A sanatorium established under the provisions of this act solely for the treatment of tuberculosis that has expended at least $10,000.00 in buildings and equipment, may, upon application to the department of community health, be placed upon the approved list of county sanatoriums. Once a sanatorium is entered upon the approved list, the sanatorium may remain listed and be entitled to state aid so long as the scope and character of its work are maintained in a manner that meets the approval of the department of community health. On the first day of July of each year the secretary of the board of the sanatorium on the approved list, shall report under oath to the department of community health, the character of the work done and the treatment given, the number and names of the persons employed and patients treated and on that date remaining in the sanatorium, the amount contributed by the county or counties for the support of the sanatorium, and such other matters as may be required by the department of community health. Upon the receipt of the report, if it appears that the sanatorium has been maintained in a satisfactory manner, the director of the department of community health shall make a certificate to that effect, together with the cost of maintenance for the year and the amount actually contributed by each county, and file it with the state treasurer. Upon receiving the certificate the state treasurer shall draw his or her warrant payable to the treasurer of each county contributing toward the maintenance of the sanatorium, for a sum equal to 1/2 the amount actually contributed by that county for the support of the sanatorium for the preceding year. However, the total sum paid as state aid shall not exceed the sum of $3,000.00 for any 1 sanatorium in any 1 year.