In any municipality which has entered into such a joint contract for the construction and maintenance of any such joint improvement or works, the municipal body or board having power to construct sewers or drains therein may from time to time by ordinance, provide for and cause to be constructed any trunk, lateral or connecting sewers and system of sewers, and all necessary appurtenances thereto, connecting with and discharging into such joint improvement or works. Such ordinances may be passed by such body or board on its own motion, without application or petition therefor.