In our previous studies, a novel NOx aftertreatment system using adsorption and reduction by nonthermal plasma desorption is proposed. In the present study, application of the system to a real stationary diesel engine generator is investigated. The NOx is first removed by adsorption, then the adsorbent is regenerated by thermal desorption using waste heat of the exhaust gas. In the regeneration process, hot exhaust gas passes through the heat exchange tubes surrounded by the adsorbent pellets. The desorbed NOx is subsequently reduced to N2 by nitrogen nonthermal plasma. This system reduces around 50% of 245 ~ 270 ppm NOx emitted by the generator for 8 hours.