The effect of PO43--P concentration on sludge settleability and nutrients removal performance

Abstract

In order to explore the effect of influent PO43--P concentration on the relationship of phosphorus remove performance and sludge settleability, three sequencing batch reactors (SBRs) operated as anaerobic/aerobic mode were used to treat wastewater with different PO43--P concentrations (same COD), and the organic loading rate (OLR) was changed through adjusting the anaerobic (aerobic) duration. The sludge settleability, nutrients removal, and microorganism species were investigated. The results showed that when the influent PO43--P were 4.3 mg·L−1 and 8.6 mg·L−1, increasing the OLR through decreasing aerobic duration could significantly improve sludge settleability, while decreasing anaerobic duration could not. It was found that increase the OLR could promote the denitrification compete for carbon sources with phosphorus release process by inhibiting the accumulation of NO2--N, leading to the decrease of phosphorus removal ability. When the influent PO43--P was 17.2 mg·L−1, sufficient nitrification was beneficial to enrich denitrifying phosphorus accumulating bacteria (DPAO), and the activities of Thauera and Flavobacterium (DPAO) were stronger. Therefore, increasing influent PO43--P concentration and reducing aerobic duration could help phosphorus accumulating bacteria (PAO) compete with denitrification for COD and enrich DPAO, thus reducing carbon source consumption.

Pollution and Risk Level Assessment of Pollutants in Surface Water Bodies

“…This result is similar to the study of Jayasiri et al (2022) [4] in Ca Mau province. High concentrations of PO4 3--P in water can be caused by runoff in agriculture, domestic and industrial wastewater, especially detergents [33,35].…”

“…The activities of discharging wastewater from livestock, aquaculture and septic tanks of poor quality have seriously contaminated the water in this area with microorganisms. Coliform contamination in water bodies is widespread in the Mekong Delta [30,35,37].…”

Aerobic granular sludge treatment of piggery wastewater: solution to the problem of non-filamentous bulking and analysis of microbial community structure in practical application.

“…The dominant genera in S2 were Zoogloea (11.07%), Flavobacterium (12.1%),Xu et al 2018). It can stabilize the AGS skeleton by secreting EPS and also removes both N and P to minimize the utilization of COD in the substrate(Peng et al 2022). This also explains the reason why nitrogen and phosphorus removal are still better in the P2 stage although the in uent COD is not high.…”