Where, at the effective date of adoption or amendment of this Zoning Regulation, lawful use of the land exists that is no longer permissible under the terms of this Zoning Regulation as enacted or amended, such use may be continued, so long as it remains otherwise lawful and is not enlarged or increased, nor extended beyond area designated non-conforming at the effective date of amendment of this Zoning Resolution, except as elsewhere provided and in accordance with the following provisions:
   (a)   Processing Operations:  Where the use of land involves a processing operation, said operation may be continued in the entire area utilized for that purpose, provided modifications in processing operations by rearrangement of facilities or changes in methods shall be considered as part of such use.
   (b)   Discontinuance: If any such non-conforming uses of land are voluntarily discontinued for a period of more than two (2) years, any subsequent use of such land shall conform to the regulations specified by this Zoning Regulation for the District and Overlay if applicable, in which such land is located.
   (c)   Non-Conforming Structures Prohibited:   No additional structure not conforming to the requirements of this Zoning Regulation shall be erected in connection with such non-conforming use of the land.
   (d)   Expansions:   Expansions of existing non-conforming uses, where allowed by the Board of Zoning Appeals, may be made only on property owned by the applicant as of the effective date of this Zoning Regulation. A non-conforming use of a structure, a non-conforming use of land, or a non-conforming use of a structure and land shall not be extended or enlarged after passage of this Zoning Regulation by attachment on a building or premises of additional signs intended to be seen from off the premises, or by addition of other uses of a nature which would be prohibited generally in the district involved.