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Waste Management

3. Mixed Wastes

 
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Mixed Waste Overview

3.1       What Is Mixed Waste?

A waste is mixed if it is classified by federal agencies as being both radioactive and hazardous. At Berkeley Lab, a waste is characterized as radioactive if either process knowledge or monitoring and sampling shows that radioactive material has been added to the waste through U.S. Department of Energy (DOE) research or support activities. Hazardous waste is governed by U.S. Environmental Protection Agency (EPA) and state of California guidelines.

Mixed-waste storage at the Hazardous Waste Handling Facility (HWHF) is governed by the Part B Permit, and is subject to dual regulations by EPA and DOE. A compliance order, known as the Site Treatment Plan, governs the treatment of mixed waste once it reaches the HWHF. This compliance order was issued to all DOE sites, because treatment technologies and facilities are scarce, and the waste must be stored in excess of one year.

In fiscal year (FY) 2003, Berkeley Lab began recharging generators for the management of mixed wastes due to the cost of management, treatment, and disposal. All mixed wastes received at the HWHF will be recharged to the generator according to the latest pricing structure.

In essence, all mixed waste must meet the segregation, packing, labeling, and storage guidelines for both radioactive and hazardous wastes. All mixed wastes should be segregated from hazardous or radioactive wastes. Below are the most common mixed- waste categories, and their description, segregation, packaging, labeling, and pickup requirements. For other waste categories, please contact your Generator Assistant.

3.2       Liquid Mixed Waste

Radioactive liquid waste is any hazardous liquid containing radioactive material. Scintillation vials are not included in this category (see Section 3.3 [Mixed Waste Scintillation Vials]). If you generate mixed waste that is corrosive (pH <2 or pH >12.5), you might be eligible for benchtop treatment (neutralization) to avoid the mixed-waste recharge. See the benchtop-treatment criteria in Section 3.5, or call your Generator Assistant for more details.

3.2.1      Segregation

Mixed radioactive liquid wastes with short-lived isotopes [e.g., <30-day half-life (32P)] should be segregated from isotopes with half-lives between 30 and 90 days (35S, 125I) and from long-lived isotopes (3H, 14C).

3.2.1.1   Decay-in-Place Storage

The Waste Management Group provides decay-in-place storage at the HWHF for liquids containing isotopes with half-lives <90 days. Once the waste has decayed through a minimum of 10 half-lives, and an analysis has confirmed that all isotopes are below minimal detectable concentrations, it will be reclassified as hazardous.

3.2.2      Packaging

All mixed radioactive liquid wastes must be stored in a container with a tight-fitting lid and a structural integrity that is compatible with the waste. A variety of containers are available from vendors. If you have questions regarding the compatibility of your waste with the container, please contact your Generator Assistant.

Accumulate mixed radioactive liquids in an appropriately sized container. If your process generates a small amount of waste, do not accumulate the waste in a 5-gallon container. Use a smaller container and request a waste pickup more frequently. Conversely, do not overfill containers. This creates a safety hazard to those around you and to the technicians upon pickup, and might create potential contamination issues. You are also charged based on the size of the container, not the amount of waste.

3.2.3      Labeling 

A hazardous-waste label (Figure 3-1) and a radioactive-material tag (Figure 3-2) must be attached to the container once the first addition of waste is placed in the container. Sections A, F, and G of the radioactive-material tag, with the exception of the generator signature, must be filled out. If there is a possibility of contaminating the radioactive-material tag while adding waste to the container, you may post the tag nearby, but the container must refer to the tag number (e.g., R0XXXX). In most cases, the radioactive liquid mixed-waste container receives multiple additions of waste until it is full. In this case, an accumulation log is used to record these multiple additions. Do not use the radioactive-material tag to record multiple additions of the same isotope to the container.

3.2.4      Storage

The storage of your liquid mixed-waste container must be in a Mixed Waste Satellite Accumulation Area (MWSAA). An MWSAA is similar to a hazardous waste SAA, but must be located inside your Radioactive Materials Area (RMA).

tag image tag image

Figure 3-1. Example of a properly
completed hazardous-waste label.
Figure 3-2. Example of a radioactive-
material tag.

 

3.2.5      Setting Up an MWSAA

The MWSAA must be located within the boundaries of your RMA, at or near the point of waste generation, and must be under the control of the generator. The MWSAA must be at or near the site where the waste is generated so the MWSAA can be controlled by staff while they are working. Your MWSAA must be located in the room where the mixed waste is generated, or in an immediately adjacent room, within your RMA (with no intervening hallway). The intent of this requirement is to provide virtually full-time monitoring of the MWSAA by the individual(s) generating the waste.

Fire code requires that the MWSAA be located away from all exit doors or areas where it could hamper egress in the event of a fire or spill. Appropriate spill cleanup materials should be located near your MWSAA, especially if large amounts of mixed wastes (up to 55 gallons) are accumulated.

The MWSAA must be clearly designated using the purple sign depicted in Figure 3-3. If there is uncertainty regarding the boundaries of the MWSAA, the area should be clearly marked off with tape, arrows, and other signage to unambiguously define the MWSAA boundary. All mixed wastes must be stored in the MWSAA. Maximum storage allowed is 55 gallons of any particular mixed-waste stream or up to 1 quart of acutely or extremely hazardous wastes (see Appendices II and III, respectively). If you wish to accumulate more than 10 gallons (and fewer than 55 gallons) of flammable-liquid mixed waste in an MWSAA, fire code requires that your MWSAA be located in a metal “flammables” cabinet. This determination might also be influenced by storage of other flammable liquids in the vicinity of your MWSAA. If you have questions concerning fire code applications in your work area, please contact the Berkeley Lab Fire Marshall at ext. 6370.

All mixed wastes must be in containers compatible with the waste. Accumulate liquid corrosive mixed wastes in polyethylene or plastic containers that are known to be compatible with acids or bases. Flammable mixed wastes may not be accumulated in plastic containers of any type other than a listed and approved safety can. (Approved safety cans are available from the Waste Management Group in 5-gallon, 2.5-gallon, and 1-gallon capacities.) If you have small amounts of flammable mixed waste, glass or metal containers may be used, but the maximum allowable glass-container size is 1 pint for Class IA liquids, and 1 quart for Class IB liquids (see Section 1.2.3.1 for further discussion of flammable liquid waste storage).

 


Figure 3-3. A Mixed Waste Satellite Accumulation Area (MWSAA) sign.

 

Keep primary waste containers tightly closed at all times except when you are adding waste. The container may be opened up to 15 minutes while you add waste. A funnel in a container opening is not considered closed unless the funnel itself seals to the container and would prevent spillage. Container closures must be secure. Cork , rubber, or ground-glass stoppers; aluminum foil; and polyethylene film or parafilm are not allowed. If the waste is likely to generate gases during storage, vented caps should be used, or the waste should be treated using an approved benchtop-treatment procedure. Plastic bags used as containers must be closed (twist-tie, ziplock, tape, staple, or spring clamp). Do not add waste to a mixed-waste container after you have submitted the pickup requisition for that container to the HWHF.

Secondary containment is required for all liquid mixed wastes and all wastes accumulated in glass containers. The secondary containers must be compatible with the chemicals they contain. The requirement for secondary containment of waste containers in an SAA or MWSAA is a best-management practice followed throughout industry and government. Secondary-containment capacity of 110% of the largest container being stored is an industry standard. The secondary-containment requirement depends only on the largest container in storage, not on the actual volume of waste being stored. Remember that physical space and segregation of incompatible chemicals in secondary containment are important as well. Each container must be stored safely.

Metal containment is acceptable for noncorrosive wastes.

All liquid mixed wastes require secondary containment based on the largest container stored in the MWSAA. For example:

A lab MWSAA contains three 1-liter bottles of waste. Secondary containment should be able to contain 110% of 1 liter or 1.1 liters. In this case, an 8” × 10” plastic photo tray is acceptable. (8” × 10” × 1” = 80 cubic inches or 1.3 liters).

Secondary-containment tubs and trays are available from several suppliers with whom LBNL has system contracts that facilitate ordering. Other plastic trays and tubs are available from suppliers such as VWR, with a two-day delivery time. Appropriate containment options can be found on the Labels/Supplies section of this Web page.

Keep incompatible wastes physically separate in secondary containment as well as in the primary container (e.g., acids and bases; oxidizers and organics; water reactives and aqueous wastes).

California regulations allow waste accumulation for up to one year in an MWSAA; however, under Berkeley Lab policy, waste may accumulate in MWSAAs for up to 275 days (nine months). This is not a HWHF permit condition. Waste containers should be requisitioned for pickup as soon as they become full. Waste remaining in an MWSAA greater than one year will be subject to an automatic Noncompliance and Corrective Action Report (NCAR)

Do not store chemicals, empty bottles, or other items in your MWSAA, because these items might be mistaken for unlabeled mixed waste. Good housekeeping practices should also be implemented to provide for easy access to your MWSAA.

 

Figure 3-4. Example of a completed radioactive/mixed-waste disposal requisition form.

3.2.6      Pickup

When your liquid mixed waste container is full, or is approaching the 275-day (nine-month) accumulation time, tighten the lid on the container and don’t add further waste. Complete the remainder of the radioactive-material tag, summarizing the isotopes (one entry for each isotope) and constituents (buffers, etc.) based on accumulation log entries. Account for 100% of the constituents (estimates are acceptable). Fill out the radioactive/mixed-waste disposal requisition form (Figure 3-4). Fax a copy of the requisition form, radioactive-material tag(s), and accumulation log(s) to the Waste Management Group at ext. 4838. After the waste-review process, your waste will be picked up by the technicians and brought to the HWHF, where it will be stored pending packaging for shipment.

3.3       Mixed Waste Scintillation Vials

Scintillation vials are typically 10–20 mL vials used in a liquid scintillation counter to measure radioactivity. Scintillation fluid is added to the vial prior to counting.

Note:  In recent months, we have discovered a regulated hazardous constituent in several batches of UltimaGold (sold by Packard) scintillation fluid. When radioactive material is added at the research bench, this becomes mixed waste and will be charged to your project account. If you are using UltimaGold scintillation fluid, please contact your Generator Assistant for batches that do not have this problem, or seek an alternative.

3.3.1      Segregation

Significant cost-efficiency can be achieved if scintillation vials are segregated into the following groups.

1.      Vials with radioactivity of ≤0.05 microcuries per mL per vial of 3H and/or 14C, and vials with isotopes with a half-life of <30 days with no other isotope.

2.      Vials with radioactivity of >0.05 microcuries per mL per vial of 3H and/or 14C, and vials with isotopes with a half-life of >30 days, excluding alpha-emitting isotopes.

3.      Vials with alpha-emitting radioactivity.

Used scintillation fluid such as Hionicfluor, Picofluor, and some batches of Ultima Gold (see above) are regulated as hazardous wastes. All vials containing mixed wastes should be segregated from nonmixed wastes. Contact your Generator Assistant for more details.

3.3.2      Packaging

Scintillation vials are collected in a plastic bag inside a 12.2 gal container (Figure 3-5). Tighten the screw caps of the scintillation vials prior to placing them in the mixed-waste container. The lid of the 12.2 gal container should be in place at all times unless you are adding vials to the bag. Do not overfill the plastic bag; overfilling creates a safety hazard to those around you and the RCTs upon pickup, and might create potential contamination issues. Since the plastic bag is the waste container, the 12.2 gal container suffices for secondary containment.

Figure 3-5. A 12.2 gal container for collecting scintillation vials.


3.3.3      Labeling 

A radioactive-material tag (Figure 3-2) must be attached to the container once the first scintillation vial is placed in the container. Sections A, F, and G of the tag, with the exception of the generator signature, must be filled out. A complete and accurate hazardous-waste label must also be attached. If there is a possibility of contaminating the radioactive-material tag while adding waste to the container, you may post the tag nearby, but the container must refer to the tag number (e.g., R0XXXX).

In most cases, the scintillation-vial container receives multiple additions of waste until it is full. In this case, a mixed-waste accumulation log (Figure 3-6) is used to record these multiple additions (e.g., number of vials, isotopes, activity). Do not use the radioactive-material tag to record multiple additions of the same isotope to the container.

 

Figure 3-6. An example of a mixed-waste accumulation log.

3.3.4      Storage

The storage of your scintillation-vial mixed-waste container must be in an MWSAA. An MWSAA is similar to a hazardous waste SAA, but must be located inside your Radioactive Materials Area (RMA).

 

3.3.5      Pickup

When your scintillation vial container is full, or is approaching 275 days (nine months) from the accumulation start date, close the bag by twisting and taping the end (Figure 3-7). Place the lid on the 12.2 gal container, and twist it shut. Complete the remainder of the radioactive-material tag by summarizing the isotopes (one entry for each isotope) and constituents (type of scintillation fluid, lot number, etc.) based on accumulation log entries. Fill out the radioactive/mixed-waste disposal requisition form (Figure 3-4). Fax a copy of the requisition form, tag(s), and accumulation log(s) to the Waste Management Group at ext. 4838. Allow two weeks for pickup.

After the waste-review process, your mixed waste will be picked up by the technicians and brought to the HWHF, where it will be stored pending packaging for shipment.

 

Figure 3-7. Twist-and-tape method of closure.

 

3.4    Miscellaneous Mixed Wastes 

The following wastes are generated infrequently. Contact your Generator Assistant for more information.

Empty containers that are contaminated with radioactivity and that previously contained an acutely or extremely hazardous waste such as arsenic compounds, cyanide compounds, beryllium compounds, cadmium compounds, or concentrated hydrochloric acid must be managed as separate items. A separate radioactive-material tag should be filled out and attached to the container. Fax the tag and radioactive/mixed-waste disposal requisition form to the Waste Management Group at ext. 4838.

Empty containers that are contaminated with radioactivity and have previously contained a hazardous waste other than an acutely or extremely hazardous waste are managed as radioactive waste. Please manage the empty container as radioactive dry waste (see Section 2.2).

Mixed waste containing only isotopes with half-lives shorter than 15 hours (18F) may be decayed for 10 or more half-lives in generator areas as long as the storage time for the waste does not exceed 275 days. Otherwise, the container must be requisitioned as mixed waste for pickup.

Transuranic mixed waste (i.e., waste with greater than 100 nCi/g of isotopes such as plutonium, americium, neptunium, curium, or californium) may be generated as long as the process by which it was generated can be tied to the United States' defense mission.

If you anticipate generating this waste, please contact your Generator Assistantwho will assist in gathering this documentation.

Discarded surface-contaminated or activated lead is currently sent for macroencapsulation as mixed waste at an off-site facility. Small quantities of contaminated or activated lead (<10 bricks) should be individually double-bagged, and each bag should be labeled as hazardous waste. Attach a radioactive-material tag for all 10 bricks. Fill out a radioactive/mixed-waste disposal requisition, and fax it to ext. 4838.

If you have larger quantities of lead, please contact your Generator Assistant.

Sealed sources with lead as an integral part of the source is mixed waste. Sealed sources are tracked by the OHP Group. Contact your RCT for information to remove your source from your authorization. Once this has been done, do the following for each source:

1.      Complete the following three documents for each source: (1) a completed radioactive-material tag, (2) a hazardous-waste label, and (3) a description of the source that specifically provides the 12 items of information listed in Section 2.6.7. Attach the hazardous-waste label and the radioactive-material tag to the container with the source.

2.      Once you’ve completed the tag and the 12-item list for each source, fax them along with a radioactive/mixed-waste disposal requisition form.

Note:  Sources with lead as an integral part of the source with less than 1 pCi of radioactivity will only be accepted as hazardous waste.

3.5       Benchtop Treatment

Benchtop treatment refers to a process used by research labs to perform authorized treatment of wastes per California regulations [3] . Benchtop-treatment methods are bounded by practices cited in “Prudent Practices in the Laboratory—Handling and Disposal of Chemicals” published by the National Research Council. Benchtop treatment is often used to neutralize corrosive mixed wastes to avoid treatment charges. However, any experimental reaction mixture or waste aqueous solution that contains nitric acid (HNO3) at more than 5% by weight, 0.8 M, or pH<1 must be either carefully diluted to reduce the concentration of the nitric acid, or neutralized. Either process must be authorized through an approved benchtop-treatment procedure. Neutralization or dilution will properly treat these wastes for safe storage. It will also prevent safety hazards in the laboratory caused by inadvertently mixing such wastes with incompatible materials.

There are several regulatory requirements that must be met before a benchtop-treatment authorization can be approved. After working with you to ensure all requirements are met, your Generator Assistant will obtain all needed signatures. The requirements include:

  • A written neutralization procedure:
      • A description of the process generating the waste and quantity [4] to be treated
      • The treatment location (as close as practical to the generating location)
      • The treatment process and materials
      • A list of personnel authorized to perform the treatment
      • A treatment log showing the dates of treatment, quantity, etc.

 

  • Knowledge of the waste. If the treated waste will be sent to the Waste Management Group for disposal, generator process knowledge may be used. If the treated waste is to be discharged to the sanitary sewer, the waste-generating process must not involve the presence of metals or organics that exceed permitted levels. A certified laboratory analysis of the waste for sanitary sewer discharge is required (your Generator Assistant will assist you in getting this analysis completed).

 

  • Written approval for discharge signed by the Environmental Services Group designee for waste that can be discharged to the sanitary sewer after treatment. If the waste is radioactive and you believe it is appropriate for sewer discharge and limited to isotopes with a <90-day half-life, additional approval must be given by your Health Physicist.

 

  • The evidence that the appropriate procedural training has been completed by each authorized person (e.g., training log showing a description of topics covered). The training record must be maintained for three years.

 

  • A treatment log indicating the date and amount of waste treated and the person who performed the treatment must be maintained for treated waste.

 

Note:  Depending on the specific circumstances, waste (e.g., aqua regia) may be required to be neutralized immediately after use. The treatment procedure will specify the appropriate treatment time. In all cases, the waste must be treated within 10 days from the date of generation.

 

Generally, treatment is limited to the neutralization of mixed waste or neutralization/quenching of oxidizing solutions such as aqua regia or piranha etch; however, other treatments can be considered. Your Generator Assistant will work with you to assure all requirements are met, and will present the information to Waste Management for approval.

Once this information has been submitted to Waste Management, you will receive specific authorization to start benchtop treatment. Please allow up to two weeks from the time this information is submitted for final approval.

3.6       Waste Review Process

When the Waste Management Group receives your radioactive-material tag, accumulation log, and requisition form, the information you’ve provided will be entered into our tracking system, and reviewed by your Generator Assistant for completeness and accuracy based on your accumulation log. Your Generator Assistant will assign the proper verification sampling, HWHF storage location, and waste stream based on this information. This process may take up to 10 days from the receipt of your requisition.

3.7       Quality Assurance Testing

Each item entering the HWHF is subject to random verification sampling. A computer-generated random-selection program chooses which wastes will be sampled for verification of the generator’s characterization. If, on review of the laboratory analysis results, it is determined that there is a discrepancy between the generator’s characterization and the analysis results, you will be contacted by your Generator Assistant.



[3] California Health and Safety Code §25200.3.1(c)

[4] Must not exceed 5 gallons per batch except where specifically authorized. (California Health and Safety Code §25200.3.1(c)(3).