The lower limestone of the Floridan aquifer is used as the injection zone (at 1,400 to 1,700 ft), and the Bucatunna clay member of the Byram formation (about 220 ft thick) serves as the confining layer. Figure 14.14 shows the local stratigraphy and the monitoring well installations. The formation water in the injection zone is a highly saline (11,900 to 13,700 mg/L total dissolved solids, TDS) sodium-chloride solution. The Eh of samples
collected from two monitoring wells located in the injection formation ranged from +23 to −32 mV, indicating reducing conditions in the injection zone that would favor anaerobic biodegradation.