Piezometer sealing

We close off vertical contaminant migration pathways to the deep aquifer

A disused piezometer is not a neutral element: it is an artificial conduit connecting previously isolated aquifer levels, and can act as a preferential pathway for contaminant migration towards the deep aquifer. At SOILUTIONS we offer contaminated land investigation and remediation consultancies a specialist service for sealing disused piezometers by pressure injection of cement-bentonite grout, restoring the ground’s original hydrogeological integrity.

Methodology

• Preliminary assessment: depth, diameter and condition of the piezometer, to calculate the volume of grout required.
• Mix preparation: Portland cement and sodium bentonite grout, proportioned to displace water and air without segregating during setting.
• Bottom-to-surface pressure injection: pumping through a tremie pipe to the bottom of the borehole, displacing the water from the bottom upwards and avoiding voids or unsealed zones, something that simple gravity pouring cannot guarantee.
• Return monitoring and sealing record with depth, volume injected, mix proportions and photographic report, ready for the closure file.

Scope

We work on 2″, 3″ and 4″ groundwater investigation and monitoring piezometers (or similar), at the depths typical of an environmental monitoring network. Large-diameter, deep wells intended for water abstraction or supply are excluded.