Biodegradable Fraction Of Municipal Solid Waste Research Articles

Coproduction of hydrogen, butanol, butanediol, ethanol, and biogas from the organic fraction of municipal solid waste using bacterial cocultivation followed by anaerobic digestion

An integrated bioprocessing approach was applied to enhance energy recovery from the biodegradable fraction of municipal solid waste (BFMSW). Clostridium acetobutylicum and Enterobacter aerogenes with complementary characteristics were cocultivated for coproduction of hydrogen, 2,3-butanediol, and acetone-butanol-ethanol (ABE). Following the fermentation process, the remaining solids were used for biomethane production. The BFMSW was first subjected to ethanolic organosolv pretreatment and then enzymatic cellulose and hemicellulose hydrolysis at 5 and 8% solid loadings. The glucose (328 g/kg raw BFMSW), xylose (37.8 g/kg raw BFMSW), and starch (152.1 g/kg raw BFMSW) portions of the pretreated BFMSW hydrolysate with 5% solid loading were cofermented to hydrogen (162.8 L/kg raw BFMSW), 2,3-butanediol (42.5 g/kg raw BFMSW), butanol (121.9 g/kg raw BFMSW), ethanol (38.9 g/kg raw BFMSW), and acetone (45.2 g/kg raw BFMSW) by the coculture, and subsequently, the residual unfermented solids were further digested to biomethane (31.7 L/kg raw BFMSW). From the bioenergy perspective, 311.8 mL gasoline equivalent (10 MJ energy) was obtained from each kg of raw BFMSW, indicating the potential of the integrated fermentation-anaerobic digestion bioprocess for biofuels production from the zero-cost substrate.

Food Waste Valorization Based on Anaerobic Digestion

The rapid urbanization that took place in the last 60 years has led to a dramatic increase in the generation of Municipal Solid Waste (MSW). The biodegradable fraction of MSW mainly consists of food waste (FW) and corresponds to about 50% of the total MSW. The disposal of FW in the environment has become a significant challenge. On the other hand, FW is an excellent substrate for anaerobic digestion (AD). This manuscript reviews the different AD technologies for the treatment of FW. Different types of bioreactors and pretreatment methods used to enhance methane production through AD of FW are discussed. The current review gives special emphasis on the methods for biogas upgrading and on technologies for FW digestate valorization. Food waste valorization through anaerobic digestion offers a wide variety of options in all process steps. From the pre-treatment of the feedstock and the selection of the suitable anaerobic digestion technology to the configuration of the process based on the desired products and the valorization of the generated digestate, the design of an integrated anaerobic digestion plant is a challenging task, which necessitates a systematic design. A systematic approach is necessary for FW valorization. The simple single-stage AD process leads to underutilization of the feedstock. There are plenty of available technologies that could be combined for the development of an integrated biorefinery that will be optimized in terms of FW valorization towards the production of biofuels and high-added value products, while introducing a circularity in the nutrients contained in the FW. FW-to-biofuel conversion technologies are high Technology Readiness Level (TRL—9) technologies and anaerobic digestion is applied worldwide at commercial scale.

Synergistic combination of pyrolysis, anaerobic digestion, and CHP plants.

The anaerobic digestion of biodegradable fraction of municipal solid waste (MSW) is a widely used process for biogas production. However, the biodegradable fraction of MSW also contains lignocellul ...

Municipal solid waste as a suitable substrate for butanol production as an advanced biofuel

The biodegradable fraction of municipal solid waste (BMSW), dominantly composed of starchy and lignocellulosic materials, has high potential to be used for liquid biofuel production. Hot water or dilute acid treatment at high temperature was utilized for the solubilization or hydrolysis of the starch fraction and pretreatment of the lignocellulosic fraction. The treatment liquor, which was rich in sugars and starch, was evaluated for acetone, butanol, and ethanol (ABE) production by Clostridium acetobutylicum, and it was found that phenolic compounds, especially tannins, critically inhibited the butanol production. To improve ABE production, the extraction of phenolic compounds prior to hot water or dilute acid treatment was evaluated. Among the evaluated extractants, i.e., acetone, ethanol, butanol, and water, ethanol showed the highest amount of tannin extraction, resulting in an 87% reduction in tannin content. Dilute acid treatment of the ethanol extracted BMSW at 140 °C for 60 min resulted in a liquor containing 23 g/L glucose and 41 g/L soluble starch, which was fermented to the highest ABE concentration of 17 g/L with productivity of 0.24 g/L/h. The fermentation of liquor obtained by dilute acid treatment of butanol, acetone, and water-extracted BMSW was accompanied by 9, 6, and 4 g/L ABE production. Even by hot water treatment, the liquor obtained from ethanol extracted BMSW was fermented to the highest ABE concentration of 8 g/L. In addition to the liquor, the pretreated lignocellulosic material was subjected to enzymatic hydrolysis and ABE fermentation, leading to production of 5–6 g/L ABE. This process resulted in the production of 83.9 g butanol, 36.6 g acetone, and 20.8 g ethanol from each kg of BMSW. Moreover, the co-production of ethanol by ABE fermentation reduced concerns about organic extractor loss in the extraction process, which was inescapable in the tannin extraction process.

Nondestructive characterization of the contaminated biodegradable fraction of municipal solid waste using synchrotron radiation-induced micro-X-ray fluorescence

Synchrotron radiation-induced micro-X-ray fluorescence (SR-μXRF) was employed to elucidate the elemental characteristics of contaminated biodegradable fraction of municipal solid waste (BFMSW). Six sectioned BFMSW samples were selected for SR-μXRF mapping and 50 individual fine particles sorbed onto BFMSW were analyzed using SR-μXRF point scanning. The results showed that heavy metals tended to be concentrated on the surface of BFMSW and highly localized to some “hot-spots”. Marked differences in heavy metal sequestering potentials among various kinds of BFMSW, and the significant role of heavy metal “hot-spots” in BFMSW contamination were identified. The lower heavy metal levels in the simulated samples compared to field samples (with longer and more intense mixing) indicated that inter-contamination during waste handling contributed significantly to heavy metal accumulation in BFMSW. Furthermore, additional information regarding elemental characteristics of individual particles could be acquired using SR-μXRF.