With landfill bans emerging across Europe, it is necessary to choose proper alternatives to landfilling. One of the alternatives can be waste-to-energy, specifically in the form of waste incineration. In some cases, such as areas with low population density, small units can be the only way to avoid large collection areas. However, in the case of incineration, it is also necessary to have a small-scale flue gas treatment. The use of flue gas treatment in a very small-scale requires its simplification. Therefore, the removal of HCl and SO2 by sodium bicarbonate at conditions allowing simultaneous removal or other pollutants was investigated. The results show that, in the case sodium bicarbonate, the reaction rate of HCl was higher than the reaction rate of SO2. The achieved sorbent conversion depended significantly on the concentration of HCl. High concentrations of HCl diminished the ability of the sorbent to remove SO2 and caused, thereby, lower conversion of the sorbent because it had to be present in higher excess to achieve the desired concentration of SO2 in the clean flue gas.