Optimization of internal bypass ratio for complete ammonium and phosphate removal in a dephanox-type two-sludge denitrification system

Vladimir Torrico, Takahiro Kuba, Tetsuya Kusuda

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The capacity of complete simultaneous ammonium and phosphate removal was studied in a laboratory scale Dephanox system in relation to its internal bypass ratio (BPR). In this configuration, most of the ammonium detected in the effluent is ammonium bypassed by the system's internal settler. Therefore, this research studies the possibility of complete simultaneous ammonium and phosphate removal by means of the balance of bypassed ammonium with ammonium requirement for growth of denitrifying phosphorus accumulating organisms in the anoxic tank. During these experiments, ammonium removal was governed by internal BPR and limited by sludge settleability. The predominant anaerobic-anoxic sludge developed a high settleability, allowing the application of drastic low BPRs. The system studied under many BPRs proved to achieve almost complete simultaneous ammonium and phosphate removal for BPRs ranging from 0.08 to 0.13 of the influent. A BPR lower than the inferior limit produced extreme accumulation of sludge into the internal settler, interfering in the distribution of sludge and consequently in removal efficiency. A positive effect of the internal settler was the extension of anaerobic contact time and anaerobic solids retention time. The increased phosphorus release suggests that a higher volatile fatty acids production might have occurred when raw wastewater was used as influent.

Original languageEnglish
Pages (from-to)536-542
Number of pages7
JournalJournal of Environmental Engineering
Volume134
Issue number7
DOIs
Publication statusPublished - Jun 30 2008

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry
  • Civil and Structural Engineering

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