Abstract
The Gela Refinery’s (Sicily Region, South Italy) hydraulic barrier consists of 67 wells, located along the refinery’s seaside border, dedicated to groundwater pumping and free product recovery, and it is part of the remediation system approved by the Public Authorities. In order to manage the hydraulic barrier, water table measurement of about 350 piezometers and weekly dynamic levels of the pumping wells are collected and inserted into a relational database that allows a real-time management of the extensive information gathered.
Every well pumping rate has been defined by hydraulic simulation modelling. Given that the aquifer is a dynamic system, periodically all collected data are analyzed and if necessary, based on the results of the simulation modelling, the well pumping rates are updated: this flow rate is called the “optimized pumping rate”. The check and control of the barrier proper operation is conducted through the daily acquisition via the distributed control system (DCS) of all the barrier operation data jointly with all the significant field information. Based on the data collected, routine and extraordinary maintenance activities are planned and implemented to guarantee optimal operation conditions of each component of the pumping system.
The acquisition of a large amount of data (freatimetric levels of all refinery piezometers, dynamic levels of wells, hydrochemical data of wells and piezometers) and their interpretation and processing using a relational database and numerical simulation modelling allows the reconstruction of the groundwater flow and of the barrier’s effect on the groundwater table.
The dynamic management of the barrier, using the simulation modelling, proved to be an essential tool to modulate the pumping rate following seasonal variability and allows the system operator and Control Authorities to verify the performance and effectiveness of the barrier, in terms of maintaining the hydraulic containment of the aquifer and of hydraulic efficiency of the remediation system.
