The appraisers shall within twenty days from the date of their appointment file their report and assessment roll with the county clerk, and any person or persons or corporation owning land affected by the proceedings may, within thirty days from the date of the appointment of the appraisers, file with the county clerk objections to the report or assessment roll, or settlement made by the appraisers on any point, including the amount or amounts proposed to be paid for voluntary releases. If no objections are filed to the report and assessment roll, the county board at its next regular or adjourned session after the expiration of the time for filing objections, shall, if deemed advisable, confirm such report and assessment roll.