CHAPTER 6: CHEMICAL WASTE MANAGEMENT

Every attempt should be made to minimize the use of chemicals and the generation of hazardous waste by considering the following: (Ranked in order of preference)

1. Reduction of the scale of the experiment.
2. Substitution of less-hazardous reagents for more hazardous ones.
3. Exchange or recovery of chemicals.
4. Disposal or recycling of all left-over starting materials and wastes.
5. Recovery of solvents for reuse.
6. Limit commingling of non hazardous and hazardous waste.
7. Disposal as a last resort.

A Hazard Determination must be completed for each chemical waste generated in lab for which the hazard status is unknown. The materials needed to carry out these Hazard Determinations are included as part of this Chemical Hygiene Plan binder. Each course should build a collection of these determinations for future reference. Once the Hazard Determination has been completed, the following guidelines as to the treatment, collection and disposal of a waste can be followed.

If a waste has been deemed non hazardous (i.e. it is not flammable, corrosive, reactive, an oxidizer, lethal, toxic or included on the MPCA hazardous chemicals list) following the determination process mentioned above, the disposal methods for this waste include either sewering the waste into a sanitary sewer system or adding the waste to the regular trash for landfilling.

The College of Saint Benedict is connected to the St. Cloud Publicly Owned Treatment Works (POTW) via the City of St. Joseph’s waste water treatment system. The City of St. Cloud, in Ordinance No. 1046, Section 360:40, sets guidelines for substances which are prohibited from discharge into the St. Cloud POTW. The following is a list of restrictions which would be applicable for sewering waste at CSB. Please note that any practical guidelines added during the development of this CHP are italicized.

1. Any combustible, flammable or explosive solids, liquids, or gases which by their nature or quantity will or are likely to cause either alone or by interactions with other substances a fire or explosion or be injurious to the POTW operations. Prohibited materials include, but are not limited to, gasoline, kerosene, naptha, fuel oil, lubricating oil, benzene, toluene, xylene, ethers, alcohols, and ketones.

2.  Any solids or viscous substances which will or are likely to cause obstruction to the flow in a sewer or interference with the operation of the waste water treatment plant. These include garbage with particles greater than one-half inch (1/2 ") in any   dimension, grease, animal guts or tissues, bones, hair, hides or fleshings, entrails, feathers, ashes, sand, spent lime, stone or marble dust, metal, glass, grass clippings, rags, spent grains, waste paper, wood, plastic gas tar, asphalt residues, residues from refining or processing of fuel or lubricating oil, glass grinding and polishing wastes.

3. Any waste water having a pH less than 5.0 or greater than 12.0 or having any corrosive property that will or is likely to cause damage or hazard to structures, equipment, or employee of the Water Utility. Any corrosive waste to be sewered should fall within the pH range of 4--10.

4. Any waste water containing toxic or poisonous pollutants in sufficient quantity, either singly or by interaction with other pollutants, that will or is likely to cause interference or constitute a hazard to humans.

5. Any noxious or malodorous solids, liquids, or gases, which either singly or by interaction with other wastes, will or are likely to create a public nuisance or hazard to life or prevent the entry of Utility employees into a sewer for its monitoring, maintenance, and repair. Thiols would be an example of non hazardous, malodorous compounds which should not be sewered.

6. Any waste water which will or is likely to cause excessive discoloration in treatment plant effluent. (e.g. dyes and indicators in concentrations > 1%)

7. Wastes, other than Domestic Wastes, that are infectious before discharging into the sewer.

8. Any waste water containing inert suspended solids (including lime slurries and lime residues) or dissolved solids (including sodium chloride) in such quantities that will or is likely to cause interference with the POTW.

9. Radioactive wastes or isotopes of such a half-life or concentration that they are in non-compliance with standards issued by the appropriate authority having control over their use and which will or are likely to cause damage or hazards to the POTW or employees operating it.

10. Any waste water containing fat, wax, grease or oil in excess of 100 mg/l that will or is likely to solidify or become viscous at temperatures between 0 ° and 65 °C and which will or is likely to cause obstruction to the flow in sewers or other interference to the POTW, including petroleum oil, non-biodegradable cutting oil, or products of mineral oil origin.

11. Any hazardous waste, unless prior approval has been obtained from the Director(of the St. Cloud POTW).

Any waste disposed of through sewering needs to be carried out in a manner which is consistent with the following guidelines:

1. Sewer disposal of chemicals can only be into a sewer system that eventually flows to a waste water treatment plant and never into a system which flows directly into surface or ground water.

2. The quantities of actual chemicals disposed of down the drain generally should be limited to not more than a few hundred grams or milliliters. Also, all solids should be in solution with water.

3. The disposal should be performed by flushing with a significant excess of water at the sink, so that the chemicals are removed from the system.

A note on dilution of a waste prior to sewering--the City of St. Cloud states the following:

"No user [of the St. Cloud Water Pollution Control Facility] shall increase the use of process water or, in any way, attempt to dilute a discharge as a partial or complete substitution for adequate treatment to achieve compliance with the limitations contained in any state requirements or federal pretreatment standards." (Ordinance 1046 Section 360:45 Subp.. 4)

Those non-recoverable and non-treatable wastes which have been determined to be hazardous (i.e. exhibits one or more of the following characteristics--flammability, corrosivity, reactivity, an oxidizer, lethal, toxic or included on the MPCA hazardous chemical lists) must be collected and labeled according to the following guidelines:

1. The waste must be collected in compatible containers which will withstand side and bottom shock (i.e. plastic, except in some situations).

2. The containers must be covered with proper caps at all times, except for when waste is being added or removed from the containers. The containers must, "have lids, caps, hinges, or other closure devices of sufficient strength and construction so that when closed they will withstand dropping, overturning or other shock without impairment of the container’s ability to fully contain the hazardous waste."

(MN Rules 7045.0526 Subp. 2. A)

3. The container label must include the following: (MN Rules 7045.0292 Subp. 6. C. & F.)

• Complete chemical description of the waste
• The words, "Hazardous Waste"
• Accumulation Start Date

4. It is helpful to consider the type of hazardous waste being collected and how this waste will react in the different environments it may encounter before its final disposal. An example would be a designation of the level, say three-fourths full, to which a container may be filled, allowing for expansion if the waste should be exposed to high and/or low temperatures. In student laboratory situations, a mark on the bottle indicating this level may be very prudent.

Copies of the department’s waste labels are available in the stockroom.

Under the regulatory guidelines of the Environmental Protection Agency and the Minnesota Pollution Control Agency, generators of waste, whether they are students or laboratory employees, are allowed to treat waste to decrease or eliminate the hazardous characteristics of the waste. However, this treatment must proceed under the following conditions:

1. Treatment must be performed in a tank or container. (Federal Register, Vol. 51; #56, March 24, 1986)
2. Waste containers are only allowed to be opened for the addition or removal of waste,therefore treatment must coincide with waste addition or removal (e.g. the addition of a precipitating agent during the addition of waste to a collection container; neutralization of a waste by adding the waste to a container which contains the neutralizing agent). (MN Rules 7045.0526 Subp. 2. A)
3. Treatment must take place within the waste accumulation time limitations. The College of St. Benedict is a Very Small Quantity Generator (VSQG), therefore waste must be treated within 180 days of accumulating 1000 kilograms of waste.

(MPCA 7045.0292. Subp. 6.H.)

Given these guidelines, the following treatment may be appropriate in the laboratory setting:

• Decomposition
• Ion-Exchange
• Neutralization
• Precipitation
• Oxidation and Reduction
• Others as applicable

For waste minimization purposes, these methods should be employed whenever possible. If students in the laboratory will be carrying out treatment as part of the experiment, explicit instructions must be included in the laboratory manual. Likewise, if other laboratory employees under the direct supervision of the Laboratory Coordinator will be carrying out these steps as part of the experimental procedure (i.e. the steps to be taken are included in the lab manuals), explicit instructions must be available for them also. If the waste is not treated by either students or lab employees, it is the responsibility of the Lab Coordinator to carry out these steps.

The books, "Prudent Practices in the Laboratory: Handling and Disposal of Chemicals", National Research Council, and "Destruction of Hazardous Chemicals in the Laboratory," Lunn and Sansone, contain detailed descriptions for the treatment of many categories of chemical compounds. These books are available from the Chemistry Department reference library.

Under the MPCA definitions, reclamation means the processing or regeneration of a waste to recover a usable product. In essence, the terms recovery, reclamation and recycling can be used interchangeably.

Waste recovery, reclamation and recycling is regulated rather uniquely. While a waste is being collected and stored prior to these processes, the waste must be managed according to the applicable collection and storage regulations. However, the actual recovery, reclamation or recycling process is outside regulatory constraint. At the end of the process, the regulations applicable to disposal of any resulting hazardous waste, such as still bottoms or residues, need to be followed. In other words, the respective regulations apply before and after the waste is being recovered, reclaimed or recycled, but the actual process itself is not regulated. This is to encourage these types of activities whenever possible.

For documentation purposes, all activities involving recovery, reclamation and recycling must be recorded by the laboratory employee who performs the process. Please use the Hazardous Waste Recovery, Reclamation and Recycling form, available from the stockroom. Completed forms should be submitted to the Stockroom Manager.

According to the Minnesota Pollution Control Agency guidelines, there are two regulations which apply to storage and inspection of hazardous waste. They are:

1. Containers that hold free liquids must be placed on a containment surface that is impermeable to the waste stored. (MN Rules 7045.0292 Subp. 6.)
2. Weekly inspections of hazardous waste containers and areas where containers are stored must be conducted. The employee conducting the inspection must look for leaks and signs of deterioration caused by corrosion or other factors, and written records of the dates and findings of these inspections must be kept. (MN Rules 7045.0626 Subp. 5.)

The responsibilities below are outlined in order to ensure clarity and accountability in the Chemistry department’s methods for identifying and handling hazardous wastes. However, experience tells us that only frequent communication between all parties concerned and attention to detail can make this process work.

1. Completing the necessary Hazard Determinations for the lab sections under their charge.
2. Determining the appropriate disposal strategies for each waste generated in the teaching labs, including types and quantities of collection containers needed and the required container labeling. These disposal strategies need to be included in the experimental "prep notes", which will serve as an in-house record keeping system.
3. Including in the laboratory manual the non-regulatory treatment steps to be taken by students as part of the experimental procedure.
4. Carrying out the non-regulatory treatment steps when it is not appropriate to involve students.
5. Providing specific instruction to students and stockroom personnel on the handling of all teaching laboratories wastes.
6. Labeling all waste containers and filling out all necessary paperwork for wastes generated in research laboratories.
7. Documenting all waste reclamation, recovery and recycling activies through the use of the Hazardous Waste Recovery, Reclamation and Recycling form. This form is available from the stockroom and should be returned to the stockroom upon completion.

1. Affixing labels to the collection containers and distribution of the containers in the teaching laboratories.
2. Preparing and packaging all teaching laboratory waste containers for off-site disposal, including filling out the appropriate paper work and maintaining the required departmental records.
3. Conducting and documenting the weekly waste container inspections.