(1) Condenser water, cooling water and ice machine water may be discharged to drains or waterways, but not to canals.

(2) Wastes after proper treatment may be discharged to a drain or wasteway, if such discharge is approved by the department of ecology. The preferred methods of disposal of milk waste are:

(a) Small receiving stations or bottling plants—connection to city sewers, or irrigation.

(b) All others—irrigation or treatment by filtration or activated sludge.

(3) Milk waste may be used directly for irrigation under a controlled system whereby no nuisance is caused.