An aftertreatment device for reducing NOx, PM, HC, and CO generated by a compression-ignition engine. In this device, lean exhaust air generated in the engine is enriched using a reactor together with an oxygen sorption device according to a target deNOx efficiency value, and heat energy is recovered. The enriched exhaust gas then passes through an oxidation catalyst, where NOx is reduced with CO and HC. PM in the exhaust gas is further trapped in a DPF. To lower energy cost, an heat exchanger is used for more effectively heating the DPF during regeneration, and an exhaust gas compressor positioned upstream from the DPF is employed to control engine back pressure. When exhaust gas temperature is low, to regenerate the DPF with minimum energy consumption, an electrical heater is used to heat dosing fuel before it is mixed with exhaust gas, and a regeneration heating process is then jump-started.