The presence of particles into turbulent gas flows can lead to modulation of the turbulence characteristics, i. e. visible in the pressure fluctuations. By means of computational fluid dynamics we can handle a variety of mathematical models to efficiently analyze the industrial applications, however, Reynolds Averaged solutions bring difficulties to detailed phase interaction investigation. Therefore, the goal of this study is to demonstrate the gas-solid interaction in Euler/Lagrange simulations and apply the wavelet Multi-Resolution Analysis (MRA) on wall pressure-time signals. Effects of particle properties and solids mass loading are evaluated. The wavelet MRA of the experimental wall-pressure fluctuations showed that the reduction of the variability is not monotonic from de highest time-scales to the lowest ones; the meso-scales (62.5 - 125 Hz) have considerable energy. Also, the presence of particles in the flow attenuates the pressure fluctuations, i.e. the clean flow has higher pressure fluctuation; the spatial micro-scales and meso-scales are the most affected scales of the energy spectrum in these operational conditions.