A tax due and unpaid under this article shall be a debt due the City. It shall be a personal obligation of the taxpayer and shall be a lien upon all property used in the business or occupation upon which such tax is imposed; provided, that no such tax lien shall be enforceable against a purchaser, including lien creditor, for valuable consideration without notice, unless docketed in the office of the Clerk of the County Court before a deed therefor to such purchaser or the lien of such creditor is delivered for record to the Clerk of the County Court. A penalty of five percent (5%) of the tax shall be added for any default for thirty days or less, and for each succeeding thirty days elapsing before payment there shall be an additional penalty of one percent (1%), all of which penalties shall be secured by the lien therein provided. (1976 Code Sec. 10-110)