Treatment of different dairy wastewater with Chlorella sorokiniana: removal of pollutants and biomass characterization

Abstract

BACKGROUND: There is a continuous need for the development of novel processes for the sustainable management of dairy wastewater. The use of microalgae for wastewater decontamination and production of valuable biomass seems a promising alternative; however, limited information currently exists on the chemical characteristics of the biomass cultivated in effluents from the dairy industry. In this paper, experiments were carried out with the microalga Chlorella sorokiniana and different types of dairy effluents (raw dairy wastewater, anaerobically treated dairy wastewater, cheese whey). The collected biomass was characterized for the existence of proteins, starch, lipids, lutein, ⊎-carotene, polyphenolic compounds and amino acids.RESULTS: The removal of chemical oxygen demand and NH 4 -N was higher than 91% and 80%, respectively, for all types of dairy effluents, while the removal of total phosphorus ranged between 20% and 84%. The protein, starch and lipid contents of the microalgal biomass ranged between 28.6% and 52.8%, 10.5% and 13.3%, and 36.8% and 40.2%, respectively. The concentration of lutein increased after treatment, reaching values up to 508 mg kg −1 , whereas amino acid concentrations were decreased due to nitrogen inefficiency. The biomass cultivated in anaerobically treated dairy wastewater was characterized by the higher total phenolic content; tyrosol concentration reached 20.2 mg kg −1 . CONCLUSION: Chlorella sorokiniana can efficiently remove the major pollutants from effluents of dairy industry, while the produced biomass is a source of proteins, carbohydrates and lipids. Additionally, it contains important amounts of pigments, phenolic compounds and amino acids. Further research is required for the conditions that achieve optimal biochemical characteristics of the produced biomass.

Microalgae, Seaweeds and Aquatic Bacteria, Archaea, and Yeasts: Sources of Carotenoids with Potential Antioxidant and Anti-Inflammatory Health-Promoting Actions in the Sustainability Era

“…These studies are mainly focused on the removal of pollutants and the production of low-value compounds, such as biofuel, bioethanol, or animal feed. An example of this is the cultivation of Chlorella vulgaris and Chlorella sorokiniana in wastewater from milk processing, dairy wastewater, or wastewater from the wine industry that obtains large amounts of lipids, mainly palmitic, oleic, and linoleic acids [ 189 , 190 , 191 ]. Arthrospira platensis (Spirulina) was also grown in an anaerobic digestion effluent containing Cu 2+ and Zn 2+ , and the obtained biomass was used as feed for animals [ 192 ].…”

Agro-Industrial Wastewaters for Algal Biomass Production, Bio-Based Products, and Biofuels in a Circular Bioeconomy

“…In experiments conducted with Chlorella sorokiniana UTEX 1230 (CCAP, Oban, UK), the microalgae were gradually adapted to medium-strength DW digestate for eight weeks. For another six weeks, the proportion of wastewater was increased from 10% to 90% in order to finally use the undiluted effluent [111].…”

A novel experimental and machine learning model to remove COD in a batch reactor equipped with microalgae

“…Also, empirical correlations are proposed to find the best ranges of operating conditions for both residual COD and COD removal. By using artificial neural networks, there is no need to describe the phenomena involved in the process mathematically, and it can be useful in simulating and increasing the scale of complex biological systems (Iliopoulou et al 2022).…”