Recovery of NH4+‒N and PO43-‒P is Promoted by competitive interactions between M. aeruginosa and MgCO3
Year: 2024
Type: article
Abstract: Here we report that the presence of MgCO 3 stimulates the extracellular polymeric substance (EPS) secretion of Microcystis Aeruginosa ( M . Aeruginosa ). This stimulation led to a significant reduction in the total concentration of NH 4 + ‒N by more than 86％, and effective recovery of PO 4 3- ‒P within three days from concentrated wastewater (WW), although the secreted EPS inhibited the conversion of MgCO 3 to specific crystal forms (MgNH 4 PO 4 .6H 2 O or MgHPO 4 .7H 2 O). Moreover, with an increase in PO 4 3− concentration in WW, these crystals appeared, thus the removal of NH 4 + ‒N and PO 4 3- ‒P nutrients can be attributed to the combined effect of M. Aeruginosa and MgCO 3 . We used Surface-Enhanced Raman Spectroscopy (SERS) combined with X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (FESEM-EDS), and X-ray Photoelectron Spectroscopy (XPS) to investigate the mechanism for competitive interactions between M. Aeruginosa and MgCO 3 in removing NH 4 + ‒N and PO 4 3- ‒P. We identified that the bound EPS accumulated amorphous Mg–P–O dense particles on M. Aeruginosa , while soluble EPS, containing –COOH groups of humic-like substances decreased the pH of the solution and coordinated with Mg 2+ ions. Therefore, both secreted bound and soluble EPS play a vital role in hindering the transformation of Mg 2+ ions or MgCO 3 to MgNH 4 PO 4 .6H 2 O or MgHPO 4 .7H 2 O crystals within WW, and they enhanced M. Aeruginosa 's ability in absorbing nutrients of NH 4 + ‒N and PO 4 3- ‒P. This mechanism plays a crucial role in the efficient recovery of NH 4 + ‒N and PO 4 3- ‒P from concentrated wastewater sources such as aerobically or anaerobically digested effluent from various sources like agriculture , livestock , and domestic wastewaters.
Source: Advanced Agrochem
Institutions: Huazhong Agricultural University, Guizhou University
Language: English
Subfield: Waste Management and Disposal
Field: Environmental Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4405092926