Effect of sludge retention time on continuous-flow system with enhanced biological phosphorus removal granules at different COD loading

Bioresour Technol. 2016 Nov:219:14-20. doi: 10.1016/j.biortech.2016.07.093. Epub 2016 Jul 25.

Abstract

The effect of sludge retention time (SRT) on the continuous-flow system with enhanced biological phosphorus removal (EBPR) granules at different COD loading was investigated during the operation of more than 220days. And the results showed that when the system operated at long SRT (30days) and low COD loading (200mg·L(-1)), it could maintain excellent performance. However, long SRT and high COD loading (300mg·L(-1)) deteriorated the settling ability of granules and the performance of system and resulted in the overgrowth of filamentous bacteria. Meanwhile, the transformation of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process was inhibited. Moreover, the results of pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading and long SRT. The PAOs specious of Candidatus_Accumlibater and system performance increased obviously when the SRT was reduced to 20days at high COD loading.

Keywords: COD loading; Continuous-flow system; EBPR granules; High-throughput pyrosequencing; Sludge retention.

MeSH terms

  • Bacteria / genetics
  • Bacteria / metabolism
  • Biodegradation, Environmental
  • Biological Oxygen Demand Analysis*
  • Environmental Restoration and Remediation / methods*
  • Glycogen / metabolism
  • High-Throughput Nucleotide Sequencing
  • Phosphorus / isolation & purification*
  • Polyhydroxyalkanoates / metabolism
  • Polyphosphates / metabolism
  • Sewage / microbiology*
  • Time Factors

Substances

  • Polyhydroxyalkanoates
  • Polyphosphates
  • Sewage
  • Phosphorus
  • Glycogen