| 摘要 |
PROBLEM TO BE SOLVED: To eliminate protrusions on a surface and a rear of a cover lid for a treating pond of water supply and sewage system. SOLUTION: The locking structure locks a cover lid 10 by locking of a lacking piece 29 of a receive frame of an opening peripheral wall C of a treating pond P with a locking piece 24 of the cover lid 10. A handle 11 and a rotary shaft 12 are received in a casing so that they may not protrude from a surface and a rear. Attaching holes 30, 31 are closed by the casing to prevent deterioration in deodorization or the like. Absence of protrusions on the surface and the rear of the cover lid 10 prevents a person from blundering, and the locking piece 24 may not collide against a floor when the cover lid 10 is put on the floor, so that damage of the floor and the locking piece 24 can be prevented. |
