Oils are defined as organic materials that are not completely dissolved in water and present in the forms of sheens, globules, droplets. If present at a construction dewatering site, oil will most likely need to be removed from water before discharge in order to meet the discharge limits for oil & grease (O&G) and/or specific contaminants of concern (COC) that oil may carry along through treatment systems. Based on the dispersion and stability in water, oils can be classified into four different forms: 1) free oil, 2) mechanically emulsified oil, 3) chemically emulsified oil, and 4) solids-bound oil.