Optimization of compost fermentation of glycerol by-product discharged from biodiesel fuel production process

Abstract

Development of a cheap system for reuse of glycerol by-product discharged from the biodiesel fuel (BDF) production process is needed in parallel with development of a low-cost BDF production system. In this article, optimization of compost fermentation of glycerol by-product was studied. The type and amount of additive nitrogen source was studied, and good utilization of glycerol was observed when 0.5 g of urea was added to a mixture of 625 g dry sawdust, 25 g of microbial seed, and 50 g of glycerol by-product. To achieve effi cient compost fermentation, repeated batch fermentation was applied and fi ve batch cultures were repeated. Although the pH level and nitrogen and water contents were maintained at suitable levels for microbial growth, the glycerol consumption rate gradually decreased with accumulation of oily compounds in the compost. Finally, a material cost evaluation of the compost fermentation proposed in this study was performed. The total material cost decreased to ¥0.57 /l of BDF when employing an existing compost system for the fermentation process, although sawdust used for mushroom cultivation was used in this study at the very high cost of ¥123 /kg dry sawdust. However, the cost of disposal of the glycerol byproduct as an industrial waste was ¥5.2 /l of BDF produced; therefore, there might be an economical advantage to compost fermentation of glycerol by-product from BDF production.

Valorization of mushroom by‐products: a review

“…However, in the case of biogas produced from mushroom by‐products, mechanical pretreatments (such as grinding or ultrasonic treatment) consume more energy than the energy (methane) they produce, which may result in the cost for pretreatments ultimately being higher than the effective return 98 . Sawdust used for mushroom cultivation was at a very high cost of $19.31 99 . It is therefore necessary to optimize the factors affecting biogas production in the future research to meet the economic feasibility of industrial production.…”

“…98 Sawdust used for mushroom cultivation was at a very high cost of $19.31. 99 It is therefore necessary to optimize the factors affecting biogas production in the future research to meet the economic feasibility of industrial production. Moisture, calorific value and ash content should be considered when using SMS as an energy substance.…”

Heat production from biological wood oxidation

“…Apart from the suggestions indicated in this thesis, there are also other recommendations to improve the BWO performance, such as addition of readily organic matters like glucose or glycerol (Jang et al, 2002;Sadano et al, 2010). It was reported that the certain amount addition of these readily degradable organic matter could improve the number of microorganisms and resulted in a further increase the degradation of the indigenous substrates (Meng et al, 2021).…”