An aircraft comprising an engine and an environmental control system (100; 300) fluidly coupled to a low-pressure bleed port of the engine, the environmental control system comprising: at least one heat exchanger comprising a first and a second heat exchanger(110, 130); a compressing device in fluid communication with the first heat exchanger, the second heat exchanger, and the engine of the aircraft, the compressing device comprising a shaft supporting a first turbine, a second turbine, and a compressor, wherein the first heat exchanger, the compressor, the second heat exchanger, a first path of a third heat exchanger via a first pass, a water extractor, the first turbine, and a second path of the third heat exchanger are fluidly coupled in series between the low-pressure bleed port of the engine and a cabin of the aircraft, wherein the compressing device is configured to receive, through the first heat exchanger, bleed air being bled from the low-pressure bleed port of the engine, pressurize the bleed air from a first pressure to a second pressure via the compressor, and provide the bleed air to the second heat exchanger, wherein the second pressure is higher than the first pressure, wherein the first turbine and the second turbine drive the compressor of the compressing device by: the first turbine providing a primary power to the compressing device by expanding the bleed air after the bleed air has been exhausted from the first heat exchanger, and the second turbine providing a supplemental power to the compressing device by expanding cabin discharge air received from the aircraft cabin, and wherein the second turbine exhausts the cabin discharge air into a ram air system of the aircraft. at least one heat exchanger comprising a first and a second heat exchanger(110, 130); a compressing device in fluid communication with the first heat exchanger, the second heat exchanger, and the engine of the aircraft, the compressing device comprising a shaft supporting a first turbine, a second turbine, and a compressor, wherein the first heat exchanger, the compressor, the second heat exchanger, a first path of a third heat exchanger via a first pass, a water extractor, the first turbine, and a second path of the third heat exchanger are fluidly coupled in series between the low-pressure bleed port of the engine and a cabin of the aircraft, wherein the compressing device is configured to receive, through the first heat exchanger, bleed air being bled from the low-pressure bleed port of the engine, pressurize the bleed air from a first pressure to a second pressure via the compressor, and provide the bleed air to the second heat exchanger, wherein the second pressure is higher than the first pressure, wherein the first turbine and the second turbine drive the compressor of the compressing device by: the first turbine providing a primary power to the compressing device by expanding the bleed air after the bleed air has been exhausted from the first heat exchanger, and the second turbine providing a supplemental power to the compressing device by expanding cabin discharge air received from the aircraft cabin, and the first turbine providing a primary power to the compressing device by expanding the bleed air after the bleed air has been exhausted from the first heat exchanger, and the second turbine providing a supplemental power to the compressing device by expanding cabin discharge air received from the aircraft cabin, and wherein the second turbine exhausts the cabin discharge air into a ram air system of the aircraft.