Ammonia nitrogen removal from acetylene purification wastewater from a PVC plant by struvite precipitation

Water Sci Technol. 2016;74(2):508-15. doi: 10.2166/wst.2016.239.

Abstract

Acetylene purification wastewater (APW) usually contains high concentrations of ammonia nitrogen (NH4-N), which is generated during the production of acetylene in a polyvinylchloride manufacturing plant. In this study, a struvite precipitation method was selected to remove NH4-N from the APW. Laboratory-scale batch experiments were performed to investigate the effects of the initial APW pH, phosphate (PO4(3-)) concentration, magnesium (Mg(2+)) concentration, and sources of PO4(3-) and Mg(2+) on NH4-N removal. The results indicated that the initial APW pH had a significant effect on the removal of NH4-N, while the other factors had relatively minor effect. The NH4-N could be effectively removed at an optimum initial APW pH of 9.5, when Na2HPO4·12H2O and MgSO4·7H2O were both applied to NH4-N at a ratio of 1.2. Under these conditions, the efficiency of removal of NH4-N, total nitrogen and chemical oxygen demand were 85%, 84% and 18%, respectively. The X-ray diffraction analysis indicated that the precipitates were dominated by struvite. The scanning electron microscopy analysis of the precipitates showed a typical morphology of stick-like and prismatic crystals with coarse surface. The energy dispersive spectroscopy analysis indicated that the precipitates contained P, O, Mg and Ca.

MeSH terms

  • Acetylene
  • Ammonia / metabolism*
  • Chemical Precipitation
  • Denitrification
  • Hydrogen-Ion Concentration
  • Industrial Waste / analysis
  • Magnesium / analysis
  • Phosphates / analysis
  • Polyvinyl Chloride
  • Struvite / chemistry*
  • Wastewater / analysis*

Substances

  • Industrial Waste
  • Phosphates
  • Waste Water
  • Ammonia
  • Polyvinyl Chloride
  • Struvite
  • Magnesium
  • Acetylene