Injection ConfiningZone Lithology and Chemistry

The lower limestone of the Floridan aquifer is used as the injection zone (at 430 to 520 m), and the Bucatunna clay member of the Byram formation (about 67 m thick) serves as the confining layer. Figure 20.11 shows the stratigraphy of the area, and Figure 20.12 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 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.

The injection zone contains about 7900 mg/L chloride, but less than 32 km (20 miles) northeast of the injection site, chloride concentrations are less than 250 mg/L. Under natural conditions, water

FIGURE 20.11 Generalized north-south geologic section through Southern Alabama and Northwestern Florida. (From U.S. EPA, Assessing the Geochemical Fate of Deep-Well-Injected Hazardous Waste: A Reference Guide, EPA/625/6-89/025a, U.S. EPA, Cincinnati, OH, June 1990.)

400 200 Sea level 200 400 600 800 1000 1200 1400 1600 1800

xWWWwwxWWWWWWN

Explanation | Cement grout

Note:

1- Bottom 20 ft of inner casing is stainless steel in the two injection wells and the two active deep monitor wells.

2- All casing grouted bottom to top.

Horizontal not to scale xWWWwwxWWWWWWN

Explanation | Cement grout

Cement plug

Note:

1- Bottom 20 ft of inner casing is stainless steel in the two injection wells and the two active deep monitor wells.

2- All casing grouted bottom to top.

Horizontal not to scale

FIGURE 20.12 Monsanto Injection Facility hydrogeologic cross-section. (From U.S. EPA, Assessing the Geochemical Fate of Deep-Well-Injected Hazardous Waste: A Reference Guide, EPA/625/6-89/025a, U.S. EPA, Cincinnati, OH, June 1990.)

in the injection zone moves slowly south-southwestward toward the Gulf of Mexico, where it is assumed to discharge about 160 km (100 miles) offshore. The pre-injection hydraulic gradient was about 0.25 m/km (1.3 ft/mile).

DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

Get My Free Ebook


Post a comment