Material lining the inside surface of a section of pipe is removed by a hydrodemolition nozzle assembly mounted on a working end of an elongated boom. The opposed end of the boom is supported outside the pipe on a movable support for inserting and retracting the boom from the inside of the pipe. The nozzles remove the liner while the working end of the boom is supported by a wheel resting on the liner that has not yet been removed and that rolls along the inside liner as the pipe is made to revolve around the boom. The nozzles are oriented to eject the liner and water downstream and away from the boom.

A method and an Internet of Things system for corrosion supervision of a gas pipeline are provided. The method includes: obtaining inspection data of a gas pipeline in a gas pipeline network; constructing a first pipeline diagram of the gas pipeline network based on the inspection data; determining a corrosion probability of the gas pipeline based on the first pipeline diagram using a corrosion probability model; determining one or more estimated pipeline corrosion regions based on the corrosion probability of the gas pipeline; obtaining in-depth inspection data of the gas pipeline by performing in-depth inspection on at least one of the estimated pipeline corrosion regions; determining corrosion features of the one or more estimated pipeline corrosion regions based on gas monitoring data and the in-depth inspection data of the gas pipeline; and determining a repair plan based on the one or more estimated pipeline corrosion regions and/or the corrosion features.