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This study investigated the feasibility of anaerobic digestion (AD) of potato peel waste (PPW) and its lactic acid fermentation residue (PPW-FR) for methane (CH 4 ) production. The experimental results showed that about 60–70% CH 4 content was obtained. The digester using PPW-FR as feedstock exhibited better performance and produced a highest cumulative CH 4 production of 273 L/kg VS fed , followed by 239 L/kg VS fed using PPW under the same conditions. However, with increasing solid loadings of PPW-FR feedstock from 6.4% to 9.1%, the CH 4 production was inhibited. The generation, accumulation, and degradation of volatile fatty acids (VFAs) in digesters were also investigated in this research. [ABSTRACT FROM AUTHOR]

Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8 L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L −1 , solids retention time of 2–4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g −1 PPW and highest productivity of 125 mg g −1 d −1 were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L −1 solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g −1 PPW and a productivity of 138 mg g −1 d −1 were achieved with a 1 d SRT. [ABSTRACT FROM AUTHOR]

Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g −1 , 0.06 g g −1 , and 0.05 g g −1 . The highest LA concentration of 14.7 g L −1 was obtained from a bioreactor with initial solids loading of 60 g L −1 at 35 °C. [ABSTRACT FROM AUTHOR]

• Successful extrusion of torrefied paper-plastic waste blends. • Extrusion of torrefied waste blend reduced variability by a factor of 7. • The plastic layer formed around the extruded fiber prevents water absorption. • The extent of torrefaction influences the combustion properties. With the continued growing U.S. population, solid waste generation will increase, which will lead to undesired and significant growth in landfilling. Thermal treatment can turn these high calorific value wastes into fuels that can be used in small-to-large power plants. This article focuses on using blends with 40% plastic and 60% fiber wastes and converting them into densified solid fuel by torrefaction and extrusion. The material was torrefied at 300 °C to obtain torrefied samples with different mass losses, ranging from 0% to a maximum of 51%. The torrefaction results showed a clear synergy between plastics and fibers. The torrefied material was then extruded into 9 mm diameter rods and the products were characterized by molecular functional group analysis, thermomechanical analysis, dynamic mechanical analysis, dynamic rheological measurement, density measurement, flexural testing, water absorption test, size distribution measurement, heat content test, and combustion test. The fiber content in the material decreased as mass loss increased, and the process reduced significantly the variability of the material. The heat content increased as the mass loss increased. The plastic in the feedstock acted as a process enabler as it imparted properties like bindability, water resistance, high heat content, and increased degradation reaction rate. [ABSTRACT FROM AUTHOR]