Thirty days after the posting of the copies of the resolution declaring any building a nuisance, the enforcement agency shall be deemed to have acquired jurisdiction to abate such nuisance by razing or removing the building, unless the nuisance is abated by the owner or other person interested within the 30-day period or any extension thereof granted by the governing board as provided for in this article. In the event that the nuisance is not abated within the time prescribed the enforcement agency may thereupon raze and remove the building so declared to constitute a nuisance or have the same done under its direction and supervision.