scholarly journals Improvement of Biomethane Production from Organic Fraction of Municipal Solid Waste (OFMSW) through Alkaline Hydrogen Peroxide (AHP) Pretreatment

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 197
Author(s):  
Alessio Siciliano ◽  
Carlo Limonti ◽  
Giulia Maria Curcio

The organic fraction resulting from the separate collection of municipal solid waste (OFMSW) is an abundant residue exploitable for biofuel production. Anaerobic digestion (AD) is one of the most attractive technologies for the treatment of organic wastes thanks to the generation of biogas with a high methane content. However, because of its complex composition, the direct digestion of OFMSW can be less effective. To overcome these difficulties, many pretreatments are under development. In this work, the efficacy of alkaline hydrogen peroxide (AHP) oxidation was assessed for the first time as a pretreatment of OFMSW to enhance its anaerobic biodegradability. In this regard, many AHP batch tests were executed at pH 9 and by changing the peroxide dosages up to 1 gH2O2/gCOD, under room temperature and pressure conditions. Afterwards, biomethane potential tests (BMP) were conducted to evaluate the performance of anaerobic digestion both on raw and pretreated OFMSW. The pretreatment tests demonstrated that AHP induces only a weak reduction in the organic load, reaching a maximum COD removal of about 28%. On the other hand, notable productions of volatile fatty acids (VFA) were found. In fact, by applying a peroxide dose of just 0.025 gH2O2/gCOD, there was a doubling in VFA concentration, which increased by five times with the highest H2O2 amount. These results indicate that AHP mainly causes the conversion of complex organic substrates into easily degradable compounds. This conversion made it possible to achieve much better performance during the BMP tests conducted with the pretreated waste compared to that carried out on fresh OFMSW. Indeed, a low methane production of just 37.06 mLCH4/gTS was detected on raw OFMSW. The cumulated CH4 production in the pretreated samples increased in response to the increase in H2O2 dosage applied during AHP. Maximum specific productions of about 463.7 mLCH4/gTS and 0.31 LCH4/gCODremoved were calculated on mixtures subjected to AHP. On these samples, the satisfactory evolution of AD was confirmed by the process parameters calculated by modeling the cumulated CH4 curves through a new proposed formulation of the Gompertz equation.

Author(s):  
Alessandra Cesaro ◽  
Valentina Cieri ◽  
Vincenzo Belgiorno

Abstract Anaerobic digestion (AD) is a well-established process for the treatment of a wide variety of solid organic substrates, including the organic fraction of municipal solid waste (OFMSW). At industrial scale, the mechanical pretreatment is a fundamental step to reduce OFMSW particle size and to promote the hydrolysis within the subsequent AD process. Among the mechanical pretreatment technologies, press-extrusion has recently raised great interest for its possible application to either enhance the organic load to the digester or improve the overall process stability and methane yields. Aim of this study was in assessing the potential of the press-extrusion pretreatment to improve the performance of OFMSW anaerobic degradation. Batch tests were set up according to a full factorial design of experiments to assess the significance of the main operating parameters. The statistical analysis of results addressed further tests, carried out under semi-continuous feeding mode, to better discuss the possible application of press-extrusion for the greatest valorization of OFMSW under anaerobic conditions.


Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 195
Author(s):  
Elena Rossi ◽  
Simone Becarelli ◽  
Isabella Pecorini ◽  
Simona Di Gregorio ◽  
Renato Iannelli

The aim of this study is to investigate the performance of a pilot-scale plug-flow reactor (PFR) as a biorefinery system to recover chemicals (i.e., volatile fatty acids (VFAs)), and biogas during the dry thermophilic anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). The effects of the hydraulic retention time (HRT) on both outputs were studied, reducing the parameter from 22 to 16 days. In addition, VFA variation along the PFR was also evaluated to identify a section for a further valorization of VFA-rich digestate stream. A particular focus was dedicated for characterizing the community responsible for the production of VFAs during hydrolysis and acidogenesis. The VFA concentration reached 4421.8 mg/L in a section located before the end of the PFR when the HRT was set to 16 days. Meanwhile, biogas production achieved 145 NLbiogas/d, increasing 2.7 times when compared to the lowest HRT tested. Defluviitoga sp. was the most abundant bacterial genus, contributing to 72.7% of the overall bacterial population. The genus is responsible for the hydrolysis of complex polysaccharides at the inlet and outlet sections since a bimodal distribution of the genus was found. The central zone of the reactor was distinctly characterized by protein degradation, following the same trend of propionate production.


2021 ◽  
pp. 0734242X2110134
Author(s):  
Rasangika Thathsaranee Weligama Thuppahige ◽  
Sandhya Babel

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 NO x 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.


2019 ◽  
Vol 11 (7) ◽  
pp. 3293-3301
Author(s):  
Mingyu Qian ◽  
Ye Zhou ◽  
Yixin Zhang ◽  
Zhenxin Wang ◽  
Ruihua Li ◽  
...  

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