AWWA JAW10245

The geohydrology of Florida allows deep-well injection of treated wastewater in some areas, if care is taken to assure protection of overlying aquifers used for public water supplies. This article discusses precautions that must be taken during construction, operation, and ultimate abandonment of the disposal wells to assure containment of injected wastes. The following precautions must be taken during construction: research on the geohydrology of the area to anticipate highly productive zones with highly mineralized artesian waters; construction of an impermeable, curbed concrete slab around the well site to allow drilling and testing; multiple-casing design with thick surrounding annular spaces to allow proper cementing and isolation of zones with differing water qualities and pressures; staged construction; vertical alignment and directional control of both pilot and ream holes to make sure that drilled sections of the holes are completely and effectively cemented; establishment of a groundwater monitoring system to check the quality of the overlying freshwater aquifer; and confirmation of the effectiveness of the confined layers overlying the receiving aquifer through the use of packer testing or other equivalent methods. During operation, precautions must be taken to control the flow rate of the injection and wellhead pressure and to monitor the effectiveness of the confining layers separating the receiving zones from the fresh or less-mineralized overlying waterbearing strata. When a disposal well is abandoned, complete sealing of the casing from the bottom to the surface is required. Includes 4 references, tables, figure.

Product Details

Edition:

Vol. 75 - No. 6

Published:

06/01/1983

Number of Pages:

4

File Size:

1 file , 1.6 MB