The charge on the respective lots, tracts, parcels of land and other property for the purpose of special assessment to pay the cost and expense in whole or in part of any construction or improvement authorized in this chapter, when assessed, and the assessment roll confirmed by the board shall be a lien upon the property assessed from the time said assessment rolls shall be placed in the hands of the county treasurer for collection. Said liens shall be paramount and superior to any other lien or encumbrance whatsoever, theretofore or thereafter created, except a lien for general taxes.