The city utility taxes provided for in Section 21-33-203 shall be collected by the chairman of the state tax commission and shall be accounted for separately from the amount of all other taxes collected for the state and city in said municipality. Said taxes shall be paid to the municipality in which collected, less five per cent thereof which shall be retained by the chairman and paid into a special fund to be expended by the chairman to defray the cost of carrying out the provisions of the City Utility Tax Law. Payments to the municipalities shall be made by the chairman on or before the fifteenth day of the month following the month in which the tax was collected. When so paid, the money may be expended by the municipalities for any purpose now authorized by law.