The board of supervisors of any county may appropriate necessary funds to advance the cost of any proposed improvement constructed under the provisions of this act, or said board of supervisors may set up and establish a revolving fund to finance proposed improvements under the provisions of this act. Whenever the cost of any improvements constructed under the provisions of this act is advanced from funds so appropriated or set up and established by the board of supervisors, the county treasurer shall credit all assessments collected from the township at large and the assessment district, including any share of delinquent tax sales apportioned thereto, directly to the fund from which the cost of said improvement was advanced.