For the purpose of carrying out the provisions of this chapter, the city council, unless otherwise provided by resolution that the work be done by the city, shall provide for the entering into a contract with any suitable and responsible person for a term of years, not exceeding fifteen years, for the exclusive right to collect garbage, rubbish and waster matter within the city, which person shall be known and designated as the city's garbage collector. An exception to the fifteen years maximum contract is authorized on a one-time basis to fulfill the requirement of a seventeen-year contract with Grass Valley Disposal, Inc. to settle litigation and such contract has been modified by a federal judge to allow settlement of all litigation as of June 30, 1988. (Prior code § 11-12)