Enhanced recovery of waste-born nutrients from sewage sludge ash and fish meal through fungal treatment: Mechanistic insights and impact of heavy metals

This study investigates the potential of Talaromyces adpressus TCPF to enhance phosphate recovery and nutrient bioavailability from sewage sludge ash (SSA) and fish meal (FM) through co-fermentation. The fungal treatment was found to significantly increase phosphate recovery, achieving up to 16 % efficiency, especially at a 10 g/L waste concentration. The key mechanism behind this enhancement is the production of low molecular weight organic acids (LMWOAs), which played a crucial role in solubilizing nutrients while also mitigating the negative effects of heavy metals like lead and cadmium. Spectroscopic analyses confirmed substantial acid-based leaching and biomineralization processes, with over 70 % of phosphorus successfully bioleached from metal-treated waste. These findings underscore the effectiveness of fungal treatments in transforming waste substrates into valuable bio-organic fertilizers. Fungal treatment boosts phosphate recovery, even in the presence of heavy metals, by employing processes such as bioweathering, bioprecipitation, biocorrosion, and bioleaching.