It shall be the duty of the assessor-collector of said irrigation district to collect and receipt for all taxes levied as herein provided in the same manner and at the same time as is required in the receipt for, and the collection of, taxes upon real estate for county purposes; provided, that such collector shall receive in payment of the district bond fund taxes above mentioned for the year in which said taxes were levied, interest coupons or bonds issued by said irrigation district maturing within said year, the same as so much lawful money of the United States, if such interest coupons do not exceed the amount of taxes for district bond fund which the person tendering the same owes. The assessor- collector shall on or before the first Monday of each month, turn over to the treasurer all monies and coupons theretofore collected or received by him or an account of such taxes.