Organic Fraction Of Municipal Solid Waste Research Articles

Fe3O4 nanoparticles facilitated anaerobic digestion of organic fraction of municipal solid waste for enhancement of methane production

ABSTRACTSince the emergence of zero waste concept, efficient waste recycling system and recovery of energy from the waste materials become challenging tasks globally. Municipal solid waste (MSW) is considered as one of a potential sources of energy. In the present study, bio-compactable iron oxide (Fe3O4) nanoparticles (NPs) were synthesized by hydrothermal method. These NPs were characterized by using atomic force microscopy (AFM), energy dispersive x-ray (EDX), and scanning electron microscopy (SEM) for size determination and surface morphology. The organic fraction of MSW (OFMSW) such as food waste (FW) was utilized as a substrate in this study. The anaerobic digestion of OFMSW in batch test was carried out under mesophilic temperature (37 ± 0.5°C). Four different concentrations of Fe3O4 NPs i.e 50mg/L, 75mg/L, 100mg/L, and 125mg/L were added in each batch test. It was observered that 75mg/L yielded maximum CH4 and followed by 50mg/L.

Selective VFA production potential from organic waste streams: Assessing temperature and pH influence

This study explored the volatile fatty acid (VFA) production potential of seven waste streams from urban and agroindustrial sources. For that purpose, batch assays were performed under acidic (pH 5.5) and alkaline (pH 10) conditions at both mesophilic (35°C) and thermophilic (55°C) temperature. Overall, the VFA yield was influenced by temperature, and it was positively affected by pH, ranging between 220 and 677mgCODg−1CODfed for liquid waste streams and between 127 and 611mgCODg−1CODfed for solid waste streams and urban sludge. The highest VFA concentration and highest VFA/sCOD ratio was obtained during the organic fraction of municipal solid waste (OFMSW) fermentation, with 8,320mgCODL−1 and 94% at alkaline pH and mesophilic temperature. The results of this study suggest that selective VFA production, i.e. via propionic, butyric and acetic acid production, might be feasible for scaling-up purposes with specific waste streams by adjusting the process parameters.

Benefits to decomposition rates when using digestate as compost co-feedstock: Part I – Focus on physicochemical parameters

Anaerobic digestion (AD) has gained a significant role in municipal solid waste management, but managing a high volume of digestate is one of the challenges with AD technology. One option is to mix digestate with fresh and/or stabilized organic waste and then feed to the composting process. In this study, the effect of co-composting anaerobic digestate (in different quantities) on a composting process was investigated. The digestate was prepared in a pilot-scale 500L high solids dry anaerobic digester and composting was completed in eight 25L reactors with different ratios of digestate to fresh feedstock from the organic fraction of municipal solid waste (OFMSW). The digestate constituted 0, 10, 20, 30, 40, 50, 75, or 100% (wet mass) of the feedstock. The co-composting experiment was conducted in two phases: active aeration and curing. Monitored parameters included: process temperature, aeration rate, oxygen concentration of the outlet gas, mass changes, total solids, organic matter, pH, and electrical conductivity. In addition, respirometry, C:N ratio, ammonium to nitrate ratio, and Solvita® tests were used to quantify stability and maturity end points. The results showed that the addition of digestate to the OFMSW increased composting reaction rates in all cases, with peak performance occurring within the ratio of 20–40% of digestate addition on a wet weight basis. Reactor performance may have been influenced by the high total ammonia nitrogen (TAN) levels in the digestate. Composting rates increased as TAN levels increased up to 5000 TAN mgkg−1DM; however, TAN may have become inhibitory at higher levels.

Assessing the public perception of islanders regarding the implementation of new technologies to optimize the municipal solid waste management system: A Mediterranean case study

One of the most important contemporary challenges for small islands is to make more sustainable human activities as the management of municipal solid waste (MSW). The recent EGADI project involved the realization of two pilot project actions in a small Mediterranean island of Southern Italy (Island of Favignana) with the goal to adapt the current MSW management system to the logic of the 3Rs approach (reduce, reuse & recycle). The actions concerned the installation of a water kiosk to reduce plastic waste production and a community composter to recover material from the organic fraction of MSW. Additionally, non-structural actions as a communication plan and an environmental education campaign were implemented with the intent of increasing public awareness on the addressed topics. In this context, the study was aimed to investigate the public perception and knowledge of islanders with reference to the two pilot actions before and after the implementation of such activities so as to provide guidance for optimizing the MSW management system of the island. A structured questionnaire was implemented and administered to the students of a secondary school and their parents before and after the implementation of the planned actions. The obtained data were processed by using descriptive statistics and Multiple Correspondent Analysis (MCA) in order to achieve a global view on the level of knowledge and public perception as well as to establish as a whole, the rate of satisfaction and the goodness of the project actions. The feedbacks on the implemented actions were critically discussed highlighting both positive and negative aspects. Some drawbacks were to be connected to the adopted communicative plan which resulted to be not so effective in reaching the target since its random character. Islanders perceived positively the new technologies implemented. The water kiosk was perceived positively if it only serves residents. Furthermore, islanders positively perceived the kerbside separate collection preferring at the same time the community composting as strategy for the management of the organic fraction, at least in the most densely populated areas. The social assessment that was conducted during the investigation provided guidance of the optimum MSW management system of the island.

Advantages and drawbacks of OFMSW and winery waste co-composting at pilot scale

The winemaking industry produces large volumes of waste which can be recycled and valorized. This study evaluates the advantages and drawbacks of valorizing skins, seeds and stalks from the processing of grapes for the production of Pedro Ximenez wine through co-composting with the organic fraction of municipal solid waste (OFMSW). The ratio of a mixture of both wastes was evaluated. According to the evaluation of the aerobic biodegradability of OFMSW and winery waste (WW) independently, a mixture ratio of 50:50% w/w was determined to be the best option. A slight decrease in the biodegradability of the OFMSW-WW mixture (40%) with respect to the biodegradability of OFMSW was found. Although the biodegradability of OFMSW-WW was lower than that of OFMSW, the co-composting of WW with OFMSW presented numerous advantages: the physico-chemical variables of WW were improved, the heavy metal content of the mixture was adequate during the composting process and corresponded to a compost type A with the exception of the Cd content. Furthermore, the odor emissions produced during the co-composting process were lower than those produced by OFMSW composting carried out under similar conditions. Consequently, co-composting might be a suitable alternative for recycling and valorizing winery waste, with the consequent environmental benefits.

The efficacy of an anaerobic digester-based biogas production from various feedstocks

ABSTRACTThe management of municipal solid waste has always been a problem for both developed and developing countries. The proper management of waste resources can improve resource efficiency as well as develop a suitable substitute for fossil fuels. A number of management options are available, but biogas recovery using anaerobic digestion is often recommended as an attractive option. Biogas production potential varies from source to source. This work focuses on wastewater sludge, organic fraction municipal solid waste (OF-MSW), and co-digestion of both wastewater sludge and OF-MSW. The digestion was performed at an optimum temperature of 36°C. The primary objective of this study was to determine and evaluate different factors such as temperature, pH, and nitrogen concentration and its influence on biogas production.

Biosurfactant-enhanced hydrogen production from organic fraction of municipal solid waste using co-culture of E. coli and Enterobacter aerogenes

The effect of biosurfactants (surfactin and saponin) on the hydrogen production from organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. The biosurfactants were applied in the concentration ranges of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 5.0% each. Cumulative hydrogen production (P), maximum hydrogen production rate (Rmax) and lag phases (λ) were analyzed using modified Gompertz model. Results revealed that both the biosurfactants were effective in hydrogen production enhancement. The maximum cumulative hydrogen production of 743.5±14.4ml and 675.6±12.1ml and volumetric hydrogen production of 2.12LH2/Lsubstrate and 1.93LH2/Lsubstrate was recorded at 3.5% surfactin and 3.0% saponin respectively. Corresponding highest hydrogen yields were 79.2mlH2/gCarboinitial and 72.0mlH2/gCarboinitial respectively. Lag phase decreased from 12.5±2.0h at control to a minimum of 9.0±2.8h and 9.5±2.1h at 3.5% surfactin and 3.0% saponin respectively. Volatile fatty acid generation was increased with biosurfactants addition.

Biochar-enhanced hydrogen production from organic fraction of municipal solid waste using co-culture of Enterobacter aerogenes and E. coli

In the present study, biochar has been used to enhance hydrogen production from organic fraction of municipal solid waste (OFMSW) using co-culture of Enterobacter aerogenes and E. coli. Biochar facilitates biofilm formation and efficient colonization of microbes on its large surface area. Biochar was also analyzed for its ammonia mitigation potential. Cumulative hydrogen production, maximum hydrogen production rate and lag phases were analyzed using modified Gompertz model. Maximum overall hydrogen yield of 96.63 ± 2.8 mlH2/gCarboinitial and a maximum of 53.3 ± 1.0% COD removal were achieved at biochar concentration of 12.5 g/L. Biochar addition shortened lag phase from 12.5 ± 0.6 hr at control with nil biochar to 8.1 ± 0.5 hr with 12.5 g/L biochar and improved hydrogen production rates. The validation experiment with ammonia addition without biochar supplementation resulted in decreased hydrogen production. When biochar was supplemented in addition to ammonia, hydrogen production was increased in all the experimental batches. Results revealed that biochar can mitigate ammonia inhibition along with hydrogen enhancement. Biochar addition also increased volatile fatty acid generation.

New criteria to determine the destabilization of the acidogenic anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW) with mixed sludge (MS)

Effect of hydraulic retention time (HRT) on bio-hydrogen production from co-digestion of organic fraction of municipal solid waste (OFMSW) and mixed sludge (MS) in dry thermophilic conditions (55°C and 20% total solids) was investigated. A decreasing sequence of six HRTs, from 2.9 to 0.8-days, was performed to evaluate the stability of the system and the influence of HRT on the organic matter solubilization, the daily hydrogen production (HP) and the specific hydrogen production (SHP).Best results were obtained operating at 1.2-days HRT: HP of 3.67L H2/Lreactor/day, SHP of 33.8mL H2/gVSadded and hydrogen percentage in biogas of 52.4%. However, HRTs lower than 1.2-days induce failure in the system due to an unbalance of the hydrolytic phase. This fact was corroborated through the evaluation of two indirect parameters, “non-solubilized carbon” (NSC) and “acidogenic substrate as carbon” (ASC), and the relationships of NSC/TOC and ASC/TOC.

Inhibition of the Hydrolytic Phase in the Production of Biohydrogen by Dark Fermentation of Organic Solid Waste

In this paper, a destabilization episode in a semicontinuous dry thermophilic acidogenic reactor was induced. The reactor was fed with different mixtures of organic fraction of municipal solid waste (OFMSW) and food waste (FW). The aim was to determinate the effect of the organic loading rate (OLR) and cosubstrate ratio on biohydrogen production by dark fermentation. OLR was increased from 21.0 to 88.8 g TVS/L/day testing three mixture ratios (OFMSW:FW) from 80:20 to 50:50 and four hydraulic retention times (HRTs; 6.6, 4.4, 2.4, and 1.9 days). Results have shown that an increment in the OLR (from 21.0 to 59.8 g TVS/L/day) and FW proportion (from 80:20 to 50:50) improves the yield process in terms of solubilized organic matter. However, from 50:50 ratio combined with OLRs higher than 70.3 g TVS/L/day and HRTs lower than 4.4 days showed a clear destabilization episode due to an imbalance of the hydrolytic phase. This fact has been corroborated by the values of two indirect parameters, “nonsolubilized carbon...

The effect of temperature, storage time and collection method on biomethane potential of source separated household food waste

The aim of this study was to mimic real conditions for storage and transport and to evaluate how much of the biomethane potential is lost before the organic fraction of municipal solid waste (OFMSW) from households in Sweden reaches the biogas plant. The laboratory biomethane potential (BMP) experiments was carried out with respect to the storage time, collection method (paper or plastic bag) and storage temperature (22°C and 6°C) in order to evaluate the effect of these factors on the biomethane potential.A recipe representative for OFMSW from households in Sweden was designed with the help of literature and modification of recipes from technical reports and scientific literature. Laboratory experiments showed that the difference in the BMP of OFMSW stored in plastic- compared to paper bags were obvious at 22°C with a lower biomethane potential for paper bags, but there was no difference at 6°C. Provided that the loss of organic matter during pre-treatment is equivalent for both paper and plastic bags it is possible to get more biomethane from OFMSW collected in plastic bags during the warmest part of the year, since they have a more preservative effect on OFMSW than paper bags.This could be explained by the plastic bags being denser than paper and therefore maintain the volatile organic compounds inside the bag and promote a pre-hydrolysis of the material rather than aerobic degradation.

Production of Caproic Acid from Mixed Organic Waste: An Environmental Life Cycle Perspective.

Caproic acid is an emerging platform chemical with diverse applications. Recently, a novel biorefinery process, that is, chain elongation, was developed to convert mixed organic waste and ethanol into renewable caproic acids. In the coming years, this process may become commercialized, and continuing to improve on the basis of numerous ongoing technological and microbiological studies. This study aims to analyze the environmental performance of caproic acid production from mixed organic waste via chain elongation at this current, early stage of technological development. To this end, a life cycle assessment (LCA) was performed to evaluate the environmental impact of producing 1 kg caproic acid from organic waste via chain elongation, in both a lab-scale and a pilot-scale system. Two mixed organic waste were used as substrates: the organic fraction of municipal solid waste (OFMSW) and supermarket food waste (SFW). Ethanol use was found to be the dominant cause of environmental impact over the life cycle. Extraction solvent recovery was found to be a crucial uncertainty that may have a substantial influence on the life-cycle impacts. We recommend that future research and industrial producers focus on the reduction of ethanol use in chain elongation and improve the recovery efficiency of the extraction solvent.

Impact of furan derivatives and phenolic compounds on hydrogen production from organic fraction of municipal solid waste using co-culture of Enterobacter aerogenes and E. coli

In the present study, the effect of furan derivatives (furfural and 5-hydroxymethylfurfural) and phenolic compounds (vanillin and syringaldehyde) on hydrogen production from organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. The inhibitors were applied in the concentration ranges of 0.25, 0.5, 1, 2 and 5g/L each. Inhibition coefficients of phenolic compounds were higher than those of furan derivatives and vanillin exhibited maximum inhibition coefficients correspondingly lowest hydrogen yield among all inhibitors. Furfural and 5-hydroxymethylfurfural addition resulted in an average decrease of 26.99% and 37.16% in hydrogen yield respectively, while vanillin and syringaldehyde resulted in 49.40% and 42.26% average decrease in hydrogen yield respectively. Further analysis revealed that Furfural and 5-hydroxymethylfurfural were completely degraded up to concentrations of 1g/L, while vanillin and syringaldehyde were degraded completely up to the concentration of 0.5g/L. Volatile fatty acid generation decreased with inhibitors addition.

Performance Evaluation of Microbial Fuel Cells Fed by Solid Organic Waste: Parametric Comparison between Three Generations

Abstract In this paper, the results of three generations of reactors for the direct conversion of the Organic Fraction of Municipal Solid Waste (OFMSW) in electrical energy are presented. The different generations corresponds to the prototype realized in the Energy Lab of the University of Naples “Parthenope” and have been monitored along a period of over three years in terms of polarization and power curves, in order to assess the feasibility of Microbial Fuel Cell as a promising source for future, sustainable energy generation.

Stimulation of the anaerobic digestion of the dry organic fraction of municipal solid waste (OFMSW) with carbon-based conductive materials

Growth of bacterial and archaeal species capable of interspecies electron exchange was stimulated by addition of conductive materials (carbon cloth or granular activated carbon (GAC)) to anaerobic digesters treating dog food (a substitute for the dry-organic fraction of municipal solid waste (OFMSW)). Methane production (772–1428mmol vs <80mmol), volatile solids removal (78%–81% vs 54%–64%) and COD removal efficiencies (∼80% vs 20%–30%) were all significantly higher in reactors amended with GAC or carbon cloth than controls. OFMSW degradation was also significantly accelerated and VFA concentrations were substantially lower in reactors amended with conductive materials. These results suggest that both conductive materials (carbon cloth and GAC) can promote conversion of OFMSW to methane even in the presence of extremely high VFA concentrations (∼500mM).

Forecasting and analysis of biogas-based power production using extremal neural network

ABSTRACTThe primary objective of this study is to design an efficient and robust method to predict the power production from the anaerobic digester by taking into consideration various factors and feedstocks (organic fraction municipal solid waste, wastewater sludge, and co-digestion). This study focuses on the influence of primary factors such as temperature, pH, and nitrogen concentration on power production. Extremal neural network tool was developed with the assistance of MATLAB programming to predict the power production. The results showed that this approach is trustworthy enough to predict the energy output with respect to the primary variables mentioned above. It is expected that this new prediction model will improve the biogas productivity and contribute significantly to energy production. Moreover, this design has an economic advantage in processing.

Centralized management of sewage sludge and agro-industrial waste through co-composting

In this research study, the co-composting process of a waste mixture containing strawberry extrudate, fish waste, sewage sludge and bulking agent (SEFW, 190:1:22:90 ratio) was carried out in a dynamic-solid respirometer at pilot scale. The aerobic biodegradability of the mixture was previously ensured in a static-liquid respirometer. The advantages and drawbacks of the SEFW co-composting process were subsequently identified through the determination of respirometric activity and the physical-chemical characterization of the waste, as well as the monitoring of odor emissions. The evolution of the physical-chemical variables showed that pH increased slightly and that the organic matter concentration, expressed as volatile solids (VS, %) or oxidable organic carbon (COXC, %), decreased by around 15% in both cases and by approximately 56% in its biodegradable form (total organic carbon, TOC, %). The low odor emission rate (OER) in the least favorable scenario (the maximum odor generation) during SEFW composting was 1.59 ouE/s, whereas this figure reached 3.52 ouE/s when only the organic fraction of municipal solid waste (OFMSW) was composted. Consequently, the co-composting of SEFW is more favorable in terms of odor emission and permits the simultaneous treatment of different types of waste.

LCA Analysis of Different MSW Treatment Approaches in the Light of Energy and Sustainability Perspectives

This study concerns with a theoretical investigation on the disposal and valorisation of Municipal Solid Waste (MSW) through a challenging approach, based on the separation of MSW into two different fractions: Refuse Derived Fuel (RDF) and Organic Fraction Municipal Solid Waste (OFMSW). Both fractions are energetically valorised through gasification and anaerobic digestion (AD) processes respectively, in both cases gas streams were burned to produce electrical and thermal energy. The sustainability of the processes from the environmental as well as the energetic point of view, has been pursued, to find out if it can represent a viable alternative to the problem raised by the management of MSW and their landfill containment. Following the Life Cycle Analysis (LCA) approach, each stream of the processes has been analyzed in order to evaluate the environmental performances. On the other hand, the energy sustainability analysis has been carried out following the evaluation of two indexes: the Energy Sustainability Index (ESI) and the Energy Return of Investment (EROI). Results highlight that this process is more sustainable than landfill technology, in particular for global warming, photochemical oxidation and eutrophication impact parameters of CML2001, and categories connected with Human Heath of Eco-indicator99 method; the comparison with traditional landfill option shows that the environmental impacts are less than 10%. The proposed MSW treatment approach is less sustainable than landfill for only two categories: acidification/eutrophication and minerals. In merit to the energy sustainability analysis, the system results to have a positive merit: it produces a surplus of Useful Energy.

Effect of Fe0 addition on volatile fatty acids evolution on anaerobic digestion at high organic loading rates

Excessive acidification frequently occurs in the anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) at high organic loading rates (OLR), due to the accumulation of non-acetic volatile fatty acids (VFA). In this study, the performance of Fe0 in enhancing various VFA production and metabolism was investigated. The butyric acid concentration in a high OLR reactor with Fe0 addition decreased from 7200 to 0mg/L after a short lag phase, and the total VFA (TVFA) concentration also decreased substantially. The corresponding dominant acidogenesis type also changed from butyric type to propionic type fermentation. Furthermore, the CH4 yield of the reactor with added Fe0 was approximately 595ml CH4/g VSadded, which was an increase of 41.7% compared with the biochemical methane potential (BMP) test results in controls without added ZVI. A microbial diversity analysis, using high throughput sequencing, showed that Methanofollis and Methanosarcina were dominant in terms of the archaeal structures of the Fe0 reactor at the butyric converting stage; however, Methanosaeta was predominant in the reactor during the control BMP test. These results suggested that Fe0 can convert non-acetic VFA to acetic VFA and improve the CH4 yield by enhancing the activity of methanogens.

Energy Contribution of OFMSW (Organic Fraction of Municipal Solid Waste) to Energy-Environmental Sustainability in Urban Areas at Small Scale

Urban waste management is one of the most challenging issues in energy planning of medium and large cities. In addition to the traditional landfill method, many studies are investigating energy harvesting from waste, not as a panacea but as a foreseeable solution. Thermo-chemical conversion to biogas, or even bio-methane under certain conditions, could be an option to address this challenge. This study focuses on municipal solid waste conversion to biogas as a local energy supply for the cities. Three urban models and their subdivision into urban areas were identified along with a typical Organic Fraction of Municipal Solid Waste (OFMSW) matrix for each urban area. Then, an energy analysis was carried out to provide an optimization map for an informed choice by urban policy-makers and stakeholders. The results highlighted how the urban context and its use could affect the opportunity to produce energy from waste or to convert it in fuel. So, in this case, sustainability means waste turning from a problem to a renewable resource.