(a) The appeal shall be heard and determined by the circuit court upon the issues raised by the notice of appeal and response according to the rules relating to the trial of civil actions, so far as applicable.

(b) If, before the date set for the hearing, application is made to the circuit court for leave to present additional evidence and the circuit court finds that the evidence is material and that there were good reasons for failure to present it in the proceeding before the Arkansas Pollution Control and Ecology Commission, then the circuit court may order that the additional evidence be taken before the commission upon such conditions as may be just. The commission may modify its findings and decision by reason of the additional evidence and shall file that evidence and any modifications, new findings, or decisions with the reviewing circuit court.

(c) (1) (A) The review shall be conducted by the circuit court without a jury and shall be confined to the record.

(B) However, in cases of alleged irregularities in procedure before the commission that are not shown in the record, testimony may be taken before the circuit court.

(2) The circuit court shall, upon request, hear oral argument and receive written briefs.

(d) The circuit court may affirm the decision of the commission or vacate or suspend the decision, in whole or part, and remand the case to the commission for further action in conformity with the decision of the circuit court if the action of the commission is:

(1) In violation of constitutional or statutory provisions;

(2) In excess of the commission's statutory authority;

(3) Made upon unlawful procedure;

(4) Affected by other error of law;

(5) Not supported by substantial evidence of record; or

(6) Arbitrary, capricious, or characterized by abuse of discretion.