Abstract: A device for inspecting the inside of an underground pipe line which makes it possible to search for cavities on the outside of the underground pipe over the entire internal peripheral surface of the underground pipe, that is, not only upward of the underground pipe, but also toward both sides and downward thereof, to obtain detailed images of the inner peripheral surface of the pipe line without using a complex mechanism, and to display patterns of cracks and irregularities on the inner peripheral surface of the underground pipe by three-dimensional convergence images. The device comprises a pipe line internal self-propelled vehicle and an on-ground control unit, and the pipe line internal self-propelled vehicle is provided with a radar antenna, a camera equipped with a fisheye lens, a gyro, a laser sensor, and an infrared encoder.

Abstract: An object of the present invention is to provide a waste water treating method and a waste water treating apparatus which are capable of treating for-treatment water containing a nitrogen compound and a phosphorus compound at low costs and efficiently. The waste water treating method is a waste water treating method for treating a nitrogen compound (nitrate nitrogen) and a phosphorus compound (phosphate ions) in for-treatment water by electrolysis as an electrochemical process, the method comprises a first treating step of immersing a pair of electrodes in the for-treatment water at least partially so as to treat the for-treatment water by electrolysis, one of the electrodes being a cathode made of a conductive material and the other of the electrodes being an anode made of iron, and a second treating step of treating the for-treatment water with hypochlorous acid, ozone or active oxygen after completion of the first treating step.