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New Hampshire Department of Environmental Services

Frequently Asked Questions
Limited Permits for Hazardous Waste Generators
  • When do I need a Limited Permit?
    Limited Permits are required for New Hampshire full quantity generators who have an elementary neutralization unit, wastewater treatment unit or wastewater evaporator if it either receives a hazardous wastestream or generates a hazardous waste sludge. Basically, if there’s hazardous waste going into the unit or hazardous waste coming out of the unit, then you need a Limited Permit. If you neutralize a wastewater that is never a corrosive hazardous waste (and it’s not hazardous for any other reason), then a Limited Permit isn’t needed. If none of the wastestreams you put into a wastewater treatment unit or evaporator is hazardous for any reason and if the unit generates a sludge that is never a hazardous waste, then a Limited Permit isn’t needed.
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  • What types of units are covered under Limited Permits?
    There are three categories of units that may require a Limited Permit.

    1. An elementary neutralization unit is a tank, tank system, container or transport vehicle or vessel in which corrosive hazardous wastes are neutralized.

    2. A wastewater treatment unit is a tank or tank system that receives and treats hazardous wastewaters or that generates a hazardous waste sludge. A wastewater treatment unit can be a system in which metals are precipitated out and solids are pressed into a filter cake. Other examples of wastewater treatment units are ion exchange columns (spent resins are considered a wastewater treatment sludge), vacuum (or "cold") distillation units (for wastewaters), cyanide destruction systems and hexavalent chrome reduction systems.

    3. Wastewater evaporators do what their name implies – they evaporate water. Evaporators are not to be used to illegally dispose of volatile hazardous wastes. When facilities apply for Limited Permits for evaporators, we require that they provide either a copy of a permit from the NHDES Air Resources Division for the evaporator or calculations to prove that emissions from the evaporator will comply with the air toxics requirements of Env-A 1400.

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  • What types of treatment can I do without a Limited Permit?
    New Hampshire small quantity generators (<100 kg/month) don’t need Limited Permits for their elementary neutralization units, wastewater treatment units or evaporators. Also Limited Permits aren’t required for material recycling units, such as solvent distillation units and silver recovery units. Oil/water separators don’t require a Limited Permit if the recovered oil is recycled. Treatment that is conducted in a totally enclosed treatment unit doesn’t require a Limited Permit. An example of totally enclosed treatment is a piping system in which two corrosive wastestreams combine and neutralize each other. (Evaporators and most tanks are not totally enclosed.) Please contact the Permit Engineer, NHDES, (contact information below) if you have questions about a specific type of treatment.
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  • What are my regulatory obligations under a Limited Permit?
    There are five operational requirements for units covered under Limited Permits:

    1. Prevent unknowing and unauthorized entry into or onto the permitted unit per Env-Hw 304.04(e).

    2. Inspect the unit according to a written schedule that you develop, keep a log of your inspections and remedy any problems you find. See additional information below.

    3. Design, construct and operate the unit to prevent spills and leaks, generation of extreme heat or pressure, production of toxic or flammable fumes or gases, damage to the structural integrity of the unit, or other conditions as specified in Env-Hw 304.04(h).

    4. At closure, all hazardous waste and hazardous waste residues shall be removed from the unit per Env-Hw 304.04(i).

    5. Within 15 days of a spill or leakage from the unit, submit a written report including the information specified in Env-Hw 304.04(j).

    Also please note that the operators of these units must have annual hazardous waste training related to their specific hazardous waste duties.

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  • What are the inspection requirements for my permitted unit?
    First, develop and follow a written inspection schedule for inspecting all monitoring equipment, safety and emergency equipment, security devices, and operating and structural equipment such as tank walls and pumps. The schedule must be kept at your facility and should identify the types of problems, such as malfunctions or deterioration (e.g., an inoperative pump, leaking fitting, heavy corrosion, etc.), that you will be looking for. Second, decide how frequently you will inspect each component of the system, based on the rate of possible deterioration and the probability of an environmental or human health incident if any deterioration, malfunction or operator error goes undetected between inspections. Third, remedy any deterioration or malfunction detected in an inspection. The remediation must be done on a schedule that ensures the problem does not lead to an environmental or human health hazard. Where a hazard is imminent or has already occurred, remedial action must be taken immediately. And finally, record your inspections in an inspection log, and maintain the log for at least three years from the date of each inspection. The log must contain, at a minimum, the following information:

    The date and time of each inspection.
    The name (not just initials) of the inspector.
    A recording of the observations made.
    The date and nature or any repairs or other remedial actions taken as a result of inspection observations.

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  • Under what circumstances do I need to modify my Limited Permit?
    Modifications may be required under the following circumstances:

    Changing the method of treatment.
    Adding a new wastestream to the treatment unit.
    Removing an existing wastestream from the treatment unit.

    Please contact the Permit Engineer, NHDES, (contact information below) if you are contemplating any of these changes. Depending on your specific circumstance, you might only need to submit a letter explaining the proposed changes. If a permit modification is indeed necessary, simply fill out the relevant portions of the Hazardous Waste Limited Permit application form and check the box for "Limited Permit Modification." The fee for modifications is currently $400.

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  • When will I need to renew my Limited Permit?
    Limited Permits are valid for five years. Although we issue reminder letters to facilities in advance, it is your responsibility to submit an application for renewal 90 days prior to the expiration of your current permit.
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  • How do I obtain a Limited Permit application form?
    Application forms are available in PDF format at, “Public,” “Forms and Applications,” and scroll to “Hazardous Waste Compliance.” The application can also be found on the CD provided in the Hazardous Waste Coordinator Certification Training Manual. If you would like an application form mailed to you, please contact the Permit Engineer (contact information below) or the Hazardous Waste Assistance Hotline at 1-866-HAZ-WAST (toll-free; in-state only) or (603) 271-2942.
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If you have any questions about Limited Permits, please contact:

Zachary Lorch, Waste Management Engineer
29 Hazen Drive; PO Box 95
Concord, NH 03302-0095
(603) 271-5328
(603) 271-2456 (fax)

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

copyright 2017. State of New Hampshire