Nothing contained in this chapter shall prevent the city from allowing the collection and hauling of garbage and refuse by licensed haulers; provided, that they conform to the methods, manner and frequency of collection as set forth in section 4-2-7 of this chapter, instead of calling for bids for exclusive handling, or after calling for such bids by notice, as provided in section 4-2-9 of this chapter, and after consideration of responses thereto, if any. (Prior code § 11-11)