No, North Dakota does not require special permits to haul hazardous material within the state. However, federal rules (which apply in ND) require commercial operators and anyone who hauls hazardous materials to have current Certificates of Registration as outlined in 49 CFR Part 107.608. Federal regulations also require a safety permit for interstate or intrastate transportation of certain radioactive, explosive, or poisonous materials which can be found in 49 CFR Part 385 Subpart E.
Farm vehicle operators driving for a farm operation are not required to have a CDL; therefore, no HM endorsement is required, even if the driver has a CDL. However, anyone operating as a commercial carrier is required to have a HM endorsement on their CDL when hauling nurse tanks.
Yes, the farm exemption in 49 CFR Part 383 does not apply to commercial transportation. You would need a CDL with the proper endorsements (tanker, HM) if the vehicle is over 26,000 lbs GCVWR or requires placarding.
If the tank has not been cleaned and purged, it is considered a bulk tank in transportation and you would need placards, shipping paper, etc. If the tank has been cleaned and purged, then you do not have to worry about HAZMAT requirements.
The tank would not be considered a bulk tank and would have less than 1000 lbs of hazardous materials so it would not require placards, but shipping papers for the hazardous material would be required.
Generally the answer is yes, but your load must meet the definition of a hazardous material in 49 CFR Part 390.5. If you still have HAZMAT in the mixture which meets the rules in the HAZMAT regulations then you will still have to comply. If the state of the material is altered, the material may no longer pose a hazard and may not require compliance, but that decision must be made in accordance with federal regulations and cannot be decided solely because you diluted it.
Generally, any tank over 119 gallons is a bulk tank requiring compliance with the federal hazardous materials rules to include placarding, licensing, shipping, etc. There are however, many exceptions to the regulations.
Basically, 49 CFR 173.5(a) and North Dakota state law state that a farm vehicle traveling on local roads between fields of the same farm and not carrying class 2 material is exempt from all HAZMAT requirements. So, a farm vehicle traveling township/county/state roads between farm fields does not have to meet HAZMAT requirements. However, if traveling on interstate highways or to a neighboring farm, the farm vehicle must comply with HAZMAT requirements because the movement does not meet the local roads/fields of the same farm exception.
The second part of the question pertains to an anhydrous ammonia nurse tank which is a class 2 material. 49 CFR 173.5 and North Dakota state law states that a farmer carrying class 2 materials is only exempt from subpart G and H (which includes training requirements and emergency response information requirements). So, a farm vehicle carrying anhydrous ammonia traveling on township/county/state roads is exempt from (1) training and emergency response information requirements in accordance with 49 CFR 173.5, (2) shipping paper requirements in accordance with 173.315(m), and (3) CDL HAZMAT endorsement requirements in accordance with 383.3(d). The vehicle does, however, have to be placarded/marked in accordance with 173.315(m).