2. After approval of an application, the commissioner and the municipality shall enter into a contract for state assistance payments toward the cost of such project which shall include the following provisions:

1. (a) A current estimate of the cost of the project as determined by the commissioner at the time of the execution of the contract.
2. (b) An agreement by the commissioner to make state assistance payments toward the cost of the project by periodically reimbursing the municipality for costs incurred during the progress of the project. Such costs are subject to final computation and determination by the commissioner upon completion of the project. For purposes of this subdivision, the approved project cost shall be reduced by the amount of any specific state assistance payments for landfill closure purposes received by the municipality from any source; provided, however, that non-specific state assistance payments, such as amounts paid pursuant to section fifty-four of the state finance law, shall not be included in such cost reduction.
3. (c) An agreement by the municipality to proceed expeditiously with the project and to complete the project in accordance with plans and reports approved by the department and with the conditions of applicable permits, administrative orders or judicial orders.