Cultivation of Chlorella sorokiniana using wastewaters from different processing units of the silk industry for enhancing biomass production and nutrient removal

Abstract

ABSTRACTBackgroundPrevious studies have documented that searching for wastewaters with appropriate nutrient profiles to cultivate microalgae directly was an effective measure to reduce the cost of algae cultivation. In this work, wastewaters collected from different processing units of the silk industry were used to cultivate Chlorella sorokiniana directly or after preliminary pretreatment for producing algal biomass and removing nutrients.ResultsThe data showed that C. sorokiniana could grow on reeling wastewater and cooking cocoon wastewater with a maximum biomass of 0.26 and 0.49 g L−1, respectively, but could not grow on frigon wastewater because of high salinity and turbidity. Furthermore, the binary mixed wastewaters were used to cultivate this alga, which were mixed according to the algal nutritional requirements. Results indicated that the highest algal biomass (0.56 g L−1), and total nitrogen and phosphorus removal efficiencies (71.7% and 97.1%) were obtained when frigon wastewater was diluted with reeling wastewater (v/v) at a dilution multiple of eight, which was used as the algal culture media. Additionally, contents of protein, lipids, carbohydrates, and pigments in the algal cells varied with the changes in nutrient profiles of wastewaters.ConclusionsIt is concluded that (i) reeling wastewater and cooking cocoon wastewater were rich in nutrients for the growth of C. sorokiniana, which could be used as algal culture medium directly; and (ii) growing C. sorokiniana on mixed wastewaters could enhance biomass production and nutrient removal. Thus, the silk industry wastewaters could be considered as suitable media to cultivate microalgae directly or by simply mixing. © 2019 Society of Chemical Industry