As used in this article, the following terms shall have the meanings indicated:
The municipalities of the City of East Orange, the Township of Hillside, the Town of Irvington, the Township of Maplewood, the Township of Millburn, the City of Newark, the Borough of Roselle Park, the Village of South Orange, the City of Summit, the Township of Union and the Town of West Orange, organized in a Joint Meeting pursuant to N.J.S.A. 40:63-68 et seq., under the terms of a contract dated June 1, 1926, as amended and supplemented, in the matter of a joint trunk and outlet sewer and treatment plant for the sewage wastewater emanating from said municipalities.
The charge levied upon all users of the treatment works for the annual cost of operation and maintenance, including replacements, of such trunk lines and such works, all as defined in the federal rules and regulations.