The main objective of the present study is to reduce unwanted vibrations of mechanical systems through a sealed tuned liquid column damper (STLCD). A nonlinear mathematical model including nonlinear damping and air stiffness of the STLCD is considered to study the dynamic behaviour of a structure- STLCD coupled system. A parametric study to investigate the influence of the main parameters of the STLCD such as length ratio and mass ratio on the dynamic behaviour of the main system subjected to ground excitation is presented. The air volume at rest is considered as an additional design parameter. The study showed that the efficiency and the range of application of the STLCD to control the system resonance vibration are better than the traditional one. In addition, it has been noticed that the gain in vibration mitigation from the STLCD with a bigger mass higher than 7% ratio is generally modest. Also the same trend is observed when increasing its horizontal length ratio over 0.8. These enhance the actual implementation of the STLCD for small horizontal space applications. Equations for the optimum value of the initial air column height ratio and its corresponding performance index for the main structure-STLCD system as a function of both mass ratio and relative length were proposed.