Full-scale enhanced biological phosphorus removal implementation: Process performance and microbial community dynamics treating potato processing wastewater

Chemical phosphorus (P) precipitation has long been the default approach for treating potato-processing wastewater, effectively meeting discharge limits but requiring substantial chemical inputs, generating excess sludge and carrying significant environmental costs. This study demonstrates that enhanced biological phosphorus removal (EBPR) can significantly reduce reliance on chemicals at full-scale, offering a more sustainable pathway for nutrient management. Over 320 days, a sequencing batch reactor was operated under a modified cycle to enrich for polyphosphate-accumulating organisms (PAOs) without compromising nitrification and denitrification, while a reference reactor maintained conventional biological nitrogen removal with chemical P-precipitation. The experimental system developed a specialized microbial community dominated by PAOs that enabled stable P-cycling and simultaneous nitrogen removal using the complex organic substrates present in the wastewater. Both systems maintained robust biological nitrogen removal throughout the study period, but the EBPR approach achieved comparable nutrient removal performance while reducing iron chloride consumption by 55%, aeration demand by 50%, and sludge production per unit COD removed by 33%. The environmental advantages extended beyond operational efficiency. The carbon footprint and economic analysis revealed that combined savings from reduced chemical usage and lower energy use delivered 91-102 tonnes CO 2 -eq in avoided emissions, far outweighing the modest loss in biogas recovery (10 tonnes CO 2 -eq), and resulting in net climate benefits of 81-92 tonnes CO 2 -eq. This full-scale demonstration shows that optimized biological treatment can meet regulatory standards for potato-processing wastewater while simultaneously reducing costs, chemical dependency, and environmental impact, establishing EBPR as a scalable solution in industrial sectors.