Laboratory procedures used in the examination of industrial wastes shall be those set forth in Standard Methods. However, alternative methods for certain analyses of industrial wastes may be used subject to mutual agreement between the Superintendent and the user; provided, they meet federal requirements as set forth in 40 C.F.R. part 36. The city may, without charge to the user, make initial analysis of the user’s wastes as well as other initial tests the Superintendent may deem advisable. Regular periodic check analyses and analyses made by the city at the request of the user shall be charged to the user according to the standard work order billing practice. All such analyses shall be binding in determining strength of wastes, surcharges and other matters dependent upon the character and concentration of wastes.