Tennessee Code Title 67. Taxes and Licenses § 67-5-604

(b)(1) The value of qualified pollution control facilities shall, for the purpose of ad valorem property taxation, be deemed to be its salvage value, that is, the estimated fair market value, if any, that could be realized upon the voluntary sale or other disposition of such property when it can no longer be used for the purpose for which it was designed. For purposes of this section, salvage value shall never exceed one-half percent (0.5%) of the acquisition value of such facilities. Facilities may qualify for the valuation provided in this subdivision (b)(1) by obtaining a certificate from the department of environment and conservation, or by such county boards of health as it may designate.

(2) Such certificate shall be issued in the event that the property used for pollution control is in compliance with the applicable rules and regulations adopted pursuant to the various provisions of §§ 68-201-101 -- 68-201-116, 68-221-101 -- 68-221-206, title 68, chapter 212, part 1 and title 69, chapter 3, part 1.

(c)(1) Application for a certificate shall be filed with the department or its designated representative, in such a manner and form as may be prescribed by regulations adopted by the department and shall contain specifications of such facilities.

(2) The department shall determine whether such application should be allowed in whole or in part, within thirty (30) days of receipt, and shall approve or disapprove the issuance of the certificate. Upon failure of the department to issue such approval or disapproval within the thirty-day period, the application for certificate shall be considered to be approved.

(3) For purposes of ad valorem taxation, the effective date of the valuation provided in this section shall be January 1, following the date of application.