Use of Chlorella sorokiniana (Chlorellaceae, Chlorellales) microalgae for purification of waste water from the brewing industry

Abstract

The paper presents some environmental problems of the brewing industry. The literature data on the methods of water purification using microalgae have been studied. The composition of wastewater from the brewing industry is shown to consist of few biogenic elements, namely: nitrogen, phosphorus and potassium, which are necessary for microalgae biomass cultivation. Therefore, the wastewater from the brewing industry can be used as a basis for making a nutrient medium to cultivate microalgae. In the experimental part, the effect of various dilutions of a suspension of microalgae Chlorella sorokiniana (C) grown on a nutrient medium with untreated wastewater (UWW) from the brewing industry was studied. Various percentage ratios of wastewater to microalga suspension were studied, namely: UWW/C = 70:30, 50:50, and 30:70 for the ability to absorb nitrogen, organic and inorganic carbon from dry matter, and to change the pH value. The dependences of the growth rate of microalgae at various percentage additives of the wastewater from the brewing industry are presented. It was shown that at a UWW:C = 30:70, this dependence is characteristic of the standard growth curve of a microorganism culture. A lag phase, phases of exponential growth and withering away are observed. At a 70:30 ratio, the harmful effect of effluents on the growth of microalgae is obvious, on the 3rd day their death occurs, the green solution acquiring a brown color to confirm the death of microalgae cells. It has been shown that the optimal UWW:C ratio is 30:70, with no loss of biomass, it grows well using pollutants for its nutrition. The color of the solution after cultivation was bright green, which corresponded to the color of healthy cells. At UWW:C = 30:70, the wastewater is purified up to 70% and 90% for total nitrogen and organic carbon, respectively. The pH value changes from acidic to neutral. Keywords: Chlorella sorokiniana, wastewater treatment, brewing industry