Characterizing the correlation between dephosphorization and solution pH in a calcined water treatment plant sludge

Environ Sci Pollut Res Int. 2018 Jul;25(19):18510-18518. doi: 10.1007/s11356-018-2036-9. Epub 2018 Apr 26.

Abstract

This study focused on characterizing the correlation between the dephosphorization process of calcined water treatment plant sludge (C-WTPS) and the solution initial pH in batch experiments. The specific aim was to illustrate the effect of different initial pH on the adsorption and desorption of phosphorous in C-WTPS. In addition, the effects of solution initial pH on the release of ammonia nitrogen and total organic carbon (TOC) from C-WTPS and the change of pH after adsorption were also investigated. The results demonstrated that the initial pH significantly influenced the adsorption of phosphorus on C-WTPS. When initial pH was increased from 3 to 10, the phosphorous absorption capacity reduced by 76.5%. Especially, when the initial pH reached to 11, the phosphorus adsorption capacity became a negative value, indicating that C-WTPS released phosphorus into the solution. The addition of C-WTPS to the solution had little impact on the initial pH of the solution. The absorbed phosphorous on C-WTPS was relatively stable in the pH range of 3 to 10. Nevertheless, when the solution pH was higher than 11, it can be easily released into the solution. Furthermore, by comparison with WTPS, C-WTPS released less ammonia nitrogen and TOC into the solution and adsorbed more phosphorus from the solution in the experimental pH range. Therefore, C-WTPS is more suitable to serve as a cost-effective sorbent for phosphorus removal.

Keywords: Absorption; Calcined water treatment plant sludge; Dephosphorization; Desorption; Phosphorus; pH.

MeSH terms

  • Adsorption
  • Ammonia / analysis
  • Carbon / analysis
  • Hydrogen-Ion Concentration
  • Organic Chemicals / analysis
  • Phosphorus / analysis*
  • Sewage / chemistry*
  • Solutions
  • Water Pollutants, Chemical / analysis*
  • Water Purification / methods*

Substances

  • Organic Chemicals
  • Sewage
  • Solutions
  • Water Pollutants, Chemical
  • Phosphorus
  • Carbon
  • Ammonia