In pulp and paper mills, steam is used for generating power and heating. Steam that is injected directly into process fluids is not recoverable, but a large amount of steam is used for indirect heating, such as in heat exchangers and paper machine dryer cans. The condensate from indirect heating applications can be returned to the boiler to be converted back into steam. Recycling condensate saves water, energy, and chemicals, so it is beneficial to recover as much condensate as possible. However, impurities in the returned condensate can cause corrosion or scale in boiler tubes and piping, which leads to poor boiler performance and/or equipment damage. So, the quality of the returned condensate is very important. This course describes the contaminants that are typically found in returned condensate, their potential sources, monitoring methods, and treatment strategies.