Section 50. Expiration and renewals of certificates and licenses

All
  certificates  of  registration  issued  under  the  provisions  of   the
  preceding   sections  of  this  article  and  all  licenses  authorizing
  connections with street sewers  or  water  mains  shall  expire  on  the
  thirty-first  day of December of the year in which they shall be issued,
  and may be renewed within thirty days preceding  such  expiration.  Such
  renewals to be for one year from the first day of January in each year.