Introduction to Dense Non-Aqueous Phase Liquid (DNAPL)

In Introduction to Dense Non-Aqueous Phase Liquid (DNAPL), you'll learn ...

• Why it is difficult to find DNAPLs with conventional drilling techniques
• How DNAPL distributes itself upon release to the subsurface
• DNAPL types, properties and migration characteristics
• DNAPL source zone investigation methods

Overview

Credit: 2 PDH

Length: 20 pages

A non-aqueous phase liquid (NAPL) is a term used to describe the physical and chemical differences between a hydrocarbon liquid and water, which result in a physical interface between the two liquids when mixed. Despite the physical dividing surface between the two liquids, compounds found in NAPL are not prevented from dissolving into the ground water.

NAPL has typically been divided into two general categories, dense and light. These terms describe the specific gravity, or the weight of NAPL relative to water. Correspondingly, light non-aqueous phase liquids (LNAPL) have a specific gravity less than water; and dense non-aqueous phase liquids (DNAPL) have a specific gravity greater than water.

Due to its unique manner of migrating and pooling within soil pores and rock fractures, DNAPL in free-phase or residual form is difficult to find and measure. DNAPLs typically contain chlorinated hydrocarbon compounds or industry-specific contaminants resulting from activities such as wood-treating, pesticide/herbicide manufacturing, or coking operations. Relatively small quantities of DNAPL that sink into soil and accumulate below the water table constitute a long-term source of groundwater contamination.

This course is intended for environmental engineers who have involvement or interest in groundwater & soil remediation, in which the source of contamination is DNAPL.