(a) In the case of a request (i) which does not involve a material change in permit conditions, then applicable law, environmental conditions or technology since the date of issuance of the existing permit, or (ii) for which an opportunity for public comment or hearing or both is not required by applicable law, the department shall on or before fifteen calendar days after the receipt of a request mail a written determination to the permit holder of its decision on the request. If the decision is to deny the request, the permit holder shall be afforded an opportunity for hearing and notice of such decision shall be given by the department in the next available issue of the environmental notice bulletin.

(b) In the case of a request which may involve a material change as described in paragraph (a) of this subdivision, or for which an opportunity for public comment or hearing or both is required by applicable law, the department shall on or before fifteen calendar days after the receipt of a request mail a written determination to the permit holder that the request shall be treated as an application for a new permit.

(c) In the case of a request for the renewal, reissuance, recertification or modification of an existing state pollutant discharge elimination system permit issued in lieu of a national pollutant discharge elimination system permit the request shall be treated as an application for a new permit. Any other request may be treated as an application for a new permit.

(d) In the case of a request for the renewal, reissuance, recertification or modification of an existing permit issued pursuant to article nineteen of this chapter, the request may be treated as an application for a new permit. If, pursuant to paragraph (a) or (b) of this subdivision, the department fails to mail a written determination to the permit holder within such fifteen calendar day period, then the provisions of paragraph (b) of subdivision three of section 70-0109 of this chapter shall apply.