Sugar Beet Processing Wastewater Treatment by Microalgae through Biosorption

Abstract

The aim of this study was to investigate the potential of environmental pollution reduction of sugar beet processing factory wastewater by the biorefinery approach and integration of microalgae biomass production. In the present study, Chlorella vulgaris was cultivated in wastewater collected from a sugar beet processing factory at the beginning and at the end of a sugar plant campaign in an aerobic bioreactor on a laboratory scale under controlled conditions, with an air flow of 0.4 L/min, a temperature of 26 °C, and pH = 8. Microalgae showed effective nutrient remediation from wastewater. During wastewater treatment, chemical oxygen demand (COD) and biological oxygen demand (BOD) removal efficiency was 93.7% and 98.1%, respectively; total organic carbon (TOC) content decreased by 95.7%. Nitrites and nitrates decreased by 96%, while the biggest decrease in metal ions was achieved for Ca and Mn (82.7% and 97.6%, respectively). The findings of this study suggest that coupling microalgae cultivation and wastewater treatment has a lot of potential for reducing contamination through biosorption, while also providing environmental advantages.

Harnessing Extremophilic Trait and Metabolic Flexibility of Microalgal Strains for the Treatment of Highly Alkaline Winery Wastewater

“…17,18 If ammonia becomes the main nitrogen source for microalgae during wastewater treatment, it may lead to a significant decrease in pH and inhibition of microalgal growth due to an extremely acidic environment. 8 Thus, the growth rates of microalgae are strongly influenced by the availability of dissolved inorganic carbon in the culture medium. 17 Although highly alkaline environments are inhospitable to most organisms, certain extremophilic microorganisms can adapt and thrive under such harsh conditions 19−21 and thus serve as an excellent bioresource for value-added applications.…”

Biotreatment of discarded fruit juices and simultaneous lipid production using Leptolyngbya sp.

“…15 Bio-treatment with microalgae (including cyanobacteria) is particularly appealing due to their ability to convert solar energy into useful biomass via photosynthesis 16 and their capacity to incorporate nutrients, such as nitrogen and phosphorus, that can otherwise cause eutrophication. 17 Additionally, microalgae can release O 2 during photosynthesis, reduce CO 2 emissions, and thus, significantly lower energy requirements. Therefore, the bio-valorization of discarded fruit juices using microalgae/ cyanobacteria could be a promising management practice.…”

“…1 Operational factors, such as light, pH, N:P ratio, temperature, and carbon source, should always be considered because they can affect biomass growth, bioactive compounds, and wastewater treatment efficiency. 17 Among these factors, the N:P ratio is a crucial parameter for growth and nutrient uptake. 18 In the bibliography, the Redfield ratio (N:P 16:1) is generally referred to as the optimum ratio for the growth of marine strains, 19 while in the case of freshwater microalgae, N:P ratios vary between 8:1-45:1.…”

“…Operational factors, such as light, pH, N:P ratio, temperature, and carbon source, should always be considered because they can affect biomass growth, bioactive compounds, and wastewater treatment efficiency 17 . Among these factors, the N:P ratio is a crucial parameter for growth and nutrient uptake 18 .…”

“…20,24 However, research employing microalgae for the treatment of food industry wastewaters mainly concerns liquid residues from fruits and vegetables [26][27][28] 28 or other food wastes that must be initially anaerobically digested or hydrolyzed (to produce liquid extracts) before being used as a growth medium. 29,30 Specifically, most of the above-mentioned research works deal with wastewaters from: different stages of the sugar industry 16,17,[31][32][33] ; dairy products 34,35 ; alcoholic or non-alcoholic beverages; 15,34,[36][37][38][39] and other food processing wastewaters, such as raisin wastewaters. 35,39 Only a few studies refer to the treatment of wastewaters from soft drink industries or fruit juice processing, 14,[40][41][42] and most of these used activated sludge or anaerobic digestion reactors (Supporting Information, Table S1).…”