A numerical modeling study was conducted to investigate the hydraulic effects of liquid waste injection on an injection system. The site investigated was a chemical refinery with an operational Class I well and an observation well, both completed in Devonian limestone. Input data for the model were obtained from available records and field investigations. The regional geologic investigation indicated that the injection system (defined here as the injection zone and its associated confining units) was laterally continuous. The hydraulic response of the injection system was numerically modeled under two injection scenarios: average historical injection rate and maximum average permitted rate. For both scenarios, pressure buildup from waste injection during the simulated 30-year injection and 30-year post injection periods did not approach the pressure calculated to be necessary to initiate or propagate fractures in the injection system. Therefore, injected waste would be contained, and waste injection at this site and for the scenarios modeled would not endanger human health or the environment. This analysis assumes that hydraulic conductivity remains constant; however, the formation of brucite within the injection zone may invalidate this assumption and the preceding analysis. Brucite formation within the injection zone requires additional study. The model was also used to investigate the response of the injection system when a hypothetical conduit was introduced. This hypothetical conduit connected the uppermost injection zone with an overlying aquifer. Differences in head buildup were not monitorable in the injection well or in an observation well completed in the injection zone. Monitorable head differences were observed only in the overlying aquifer, when the hydraulic conductivity of the hypothetical conduit was greater than or equal to 1x10-10 m2.
|Name||RR Series (Hazardous Waste Research and Information Center)|
- Factory and trade waste
- Waste disposal in the ground