Subsurface injection of liquid waste in Florida, U.S.A

The present practice of subsurface injection of liquid wastes in Florida is reviewed involving a total of 10 injection wells, of which five inject liquid industrial waste at the rate of 21,000 m3 per day and the remainder inject 144,000 m3 per day of municipal sewage effluent. Oil-field brines are also injected at two other locations and further injection projects are in the preliminary stages. The geological features of the Florida peninsular and the factors influencing the selection of injection sites are discussed, together with the system of monitoring wells required to control the operation and consisting of boreholes for facilities monitoring and aquifer-system monitoring; these two types are also termed on-site and satellite wells in view of their respective locations. All the operational systems inject into carbonate strata, principally of Eocene age; these are saltwater bearing parts of the major Floridan aquifer, and extensive precautions are required to ensure that underground freshwater resources do not become contaminated either with the waste itself or the salt water it displaces.