Organic Fraction Of Municipal Solid Waste Research Articles

Economic and environmental assessment of bacterial poly(3-hydroxybutyrate) production from the organic fraction of municipal solid waste

The management of municipal solid waste is a major logistic and environmental problem worldwide. Nonetheless, the organic fraction of municipal solid waste (OFMSW) is a valuable source of nutrients which can be used for a variety of purposes, according to the Circular Economy paradigm. Among the possible applications, the bioproduction of a biodegradable polyester, poly(3-hydroxybutyrate) [P(3HB)], using OFMSW as carbon platform is a promising strategy. Here, an economic and environmental assessment of bacterial P(3HB) production from OFMSW is presented based on previously published results. The SuperPro Designer® software was used to simulate P(3HB) production under our experimental parameters. Two scenarios were proposed depending on the fermentation medium: (1) enzymatic hydrolysate of OFMSW supplemented with glucose and plum waste juice; and (2) basal medium supplemented with glucose and plum waste juice. According to our results, both scenarios are not economically feasible under our experimental parameters. In Scenario 1, the low fermentation yield, the cost of the enzymes, the labour cost and the energy consumption are the factors that most contribute to that result. In Scenario 2, the cost of the extraction solvent and the low fermentation yield are the most limiting factors. The possibility of using process waste as raw material for the generation of other products must be investigated to enhance economic feasibility. From an environmental viewpoint, the photochemical oxidation potential (derived from the use of anisole as extraction solvent) and the generation of acid rain and global warming effect (caused by the burning of fuels for power generation) are the most relevant impacts associated to P(3HB) production under our experimental parameters.

Effects of Activated Carbon on the Fate of Antibiotic Resistance Genes During Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste

The organic fraction of municipal solid waste (OFMSW) has become one of the sources and reservoirs of antibiotic resistance genes (ARGs). It is essential to explore the fate of ARGs during biological treatment of OFMSW. Therefore, the changes in several types of ARGs and integron genes during anaerobic digestion of the OFMSW were analyzed by quantitative PCR. Furthermore, the effects of different particle sizes of activated carbon on the behaviors of the target genes and the potential microbial mechanisms of ARGs dynamics were investigated. The results showed that the total ARGs in the initial system were reduced after anaerobic digestion with or without the presence of activated carbon. The removal rate of the absolute abundance of total ARGs was 29.95%-63.40%. In the final system of anaerobic digestion of the OFMSW, the abundance of total ARGs in powdered activated carbon (PAC) groups was significantly higher than that in the control group (P<0.05). The supplementation of PAC inhibited the reduction of ARGs, and the supplementation of granular activated carbon had no significant effect on the change in ARGs. The potential host bacteria of ARGs were mainly Clostridia, Bacteroidia, and Synergistia during anaerobic digestion. The enrichment of host bacteria caused by PAC addition was the main reason for the increase in the target genes. Moreover, Clostridia might have been the main driving factor for the growth and decline of ARGs. These results will help us to understand the dissemination of ARGs and the impacts of activated carbon addition on ARGs during anaerobic digestion of the OFMSW.

Multiphase analysis of hydrochars obtained by anaerobic digestion of municipal solid waste organic fraction

Digestate is a nutrient-rich substance produced by anaerobic digestion that contains organic, inorganic, and biological matter. The European Nitrates Directive (91/676/EEC) provides regulations regarding the wider implementation of the digestate. Owing to a significant amount of organic matter in the digestate, it can be utilised as a solid biofuel, soil amendment substance, or substrate for activated carbon production. However, the solid by-products of the anaerobic digestion of the municipal solid waste wet fraction cannot be used for such applications because it is still considered a waste. Hydrothermal carbonisation (HTC) was investigated as a pre-treatment method for the digestate obtained by anaerobic digestion of the municipal solid waste wet fraction. HTC was carried out at temperatures of 180, 200 and 230 °C and residence times of 30, 60 and 120 min. The value of pressure was determined based on water temperature and partial pressure of the gaseous by-products. The HTC process resulted in changes in the physical and chemical properties of the hydrochars compared to those of the raw materials. A temperature of 200 °C and residence time of 60 min during HTC were optimal for energy consumption; this hydrochar exhibited the best combustion parameters and physical properties (specific surface area).

Life cycle analysis of a biorefinery for activated carbon and biomethane production

A Life Cycle Analysis (LCA) based on ReCiPe 2016 model of a biorefinery case-study was performed. On the basis of an existing Portuguese Anaerobic Digestion plant, the proposed biorefinery hypothesized the use of (i) Maize Cob Waste (MCW) as co-substrate for Anaerobic co-Digestion (AcoD) with Organic Fraction Municipal Solid Waste (OFMSW), (ii) the use of MCW derived activated carbons (ACs) in a H2S removal unit, and (iii) the biogas upgrading to biomethane in a Pressure Swing Adsorption unit. The main aim was to compare the environmental benefits obtained from distinct uses of biogas, specifically the cogeneration of electricity/heat and biomethane production.Three biogas production configurations were considered: (i) AD of standalone hydrolysed OFMSW (hOFMSW); (ii) AcoD of hOFMSW and MCW pre-treated with H2O2 (hOFMSW + PreMCW); and (iii) AcoD of hOFMSW with non-pre-treated MCW (hOFMSW + MCW). The increase of biogas and methane yields obtained with AcoD of hOFMSW + MCW provided an overall better environmental performance than other configurations. With this configuration the FRS, MRS and GW (hh) categories of impacts provided values of 3.12E-02 and -2.49E-05 US$2013, and 4.87E-09 DALY, respectively, that are 47%, 15% and 97% lower than the corresponding value obtained with AD of standalone OFMSW.The biogas upgrading to biomethane from AcoD of hOFMSW + MCW generated higher environmental impacts than cogeneration, due to the AC production and upgrading processes. If an optimised H2S adsorption capacity is considered, the Fossil Resource Scarcity, Mineral Resource Scarcity, and Global Warming human health impact categories decreased by 20%, 15%, and 17%, respectively, when compared to the base-case upgrading scenario. Further decreases of up to 52%, 23%, and 28% for those impact categories, respectively, are observed when the natural gas used in the OFMSW collection and transportation fleet is substituted by biomethane produced in the biorefinery.

Parametric optimization of the dark fermentation process for enhanced biohydrogen production from the organic fraction of municipal solid waste using Taguchi method

In this work, the Taguchi method was used to optimize the dark fermentative H2 production from the organic fraction of municipal solid waste (OFMSW). The experiments were planned using the L16 orthogonal array design with each trial conducted at different levels of substrate concentration, inoculum-to-substrate ratio (ISR), and temperature. Based on the results, the optimal setting of the process parameters was the substrate concentration of 6 g-VS/L, ISR 0.5, and temperature of 55 °C. Furthermore, substrate concentration was the most important parameter affecting bio-H2 production among the three process parameters considered. Finally, a confirmation experiment under optimal conditions yielded 62.5 mL H2/g-VSadded, which was higher than all the bio-H2 yield values obtained in the other conditions tested in this study. The measured and predicted bio-H2 yields in the verification test were also very close to each other, confirming the reliability of the Taguchi method in optimizing the bio-H2 production process.

Environmental impact assessment of organic fraction of municipal solid waste treatment by anaerobic digestion in Sri Lanka.

The management of organic fraction of municipal solid waste (OFMSW) has continued to be a significant challenge in Sri Lanka. Anaerobic digestion is one of the management options of OFMSW. However, it generates unavoidable environmental impacts that should be addressed. The present study focuses to assess the environmental impact of a full-scale anaerobic digestion plant in Sri Lanka from a life cycle perspective. The inventory data were obtained from direct interviews and field measurements. Environmental burdens were found to be in terms of global warming potential (230 kg CO2 eq) ozone formation on human health (6.15 × 10-6 kg NOx eq), freshwater eutrophication (2.92 × 10-3 kg P eq), freshwater ecotoxicity (9.27 × 10-5 kg 1,4 DCB eq), human carcinogenic toxicity (3.98 × 10-4 kg 1,4 DCB eq), land use (1.32 × 10-4 m2 a crop eq) and water consumption (2.23 × 10-2 m3). The stratospheric ozone depletion, fine particulate matter formation, ozone formation on terrestrial ecosystems, terrestrial acidification, marine eutrophication, ecotoxicity (terrestrial and marine), human non-carcinogenic toxicity, mineral resource scarcity and fossil resource scarcity, were avoided due to electricity production. Results show that the direct gaseous emissions and digestate generation should be addressed in order to reduce the burdens from the anaerobic digestion plant. Finally, the results of the study could help in policy formation and decision-making in selecting future waste management systems in Sri Lanka.

Powdered activated carbon amendment in percolate tank enhances high-solids anaerobic digestion of organic fraction of municipal solid waste

Despite many studies recently investigated the addition of conductive materials for enhancing biomethane recovery in anaerobic digestion, there have been limited efforts to adopt this strategy in high-solids anaerobic digestion (HSAD) with percolate recirculation. In this study, two identical lab-scale mesophilic (36 °C) HSAD systems were operated with the organic fraction of municipal solid waste (OFMSW) under similar operating conditions, including food to microorganism ratio and daily percolate recirculation rate. The percolate tank of the test HSAD system was amended with 15 g/L of powdered activated carbon (PAC). After 30 days of operation, the cumulative biomethane yield for the test reactor was 17 % higher than the control reactor (109 vs. 93 L CH4/kg VS). Furthermore, PAC addition showed additional benefits by lowering free ammonia nitrogen (FAN) and volatile fatty acids (VFAs) concentrations that can inhibit anaerobic digestion. Nonetheless, the preliminary economic analysis suggested that the HSAD amended with PAC is practically challenging and will only be economically feasible if PAC can be recycled and reused for the long-term operation or several cycles.

MSW A Potential Energy Resources: A Two Stage Anaerobic Digestio

Present investigation reveals the biodegradability of municipal solid wastes (MSW) in context of Jabalpur city [1] (at 23˚10 North latitude and 79˚57 East longitude, at an altitude of 393 meters above mean sea level) and harnessing energy through two stage anaerobic digestion. A critical study of various process parameters affecting the anaerobic digestion has been analyzed. During the anaerobic digestion of MSW it has been seen that the retention time of the process increases as compared to other waste such as fruits and vegetable waste, cow dung, agricultural residues etc. With the use of suitable bio-methanization technology the twin objectives (a) waste reduction and (b) the environmental problems can be achieved. The present work will help all academicians, rural and urban energy industry people in generating eco-friendly energy and maintaining environment too. In this study the biodegradability of the MSW organic fraction has been tested and in particular a comparison between the production of biogas from landfills and organic wastes in anaerobic conditions has been performed. Two stage digestion of this kind of wastes were proved a better efficiency than single stage digestion.

Silage of the organic fraction of municipal solid waste to improve methane production

The silage of the organic fraction of municipal solid waste (OFMSW) is a common practice in biogas plants. During silage, fermentation processes take place, affecting the later methanisation stage. There are no studies about how OFMSW silage affects methane production. This work aimed to determine the effects of silage (anaerobic acid fermentation) at different solids concentrations and temperatures on methane production. OFMSW was ensiled at 20, 35, and 55 °C with total solids (TS) concentrations of 10, 20, and 28% for 15 days. The ensiled OFMSW was then tested for methane production at the substrate to inoculum ratios (S/I) of 0.5, 1.0, and 1.5. Independently of the temperature, the production of the metabolites during silage increases with decreasing solids concentration. The highest production was of lactic acid, ethanol, and acetic acid, representing together 95% of the total. Methane production from ensiled OFMSW at 10% solids concentration shows, under every tested condition, better methane production than from fresh OFMSW. Ensiled OFMSW produces more methane than fresh OFMSW, and methane production was highest at 35 °C.

Treatment of the Supernatant of Anaerobically Digested Organic Fraction of Municipal Solid Waste in a Demo-Scale Mesophilic External Anaerobic Membrane Bioreactor.

Conventional aerobic biological treatments of digested organic fraction of municipal solid waste (OFMSW) slurries–usually conventional activated sludge or aerobic membrane bioreactor (AeMBR)–are inefficient in terms of energy and economically costly because of the high aeration requirements and the high amount of produced sludge. In this study, the supernatant obtained after the anaerobic digestion of OFMSW was treated in a mesophilic demo-scale anaerobic membrane bioreactor (AnMBR) at cross flow velocities (CFVs) between 1 and 3.5 m⋅s–1. The aim was to determine the process performance of the system with an external ultrafiltration unit, in terms of organic matter removal and sludge filterability. In previous anaerobic continuous stirred tank reactor (CSTR) tests, without ultrafiltration, specific gas production between 40 and 83 NL CH4⋅kg–1 chemical oxygen demand (COD) fed and removals in the range of 10–20% total COD (tCOD) or 59–77% soluble COD (sCOD) were obtained, for organic loading rates (OLR) between 1.7 and 4.4 kg COD⋅m–3reactor d–1. Data helped to identify a simplified model with the aim of understanding and expressing the process performance. Methane content in biogas was in the range of 74–77% v:v. In the AnMBR configuration, the COD removal has been in the ranges of 15.6–38.5 and 61.3–70.4% for total and sCOD, respectively, with a positive correlation between solids retention time (SRT, ranging from 7.3 to 24.3 days) and tCOD removal. The constant used in the model expressing inhibition, attributable to the high nitrogen content (3.6 ± 1.0 g N-NH4+⋅L–1), indicated that this inhibition decreased when SRT increased, explaining values measured for volatile fatty acids concentration, which decreased when SRT increased and OLR, measured per unit of volatile suspended solids in the reactor, decreased. The alkalinity was high enough to allow a stable process throughout the experiments. Constant CFV operation resulted in excessive fouling and sudden trans-membrane pressure (TMP) increases. Nevertheless, an ultrafiltration regime based on alternation of CFV (20 min with a certain CFVi and then 5 min at CFVi + 1 m⋅s–1) allowed the membranes to filter at a flux (standardized at 20°C temperature) ranging from 2.8 to 7.3 L⋅m–2⋅h–1, over 331 days of operation, even at very high suspended solids concentrations (>30 g total suspended solids⋅L–1) in the reactor sludge. This flux range confirms that fouling is the main issue that can limit the spread of AnMBR potential for the studied stream. No clear correlation was found between CFV or SRT vs. fouling rate, in terms of either TMP⋅time–1 or permeability⋅time–1. As part of the demo-scale study, other operational limitations were observed: irreversible fouling, scaling (in the form of struvite deposition), ragging, and sludging. Because ragging and sludging were also observed in the existing AeMBR, it can be stated that both are attributable to the stream and to the difficulty of removing existing fibers. All the mentioned phenomena could have contributed to the high data dispersion of experimental results.

Solid-state anaerobic co-digestion of organic fraction of municipal waste and sawdust: impact of co-digestion ratio, inoculum-to-substrate ratio, and total solids.

Municipal solid waste contains mainly organic wastes that can be a good source for anaerobic digestion. Solid-state anaerobic digestion is an affordable and suitable technique to mitigate the organic fraction of municipal solid waste (OFMSW). However, as the organic loading of OFMSW is high, co-digestion with other materials can improve the system's performance. This study aimed to investigate the performance of the co-digestion of OFMSW and sawdust and study the parameters affecting its performance. Based on the experiments, the optimum sawdust/OFMSW ratio was achieved 1:2 with the methane production of 0.3L/g VS. In addition, the inoculum-to-substrate ration (I/S) was investigated at 1:4, 1:2, 1:1, 2:1 ratios. The best result was obtained at 2:1 ratio with a total methane yield of 0.28 L/g VS. The results also indicated that I/S ratios less than 1:1 led to fatty acid accumulation and acidic pH condition. The effect of total solids content on the co-digestion process was also examined in this study. According to the results, as the total solids increased, the biomethane yield decreased while the biogas content increased.

Locally Available Organic Waste for Counteracting Strawberry Decline in a Mountain Specialized Cropping Area

Crop decline caused by soil borne fungal pathogens affects specialized cropping systems such as fruit trees and strawberry. A study was carried out to investigate the effectiveness of pre-plant application of waste-derived biomasses in strawberry (Fragaria × ananassa) to reduce that phenomenon. A field experiment was carried out in an alpine strawberry specialized valley in South Tyrol (Italy), in a long term cultivated field selected for yield reduction over recent years. In July 2018, one month before strawberry transplanting, a field experiment with four soil treatments was set up: anaerobic digestate (solid fraction) of liquid manure, compost from anaerobic digestate of organic fraction of municipal solid waste (OFMSW), untreated control and Dazomet as chemical control. Plants were grown for two cycles (2019 and 2020). Dazomet always gave a significant (over 50%) increase in marketable yield per plant in both the years, anaerobic digestates did not improve strawberry production; compost from OFMSW gave phytotoxic effects in the first year, but improved strawberry yield like Dazomet in the second. Changes of rhizosphere bacterial populations and difference in root pathogen abundance, especially that of Dactylonectria torresensis, were correlated to the crop response to treatments. Findings suggest that waste-derived biomasses are a promising eco-friendly option for counteracting strawberry yield decline. Their positive impact was mostly linked to functional improvements induced by microbial variations. However, the use of such organic amendment requires careful evaluation of composition, doses and above all application times to reduce phytotoxic effects that in some cases can occur in the first months after application.

Influence of Digester Temperature on Methane Yield of Organic Fraction of Municipal Solid Waste (OFMSW)

This study evaluates the anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) and digested sewage sludge (DSS) at lowered temperatures. AD batch tests for CH4 yield determination were carried out with DSS as inoculum between 23 and 40 °C. All results were related to organic dry matter and calculated for standard conditions (1013 hPa, 0 °C). The AD experiments at 40 °C and at 35 °C delivered specific CH4 yields of 325 ± 6 mL/g and 268 ± 27 mL/g for OFMSW alone. At lower temperatures, specific CH4 yields of 364 ± 25 mL/g (25 °C) and 172 ± 21 mL/g (23 °C) were reached. AD at 25 °C could be beneficial regarding energy input (heating costs) and energy output (CH4 yield). Plant operators could increase AD efficiencies by avoiding heating costs. The co-digestion of OFMSW together with DSS could lead to further synergies such as better exploitation of the energy potentials of DSS, but the digestate utilization could become problematic due to hygienic requirements. Efficiency potentials through lowered operating temperatures are limited. In further research, lowered process temperatures could be applied in the AD of energy crops due to large numbers of existing plants.

Strategies for resource recovery from the organic fraction of municipal solid waste

Rapid population growth and urbanization have led to the generation of huge quantities of municipal solid waste (MSW) in urban areas. The organic fraction of municipal solid waste (OFMSW) represents up to 57 % of the municipal waste generated globally. In the context of accomplishing a bio-based circular economy, resource recovery from OFMSW has become a necessity. This study describes the different technologies that are practically used to recover valuable resources (e.g., bio-oil, biochar, biomethane) from OFMSW, such as anaerobic digestion, composting, hydrothermal carbonization, pyrolysis and landfilling. However, for the successful implementation of these technologies under the local conditions, it is a pre-requisite that these technologies also meet the regulatory requirements and get support and commitment from the national and local governments.

Temperature phased anaerobic digestion (TPAD) of organic fraction of municipal solid waste (OFMSW) and digested sludge (DS): Effect of different hydrolysis conditions

Hydrolysis is the most critical stage in high solids Temperature Phased Anaerobic Digestion (TPAD). In this paper two different Organic Fraction of Municipal Solid Waste (OFMSW) types were tested in co-digestion with Digested Sludge (DS) at different temperatures: 37, 55 and 65 °C. Volatile fatty acids (VFAs), soluble chemical oxygen demand (CODs) and Biochemical Methane Production (BMP) were measured and calculated after 0, 24, 48 and 72 h hydrolysis. The results showed that both the BMP and the methane production rate improved. A Solids Retention Time (SRT) of 72 h at a temperature of 55 °C gave the best results: the reaction rate constant k was 0.34 d-1 and the BMP was 250 mLCH4/gMV, which were 47% and 19% higher compared to the reference (0 h hydrolysis). The CODs and VFAs profiles during hydrolysis showed how OFMSW initial characteristics can affect the performance of temperature phased anaerobic digestion.

Life-cycle modeling of nutrient and energy recovery through mixed waste processing systems

There is increasing interest in recovering nutrients and energy from the organic fraction of municipal solid waste (OFMSW). Given the costs associated with separate collection of OFMSW, and the potential difficulty in finding clean feedstocks, there are potential benefits in beneficial recovery of OFMSW as part of residual MSW. Therefore, this study compared the life-cycle impacts associated with management alternatives for recovering energy and/or nutrients from the OFMSW through mixed waste processing systems. The considered treatment alternatives include landfilling, mass burn waste-to-energy, gasification and syngas combustion (GC) for electricity production, gasification Fischer–Tropsch (GFT) for transportation fuel production, aerobic composting (AC), and anaerobic digestion (AD). Seven environmental impacts include global warming potential (GWP), cumulative energy demand, acidification, eutrophication, photochemical oxidation, ecotoxicity, and human toxicity were assessed for five sets of state and one U.S. national waste compositions. The mass burn waste-to-energy and GC scenarios generally have the lowest environmental impacts, while landfilling and GFT have the greatest impacts. Separating out organics for AC increased environmental impacts compared to sending them to GC, while sending them to AD decreased GWP and increased the other impacts. Sensitivity analyses suggest that these conclusions are generally robust to uncertainty in input values.

Effect of C/N ratio on the PHA accumulation capability of microbial mixed culture fed with leachates from the organic fraction of municipal solid waste (OFMSW)

Activated sludge was submitted to the aerobic dynamic feeding strategy in a Sequencing Batch Reactor (SBR) to evaluate the effect of the carbon/nitrogen (C/N) ratio on the polyhydroxyalkanoates (PHA) accumulation capability. The SBR was operated for 233 days using leachates from the stabilization of the organic fraction of municipal solid wastes (OFMSW) as carbon source, with a Volatile Fatty Acids (VFA) content of 13.95 ± 7.81 g COD/L. The influence of the C/N ratio on PHA accumulation capability was evaluated by supplementing the leachates with acetate or ammonium, then applying C/N ratios within the range of 13.3 to 42.1. Low C/N ratios of 13.3 and 23.3 promoted PHA accumulation in form of polyhydroxybutyrate (PHB), reaching a maximum of 16.8 % stored, whereas the application of the highest C/N ratios led to a reduction on the PHA accumulation capacity, this probably due to an inhibition induced by the high carbon concentration. Moreover, during the experimental period it was observed that the reduction on the respiration activity of the culture, reflected in a decreasing on the Specific Oxygen Uptake Rate (SOUR) from 1.67 down to 0.42 mg O2/g VSS min This phenomenon could be the result of the continuous exposure of the microorganisms to long famine periods as well as the inhibitory effect of specific organic compounds commonly found in leachates. Overall, the PHB production is negatively affected when the MMC is submitted to the operation at high C/N ratios along with long famine periods.

Single-phase anaerobic digestion of the organic fraction of municipal solid waste without dilution: Reactor stability and process performance of small, decentralised plants

Currently, centralised plants are the most favoured approach for the anaerobic treatment of the organic fraction of municipal solid waste (OFMSW). However, centralised solutions imply certain environmental impacts, which prevent large-scale implementation of the anaerobic digestion (AD). As a result, we are digesting <5% of organic waste both in Europe and the USA even today. Pursuing the criteria for maximising the balance between profit and impacts, an innovative layout with the ultimate goal of promoting the use of small, decentralised AD plants is proposed. In this study, source-separated OFMSW (SS-OFMSW) was treated in a mesophilic plug flow reactor by applying an atypical combination of conditions such as high SS-OFMSW solid content (214.5 g·kg−1), high organic loading rate (6.2 kg VS·m−3·d−1), and no dilution or co-substrate addition. A suitable and an efficient mixing system is essential to control the process. Accordingly, the process was stable in a single-stage reactor, in the absence of digestate recirculation, obtaining specific gas production of 0.67 m3·kg−1 VS in terms of biogas and 0.41 m3·kg−1 VS in terms of methane. High reactor volume exploitation and small plant construction were feasible, reaching a gas production rate of 4.5 m3·m−3 d−1. The estimated costs in terms of capital and operating expenditure are expected to realize gross economic sustainability of full-scale installation.

Molecular Characterization of the Organic Fraction of Municipal Solid Waste and Compositional Evolution during Oxidative Processes Assessed by HR-MAS 13C NMR Spectroscopy

The use of high-resolution magic angle spinning (HR-MAS) 13C NMR spectroscopy is proposed here as an innovative and non-destructive approach to investigate the chemical composition of the organic fraction of municipal solid waste (OFMSW) and for monitoring the evolution of their composition during the oxidative iron-based Fenton treatment to which the initial matrix is subjected. The high quality and the good resolution of the 13C HR-MAS NMR spectra allowed an accurate assignment and quantification of the various types of carbon present in the analyzed organic matrix. Moreover, the HR-MAS has also shown its effectiveness in monitoring the different oxidative processes to which the same initially organic matrix has been subjected. The results obtained from the HR-MAS spectra on the collected samples during the different oxidative experiments, indicate that Fenton treatment is able to modify the percentage of the different types of carbons as a function of the concentrations of both Fenton reactants, H2O2 and Fe2+ salt, and of the oxidative process time.

The materials flow and membrane filtration performance in treating the organic fraction of municipal solid waste leachate by a high solid type of submerged anaerobic membrane bioreactor

The anaerobic digestion of leachate from organic fraction of municipal solid waste (OFMSW) is a long-standing challenge. A submerged anaerobic membrane bioreactor (AnMBR) embedding three flat sheet membrane was therefore continuously operated for 63 days to investigate the materials flow and membrane performance. The results obtained show that approximately 90% COD was removed and 86% was converted into methane under an OLR of 5.6 kgCOD/m3·d corresponding to a HRT of 10 days. Under the high solid condition (34.5–61.1 g/L total solids in AnMBR) and flux of 5 and 6 LMH, the membranes was operated practically at constant trans-membrane pressure (TMP). When the membrane was operated at a high flux of 7 LMH the TMP rapid increase occurred in 22 h resulting in a non-recoverable permeability. A sustainable flux was thus identified. This study demonstrated the feasibility of AnMBR treating OFMSW leachate under high solid condition with high flux.