The Effects of Salinity on the Removal of Contaminants of Concern during Biological Water Reclamation
Peter Fox, Arizona State University
Conventional wastewater treatment operations are dependent on the settleability of biosolids. Past research has shown that biosolid flocculation is dependent on the monovalent-to-divalent-cation ratio (M/D ratio). In other words, bioflocculation (aggregation of biological solids) is enhanced by the presence or absence of divalent cations such as calcium and/or magnesium ions and deteriorates with high concentrations of monovalent cations such as sodium, potassium, and ammonium ions. Some hydrophobic contaminants of concern are primarily removed during wastewater treatment by sorption into biosolids. Most estrogenic compounds are hydrophobic, and they were used as model compounds for this study.
Water softeners have a clear impact on reclaimed water quality by increasing the concentration of monovalent cations. This impact has become most pronounced when reclaimed water is used for irrigation, and the high salt content has a negative impact on plants and soil properties. This research demonstrates that water softeners may also be affecting the ability of water reclamation plants to remove hydrophobic compounds that are difficult to biodegrade. Many known estrogenic compounds are in this category, and estrogenic compounds were used as model compounds in this study.
(2009, 99 pages, 05-008-1)
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