Work

Staggered supply of ferric citrate and oxygen as electron acceptors promote the co-recovery of vivianite and bioplastics PHB from wastewater

Year: 2025

Type: article

Abstract: Biodegradable bioplastic polyhydroxyalkanoate (PHA) produced and recovered from wastewater offered an effective strategy to replace synthetic plastics while mitigating plastics waste pollution. In addition to the recovery of high-value organic products like PHA, the synthesis of vivianite mineral from wastewater demonstrated great potential as a highly effective method for phosphorus recovery. To facilitate the co-recovery of vivianite and PHA, we investigated the staggered supply of ferric citrate and oxygen as dual electron acceptors, aiming to enhance the concurrent recovery of high-value organics and phosphorus. When 6 mM of ferric citrate was used as the sole electron acceptor, the vivianite recovery increased from 34% with one single dose of the electron acceptor to 49% with twice the dose. Simultaneously, the yield of polyhydroxybutyrate (PHB), a typical PHA, was only 0.17 g PHB/g COD HAc. However, when ferric citrate and oxygen were used as dual electron acceptors, the vivianite formation efficiency was stabilized at 50%. Simultaneously, the PHB yield boosted to 0.79 g PHB/g COD HAc, 3.6 times higher than with ferric citrate as sole electron acceptor and significantly exceeding that in previous studies using oxygen alone. PHB-producing bacteria, including Candidatus Competibacter, Paracoccus , and Thauera , were effectively enriched through the staggered supply of the dual electron acceptors. As a result, the staggered supply of dual electron acceptors represented an efficient and sustainable method for the co-recovery of PHB and vivianite from wastewater.

Source: Water Research X

DOI: 10.1016/j.wroa.2025.100371