Organic Fraction Of Municipal Solid Waste Research Articles

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.

Competitive sorption and desorption of cadmium, lead, and zinc onto peat, compost, and biochar

Soil and water contamination by potentially toxic metals (PTMs) has exerted adverse environmental impacts, which justifies studies of promising remediation alternatives. This article investigated the competitive sorption of cadmium (Cd), lead (Pb), and zinc (Zn) onto peat, compost, and biochar derived from the organic fraction of municipal solid waste (OFMSW), but its main innovation was the post-sorption assessment. The effects of contact time on competition between contaminants were systematically analyzed by batch experiments and the effectiveness of the sorption process was evaluated in desorption tests (H2O, HCl, NaOH, and NaCl) and sequential extraction. Kinetic data were well-fitted to pseudo-first-order (PFO) and pseudo-second-order (PSO) models and the intra-particle diffusion model revealed the existence of multiple linear regions, indicating the sorption process was controlled by a multi-step mechanism. The sorption capacities followed a biochar > compost > peat order, with biochar retaining more than 99% of Cd, Pb, and Zn in all samples. The general order of desorption percentage was peat > compost > biochar, with a below 0.60% biochar release, suggesting the importance of chemical processes. HCl solution (more acid pH) showed the highest release of previously sorbed contaminants and, therefore, can be employed for the reuse of sorbents (sorption/desorption cycles). The only exception was Pb desorption on biochar, with maximum release in NaOH solution. A negative Pearson correlation with F1 (acid-soluble/exchangeable fraction) for Cd and Zn and a positive one with the other steps were reported. Pb exhibited an opposite behavior, showing the highest sorption performances and the lowest desorption rates for all sorbents, justified by positive correlations with F4 (residual fraction) and negative ones with desorption. The findings suggest the evaluated sorbents, especially compost and biochar, can be effective materials in the simultaneous sorption of Cd, Pb, and Zn in wastewater, as well as an amendment for PTMs immobilization in contaminated soils.

Valorisation of eyewear bioplastics through HTC and anaerobic digestion: Preliminary results

Bioplastics are increasingly replacing traditional plastics in many sectors, but the legislative and operative frameworks for their disposal remain unclear: they should be collected and treated together with the organic fraction of municipal solid waste (OFMSW), but often do not biodegrade satisfactorily in the plants that treat OFMSW. This work focuses on a type of cellulose diacetate employed in the eyewear industry to analyse hydrothermal carbonization (HTC) as a pre-treatment before anaerobic digestion (AD). The results show that HTC can hydrolyse this bioplastic even at moderate temperatures, reaching an almost total dissolution in the liquid phase at 210 °C and, at higher temperatures, producing hydrochar. When the HTC slurry obtained at 210 °C is fed to mesophilic or thermophilic AD, both the amount and the production rate of biogas are enhanced compared to the raw bioplastic. In particular, in thermophilic conditions, the amount of produced biogas undergoes at least a threefold increase compared to the untreated cellulose diacetate. Thus, this work confirms that a prior HTC step may be a suitable approach to enhance the disposal and energy recovery of bioplastics through AD.

Effects of adding micro- and nano-sized biomass fly ash on two-stage biohythane production from the urban organic solid waste

In this work, the effect of ash particle size on the sequential production of bioH2 and bioCH4 for biohythane recovery from the organic fraction of municipal solid waste (OFMSW) was investigated for the first time using micro- and nano-sized biomass fly ash (FA). In the first hydrogenogenic stage, the highest bioH2 yield of 215 mL/g VSadded was noticed in the reactor added with micro-sized FA. On the contrary, in the second methanogenic stage, the maximum bioCH4 yield of 676 mL/g VSadded was witnessed in the reactor fed with acidogenic effluent containing nano-sized FA. In the integrated two-stage process, the addition of FA with nano-sized particles showed superiority over micro-sized FA supplementation and led to an increase of about 582 and 595% in organic matter conversion and energy yield, respectively, compared to the control test, as well as achieving biohythane with an optimal hydrogen content of 15% v/v.

The fate of biodegradable plastic during the anaerobic co-digestion of excess sludge and organic fraction of municipal solid waste

Co-digestion of the organic fraction of municipal solid waste (OFMSW) and excess sludge has several benefits especially related to improved methane production and better process stability. In recent years, the presence of biodegradable plastics is increasingly common in OFMSW especially since, as in Italy, biodegradable bags are used for its collection. In this paper, the influence and the fate of biodegradable bags during anaerobic co-digestion of excess sludge and OFMSW are assessed. The best results in terms of methane yield (about 180 NmL/gVS) have been obtained with the 50:50 (VS basis) co-digestion of excess sludge and OFMSW with an organic loading rate of 2 kgVS/m3·d. Bioplastic degradation is very limited during the co-digestion but it does not influence methane production or digestate chemical characteristics. However, the feeding of bioplastic bags seems to induce a higher phytotoxicity and the presence of undigested fragments is anyway a problem for further treatment or direct utilization of digestate.

Removal of H2S from Biogas Using Thiobacillus sp.: Batch and Continuous Studies

Anaerobic digestion produces biogas which usually contains 60-70% of methane (CH4), 30-40% of carbon-di-oxide (CO2), and 10-2,000 ppm hydrogen sulfide (H2S). The concentration of H2S depends upon the type of substrate. H2S tends to corrode pipes and machines carrying them. The high concentrations of H2S present in biogas may adversely affect electricity generation. Hence, the removal of H2S and enrichment of biogas with CH4 is an essential step towards higher energy production. In the present study, the biological method of removing H2S using Thiobacillus sp. was demonstrated for a one cu.m anaerobic co-digestion (ACD) unit running on an organic fraction of municipal solid waste (OFMSW) and septage sludge. Initial lab scale studies were conducted by collecting the biogas generated from 1 cu.m digesters, and continuous experiments were optimized for the process parameters such as flow rate, the volume of medium with culture, time, the height of the column, column composition, etc. The raw biogas was purged in a liquid medium (LM) with a culture containing Thiobacillus sp. The studies with the LM containing Thiobacillus sp. culture showed a 68% removal of H2S in the first 8 min, and the saturation occurred at 75 min when the time-dependent experiment was studied. The smaller flow rate (0.48 L.min-1) and highest volume of culture (500 mL) showed better results than other parameters. The highest and average oxidation rates of sulfate were recorded as 39 and 40.3 ppm.sec-1, respectively, for 0.48 L.min-1 flow rate and 500 mL of the culture volume. In the column studies, a column containing cocopeat (CP) was studied for its efficiency in removing H2S. At a flow rate of 0.9 L.min-1, 25% adsorption was encountered and reached saturation at 90 min. The bed height of 9 inches with CP and plastic support (PS) showed a 20% H2S removal. The filling ratio of CP and PS (1:1) was the best ratio for proper gas passage with optimal time for adsorption/absorption. The kinetic, isotherm, and continuous models helped to understand the capacity of the adsorbent. Freundlich, Yoon-Nelson, and BDST model were best fit for the present study. A pilot scale setup for one cu.m biogas reactor showed an average of 50% removal of H2S for LM with culture, and an additional 20% removal was possible by the introduction of a column along with the liquid bed in series. An overall efficiency of 70-75% of H2S removal was achieved. No significant CH4 loss was encountered during the study.

Effect of Mineral or OFMSW Digestate Fertilization on Ryegrass and Nitrogen Leaching

The current guidelines of waste management are aimed at the recovery and recycling of biowaste while respecting the protection of human health and the environment. The recent European legislation on fertilizers provides for the use of digestates derived from the organic fraction of municipal solid waste (OFMSW). The objectives of this study were to verify the fertilizing effect of three types of OFMSW digestates on the ryegrass culture comparing mineral fertilization and to evaluate the nitrogen lost to leaching in soil diversely fertilized following simulated rainfall. The ryegrass was grown in pots. The soil was fertilized with mineral fertilizer or OFMSW digestates. For each treatment, five mowing procedures were performed on the crop, and the ryegrass biomass production and nitrogen concentration were determined from the ryegrass samples. During the experiment, six rains were simulated, and the leached nitrogen was analyzed. The results showed that: (i) the fertilizing effect of OFMSW digestates on nitrogen nutrition of ryegrass was similar to ammonium sulphate fertilization, confirming the agronomic validity of these by-products to reduce the use of synthetic fertilizers; (ii) soil fertilization with OFMSW digestates had a positive effect limiting nitrogen loss due to leaching compared to mineral fertilization, highlighting the soil-improving properties of these by-products, in particular of the composted digestate.

Environmental impact scenarios of organic fraction municipal solid waste treatment with Black Soldier Fly larvae based on a life cycle assessment

Biowaste treatment with Black Soldier Fly (BSF) larvae is an alternative option for organic waste valorization. Its environmental impacts should be assessed and compared with conventional treatment options. The research aims to evaluate the treatment of organic fraction of municipal solid waste (OFMSW) with BSF larvae through a life cycle assessment (LCA). This study employed data inventories from literature and aimed to provide a wide range of production parameter values to identify the potentialities of BSF treatment in the best-case and worst-case scenarios. The SimaPro9, the database Ecoinvent3.5, and the impact assessment method IMPACT 2002+ have been employed for the analysis. A sensitivity analysis of relevant parameters was conducted, considering the avoided impacts that can be obtained thanks to the exploitation of larvae proteins for bioplastics or fishmeal production. Research findings highlight six main environmental impact indicators: respiratory inorganics (kg PM2.5-eq), ozone layer depletion (kg CFC-11-eq), terrestrial ecotoxicity (kg TEG soil), land occupation (m2 organic arable), global warming (kg CO2-eq), and non-renewable energy (MJ primary). The most relevant process generating impacts is BSF breeding, followed by boiling, storage, and OFMSW treatment. The environmental performance is better when the conventional fishmeal substituted, thanks to BSF larvae production, is made from areas 10,000 km far, implementing a 100% renewable energy scenario, reducing the energy consumption by 50%, increasing the lifespan of the equipment to 15 years, and products are employed locally. The current study represents the first attempt to evaluate the global higher or lower environmental impact scenario related to OFMSW treatment through BSF larvae.Graphical

Application of Doehlert design in optimizing the solid-state hydrogenogenic stage augmented with biomass fly ash in a two-stage biohythane production process

This study aimed to optimize the solid-state hydrogenogenic stage supplemented with biomass fly ash in a two-stage anaerobic digestion (AD) process for biohythane production from the organic fraction of municipal solid waste (OFMSW). Doehlert’s experimental design was used to obtain the optimal set of two investigated variables, namely total solids (TS) content and biomass fly ash dosage in the defined ranges of 0–20 g/L and 20–40%, respectively. Applying the optimal conditions of TS content (29.1%) and fly ash dosage (19.2 g/L) in the first stage led not only to a total H2 yield of 95 mL/gVSadded, which was very close to the maximum H2 yield predicted by the developed model (97 mL/gVSadded), but also to a high CH4 yield of 400 mL/gVSadded (76% of the theoretical CH4 yield). Moreover, the biohythane obtained from the optimized two-stage process met the standards of a biohythane fuel with an H2 content of 19% v/v.

Development of an electrochemical membrane bioreactor for succinic acid production and in situ separation with engineered Yarrowia lipolytica cultivated on municipal biowaste hydrolysate

A novel electrochemical membrane bioreactor (EMB) integrating succinic acid (SA) production and in situ separation in the anode compartment through an anion exchange membrane was employed in fed-batch fermentations with Y. lipolytica PSA02004 using hydrolysates from the organic fraction of municipal solid waste (OFMSW) as feedstock. The initiation of electrolysis cell operation and the reduction of pH from 6 to 5.5 at 30 h in a 6.7 L bioreactor improved the SA production efficiency, resulting in 66.7 gSA/L, 0.51 g/g yield, 0.78 g/(L·h) productivity, high coulombic efficiency (66.2%) and relatively low electricity consumption for SA separation (2.6 kWh/kgSA). The recirculation of the fermentation broth in the cathode compartment and the OH– produced by water reduction reduced NaOH consumption (35.4%) for pH control during fermentation. The fermentation was efficiently replicated in a 30 L bioreactor with a low membrane surface area (100 cm2) electrolysis cell, but it failed with a higher membrane surface area (702 cm2) electrolysis cell indicating that yeast cell viability, cell design and EMB configuration are important aspects for process scale-up. SA crystals were purified, at 99.95% purity and 95% yield, from the anolyte solution via activated carbon treatment, evaporation, crystallization and drying. Cell removal via centrifugation and acidification stages were not required as in conventional SA purification processes. The produced SA crystals were suitable for the production of polyester polyols for polyurethane urea dispersions applications.

Effect of Leached and Co-Composted Organic Fraction of Municipal Solid Waste with Bulking Agents on Soil Properties and Sweet Pepper Plant Development Under Calcareous Soil

ABSTRACT Composting of the organic fraction of municipal solid waste (OFMSW) and its utilization for agriculture has gained great popularity all over the world. However, the safe use of municipal solid waste compost (MSWC) in agriculture has been regarded with skepticism because of concerns over the possibility of excessive salt content. A field experiment was conducted to evaluate the effect of the leached and co-composted OFMSW with wheat straw (WS) and wood shaving (WSH) as bulking agents (BAs) on soil properties and sweet pepper performance. Six mixtures of compost were prepared including; T1= (OFMSW), T2= (OFMSW+WS) and T3= (OFMSW+WSH). The last three piles, where OFMSW was subjected to leaching (L), including: T4= (LOFMSW), T5= (LOFMSW+WS) and T6= (LOFMSW+WSH). The compost was applied to the field at rates of 0, 40, and 80t/ha alone, as well as in a combination with NPK fertilizer. Plant growth and quality parameters were improved with the addition of compost containing BAs. The application of leached compost significantly reduced (P < .001) electrical conductivity (EC) and sodium (Na) in the soil. Most of the growth and yield plant parameters were increased at a compost rate of 40 t/ha + NPK. Increasing compost rates combined with NPK increased EC, and soil available nitrogen (N), potassium (K), phosphorus (P), and sodium (Na), while soil organic matter (SOM) increased with compost alone. Soil pH was lowered with increasing compost + NPK. Overall, findings suggest that applying leached compost with BAs could provide better results on soil and plant.

A biorefinery platform to valorize organic fraction of municipal solid waste to biofuels: An early environmental sustainability guidance based on life cycle assessment

The biorefining of biowastes, specifically the organic fraction of municipal solid waste (OFMSW), into biofuels and high-value products is an energy-demanding process, still immature, and largely dependent on the process configuration and efficiency of employed microorganisms. Such issues might undermine the environmental sustainability of the biorefinery by inducing adverse impacts on human health, ecosystem quality, climate change, and resources, which need to be explored before the process scale-up. Hence, this study was performed as early sustainability guidance to investigate the environmental impacts of different biorefinery platforms for biofuels production from OFMSW. More specifically, three pretreatment methods (i.e., acetone organosolv, acid, and hot water), two hydrolysis treatments (i.e., acidic and enzymatic), and two fermentation alternatives (i.e., ethanolic fermentation and acetone-butanol-ethanol (ABE) fermentation) were investigated. Based on European Commission's Joint Research Center instruction, the environmental impacts were studied using consequential life cycle assessment for the macro-level decision context. The results demonstrated that ABE fermentation scenarios were not environmentally favorable because the avoided impacts from final products were not significant enough to compensate for the induced environmental burdens from acetone pretreatment. On the contrary, the ethanolic fermentation scenarios with either acid or hot water pretreatment outperformed both ABE fermentation and ethanolic fermentation with acetone pretreatment. Based on the results, the scenario including simultaneous dilute acid pretreatment and hydrolysis of OFMSW followed by ethanolic fermentation manifested the best performance in all damage categories, as compared to those including acetone pretreatment or higher consumption of enzymes. Such improvements in this scenario led to the highest net saving of −842 potentially disappeared fraction (PDF)/m2/yr, −249.95 kg CO2 eq, and −3275.22 MJ primary per ton of OFMSW on ecosystem quality, climate change, and resources, respectively, and the lowest net burden of 1.54 × 10-5 disability-adjusted life years (DALY) per ton of OFMSW on human health. The results of sensitivity analysis on this scenario demonstrated that the substitution of excess heat for marginal heat with fossil origin can considerably decrease impacts on human health.

Valorization of biogas from the anaerobic co-treatment of sewage sludge and organic waste: Life cycle assessment and life cycle costing of different recovery strategies

Nowadays, biogas produced from the anaerobic digestion of biowaste is considered a valuable renewable energy source to implement the transition to a climate-neutral society. Recently, biogas upgrading to biomethane, instead of the usual co-generation of heat and electricity (CHP), has been an attractive option, as biomethane can be used for different purposes. This study performed the life cycle assessment (LCA) and life cycle costing (LCC) of different scenarios for the valorization of the biogas produced from the anaerobic co-digestion (AcoD) of secondary sewage sludge (SS) and organic fraction of municipal solid waste (OFMSW), pre-treated by an anaerobic dark co-fermentation (DF) process. Four configurations were compared, exploring the recovery of one or more of the following: heat, electricity and biomethane. Furthermore, two sensitivity analyses were performed on LCA analysis, considering the use of the produced biomethane as a fuel for transport and the European electricity mix expected by 2050, respectively. The use of biogas for CHP was the most environmentally friendly solutions in 8 out of 11 impact categories provided by the CML-IA baseline method; however, biogas upgrading-based scenarios showed less impacts in relevant categories, such as global warming potential (up to −1.14E+05 kg CO2 eq. y−1) and ozone layer depletion potential (up to −4.73E-01 kg CFC-11 eq. y−1). Sensitivity analyses confirmed that the biogas upgrading processes should have generally a lower impact on climate change than CHP systems. Furthermore, the use of biomethane to replace petrol resulted to be the best option in terms of global warming potential (up to −5.67E+05 kg CO2 eq. y−1). All the proposed configurations represented economically sustainable projects, as they reported positive net present values (NPV) in 20 years (up to 10,518,291 €). Biogas upgrading-based scenarios showed the highest NPVs; nevertheless, the combined production of heat, electricity and biomethane was the most cost-effective option, thanks to biomethane revenues and electricity sales, despite the latter being modest. In conclusion, contrary to most of the previous studies in the literature, we found that CHP should not be neglected, as the optimal configuration may lie in the combined recovery of biomethane, electricity and heat.

Experimental and modelling optimisation of sustainable techniques for the pre-treatment of the organic fraction municipal solid waste to improve anaerobic digestion

The study investigated and compared the anaerobic digestion (AD) of real organic fraction municipal solid waste (OFMSW) prior pre-treated with four types of pre-treatments: mechanical, thermal, hydrodynamic-cavitation (HC), and ultrasound (US). The tested pre-treatments and AD configurations were selected through Design of Experiments and then regression models were built to find the most promising configurations in terms of biogas production and energetic sustainability of the whole process. The novelty of the research is the simultaneously study of the working conditions of the pre-treatments; and AD parameters like the two origins of the inoculum, its incubation time, and the substrate: inoculum ratio (SI).The results demonstrated that the best configurations of pre-treatments and AD were the ones performed with thermal pre-treatment at 120 °C for 45 min (with inoculum incubation of 10 d at substrate: inoculum (SI) ratio of 2:1) and HC at 55 °C (with inoculum incubation of 10 d at SI of 3:1). The thermal, and to some extent the mechanical pre-treatment, evidenced as significant the interaction between the pre-treatment time and the inoculum incubation time. AD of US-OFMSW achieved the lowest performances since inhibition occurred, probably due to the lignocellulosic inhibitors release after ultrasound pre-treatment.

Supplemental Sewage Scum and Organic Municipal Solid Waste Addition to the Anaerobic Digestion of Thickened Waste Activated Sludge: Biomethane Potential and Microbiome Analysis

Sewage scum (SS) is collected from sedimentation tanks in wastewater treatment plants (WWTPs). Despite its huge biogas potential, there is limited information on its potential as a co-substrate and microbial ecology, especially during anaerobic co-digestion (ACo-D) of the organic fraction of municipal solid waste (OFMSW) and thickened waste activated sludge (TWAS). In this biomethane potential (BMP) study, the bioenergy yield achieved by the supplemental addition of SS and OFMSW to TWAS was investigated, along with the microbial ecology. Compared with the digestion of TWAS alone, which produced 184.6 mLCH4 gVS−1, biomethane yield was enhanced by as much as 32.4–121.6% in trinary mixtures with SS and OFMSW, mainly due to the positive synergistic effect. Furthermore, a mixture of 40%SS + 10%TWAS + 50%OFMSW produced the highest biogas yield of 407 mLCH4 gVS−1, which is proof that existing WWTPs can produce additional energy by incorporating external bioresources, thereby reducing greenhouse gas emissions. Modified Gompertz and logistic function estimates showed that methane production rate improved by as much as 60% in a trinary mixture compared with the digestion of TWAS alone. The genus Methanosaeta, capable of generating methane by the acetoclastic methanogenic pathway among all the archaeal communities, was the most prominent, followed by hydrogenotrophic methanogen Methanospirillum.

Wet Anaerobic Codigestion of Sewage Sludge and OFMSW in Pilot-Scale Continuously Stirred Tank Reactors: Focus on the Reactor Microbial Communities

Dark fermentation (DF) is a simple method for hydrogen (H2) production through the valorization of various organic wastes that can be used as feedstock. In particular, an organic fraction of municipal solid waste (OFMSW) is a fermentation substrate that can easily be gathered and provides high yields in biogas and value-added organic compounds such as volatile fatty acids (VFAs). DF is coupled with a methanogenic reactor to enhance biogas production from the OFMSW. In this study, a two-stage reactor was conducted and monitored to optimize the methane yield by reducing the HRT at the DF reactor. A focus of the functional inference based on a next-generation sequence (NGS) metabarcoding analysis and comparison of microbial communities that populate each reactor stage was performed. Concerning gas quality, the two-stage system observed a hydrogen-rich biogas in the first fermentative reactor (on average 20.2%) and an improvement in the methane content in the second methanogenic digester, which shifted from 61.2% obtained for the one-stage experiment to 73.5%. Such increases were due to the improvement in substrate hydrolysis. As for the specific biogas production, the results showed an overall increase of 50%.

Anaerobic co-digestion of yard waste, food waste, and pig slurry in a batch experiment: An investigation on methane potential, performance, and microbial community

Anaerobic co-digestion (ACoD) of organic fraction of municipal solid waste (OFMSW) appears to be an efficient approach for biomethane production. This study conducted ACoD of yard waste (YW), food waste (FW), and pig slurry at varying percentages of YW, and the corresponding evolution of microbial community structure was observed. The results demonstrated that methane productivity increased with decreasing YW content. After 45 days, the system with 20%YW feedstock had the highest productivity with a maximum cumulative methane yield of 368.6 ± 21.6 mL/gVS. Interestingly, our findings revealed important cellulose-degrading bacteria like Ruminofilibacter, Pantoea, and Blvii28 wastewater-sludge group, along with acetoclastic and hydrogenotrophic methane producers like Methanosaeta and Methanoculleus, respectively. The microbial community profile is a potential guideline for microbial enrichment to produce high-efficiency inoculum for biomethane production from yard, agriculture, and livestock waste.

Techno-Economic Assessment of APS-Based Poultry Feed Production with a Circular Biorefinery Process

Poultry livestock profitability significantly depends on feed, accounting for 60–70% of the total production cost, of which protein sources are among of the most expensive ingredients. The maintenance of profitability while meeting feed demand and reducing the environmental impact represents a considerable challenge driving research of alternative protein sources (APS), such as insects and algae meals. This study employs, for the first time, techno-economic assessment (TEA) methodology to evaluate the technological performance and the industrial feasibility of an APS-based poultry feed production method based on the valorization of the pre-treated organic fraction of municipal solid waste (OFMSW) as a substrate for Hermetia illucens larval growth and microalgae cultivation. The Excel-based analysis, which evaluated the mass and energy balance as well as the income statement, was integrated with a thematic analysis focused on exploring how the overall value attributed to the sustainability concept is reflected in the willingness to adopt sustainable business models by entrepreneurs in the poultry sector. Despite the ability to generate revenues, the model cannot be said to be profitable for animal feed production due to the strong dependence of its profitability on scale economy logics. Enabling solutions could be derived from the recovery of abandoned infrastructures, government financial incentives, and integrated systems associating OFMSW treatment with poultry farming, thus resulting in marked economic sustainability and profitability: key elements from the poultry entrepreneurs’ point of view.

Trace metal fate in soil after application of digestate originating from the anaerobic digestion of non-source-separated organic fraction of municipal solid waste

Introduction: Digestate originating from anaerobic digestion of non-source-separated organic fraction of municipal solid waste (OFMSW) is produced abundantly worldwide and generally discarded in landfills. However, it can be a valuable resource for many bioeconomy strategies as land restoration, only if a consolidated understanding of the contaminants’ presence and behaviour in digestate-amended soil is achieved. This study aimed to investigate the fate of trace metals, namely Zn, Cu, Pb, and Cr found in the digestate, along the soil profile after digestate application on soil, and the influence that other contaminants as pharmaceutical compounds can have on their behaviour in the soil system.Methods: For that, a 90-day soil column experiment was conducted using a fine loamy sand soil topped with a layer of digestate-amended soil. Digestate-amended soil had a soil to digestate proportion of 14 to 1 (dry weight). Two experimental conditions were tested: soil amended with digestate, and soil amended with digestate spiked with the antidiabetic drug metformin. Soil samples were taken at 4 depths on days 1, 7, 21, 35 and 90, and total trace metals concentrations and fractionation were determined via atomic absorption spectroscopy.Results: Results showed that Zn, Cu, Pb ad Cr initially present in the digestate were transferred from the digestate-amended soil layer to the underlying soil layer over time, although in low amounts. Nevertheless, no transfer was detected to the deeper soil layers. Trace metals in soil were predominantly in immobile and less bioavailable forms associated with clay and silicate mineral groups, whereas in the digestate-amended soil they were in more bioavailable forms, which could be related to metals’ migration in the soil layers below. Results also show that the presence of metformin had no influence on trace metal behaviour, giving insight also on possible interactions with other potentially present contaminants as microplastics.Conclusion: The current study showed that OFMSW digestate can be a promising organic nutrient-rich matrix for land restoration even if it may contain high metals’ concentrations because low metal mobility along the soil profile can be expected.

Energy production potential of organic fraction of municipal solid waste (OFMSW) and its implications for Nigeria

&lt;abstract&gt; &lt;p&gt;The issue of climate change and management of municipal solid waste (MSW) necessitates transition to renewable energy, including bioenergy. This work assessed energy production from organic fraction of municipal solid waste (OFMSW) in the thirty-six state capitals and Federal Capital Territory (FCT), Abuja, Nigeria. Secondary research method (qualitative and quantitative analysis) was adopted. The four valorization methods considered were incineration, anaerobic digestion (AD), landfill gas-to-energy (LFGTE) and densification. MSW and OFMSW generation rate (kg/cap/day) for the thirty-six state capitals and the FCT, Abuja were obtained. The paper estimated that about 4.7 million tons per year (TPY) of OFMSW is generated in the 37 cities. Daily OFMSW generation ranges from 10416 tons per year (TPY) in Damaturu, to 1.6 million TPY in Lagos. The estimates show that about 1.82 billion Nm&lt;sup&gt;3&lt;/sup&gt; of biogas could be obtained from anaerobic digestion (AD) of OFMSW generated in the cities each year; about 984 Gg (1085688 tons) of methane can be recovered from the landfill gas technology, while drying and densification will produce about 1.82 million tons of solid fuel. Based on secondary sources, the cost per ton waste and emissions (kg/ton) processed were also presented.&lt;/p&gt; &lt;/abstract&gt;