Any city may acquire by purchase or condemnation proceedings any lands within or without its corporate limits necessary for disposing of sewage or for obtaining or protecting a water supply for the city and the inhabitants thereof, and may acquire by purchase or condemnation proceedings when authorized by the electors of such city any public utility and any water power and water rights for the use of such city within the corporate limits of said city. The jury in condemnation proceedings shall consist of 12 freeholders drawn from the body of the county and if they find the necessity for such use exists and, in case of sewage that the use proposed will not materially injure the health or safety of persons living adjacent to the land, they shall award the compensation to be paid therefor. Other proceedings in such cases shall conform to the general law authorizing cities and villages to take or hold land or property outside of their corporate limit as contained in chapter 90 of the Compiled Laws of 1897, or any other appropriate act now or hereafter existing.