Where no such board is provided for by law or by such ordinance, the governing body, upon the completion of any local improvement, may appoint by resolution three discreet freeholders, residents of the municipality, in no way interested in the improvement, as commissioners to make the assessments for benefits for such improvement. If such local improvement shall be of a general nature affecting the greater part of the real estate in the municipality, no commissioner shall be disqualified to act by reason of the fact that he may own real estate included in such assessment.