Design and construction of a prehydrated sand–bentonite liner to contain brine

Abstract

The containment of brine in shallow ponds is one of the most serious problems facing waste-management engineers today. Brine waste is produced in many mining and processing operations. It is characterized by high salt concentrations which may seriously contaminate groundwater if not successfully contained. However, brine reacts chemically with clays used in liner construction. As brine permeates the liner, physicochemical interactions between the clay and brine lead to a reduction in volume of the liner. This shrinkage may cause cracking of the liner and the creation of a highly fractured permeable macrostructure.Numerous techniques have been tried to find an effective and economical method of containing brine. Some of these techniques have involved the use of soil, concrete, asphalt, and synthetic liners. However, all of these techniques have major deficiencies in either cost or effectiveness. This paper presents a case study of the first attempt to solve the volume change problem by designing and constructing a sand–bentonite liner prehydrated with brine. The design was based on the results of a triaxial permeability testing program. The results of the testing program and monitoring of the liner since construction indicate that brine prehydration of sand–bentonite liners is an effective technique for use in brine containment. Key words: bentonite, brine, liner, prehydration, containment, waste management, physicochemical effects, clays.