Water quality transformations during soil aquifer treatment at the Mesa Northwest Water Reclamation Plant, USA

Peter Fox, K. Narayanaswamy, A. Genz, J. E. Drewes

Research output: Contribution to journalArticle

45 Scopus citations

Abstract

Water quality transformations during soil aquifer treatment at the Mesa Northwest Water Reclamation Plant (NWWRP) were evaluated by sampling a network of groundwater monitoring wells located within the reclaimed water plume. The Mesa Northwest Water Reclamation Plant has used soil aquifer treatment (SAT) since it began operation in 1990 and the recovery of reclaimed water from the impacted groundwater has been minimal. Groundwater samples obtained represent travel times from several days to greater than five years. Samples were analyzed for a wide range of organic and inorganic constituents. Sulfate was used as a tracer to estimate travel times and define reclaimed water plume movement. Dissolved organic carbon concentrations were reduced to approximately 1 mg/L after 12 to 24 months of soil aquifer treatment with an applied DOC concentration from the NWWRP of 5 to 7 mg/L. The specific ultraviolet absorbance (SUVA) increased during initial soil aquifer treatment on a time-scale of days and then decreased as longer term soil aquifer treatment removed UV absorbing compounds. The trihalomethane formation potential (THMFP) was a function of the dissolved organic carbon concentration and ranged from 50 to 65 μg THMFP/mgDOC. Analysis of trace organics revealed that the majority of trace organics were removed as DOC was removed with the exception of organic iodine. The majority of nitrogen was applied as nitrate-nitrogen and the reclaimed water plume had lower nitrate-nitrogen concentrations as compared to the background groundwater. The average dissolved organic carbon concentrations in the reclaimed water plume were less than 50% of the drinking water dissolved organic concentrations from which the reclaimed water originated.

Original languageEnglish (US)
Pages (from-to)343-350
Number of pages8
JournalWater Science and Technology
Volume43
Issue number10
StatePublished - Jul 18 2001

Keywords

  • Dissolved organic carbon
  • Groundwater
  • Soil aquifer treatment
  • Travel time

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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