Organic-Based Permeable Reactive Barriers for the Treatment of Heavy Metals, Arsenic, and Acidity - Permeable Reactive Barrier: Sustainable Groundwater Remediation - page 135

8
Organic-Based Permeable Reactive
Barriers for the Treatment of Heavy Metals,
Arsenic, an d Acidity
Ralph D. Ludwig, Richard T. Wilkin, Steven D. Acree,
Randall R. Ross, and Tony R. Lee
CONTENTS
8.1 Louisiana PRBs ........................................................................................... 136
8.1.1 Methods ........................................................................................... 137
8.1.2 Results ............................................................................................. 137
8.1.2.1 Hydrologic Evaluation .................................................... 137
8.1.2.2 Chemical Monitoring ..................................................... 138
8.1.2.3 pH ...................................................................................... 138
8.1.2.4 Acidity .............................................................................. 141
8.1.2.5 Alkalinity ......................................................................... 142
8.1.2.6 Lead (Pb), Cadmium (Cd), and Nickel (Ni) ................. 142
8.1.2.7 Arsenic .............................................................................. 144
8.1.2.8 Sulfate/Sulfide ................................................................. 145
8.1.2.9 Dissolved Organic Carbon ............................................ 146
8.2 South Carolina PRB ................................................................................... 147
8.3 Conclusions ................................................................................................. 148
References ............................................................................................................. 149
Three different organic-based permeable reactive barrier (PRB) systems were
evaluated for their effectiveness in treating heavy metals, arsenic and acidity
in groundwater. One PRB, a full-scale system consisting of composted cow
manure and limestone gravel, was installed at a former battery recycling
facility site located in Louisiana. The second PRB, a pilot, was installed at the
same location in Louisiana. It consisted of composted cow manure, limestone
gravel, and wood chips. The third PRB, also a pilot, was installed at a former
phosphate fertilizer manufacturing facility site in South Carolina. It consisted
of a mixture of municipal yard compost, zero-valent iron (ZVI), limestone,
and granite pea gravel. In all three cases, the PRBs were designed to treat low
pH, high acidity groundwater containing heavy metals and arsenic, by rais-
ing pH and promoting microbially mediated sulfate reduction.
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