The Department of Public Health shall hold at least four examinations each year, at such times and in such locations as may be convenient. Notice of the time and place of each examination shall be given in writing to each applicant at least ten days prior to the examination. To obtain a license an applicant shall furnish such evidence of competency as said department shall require. The applicant shall satisfy said department that he has the requisite skill to perform the work of a subsurface sewage disposal system installer or cleaner and can comply with all other requirements of this chapter. Upon application to said department for a license, the applicant shall pay to said department a fee of fifty dollars for a subsurface sewage disposal system installer license or twenty dollars for a subsurface sewage disposal system cleaner license. The applicant shall present himself at the next regular examination. The Department of Public Health shall conduct such written, oral and practical examinations as it deems necessary to test the knowledge of the applicant for a subsurface sewage disposal system installer’s license on sewage disposal system construction and installation or to test the knowledge of the applicant for a subsurface sewage disposal system cleaner on subsurface sewage disposal system cleaning and servicing. When an applicant has qualified for a license, the department shall issue to such person a license entitling him to engage in the work or occupation of subsurface sewage disposal system installer or subsurface sewage disposal system cleaner until the date for renewal under § 19a-88. All fees collected by said department shall be promptly transmitted to the State Treasurer.