Sewage phosphorus recovery through sachets loaded with water treatment plant sludge

• Published in: Water science and technology Vol. 88; no. 4; pp. 922 - 931
• Main Authors: Coelho, Miriam Gabrielle, Franco, Débora de Melo, Siqueira, Juliano Curi de, Ribeiro, Ivan Célio Andrade, Crippa, Rodolfo Appoloni, Fia, Ronaldo, Matos, Mateus Pimentel de
• Format: Journal Article
• Language: English
• Published: London IWA Publishing 15.08.2023
• Subjects: Activated carbon; Chemical composition; Chemical elements; Effluents; Experiments; Fertilizers; Iron; nutrient removal; Phosphorus; Phosphorus removal; precipitation; Removal; Sewage; Sewage treatment; Sludge; solid waste; Solid wastes; sorption; Treated sewage; Turbidity; Wastewater treatment; Wastewater treatment plants; Water treatment; Water treatment plants; Brazil
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2023.247

Abstract Conventional wastewater treatment plants (WWTPs) present low phosphorus (P) removal capacity. Conversely, water treatment plants (WTPs) produce sludge with great P sorption from wastewater; however, directly adding the sludge into the wastewater treatment system could increase the effluent turbidity. As a novel approach, the present study evaluated the performance of WTP sludge within paper sachets for P removal from treated sewage. Different sludge concentrations (2–30 g L−1) and contact times (1–27 d) were applied to treat sewage from a university WWTP outlet. The sludge was characterized by P, Fe, and Al content. Larger sludge masses showed higher P removal efficiencies due to their high Fe content, especially at longer contact times (up to 100% at the final of the experiment). However, there is a more significant P reduction in the first 10 d (more than 90% in the most efficient treatment – 30 mg L−1). Based on the kinetic and isotherm analyses and the sludge chemical composition, precipitation proved to be a mechanism of great importance in P removal. Therefore, WTP sludge sachets can be a promising way to remove P from sewage, and the formed solid waste might be reused as an alternative fertilizer.