The assessment shall be collected by the county trustee as county taxes are collected, except as provided in this section, and the funds so collected shall be kept as a separate fund, and shall be paid out only for purposes properly connected with such improvement on the order or warrant of the county mayor; provided, that such assessments may be collected in chancery, as provided in part 8 of this chapter, and no personal property of the owner of land so assessed shall be liable or distrained for such assessment, but the land so assessed only shall be liable for such assessment.