Aircraft Water & Waste Management Systems

• Aircraft water and waste systems are essential for passenger well-being.
• The water system provides potable water to lavatories and galleys.
• The waste system removes waste from toilets.

Water System Basics

• Potable water is water that can be consumed
• Gray water is all water that has been used

Potable water system subsystems:

• Storage and distribution
• Water quantity indication
• Water heating

Waste disposal system subsystems:

• Gray water drain system
• Vacuum waste system

Water Storage and Distribution

• The water storage and distribution system supplies potable water to lavatories and galleys.
• Water in the tanks supplies the galley and lavatories.
• There are three water tanks that contain potable water.
• Tanks are pressurized to about 40 psi by compressed air.
• They can be filled from the aft potable water service panel and pre-select overflow valve.
• The overhead distribution line supplies water to lavatories and galleys.
• A water heater ensures warm water is available.
• Isolation and drain valves are in the forward and aft parts of the system.
• These valves isolate parts of the system to drain the forward part to the forward drain valve.
• Each lavatory and galley has a water supply shutoff valve.
• Each lavatory has a drain valve which drains water from the water distribution lines in the lavatory.
• The galley faucet drains the galley distribution lines.
• There are three drain valves that let water drain from the distribution system and the water tanks:
  • Forward system drain
  • Aft system drain
  • Tank drain.
• Connect the water supply house to the service port.
• The tank fill valve handle can be turned to fill.

Preselect/fill overflow valve functions

• Water flows into the potable water tanks.
• Air vents as water fills the tank.
• It closes when the tanks fill to the selected level.
• Water flows overboard during overfilling of the tanks.
• The air supply to the water tank is switched off.

Water Quantity Indication System

• The water quantity indication system uses a water quantity transmitter in the water tank.
• The transmitter indicates the water quantity on the:
  • Aft potable service water panel.
  • Cabin system control panel (CSCP).
  • Cabin area control panels (CACPs).

Gray Water Drain System

• The gray water drain system allows waste water to drain overboard.
• Waste water flows from the lavatory and galley sinks.
• Waste water then flows through forward or aft drain masts on the bottom of the aircraft.
• When pressure rises beyond a limit, the pressure switch opens.
• This de-energizes the motor and valves, which removes any line blockages.
• A gray water drain restrictor valve limits air flow out of the plane, reducing noise in the lavatories and galleys.

Boeing 777 Vacuum Waste System

• This vacuum waste system removes waste from toilets and stores it in waste tanks.
• Waste stays in waste tanks until serviced.
• Waste collects in the toilet before being vacuumed to waste tanks.
• Suction is generated by a vacuum blower.
• The difference between cabin and outside pressure also moves waste to the waste tanks.
• Waste is removed through the waste service panel.

Vacuum Waste System: Waste tank

• Waste tanks collect waste from the toilets.
• Three waste tanks are installed on the airplane.
• The forward and mid tanks can hold 314 litres.
• The aft tank can hold 239 litres.

Vacuum Waste System: Continuous Level Sensor

• Continuous level sensors are in the tank drain lines and calculate the waste amount.
• Data is displayed on cabin area control panels (CACP) and cabin system control panels (CSCP).
• The waste tank continuous level sensor is a capacitance-type pressure sensor.
• Wires connect the electrical connector to a logic control module (LCM).
• Pressure of the air in the tank is determined by the remote diaphragm and the capillary tube.
• The sensor calculates the difference to determine the amount of waste.

Vacuum Waste System: Point Level Sensor

• The waste tank quantity indication system includes:
  • Point level sensors
  • Continuous level sensors
  • Logic control modules (LCM's)
• Point level sensors attach to the upper part of the tanks, and sends signals to the LCM when full.
• There are 6 sensors, two on each tank.
• The sensors are a capacitance type.

CSCP/CACP Indications

• The cabin system control panel (CSCP) and cabin area control panels (CACP) control and monitor:

  • Lavatory functions
  • Waste tank levels

• The lavatory waste tank status screen monitors conditions in the lavatories and waste tanks.

• The lavatory inoperable control screen indicates conditions and status of each lavatory.

• Operational lavatories show "OP"

• Inoperative lavatories are "INOP"

• INOP indicates automatically for all lavatories connected to the same full tank.

Vacuum Waste System: Waste Tank Rinse

• The waste tank rinse fitting assembly routes supply water to rinse the waste tanks.
• The waste tank rinse filter removes small particles as rinse water goes through it.
• The waste tank rinse nozzle points rinse water at the point level sensors.
• It also points at the tank interior to remove sensor material and pre-charge the waste tanks.

Vacuum Waste System: Draining of Waste

• Waste tank drain ball-valves and control cables allow for draining.
• A T-handle is attached to the end of each cable.
• Actuation lever which allows for opening and closing of the drain-ball valve is attached to the other side.
• The limit switch stops operation of the vacuum blower when the tank is not closed.

Vacuum Waste System: Vacuum Toilet Assembly

• The vacuum blower supplies suction for the waste system.
• Vacuum then moves the toilet rinse water and its contents to the holding tank.
• The liquid separator removes moisture and particles before venting.
• Air circulates within the separator.
• Centrifugal force removes moisture from the air.
• Moisture drains through the bottom of the liquid separator.
• Air goes to the overboard vent line.
• Vacuum blowers operate if the aircraft altitide is below 16,000 feet after flush selection.
• Vacuum blowers create different pressures to move waste from the lavatories to storage tanks.
• The filter removes particles from the air cooling the blower motor.
• The vacuum check valve prevents reverse air flow through the bypass line when the blower is on.
• Vacuum blowers do not operate if the aircraft altitude is above 16,000 feet .
• Low pressure creates vacuum air.
• The vacuum blower barometric switch de-energizes the vacuum blower when the airplane is above 16,000 feet.

Explore aircraft water and waste management systems, including potable and gray water, waste tank functions, and system components. Understand pressurization, distribution, and vacuum waste principles. Learn about Boeing 777 specific systems for efficient sanitation.