Durban - A recent study conducted at a Durban brewery found that brewery wastewater has the potential to become bioenergy.
The study, which was published in the journal “Water”, titled “Characterization of South African Brewery Wastewater: Oxidation-Reduction Potential Variation”, was co-authored by Mangosuthu University of Technology (MUT) acting dean of the Faculty of Engineering Professor Babatunde Bakare, Professor Sudesh Rathilal from Durban University of Technology (DUT), Siphesihle Mangena Khumalo and Emmanuel Kweinor Tetteh.
In a statement on Tuesday, MUT said as water continues to be a scarce resource globally and the energy crisis strengthens its grip on South Africa, researchers are trying to find environmentally friendly ways of extracting the full benefits of the resources that we already have.
MUT said the findings of this study are important because although the brewing industry is essential for the South African economy, brewing requires a lot of water.
“Generally, brewing of beer requires substantial amounts of water: to make 1m³ of beer, a volume of wastewater of 10–20m³ is produced,” the study explained. “The brewing process includes malting, mashing, wort filtering, wort boiling, fermentation, maturation, stabilization, and clarification.”
In terms of the Oxidation Reduction Potential (ORP), the study found that “brewery wastewater can be treated by biological processes on the basis that the reported ORP range permits biological activities”.
The university said as far as the brewery wastewater composition is concerned, the study found that the contents of the water depended largely on the activities that were taking place at the brewery.
“The brewery wastewater treatment plant influent stream composition fluctuates significantly owing to the brewery in-house activities (i.e., washing of malted barley, which is rich in carbohydrates, brewing kettles, yeast fermentation tanks, as well as other beer processing units) and the chemical utilised.
“The high concentration in terms of orthophosphates and ammoniacal nitrogen could be a result of the type of acids used during brewing yeast cleaning, such as phosphoric acid and nitric acid,” the study found.
MUT said the contents found in the wastewater give the brewery wastewater a high potential for it to be turned into bioenergy.