After April 14, 1975, any use established and any building, structure, or tract of land developed, constructed or used for any permitted or special use shall comply with the applicable performance standards set forth herein.

If any existing use or building or other structure is extended, enlarged, moved, structurally altered, the standards included within this section are to be considered applicable to these activities and they shall be considered minimum standards. [Ord. 4508, § 2-6.01, 12-17-75; Ord. 4107, § 6.01, 4-14-75.]