Denitrifying sulfur conversion-EBPR (DS-EBPR) process for treatment of seawater-based highly saline wastewater: Evaluation on performance, kinetics and microbial community structure. (October 2020) - Wu, Zhongwei
Graphical abstract: Highlights: Long-term impacts of different salinity (0.7% and 1.0%) on DS-EBPR were studied. Shock of four levels of salinity (1.0, 1.4, 2.5 and 3.5%) on DS-EBPR was tested. High salinity decreases/limits the efficiencies of S cycle driven-P removal. XRD and XPS analysis have been conducted to determine the P precipitates. The functional bacteria (SRB and SOB) were tolerant to high salinity. Abstract: DS-EBPR is an alternative to the conventional activated sludge process which face great challenge for treatment of seawater-based highly saline wastewater. This study aims to investigate the impacts of long-term (248 days) 20% and 30% seawater fractions and short-term shock of 30%, 40%, 70% and 100% seawater fractions (corresponding to 1.0, 1.4, 2.5 and 3.5% of salinity) on the DS-EBPR performance, kinetics and microbial community structure. Long-term operation with high fraction (30%) of seawater marginally decreased the sulfur conversion and phosphorus uptake, which correlated well with the microbial dynamics. Temporal salinity shock from 1.0% (30% seawater) to 3.5% (100% seawater) remarkably reduced the phosphorus release/uptake by 36–44%, which was partly due to the decrease in the abundance of functional bacteria and chlorapatite (Ca5 [PO4 ]3 Cl) forming as P precipitates with 70–100% seawater addition. The formed chlorapatite contributed to approximately 8–26% of total P removal estimated by X-ray photoelectron spectroscopy analysis.