When part of the facilities of a sanitarium established and maintained under this Division are vacant and not needed for the care and treatment of persons afflicted with tuberculosis, the board of directors, after first obtaining approval of the County Board, may, for a consideration to be determined by the county board: (a) extend the privileges and use of the sanitarium for the care and treatment of persons who are afflicted with chronic pulmonary diseases other than tuberculosis and persons who are convalescent or chronically ill, or (b) rent the same to any branch, department or agency of the State or Federal government, or to any municipal corporation, quasi municipal corporation, political subdivision or body politic, or agency thereof or any not-for-profit corporation or any non-profit organization or association, provided such lessee or lessees be engaged in public health or welfare work or services in such county; provided such vacant facilities shall be separate so that tuberculosis patients shall be isolated from the convalescent and chronically ill and such rented facilities. Such vacant part may be used partly for any one or more of the uses set forth in (a) and (b). Any services provided by such sanitarium or board may be made available with such rented facilities. Non-profit organization or association means any organization or association, no part of the net earnings of which inures or may lawfully inure to the benefit of any individual. The charge for providing care and treatment of those afflicted with chronic pulmonary disease other than tuberculosis and the convalescent or chronically ill shall not be less than the actual cost of providing such care and treatment.