The Affects of the Monovalent to Divalent Cation Ratio on Sorption of Estrogens in Biosolids

Conventional wastewater treatment operations are dependent on the settleability of biosolid flocculates. Past research has shown that biosolid flocculate settleability is dependent on the monovalent to divalent cation ratio (M/D ratio). Natural and synthetic estrogens found in wastewater are primarily removed from the wastewater by sorption into biosolids. This research study focused on the potential effect of the M/D ratio and cationic strength on sorption of estrogenic compounds. The sodium azide isotherm results indicate that the sorption capacity parameter is strongly affected by the M/D ratio and supports the hypothesis that an increase in M/D ratio decreased sorption capacity. However, isotherms performed on live biosolids did not show a clear pattern that supports the hypothesis that the M/D ratio effects sorption capacity. This may be due to the production of colloids by living biosolids or by competitive sorption by other compounds.