The state is hereby authorized to make grants to any local public body to assist such local public body in the construction of a project. Such grants shall be administered by the authority. The authority acting by and through any authorized officer is hereby authorized to enter into an agreement obligating the state to pay such portion of the estimated reasonable cost of the projects of each local public body as may be required in order that such project shall be eligible for the maximum obtainable federal grant under the Federal Water Pollution Control Act.