Methodologies to Develop Water-Repellency in USGA Grade Sand.

The objective of this study was to develop stable and consistently hydrophobic USGA grade sand for the use in laboratory or field-based studies.  Different methodologies for developing hydrophobic sand were compared alongside naturally occurring hydrophobic sand, and their hydrophobicity was quantified by the Molarity of Ethanol Droplet (MED) test.  The methodologies evaluated for the development of hydrophobic sand included ethanol or acetone extraction of peat moss, and baking a 1:10 peat-sand (g/g) mixture at 185 °C for 2 hours.  The persistence of soil hydrophobicity after cycling of water flushes and subsequent drying was assessed using the MED test as well.    Results suggest that ethanol and acetone extracts of peat moss yielded the most hydrophobic sand, with MED values of 4.3 and 4.1 molar, respectively.  Baking a peat-sand mixture yielded less hydrophobic sand with an MED value of 3.4 molar.  In comparison, naturally occurring hydrophobic sand collected from a local putting green exhibited the lowest MED value of 1.9 molar.  After one dry-wet cycle, all artificially made hydrophobic sand evaluated remained at a similar level of hydrophobicity.  However, naturally occurring hydrophobic sand showed a significant increase in MED value from 1.9 to 3.1 molar following one water flush and subsequent drying.  Additional water flushing, drying, and subsequent MED testing as well as organic carbon results will be discussed.