A process removes or eliminates altogether accumulations of solid and semi-solid, water immiscible materials adhering to walls, and equipment, particularly near the high liquid mark, in tanks of waste liquid lift stations. Compressed gas is used to generate large bubble masses of six inches to several feet in diameter within the waste liquid. As these large bubble masses rise through the liquid in the tank, convection currents generated by the rising bubbles agitate and loosen pieces of accumulations adhering to the tank and lift station equipment, resulting to in a slurry of waste liquid and immiscible materials which can then be pumped from the tank by lift station equipment for further processing. In some embodiments, continuous or frequent periodic generation of the large bubble masses prevents the accumulation of such materials altogether. In some embodiments, wastewater aeration is also provided, which, in combination with biological augmentation, further enhances the effectiveness of accumulated material removal.