Industrial Pilot for Assessment of Polymeric and Ceramic Membrane Efficiency in Treatment of Liquid Digestate from Biogas Power Plant

Abstract

Due to the depletion of available water resources and the consistently rising environmental pollution levels, the exploitation of the digestate generated as an unfavorable by-product of the industrial wastewater treatment plants, could not only offer a readily available source of recycled water, but also an efficient agricultural fertilizer. However, the first step for the utilization of the digestate is the removal of any potentially harmful contaminants, and ultrafiltration membranes can provide successful remediation routes in this direction. This work investigates the industrial pilot-scale purification and reusability of the liquid digestate derived from the anaerobic treatment of waste mixtures of high organic content, using ultrafiltration membrane technology. Two different types of ultrafiltration membranes, polymeric and ceramic, were evaluated regarding their efficiency and long-term performance, parameters that heavily affect the overall costs of the operational unit. Our results indicate that the ceramic membranes exhibited a superior performance compared to its polymeric analogues, such as a higher flux, as well as significantly increased lifetime, signifying promising cost-effective and long-term applicability on an industrial level. In addition, the analytical physicochemical characterization of the ultrafiltration reject indicated its high nutrient value, suggesting its highly promising exploitation as an added value fertilizer, further enhancing the sustainability of the proposed approach.