In case of the refusal of the municipal authorities of another municipality, to grant such permission, the municipalities making the application may, within thirty days after such refusal, apply to the state department of health, which shall have power to reverse the decision of the local authorities of such municipality, and grant, after hearing, the application for the erection of said disposal or other plants, upon being satisfied that such erection will best serve the interest of the public health and the general welfare of the municipalities affected and of the state.