The funds received from the collection of the rates and charges provided by this chapter shall be deposited as received with the City Treasurer, who shall keep the same separate from all other funds in his possession and in a separate fund designated Sewerage Revenue Fund. Subject to the provisions of any ordinance or indenture of mortgage authorizing the issuance of and securing mortgage revenue bonds for the system, moneys in such Fund shall be used for the payment of the cost and expense of operation, maintenance, repair and replacement of the sewage collection and sewage treatment system and for payment of debt charges on bonds issued for extensions and improvements of the system. Any surplus in the Fund over and above the requirements hereinbefore mentioned may be used for enlargements of and replacements to the system and parts thereof. (Ord. 64-99. Passed 10-19-99.)