Fraction Of Municipal Solid Waste Research Articles

Production and emission characterization of briquette for sustainable development: MSW transformation.

Global community is increasingly alarmed by resource depletion and environmental pollution. In light of pressing environmental concerns and depletion of finite resources, the surge in fossil fuel usage has sparked twin crises: dwindling fossil fuel reserves and escalating environmental pollution. The current study introduces a novel approach to minimize waste by transforming it into briquettes suitable for large-scale production. Production of briquettes involves multiple stages, including collection, drying, crushing, screening, blending, compacting, and storage. The main objective of this research is to demonstrate and investigate the physico-mechanical and emission properties of briquettes produced with readily available organic fraction of municipal solid waste (MSW) such as food and garden waste. The physical, mechanical, and elemental characteristics such as calorific value, moisture content, ash, volatile matter, fixed carbon, density, compressive strength, and SEM-EDAX were determined. A combustibility test along with emission and water boiling test was also carried out. The MSW briquettes were prepared in a densification system at 130°C temperature and 20MPa. The study's conclusion suggests that the MSW briquette with lignin content of 25-30%, calorific value of 22.53MJ/kg, compressive strength of 14.517 N/mm2, and density of 1124.12kgm-3 could be used to retain energy and lessen the harmful effects of climate change while also enhancing sustainability. Flue gas emissions from burning MSW briquettes in a biomass stove were examined in this study using flue gas analyzer and smoke meter. Furthermore, the generated briquettes exhibit a density of 1124.12kgm-3 which is on par with coal, making them suitable for co-firing in boilers. Likewise, the determined parameters are compared with the biomass briquettes and firewood. Further investigation is required to elevate its quality and economic potential.

Decentralized Composting Analysis Model—The Qualitative Analysis Path

The organic fraction of municipal solid waste (OFMSW) is a significant environmental threat, and an economic and social challenge to manage. As such, the efficient treatment of OFMSW is a significant key factor in achieving sustainable waste management. Decentralized composting (DC) offers a new framework of waste management. The DC analysis model (DCAM) proposed in our previous study provides a powerful tool for decision makers, based on the quantification of the DC project characteristics. In this paper, we focus on qualitative analysis as a complementary tool to support decision making in cases where the quantitative analysis is equivocal. The qualitative analysis identifies the main players in the field, the critical stakeholders, and the potential conflicts between them. It also reveals the root problems and the core competencies for the project’s implementation. The DCAM qualitative analysis in the Shefa-Amr case study indicates that unresolved root problems, such as “lack of national regulation”, “clear ownership of the project”, and “lack of ongoing budget” can result in an unsustainable composting system. Countering that, “commitment of the municipality” together with “economic viability” and securing “suitable areas for placing composters” are among the most important core competencies for the effective implementation of DC projects.

Improvements in dewaterability and fuel properties of hydrochars derived from hydrothermal co-carbonization of sewage sludge and organic waste

The hydrothermal co-carbonization of sewage sludge and organic additives, namely 10 and 20 % of charcoal, fir, grass, and an undersieved fraction of municipal solid waste, was studied. The benefits of this combined process included the spectacular dewaterability performance of slurry, proved by positive filtration tests and shorter capillary suction times. For instance, a 20 % fir addition decreased c.a. 60 % of pressure filtration time when compared to the hydrothermal carbonization of sewage sludge. A 10 % undersieved fraction of municipal solid waste resulted in 15.72 s of capillary suction time. Moreover, hydrothermal co-carbonization produced effective solid energy sources. The addition of organic origin waste to sewage sludge prior to the process caused higher heating values, carbon and fixed carbon contents of hydrochars (e.g. a 20 % charcoal addition generated 21 % higher heating value, 30 % carbon and 2.8 times higher fixed carbon), which corresponded with easier and more stable combustion processes compared to hydrochar from sewage sludge determined by thermal analysis. Possible exploitation problems during combustion have been assessed by determining the tendency risks of slagging and fouling based on oxides identified in ash by XRF analysis. Furthermore, changes in the structural and morphological properties of hydrochars were identified by SEM and FTIR analyses.

Effects of carbon-based conductive materials on semi-continuous anaerobic co-digestion of organic fraction of municipal solid waste and waste activated sludge

Organic fraction of municipal solid waste (OFMSW) and waste activated sludge (WAS) are the most produced organic waste streams in urban centres. Their anaerobic co-digestion (AcoD) allows to generate methane (CH4) and digestate employable as renewable energy source and soil amendment, respectively, fully in accordance with circular bioeconomy principles. However, the widespread adoption of such technology is limited by relatively low CH4 yields that fail to bridge the gap between benefits and costs. Among strategies to boost AcoD of OFMSW and WAS, use of conductive materials (CMs) to promote interspecies electron transfer has gained increasing attention. This paper presents one of the few experimental attempts of investigating the effects of four different carbon(C)-based CMs (i.e., granular activated carbon – GAC, graphite – GR, graphene oxide – GO, and carbon nanotubes – CNTs) separately added in semi-continuous AcoD of OFMSW and thickened WAS. The presence of C-based CMs has been observed to improve CH4 yield of the control process. Specifically, after 63 days of operation (concentrations of GAC and GR of 10.0 g/L and of GO and CNTs of 0.2 g/L), 0.186 NL/gVS, 0.191 NL/gVS, 0.203 NL/gVS, and 0.195 NL/gVS of CH4 were produced in reactors supplemented with GAC, GR, GO, and CNTs, respectively, compared to 0.177 NL/gVS produced in the control process. Likewise, at the end of the test (i.e., after 105 days at concentrations of C-based CMs half of the initial ones), CH4 yields were 0.193 NL/gVS, 0.201 NL/gVS, 0.211 NL/gVS, and 0.206 NL/gVS in reactors supplemented with GAC, GR, GO, and CNTs, respectively, compared to 0.186 NL/gVS of the control process. Especially with regard to GR, GO, and CNTs, results obtained in the present study represent a significant advance of the knowledge on the effects of such C-based CMs to realistic and scalable AD process conditions respect to previous literature.

Efficient reuse of Sargassum spp. biomass and organic fraction of municipal solid waste by anaerobic co-digestion in the Dominican Republic: Evaluation of biochemical methanogenic potential and reaction rates

Anaerobic digestion (AD) is a potential solution to valorize invasive pelagic Sargassum spp. Sargassum spp. (SP) biomass is characterized by a low carbon/nitrogen (C/N) ratio, which, in addition to the presence of indigestible fiber, sulfide, salt, ash, and polyphenol content, are inhibitors to the AD process. Furthermore, its chemical composition depends on the season and region of harvesting. To increase biogas yields, biomass must be subjected to pre-treatment or an anaerobic co-digestion process with other waste biomass. In this paper results of co-digestion of Sargassum spp. and municipal solid waste (OFMSW) batches with different weight ratios are reported and compared with the mono-digestion of the two organic matrices. The objective is to provide an optimized SP to OFMSW ratio for the sustainable production of biogas in the Dominican Republic. Mono-digestion of Sargassum spp. showed the longest reaction time and the lowest biomethane yield as it lasted 30 days and provided a cumulative volume of biomethane equal to 79.68 NmLg−1VS. The addition of OFMSW led to the shortening of the reaction time to 10 days and to the increase of the yield and cumulative volume of biomethane. It can be attributed to the more favorable C/N ratio, to the presence of more readily digestible compounds and lower ash content of those batches. The reaction kinetics of all the investigated batches is properly fitted by the Modified Gompertz model. The system with a Sargassum spp.-OFMSW weight ratio of 33:67 allows to obtain a notable bio-methane volume of 327.27 ± 15.93 NmLg−1VS, ten times higher than from Sargassum spp. alone.

Characterization of biochars of different origin and application to the anaerobic digestion of source-selected organic fraction of municipal solid waste under batch conditions and at different dosages

Anaerobic digestion (AD) is a wide-spread strategy to manage organic waste and recover valuable products but faces some limitations that could be overcome with additives like biochar (BC). The production of BC defines its properties, which in turn determine its effect on AD performance and methane yield. In this study, three biochars (BC1, BC2 and BC3) were characterized using several techniques (SEM imaging, BET, GC, ICP and FTIR). The properties of BC were found to be defined both by the feedstock and the production process. The BC were then applied to the AD of the organic fraction of municipal solid waste (OFMSW) using three doses (1, 5% and 10% w/w TS). Compared to the control, there was an increase in methane production in BC3 at doses 1% and 5% (+15 and +30%, respectively) and a decrease in BC1 and BC2 at 1% (−33% and −19%, respectively). The decrease in biogas production was often paired with an increased methane content. A two-way ANOVA analysis showed that the interaction of biochar dose and type had a significant effect on methane yield, meaning that the effect of BC on AD cannot be predicted with the dose or the type alone. When a second substrate feeding was performed, no significant differences on methane production were observed among the experimental conditions. Key aspects to properly assess the economic viability of the process have been also discussed. Further experiments could help to fill knowledge gaps and clarify the roles of BC characteristics and dose on AD performance.

Combining anaerobic digestion slurry and different biochars to develop a biochar-based slow-release NPK fertilizer

In this research, we developed a biochar-based fertilizer using biogas slurry and biochar derived from lignocellulosic agro-residues. Biogas slurry was obtained through the anaerobic digestion of the organic fraction of municipal solid waste (fresh vegetable biomass and/or prepared food), while biochars were derived from residues from quinoa, maize, rice, and sugarcane. The biochar-based fertilizers were prepared using an impregnation process, where the biogas slurry was mixed with each of the raw biochars. Subsequently, we characterized the N, P and K concentrations of the obtained biochar-based fertilizers. Additionally, we analyzed their surface properties using SEM/EDS and FTIR and conducted a slow-release test on these biochar-based fertilizers to assess their capability to gradually release nutrients. Lastly, a bioassay using cucumber plants was conducted to determine the N, P, and K bioavailability. Our findings revealed a significant correlation (r > 0.67) between the atomic O/C ratio, H/C ratio, cation exchange capacity, surface area, and the base cations concentration with N, P, and/or K adsorption on biochar. These properties, in turn, were linked to the capability of the biochar-based fertilizer to release nutrients in a controlled manner. The biochar-based fertilizer derived from corn residues showed <15 % release of N, P and K at 24 h. Utilization of these biochar-based fertilizers had a positive impact on the mineral nutrition of cucumber plants, resulting in an average increase of 61 % in N, 32 % in P, and 19 % in K concentrations. Our results underscore the potential of biochar-based fertilizers in controlled nutrient release and enhanced plant nutrition. Integration of biochar and biogas slurry offers a promising and sustainable approach for NPK recovery and fertilizer production in agriculture. This study presents an innovative and sustainable approach combining the use of biochar for NPK recovery from biogas slurry and its use as a biochar-based fertilizer in agriculture.

Potential of solid recovered fuel production from autoclave treated healthcare waste in Sultanate of Oman

ABSTRACT Economic growth has a potential impact on waste generation worldwide. Growing recognition for resources recovery from waste including production of a clean energy has led to the development of standards for, and the generation of, Solid Recovered Fuel (SRF). SRF, according to BS EN ISO 21640 is a fuel prepared from nonhazardous/treated waste to be utilized for energy recovery in incineration or co-incineration plants which meets the classification and specification. The amount of combustible fractions (i.e., plastic, textile and paper) that are present in Healthcare Waste (HCW) and Municipal Solid Waste (MSW) provides an opportunity for SRF production. HCW is defined as clinical waste generated from healthcare facilities. Limited efforts in utilizing treated HCW in production of SRF were noted, despite the fact that high content of combustible fractions, hence the novelty of this research. This research addresses the opportunities of utilizing autoclaved HCW as an alternate fuel; through a detailed chemical and physical analysis of autoclaved HCW collected from the Sultanate of Oman hospital and healthcare facilities. Furthermore, this study examines the possible uses of such materials instead of landfilling. The utilization of treated HCW as an alternative fuel is not only saving the land space, but also reduces the carbon emissions originating from landfilling. This in fact would also support the government in achieving its aspiring goal of the net zero carbon emissions by 2050 through better utilization of these materials in production of SRF as an alternative to fossil fuel combustion. The study revealed that autoclaved HCW appears to have a high quality SRF and is classified as (NCV 4, Cl 3); which complies with the potential end users’ specifications. It is estimated that the combined energy output from MSW and HCW combustible fractions could cover about 12.75% of the energy requirements for Oman cement factories. Implications: The results confirm the viability of using autoclave (HCW) as an alternative fuel due to its high thermal energy content. Based on mean Net Calorific Value (NCV) of analyzed HCW that is found around 14 (MJ/Kg (ar)), and the mean Cl level (i.e., 0.814 ± 0.213% (d)); the SRF is classified as (NCV4, Cl 3). This grade is found to be well within the end users accepted range. This opens up the opportunity for creating a market demand for HCW that not only it could boost its recovery, but it could also unlock the value that can generates.

Assessment of emissions and potential occupational exposure to carbon monoxide during biowaste composting.

To date, only a few studies focused on the carbon monoxide (CO) production during waste composting; all targeted on CO inside piles. Here, the CO net emissions from compost piles and the assessment of worker's occupational risk of exposure to CO at large-scale composting plants are shown for the first time. CO net emissions were measured at two plants processing green waste, sewage sludge, or undersize fraction of municipal solid waste. Effects of the location of piles (hermetised hall vs. open yard) and turning (before vs. after) were studied. Higher CO net emission rates were observed from piles located in a closed hall. The average CO flux before turning was 23.25 and 0.60 mg‧m-2‧h-1 for hermetised and open piles, respectively, while after- 69.38 and 5.11 mg‧m-2‧h-1. The maximum CO net emissions occurred after the compost was turned (1.7x to 13.7x higher than before turning). The top sections of hermetised piles had greater CO emissions compared to sides. Additionally, 5% of measurement points of hermetised piles switched to 'CO sinks'. The 1-h concentration in hermetised composting hall can reach max. ~50 mg CO∙m-3 before turning, and >115 mg CO∙m-3 after, exceeding the WHO thresholds for a 1-h and 15-min exposures, respectively.

Sustainable biogas production potential in Nepal using waste biomass: A spatial analysis

AbstractBiogas plays a significant part in replacing solid biomass and fossil fuels for cooking. However, the implementation of appropriate policies to promote the development of biogas plants is hindered by a lack of adequate assessment of the biogas potential in Nepal. Thus, we estimate the potential of biogas production at the district level of Nepal from available waste biomass, including livestock manure, agricultural residues, and organic fraction of municipal solid waste (OFMSW). Our estimates show the theoretical potential of biogas production from livestock manure of 1890 million m3 year−1, agricultural residues of 2290 million m3 year−1, and OFMSW of 234 million m3 year−1. The total biogas production is 4412 million m3 year−1, equivalent to 153 million liquefied petroleum gas (LPG) cylinders yearly. Using this biogas potential to replace LPG and solid biomass for cooking could result in avoided CO2, CO, and PM2.5 emissions of 6.3 million tons year−1, 0.4 million tons year−1, and 0.04 million tons year−1, respectively. Our findings suggest that the Terai districts of Morang, Sunsari, Saptari, and Banke, as well as the Hilly districts of Kavrepalanchok, Dhading, and Nuwakot, have a significant amount of biogas‐producing potential. Utilising this potential could also contribute to achieving several Sustainable Development Goals and a clean cooking energy transition in Nepal. For this, governments need careful planning, designing, policy support, and facilitation on bio‐resource management and utilisation at the local level.

Post-sorption of Cd, Pb, and Zn onto peat, compost, and biochar: Short-term effects of ecotoxicity and bioaccessibility

Contamination by potentially toxic metals and metalloids (PTMs) has become a significant health and environmental issue worldwide. Sorption has emerged as one of the most prominent strategies for remediating both soil and water contamination. New sorbents are being developed to provide economically viable and environmentally sound alternatives, in alignment with the principles of the Sustainable Development Goals. This research aimed to assess the potential effects on human health and environmental toxicity following the sorption of cadmium (Cd), lead (Pb), and zinc (Zn) using peat, compost, and biochar as sorbents. The peat was collected in Brazil, a country with a tropical climate, while the compost and biochar were produced from the organic fraction of municipal solid waste (OFMSW). In terms of bioaccessibility, the results showed the following order: compost < biochar < peat for Pb, and compost < peat < biochar for Cd and Zn. There was a significant growth inhibition for Eruca sativa and Zea mays exposed to increasing concentrations of PTMs treated with peat and compost. The presence of contaminants played a decisive role on immobilization of neonates of Ceriodaphnia silvestrii after treatments with compost and, especially, peat. However, the biochar addition rate caused a significant influence on the outcomes of ecotoxicity across all tested species. Although the samples treated with biochar exhibited lower residual concentrations of PTMs than those treated with compost and peat, the inherent toxicity of biochar might be attributed to the material itself. The exposure to residual PTM concentrations post-desorption caused ecotoxic effects on tested species, emphasizing the need to assess PTM desorption potential. Peat, compost, and biochar are promising alternatives for the sorption of PTMs, but the addition rates must be properly adjusted to avoid the occurrence of undesirable ecotoxicological effects. This research offers valuable insights for sustainable environmental management and protection by thoroughly investigating the impacts of different sorbents and contaminants on aquatic and terrestrial ecosystems.

Exploring biorefinery alternatives for biowaste valorization: a techno-economic assessment of enzymatic hydrolysis coupled with anaerobic digestion or solid-state fermentation for high-value bioproducts

ABSTRACT Enzymatic hydrolysis of organic waste is gaining relevance as a complementary technology to conventional biological treatments. Moreover, biorefineries are emerging as a sustainable scenario to integrate waste valorization and high-value bioproducts production. However, their application on municipal solid waste is still limited. This study systematically evaluates the techno-economic feasibility of the conversion of the organic fraction of municipal solid waste (OFMSW) into high-value bioproducts through enzymatic hydrolysis. Two key variables are examined: (a) the source of the enzymes: commercial or on-site produced using OFMSW, and (b) the treatment of the solid hydrolyzate fraction: solid-state fermentation (SSF) for the production of biopesticides or anaerobic digestion for the production of energy. As a result, four different biorefinery scenarios are generated and compared in terms of profitability. Results showed that the most profitable scenario was to produce enzymes on-site and valorize the solid fraction via SSF, with an internal rate of return of 13%. This scenario led to higher profit margins (74%) and a reduced payback time (6 years), in contrast with commercial enzymes that led to an unprofitable biorefinery. Also, the simultaneous production of higher-value bioproducts and energy reduced the economic dependence of OFMSW treatment on policy instruments while remaining energetically self-sufficient. The profitability of the biorefinery scenarios evaluated was heavily dependent on the enzyme price and the efficiency of the anaerobic digestion process, highlighting the importance of cost-efficient enzyme production alternatives and high-quality OFMSW. This paper contributes to understanding the potential role of enzymes in future OFMSW biorefineries and offers economical insights on different configurations.

Modelling of technical, environmental, and economic evaluations of the effect of the organic loading rate in semi-continuous anaerobic digestion of pre-treated organic fraction municipal solid waste

The study concerned technical feasibility, economic profitability, and carbon footprint (CF) analysis of semi-continuous anaerobic digestion (sAD) of organic fraction of municipal solid waste (OFMSW). The research assessed the pre-treatment effect on sAD by varying organic loading rates (OLR) from 3.38 to 6.75 kgvs/m3d. Three sAD configurations were investigated: hydrodynamic-cavitated (HC-OFMSW), enzymatically pre-treated (EN-OFMSW), and non-pre-treated (AD-OFMSW). Principal Component Analysis and Supervised Kohonen's Self-Organizing Maps combined the experimental, economic, and environmental evaluations.The sAD configurations were grouped predominantly according to the OLR however, within each OLR group the configurations were clustered according to the pre-treatments.The finding highlighted that pre-treatments offset inhibition in sAD of OFMSW due to the OLR increase, being economically profitable and CF negative up to 4.50 kgvs/m3d for EN-OFMSW and to 5.40 kgvs/m3d for HC-OFMSW. Whereas sAD-OFMSW remained economically and environmentally viable only up to 3.87 kgvs/m3d.HC-OFMSW reached the highest performance. In detail, for HC-OFMSW the NPV and CF ranged from 17679.30 to 43827.12 euros and from −51.08 to −407.210 kg CO2eq/1 MWh daily produced, by decreasing the OLR from 5.40 to 3.87 kgvs/m3d.These results are fundamental since pre-treatment is usually expensive due to additional energy or chemical requirements.

Operational process stability in pilot dry anaerobic digester of source‐sorted organic fraction municipal solid waste

AbstractThe organic fraction of municipal solid waste (OFMSW) is a major portion of solid waste in Malaysia, with 44.5% of the total waste being food waste‐derived sources. This study investigates the performance of dry anaerobic digester (DAD) operation using the pilot dry anaerobic digester (PDAD), a plug flow reactor, in treating source‐sorted organic fraction municipal solid waste (SS‐OFMSW) for biogas production. A commercial Malaysian food waste (CMFW) sample has been used to represent SS‐OFMSW. The anaerobic digestion was performed in a semi‐continuous operation using a 15 m3 PDAD with organic loading rates (OLRs) ranging from .63 to 5.46 kg volatile solid (VS)/m3·day under mesophilic conditions. The maximum methane composition was achieved at 56.0% at OLR 5.17 kg VS/m3·day with specific methane production (SMP) of .57 m3·CH4/kg VSfed and gas production rate (GPR) 5.27 m3·gas/m3·digester·day. As indicated by a pH and alkalinity ratio, the PDAD system was stable ranging from pH 6.7 to 8.3, alkalinity ratio of .3 with an inclination of total ammonia nitrogen (TAN) up to 1056 mg/L. The SMP achieved is between 1.58 and .4 m3·CH4/kg VSfed and potentially to fuelled 475 MW commercial biogas plant fed by CMFW. The DAD deployment strengthened the circular economy and decarbonization initiatives.

A Review on Dry Anaerobic Digestion: Existing Technologies, Performance Factors, Challenges, and Recommendations

With the increase in the growing rate of municipal solid waste throughout the world and due to the high moisture and organic components of the organic fraction of municipal solid waste, dry anaerobic digestion has become the future direction to cope with this waste while reducing the impact on the environment, including climate change. Dry anaerobic digestion has become a promising technology that converts the organic fraction of municipal solid waste into combustible biogases, which can be used as an alternative energy source. However, the technology faces several challenges that must be addressed to enhance its performance and adoption. This paper provides a comprehensive analysis of the current technologies used for dry anaerobic digestion in OFMSW and delves into the various factors that influence the performance of these technologies. This review paper also identifies and discusses the challenges faced in optimizing and scaling up these technologies, such as feedstock pretreatment requirements, characteristics of inoculum, and other crucial parameters.

Adding Granular Activated Carbon and Zerovalent Iron to the High-Solid Anaerobic Digestion System of the Organic Fraction of Municipal Solid Waste: Anaerobic Digestion Performance and Microbial Community Analysis.

Anaerobic digestion (AD) performance and microbial dynamics were investigated in a high-solid anaerobic digestion (HSAD) system of the organic fraction of municipal solid waste (OFMSW). 1, 5, 10, and 15% (w/w, dry weight of the OFMSW) of granular activated carbon (GAC) and zerovalent iron (ZVI) were added to the HSAD system. The results showed that adding ZVI and GAC can improve the methane yield of the OFMSW. Notably, R-(GAC + ZVI) exhibited the highest cumulative methane yield of 343.0 mL/gVS, which was 57.1% higher than that of the R-control. At the genus level, the dominant bacteria included norank_f__norank_o__MBA03, norank_f__norank_o__norank_c__norank_p__Firmicutes, Fastidiosipila, norank_f__Rikenellaceae, and Sphaerochaeta, while Methanoculleus, Methanobacterium, and Methanosarcina were the dominant archaea. The highest relative abundance of norank_f__norank_o__norank_c__norank_p__Firmicutes was 30.8% for the R-(GAC + ZVI), which was 71.4% higher than that of the R-control. The relative abundance of Methanoculleus and Methanobacterium for the R-(GAC + ZVI) and the R-control group accounted for 79.0 and 90.8% of the total archaeal abundance, respectively. Additionally, the relative abundance of Methanosarcina was 10.6% for R-(GAC + ZVI), which was higher than that of the R-control (1.1%). After the addition of GAC and ZVI, the electron transfer capacity of the HSAD system was enhanced, resulting in promoted methane production. Thus, the simultaneous addition of GAC and ZVI to the HSAD system can be an effective strategy to promote the cumulative methane yield of the OFMSW.

Sustainability assessment of biofuel and value-added product from organic fraction of municipal solid waste

The current study aims to examine the techno-economic and environmental assessment of biorefinery development within a circular bioeconomy context by using an organic fraction of municipal solid waste (OFMSW) by extraction of lipids, carbohydrates, and proteins with 98, 51 and 62 % by mass of conversion efficiency and yield recovery, and value-added fractions production as well. Fatty acid methyl ester (biodiesel) and glycerol (biofuel) were produced by applying transesterification process, and the remaining biomass was converted into biocrude oil by thermal liquefication. The biorefinery using 613 kg of OFMSW produced biodiesel, glycerol, and bioethanol with 126 litter, 14.3 kg, and 172 litter respectively, as well as value-added fractions, such as biocrude oil with 78 kg. The environmental impact was assessed using the life cycle assessment (LCA) framework, ReCiPe2016 Mid-point (H) approach, through 18 different environmental categories. The key findings elucidate that Terrestrial ecotoxicity, Climate change, Fossil depletion and Human toxicity were the main impact categories which are potentially contributed 9.81E+02 kg 1,4-DB eq., 1.43E+03 kg CO2 eq., 2.04E+02 kg oil eq., and 8.08E+01 kg 1,4-DB eq. The normalization (person per equivalent) analysis revealed that only categories of resource reduction (fossil and metal depletion) are the key contributors to environmental degradation. The biorefinery system's total revenue was estimated at USD 6.817,509 million annually. The calculated revenue was USD 0.026 million daily in a shift of 8 h. The Net present worth (NPW) was calculated at USD 499.97 million by assuming a discount factor of 10 % and inflation rate of 5 % for 15 years. The project is considered feasible by demonstrating 7.15 payback year. This research showcased the efficient portrayal of the biorefinery system and succinctly conveyed the significant circular bioeconomy for a greener future. Thus, it could be helpful to the stakeholder's context towards techno-economic and environmental evaluation.

Wet anaerobic digestion of organic fraction of municipal solid waste: experience with long-term pilot plant operation and industrial scale-up

This paper presents the analysis of a pilot anaerobic digestion plant that operates with organic fraction of municipal solid waste (OFMSW) from a wholesale market and can treat up to 500 kg d−1. The process was monitored for a period of 524 days during which the residue was characterized and the biogas production and methane content were recorded. The organic load rate (OLR) of volatile solids (VS) was 0.89 kg m−3 d−1 and the Hydraulic Retention Time (HRT) was 25 d during the process. The yield was 82 Nm3 tons OFMSW−1 biogas, equivalent to 586 Nm3 tons CH4 VS−1. The results obtained in the pilot plant were used to carry out a technical–economic evaluation of a plant that treats 50 tons of OFMSW from wholesale markets. A production of 3769 Nm3 d−1 of biogas and 2080 Nm3 d−1 of methane is estimated, generating 35.1 MWh d−1 when converted to electricity.

Electronic regulation to achieve efficient anaerobic digestion of organic fraction of municipal solid waste (OFMSW): strategies, challenges and potential solutions

Anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW) is prone to system breakdown under high organic loading rates (OLRs) condition, which subsequently reduces the efficiency of digestion process and results in substantial economic losses. In this perspective paper, the substances metabolisms, electrons flow, as well as microbial interaction mechanisms within AD process are comprehensively discussed, and the underlying bottleneck that causes inefficient methane production is identified, which is “electrons surplus”. Systems encountering severe electron surplus are at risk of process failure, making it crucial to proactively prevent this phenomenon through appropriate approaches. On this basis, the present perspective proposes three potential electronic regulation strategies to prevent electrons surplus, namely, electron shunt, accelerating electron transfer and regulating methanogenic metabolism pathway, and presents specific methodologies for each strategy. Furthermore, the potential solutions to challenges that may occur during the electronic regulation process are also presented in this paper. This perspective aims to provide innovative approaches to achieve the efficient and stable operation of OFMSW anaerobic digestion, especially under high OLRs condition.

TREATMENT OF LEACHATE BY THE CARBON MATERIAL OBTAINED FROM POLYMER FRACTION OF MUNICIPAL SOLID WASTE

In the study, the process of anaerobic thermal processing of polymer fraction of municipal solid waste using a horizontal and vertical type of reactor has been developed in order to obtain a new carbon sorbent. The productivity of carbon material by the horizontal method is 20%, while vertical type of reactor is about 30%. The sorption potential of some heavy metals and microbiological indices from leachate water of Tbilisi municipal solid waste polygon has been studied. According to estimates, the sorption potential of pollutans from wastewater using our new sorbent is average 60-98%.