(a) By March 1, 1991, each county with a population of 100,000 or more and each municipality with a population of 1,000,000 or more, and by March 1, 1995, each county with a population of less than 100,000, shall submit to the Agency an officially adopted plan for the management of municipal waste generated within its boundaries. Such plan shall conform with the waste management hierarchy established as State policy in subsection (b) of Section 2 of the Illinois Solid Waste Management Act.(b) The Agency shall review each county waste management plan to ensure consistency with the requirements of this Act and, if warranted, return it to the county with specific recommendations for improving the plan within 90 days after the plan is submitted. If the plan is returned, the county shall consider the Agency recommendations, make any appropriate revisions, and adopt a revised plan by September 1, 1991, or by September 1, 1995 in the case of a county with a population of less than 100,000.(c) Each waste management plan shall contain, at a minimum, the following provisions: (1) A description of the origin, content and weight or volume of municipal waste currently generated within the county's boundaries, and the origin, content, and weight or volume of municipal waste that will be generated within the county's boundaries during the next 20 years, including an assessment of the primary variables affecting this estimate and the extent to which they can reasonably be expected to occur.(2) A description of the facilities where municipal waste is currently being processed or disposed of and the remaining available permitted capacity of such facilities.(3) A description of the facilities and programs that are proposed for the management of municipal waste generated within the county's boundaries during the next 20 years, including, but not limited to their size, expected cost and financing method.(4) An evaluation of the environmental, energy, life cycle cost and economic advantages and disadvantages of the proposed waste management facilities and programs.(5) A description of the time schedule for the development and operation of each proposed facility or program.(6) The identity of potential sites within the county where each proposed waste processing, disposal and recycling program will be located or an explanation of how the sites will be chosen. For any facility outside the county that the county proposes to utilize, the plan shall explain the reasons for selecting such facility.(7) The identity of the governmental entity that will be responsible for implementing the plan on behalf of the county and explanation of the legal basis for the entity's authority to do so.(8) Any other information that the Agency may require.(d) Any county may delegate power to a municipality within the county or Municipal Joint Action Agency for the specific purpose of preparing the waste management plan or any portion thereof under this Act.(e) Counties may, by intergovernmental agreement, jointly create and administer their solid waste management plans, provided that such joint plans fulfill all the requirements of this Act.