Any person having been granted authority by the approving authority to discharge sewage into the city's public sewers and who shall change or cause to be changed the nature or quantity of the sewage, shall before making the change, receive the approval of the approving authority of the change and may be required to furnish the approving authority a complete analysis of a composite sample of the sewage as determined by an independent laboratory.
(`95 Code, § 4-2-29)