentates from cascade membrane filtration of hydrothermal carbonisation effluent

Organic fraction of municipal solid waste is a type of biomass that is attractive due to its marginal cost and suitability for biogas production. The residual product of organic waste digestion is digestate, the high moisture content of which is a problem, even after mechanical dewatering, due to the significant heat requirement for drying. Hydrothermal carbonisation is a process that can potentially offer great benefits by improved mechanical dewatering and valorisation of the digestate into a better-quality solid fuel. However, such valorisation produces liquid by-product effluent rich in organic compounds. Membrane separation could be used to treat such effluent and increase the concentration of the organic compounds while at the same time facilitating the recovery of clean water in the permeate. This work presents the results of the investigation performed using polymeric membranes. The study showed that membrane separation keeps a significant fraction of organics in the retentate. Such concentration significantly increases the biomethane potential of such effluent as well as the energy that could be theoretically used for the generation of process heat using the concentrated retentate in the wet oxidation process.

Development of a simple and versatile process for commercial and municipal lignocellulosic waste conversion into fermentable sugars

Lignocellulosic wastes are valuable feedstock in biorefinery thanks to their high sugars content and low level of fibers intricacy. However, their massification is often a limiting parameter in the development of industrial projects. Hence, this study aims to develop an efficient process enabling the conversion of several waste streams within the same process line. Several pretreatment and enzymatic hydrolysis parameters were firstly evaluated with Old Corrugated Cardboards (OCC) as a model substrate. A chemical free pretreatment followed by an enzymatic hydrolysis (Cellic Ctec 3 enzymatic cocktail at 0.06 g of cocktail per g of Total Sugars (TS)) efficiently depolymerized OCC into monomeric sugars (0.50 g/gTS) consequently fermented into ethanol (0.24 g/gTS). Then, the suitability of this process was validated for sugars production from Pulp and Paper (P&P) sludge (0.48 g/gTS), sieved toilets papers (0.40 g/gTS), the Organic fraction of municipal solid waste (0.37 g/gTS) and Waste Wood B (0.08 g/gTS).

Sustainable Handling of OR Waste - a Difficult Issue with Great Potential

Surgical interventions often result in large amounts of waste. Contaminated waste must not be separated in recyclable fractions but must directly be burned for thermal recycling. Clinical waste is classified according to the potential dangers in accordance with the European Waste List (EWL). Unfortunately the waste number does not contain information about recyclable material. Only about 5% of clinical waste is hazardous waste resulting from contact with notifiable diseases in accordance with the definition of §6, German Law on Infection Protection. This waste must be burned or be further sterilised. By using separate collection of packaging material without contamination with body secretions, up to 50% of waste from operating rooms can be disposed of via the German "Dual System" free of charge. Nearly 30% of packaging waste will undergo material recycling. The recycling of contaminated high-class single use surgical instruments (SUSI) is not allowed unless they pass through a disinfection procedure that is certified by the responsible authorities. Two examples will be presented. Other separated waste fractions (for example paper, pasteboard, cardboard packaging or light packaging like PET etc.) can be sold directly to specialised recycling companies. Conclusion: Responsible handling of clinical waste from operating theatres preserves our environment, can save money and motivates staff members who care for the future of our planet earth. When sustainable waste management is introduced, all staff members must be introduced from the start. Doctors must function as role models.