Upon the filing of such a petition the President of the Committee shall appoint some competent person who is a resident and elector of the county to make a true and impartial assessment of, the cost of the specified improvement upon the property benefited by the improvement.
     The levying officer shall apportion and assess the amount found to be of benefit to the property contiguous or abutting upon the improvement upon the several lots, blocks, tracts and parcels of land in the proportion in which they will severally be benefited by the improvement. No lot, block, tract or parcel of land shall be assessed a greater amount than it will actually be benefited. In levying any special assessment each lot, block, tract or parcel of land shall be assessed separately in the same manner as upon the assessment for general taxation.