Effects of carbon-to-sulfur (C/S) ratio and nitrate (N) dosage on Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorus Removal (DS-EBPR)

Abstract

In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the role of wastewater compositions in DS-EBPR performance. The optimal specific P release and uptake rates (0.4 and 2.4 mg P/g VSS/h, respectively) were achieved at C/S/P/N mass ratio of 150/200/20/20, and poly-S is supplied as a potential electron and energy storage. The nitrate dosage in a range of 10–50 mg N/L had no significant influence on P uptake rates (2.1 ~ 2.4 mg P/g VSS/h), but significantly affected the storage of inclusion poly-S, the poly-S oxidation rate was increased about 16% while dosing nitrate from 20 to 30 mg N/L. It implies that nitrate is denitrified in the P uptake phase, and excess nitrate is further consumed by poly-S. Moreover, the microbial analysis showed that the functional bacteria should mostly belong to denitrifying bacteria or Unclassified genera.

Spatiotemporal heterogeneity of core functional bacteria and their synergetic and competitive interactions in denitrifying sulfur conversion-assisted enhanced biological phosphorus removal

“…2 (C and P conversions, as well as S and N conversions). The results demonstrate a clear association between S conversion and biological denitrifying P removal as reported in our previous study 11 , 23 . Based on the experimental data in Table 1 such as the acetate uptake rate, the nitrate consumption rate, the sulfate reduction rate and the sulfide oxidation rate, the Spearman correlation was analyzed to investigate the significance of the operating conditions and reactor performance, and the results are shown in Supplementary Table S2 .…”

“…Based on this and our previous studies 11 , 17 , 22 , 23 , we propose for the first time that competitive and cooperative metabolic interactions (Fig. 5 ) occur within the microbial community in the DS-EBPR system.…”

“…Thauera is likely a major contributor to P removal. Equation ( 1 ) describes the generation and degradation of poly-P 23 . Other PAO-related bacteria may have been present but went undetected because their concentrations were too low and the functional traits of their genomes are unknown.…”

“…As DS-EBPR was only recently developed, few studies have been conducted and the ones available are mainly focused on process development, performance verification and evaluation. Some of these studies have touched on the microbial community governing this process and have even speculated about its underlying mechanism 11 , 17 , 22 , 23 . For instance, one study using 454-pyrosequencing detected none of the conventional PAOs (i.e.…”

Elucidating functional microorganisms and metabolic mechanisms in a novel engineered ecosystem integrating C, N, P and S biotransformation by metagenomics

“…Under anoxic conditions, P will be luxuriously uptaken associated with Poly-P and glycogen formation, sulfur-driven denitrification as well as PHA and Poly-S degradation (Wu et al, 2013). Compared with the conventional Enhanced Biological Phosphorous Removal (EBPR) process, the DS-EBPR system enables successful biological sludge reduction and simultaneous removal of C, N and P in a broad range of operational conditions (such as pH and temperature) with association of S biotransformation (Wu et al, 2013(Wu et al, , 2014Yu et al, 2016).…”