1. Every permit for the discharge of sewage from a sewer system or for the discharge of refuse or waste matter from a shop, factory, mill or industrial establishment, shall when necessary to conserve the public health, be revocable or subject to modification or change by the commissioner on due notice after an investigation and hearing and an opportunity for all interested therein to be heard thereon being served on the public authorities of the municipality owning and maintaining the sewer system, or on the proprietor, lessee or tenant of the shop, factory, mill or industrial establishment.

2. Plans for any such modification shall be submitted to and approved by the department.

3. The length of the time after receipt of the notice within which the discharge of sewage or of refuse or waste matter shall be discontinued may be stated in the permit, but in no case shall it exceed two years in the case of a sewer system, or one year in the case of a shop, factory, mill or industrial establishment, and if the length of time is not specified in the permit, it shall be one year in the case of a sewer system, and six months in the case of a shop, factory, mill or industrial establishment.

4. On the expiration of the period of time prescribed after the service of a notice of revocation, modification or change from the commissioner, the right to discharge sewage or refuse or waste matter into any of the waters of the state shall cease and terminate and the prohibition of section 17-1701 against such discharge shall be in full force as though no permit had been granted, but a new permit may thereafter again be granted as hereinbefore provided.

* NB Expired September 1, 1973