DARWIN has developed, in collaboration with Alicorp, one of the largest edible oil industries in Peru with presence in Colombia, Ecuador, Bolivia, and Uruguay, a biological treatment based on SRB (sulfate-reducing bacteria), capable of removing more than 30% of sulfates from contaminated waters.

To achieve this, we conducted a metataxonomic analysis to study the established interdependencies between SRB and the native microbiota present in the wastewater samples, and quantified the consortium’s performance for different sulfate concentrations in laboratory-scale reactors.

Problem

Vegetable oils are a rich nutrient source and one of the main food or food ingredients consumed worldwide. However, the by-product of their manufacturing process is acidic wastewater rich in lipids characterized by a high sulfate concentration, which often reaches levels exceeding >30,000 ppm.

The effluents from vegetable oil processing industries often exceed the maximum sulfate concentration allowed by each country’s legislation. Therefore, wastewater must be treated to reduce these sulfate levels before being discharged into the environment.

Non-biological strategies applied for wastewater remediation, such as chemical oxidation processes involving air, ozone, hydrogen peroxide, metal extraction, and precipitation, result in the generation of chemical wastes, high costs, and unwanted sulfate production.

Solution

Biological sulfate reduction is a promising alternative for sulfate removal in this type of wastewater. For bioremediation, we introduced a microbial consortium with Desulfovibrio sp. as one of the key players. These bacteria utilize sulfates for growth and transform them into hydrogen sulfide (H2S). This molecule, combined with iron ions, forms iron sulfide (FeS), which turns the liquid black. Through this process, the sulfate concentration in the water is reduced by more than 30%.

Year of Completion: 2022

Success

The outcome, a bioremediation treatment capable of removing more than 30% of sulfates from contaminated waters, paves the way for the use of the developed consortium (SRB) as a sustainable and cost-effective alternative to treat large volumes of wastewater generated by vegetable oil processing industries.

Papers

• Pascual J, Rodríguez A, Delgado CE, Patrón AR, Porcar M, , Vilanova C. A Microbial Consortium for the Bioremediation of Sulfate-Rich Wastewater Originating from an Edible Oil Industry. Microbiol. Biotechnol. Lett 2022;50:110-121. https://doi.org/10.48022/mbl.2201.01003