Pig Slaughterhouse Wastewater: Medium Culture for Microalgae Biomass Generation as Raw Material in Biofuel Industries

Abstract

Microalgae are photosynthetic microorganisms with high lipid content, capable of degrading nutrients from wastewater. In this research, two strains of microalgae, Scenedesmus sp. and Chlorella vulgaris were cultivated in sterilized pig slaughterhouse wastewater using outdoor flat photobioreactors. Cell growth, total lipids, free fatty acids (FFA), fatty acid methyl esters (FAME) and physicochemical parameters of wastewater were measured. The results indicated that pig slaughterhouse wastewater is adequate to grow these species of microalgae, obtaining a higher biomass growth for Scenedesmus sp. compared to Chlorella vulgaris (0.41 g/L vs. 0.2 g/L); additionally, these species can be used in bioremediation processes due to the nutrient removal achieved in terms of Total Nitrogen (TN), Total Phosphorous (TP) and Total Organic Carbon (TOC). Methylcyclohexane, chloroform: methanol (1:2) and ethyl acetate had better yield of lipids and FFA. The percentages of FAMEs from FFA were in the range of 52.5–89.5 wt% for Scenedesmus sp. and for Chlorella vulgaris from 52–80.5 wt%. Although the values of lipids, FFA and FAME are below of the range reported by other authors, the use of this type of wastewater as culture medium for the two species cannot be ruled out for lipid extraction in biofuel production.

Simultaneous Phycoremediation and Lipid Production by Microalgae Grown in Non-Sterilized and Sterilized Anaerobically Digested Brewery Effluent

“…Scenedesmus sp. accumulated a similar content of lipids when it was cultivated in brewery effluent (this study), pig slaughterhouse wastewater [65], municipal wastewater [66], and institutional wastewater [27]. However, Silambarasan et al [67] reported a higher lipid content of 33% for Scenedesmus sp.…”

“…Furthermore, the lipid content variation in Scenedesmus sp. may be due to the extracting solvent used in the given study [65]. Generally, wastewater utilization for microalgae growth generally enhances the sustainability of lipid production from microalgal biomass and its subsequent conversion into biodiesel.…”