In addition to all other powers and duties not conferred by law upon county courts, such courts are hereby empowered to acquire, by purchase, right of eminent domain, lease, gift, or otherwise, and to operate and maintain, sewerage systems and sewage treatment plants, and to pay the cost of operation and maintenance thereof out of a special fund to be derived from sewerage service fees paid by the users of such sewerage system or sewage treatment plant: Provided, however, That the power and authority hereby conferred on county courts shall not extend into territory within the boundaries of any municipal corporation, sanitary district or public service district.