Hazardous Waste

Drain Disposal

Sanitary Sewer System Discharges
Preventing chemical discharges to a drain is important in eliminating adverse impacts on the Ann Arbor Wastewater Treatment Plant and the Huron River. OSEH surveys and samples discharges from University facilities to determine if discharges exceed target levels at the Ann Arbor Wastewater Treatment Plant. Pollution prevention projects help to locate contaminants and eliminate them from our waste stream.

Your Guide to What Can Go Down the Drain

Wastewater discharged from inside University of Michigan (UM) facilities flows into the sanitary sewer system and is treated at the Ann Arbor Wastewater Treatment Plant (WWTP) prior to discharge into the Huron River watershed. The purpose of the WWTP is to clean the water at a faster rate than nature. Excessive pollutants prevent the WWTP from thoroughly treating the water before release into the Huron River.

Pouring other materials (pollutants) down the drain such as chemicals, metals, solids, and oils can interfere with the treatment process. For example:

  • Metals and other toxic chemicals may not be treated by the WWTP. Even small quantities of these substances can be harmful to both the WWTP and the Huron River.
  • Some chemicals ‘poison’ and kill the microorganisms used in the treatment process.
  • Volatile or corrosive materials damage piping and may endanger the health and safety of workers.
  • Various pollutants can interact with one another, forming more hazardous pollutants. For example, cyanide base reacts with acids, and ammonia and bleach react to form toxic gases.

General Guidelines for Drain Disposal at UM:

All 6 of the following criteria must be met prior to disposal of wastewaters into the sanitary sewer system:

  1. Liquids only – No solids, sludges, or viscous materials. No insoluble substance retained by a standard No. 8 sieve or having any dimension greater than ½-inch (1.27 centimeters)
  2. No RCRA hazardous wastes - Resource Conservation & Recovery Act; See Characteristic (D-codes) & Listed Wastes (F,K, P and U-codes). Also refer to OSEH’s Chemical Waste page for additional information on management of these waste streams.
    Some examples of these RCRA hazardous wastes include:
    • Corrosives (pH less than 2 or greater than 12.5)
    • Flammables (flash point less than 140° F)
    • Oxidizers (e.g., perchloric acid, chromic acid, hydrogen peroxide, etc.)
    • Metal-containing wastes
    • Reactive wastes (water, cyanide or sulfide reactive, etc.)
    • Solvents (halogenated and non-halogenated)
    • Unused and/or outdated chemicals (P-Codes and U-Codes)
  3. No Michigan hazardous wastes or Liquid Industrial Wastes – See MI Act 451 Part 111 and the Part 111 Administrative Rules for Michigan’s Hazardous waste information and Part 121 for liquid industrial waste information. Also, see OSEH’s Chemical Waste page for additional information on management of these waste streams.
  4. No Radioactive wastes
  5. No Biohazardous, untreated wastes. See OSEH’s Biohazardous Waste page for additional information on management of these waste streams.
  6. All wastes must comply with the limits established in the Ann Arbor Sewer Use Ordinance; see City of Ann Arbor - City Code, Chapter 28 including, but not limited to the following:
    General
    • Biochemical Oxygen Demand (BOD) limit of 250 mg/l.
    • Chemical Oxygen Demand (COD) limit of 600 mg/l.
    • Cyanide, Total limit of 1.0 mg/l.
    • Fats, oil and grease limit of 50 mg/l.
    • Flashpoint must be 140° F, or greater.
    • Petroleum oil or grease, non-biodegradable cutting oil, mineral oil, whether or not the oils or grease are used oils or grease are prohibited.
    • pH must be between 5-10 standard units.
    • Phenols, Total limit of 0.5 mg/l.
    • Phosphorus, Total limit of 13 mg/l.
    • Specific Gravity must not exceed 2.65
    • Suspended solids, Total (TSS) limit of 250 mg/l.
    Metals
    • Beryllium, Total limit of 0.01 mg/l.
    • Cadmium, Total limit of 1.0 mg/l.
    • Chromium, Total limit of 4.0 mg/l.
    • Copper, Total limit of 4.0 mg/l.
    • Lead, Total limit of 0.5 mg/l.
    • Mercury, Total limit of 0.0002 mg/l.
    • Molybdenum, Total limit of 4.9 mg/l, per request of City WWTP staff.
    • Nickel, Total limit of 3.0 mg/l.
    • Zinc, Total limit of 3.0 mg/l.

Additional Information

Questions & Answers on Drain Disposal

What can I pour down the sanitary drains?
Only pour consumable products, such as pop and coffee, and household products down the drain. Be sure to use the household products in the manner intended and to follow the directions for disposal procedures. Other chemical products may interfere with the wastewater treatment process, and can result in a release of polluted water into the Huron River.

What do I do if there is an accidental spill into a drain?
Prevent additional material from entering the drain and immediately call the Department of Public Safety at 763-1131 to report the incident. OSEH can assist with the spill cleanup, if needed.

How do I dispose of waste materials that cannot be discharged into the sanitary drains?
Consult your operating procedures or the Material Safety Data Sheet (MSDS) for chemical constituents in the material and call the OSEH Hazardous Materials Management program at 763-4568 for pickup and disposal. See OSEH’s Hazardous Waste page for additional information on proper waste management.

I use chemical products at home, why can’t I drain these products at work?
At home, small quantities of cleaning compounds are occasionally used and rinsed down the drain. There are several groups that offer alternative disposal options for chemicals used in the household, at Household Hazardous Waste collection events. At work, a large number of laboratories and various operations frequently use numerous and sometimes unusual chemicals. These operations produce a large volume of waste water that could potentially contain pollutants. There are State and Federal laws which govern management of these wastes generated at businesses.

Why should I be concerned with water quality?
Communities obtain their water supply from the river or from groundwater. Pollutants from one community that are not removed by the wastewater treatment process have the potential to end up in the drinking water of a downstream community. Also, metals may potentially bioaccumulate in the fish, impacting this food source.

Are there any waste water disposal considerations when working outside the buildings?
Yes. Do not pour anything down the drains outside buildings. These drains are connected to the storm water system, which drains directly to the Huron River without any treatment. When working outside, be sure to collect ALL paints, chemicals, washwaters and materials and call OSEH Hazardous Materials Management at 763-4568 for disposal.

Work outside the building should be evaluated for disposal concerns. This would include, but is not limited to any activities at the loading dock, painting, cleaning, masonry cutting, washing equipment, power washing and any other activity that generates wastewater. If you plan to perform any of these activities contact OSEH to determine whether a containment system is required and to identify proper waste handling procedures.

Who do I contact for more information?
Please contact the OSEH Environmental Protection & Permitting Program at 936-1920.

Acids & Bases
What should I do with acids and bases?
Although the WWTP will accept discharges that have a pH between 5 and 10, this can only be done if the wastewater does not contain any metals, solvents, oils, stains, etc. See General Guidelines for Drain Disposal at UM for more detail. Most acid and base wastewaters (and buffer solutions in general) must be collected for disposal by OSEH. Contact OSEH Hazardous Materials Management at 763-4568 to schedule waste pickups.

Alcohols
What do I do with chemicals such as alcohols or formalins?
Collect them for disposal by OSEH. Please contact OSEH HMM at 763-4568 for pick up.

Alternative Products
How can I find more environmentally friendly products?
Some products contain hazardous chemicals. If these materials are mixed with waste products, they can create large volumes of hazardous waste. For example, some degreasers contain xylene. If the degreaser comes in contact with a material such as waste oil, it has the potential to cause all the waste oil to become hazardous. To prevent this from happening, many products can be substituted with more environmentally friendly ones. Contact the Office of Campus Sustainability (734-647-1143) for further information about product substitution, Pollution Prevention or to research alternative practices.

Blood & Blood Products
How do I dispose of blood and blood products?
Any chemically contaminated blood solutions should be collected as biohazardous chemical waste. Treat non-chemically contaminated biohazardous liquids with 1:10 dilution of household bleach to waste. Once treated, the liquid can be poured down the sanitary sewer drain. Precautions are required to avoid splash exposure during this procedure. Solids such as tissues and blood clots should be collected for disposal as biohazardous material.

Chemical Storage
Where should chemicals be stored when not in use?
Never store chemicals in or near sinks. All hazardous and flammable chemicals should be kept in fireproof storage cabinets with the doors securely shut. Be sure to store incompatible materials separately. Consult your Chemical Hygiene Plan for additional tips on chemical storage.

Clay / Sediment
How do I prevent clay from plugging the drain?
Studios have sediment traps installed beneath their sinks. These traps prevent sediment from being flushed down the drain by allowing it to settle out. Sediment traps should be cleaned regularly to keep them working properly. Contact the lab monitor for trap cleaning when a trap is full.

Dyes
What are the disposal requirements for paints, dyes, and glazes?
Watercolors, acrylics, and latex paints can be rinsed down the drain when washing brushes and other tools used to apply them. The sanitary sewer should not be used to dispose of unwanted paint. Excess, unwanted paint should be offered for use elsewhere on campus. If it cannot be used contact OSEH Hazardous Materials Management at 734-763-4568 to schedule a waste pickup. Solvents such as mineral spirits and paint thinners should also be collected for disposal by OSEH-HMM.

Glazes should not go down the drain. These materials contain metals that can be harmful to the WWTP. Dyes may also contain metals. If excess glazes or dyes cannot be used, call OSEH for proper disposal.

Formalins
What do I do with chemicals such as alcohols or formalins?
Collect them for disposal by OSEH. Please contact OSEH HMM at 763-4568 for pick up.

Glassware - Rinses
Can I clean chemically contaminated glassware over the sink?
You may use alcohol to rinse beakers and other glassware; however, you must collect all residuals for disposal as chemical waste. After the glassware is entirely emptied of alcohol and chemical residuals, you should triple rinse with water as a final step. Only this final rinse water may be drained to the sanitary sewer.

Glazes
What are the disposal requirements for paints, dyes, and glazes?
Watercolors, acrylics, and latex paints can be rinsed down the drain when washing brushes and other tools used to apply them. The sanitary sewer should not be used to dispose of unwanted paint. Excess, unwanted paint should be offered for use elsewhere on campus. If it cannot be used contact OSEH Hazardous Materials Management at 734-763-4568 to schedule a waste pickup. Solvents such as mineral spirits and paint thinners should also be collected for disposal by OSEH-HMM.

Glazes should not go down the drain. These materials contain metals that can be harmful to the WWTP. Dyes may also contain metals. If excess glazes or dyes cannot be used, call OSEH for proper disposal.

Glycol
What are the disposal requirements for Ethylene Glycol and Propylene Glycol?
U-M OSEH requires that all antifreeze (glycol) solutions and first flush rinse water from equipment such as heating or cooling loops be collected and not be discharged to storm or sanitary sewer drains. Discharges to the sanitary sewer must contain less than 1% glycol. Antifreeze (glycol) that will not be stored for reuse must be managed by the U-M OSEH Hazardous Materials Management (HMM) Program for proper disposal. Please contact OSEH HMM at 734-763-4568 to arrange for collection drums/containers and to schedule waste pick-ups. If material is collected for reuse, please refer to the Spill Prevention Control and Countermeasures (SPCC) guidelines under the OSEH Environmental Protection tab for storage requirement information.

Lab Equipment Cleaning
How do I clean laboratory equipment that is too large for the sink?
You may wash non-chemically contaminated equipment on the grass away from all storm drains. Rinse the item and allow it to drain onto the ground. Protect storm drains to ensure no discharge into the storm drains occurs. Do not use detergents of any kind. Contact OSEH if you have chemically contaminated items that are too large to wash in a sink.

Metals
Are there concerns regarding work with metals?
Yes. Even small quantities of metals in the wastewater can be harmful to both the WWTP and the Huron River. Consult your operating procedures or the Material Safety Data Sheet (MSDS) for chemical constituents in the material and call the OSEH Hazardous Materials Management program at 763-4568 for pickup and disposal. See OSEH’s Hazardous Waste page for additional information on proper waste management.

The jewelry studio has sediment traps to collect metals. To keep the traps working properly, contact the lab monitor when a trap is full and contact HMM for pickup and disposal.

Paints
What are the disposal requirements for paints, dyes, and glazes?
Watercolors, acrylics, and latex paints can be rinsed down the drain when washing brushes and other tools used to apply them. The sanitary sewer should not be used to dispose of unwanted paint. Excess, unwanted paint should be offered for use elsewhere on campus. Please contact the Office of Campus Sustainability for pickup as part of the Chemical Reuse Program. If it cannot be used contact OSEH Hazardous Materials Management at 734-763-4568 to schedule a waste pickup. Solvents such as mineral spirits and paint thinners should also be collected for disposal by OSEH-HMM.

Glazes should not go down the drain. These materials contain metals that can be harmful to the WWTP. Dyes may also contain metals. If excess glazes or dyes cannot be used, call OSEH for proper disposal.

Phenol Alternatives for Cleaning Compounds
What is the preferred cleaning compound alternative to phenols?
The Michigan Hospital Association recommends the use of quaternary ammonium compounds as a suitable replacement for phenols. Make every attempt to reduce the number of cleaners containing phenols used in your lab. The WWTP is limited in its ability to treat phenols. Bleach is an alternative for surface disinfection.

Phosphorus
Why should I be concerned about phosphorus?
Phosphorus is a nutrient that is required by all living things to survive. In many aquatic systems, phosphorus is often a limited resource and its scarcity helps to keep the systems in balance. When phosphorus and other nutrients flow into a water body they fertilize the plants, which can then grow out of control and increase the appearances of "pond scum." Increased plant growth also depletes the water of oxygen, killing fish and other aquatic animals. Over long periods of time, the addition of nutrients and sediments can permanently turn shallow lakes into dry land.

To help control the amount of phosphorus that is discharged to the Huron River, the WWTP uses a process that removes it from the wastewater it receives. This process is limited, however, in its ability to remove all of the phosphorus. Discharging products that contain phosphorus down the drain may reduce the effectiveness of the WWTP’s process and lead to a discharge of phosphorus to the Huron River. As a result, the City of Ann Arbor established a discharge guideline for phosphorus in the City of Ann Arbor Sewer Use Ordinance.

To be sure the requirements in the guideline are met, do not pour any materials that contain phosphorus down the drain; common products that contain it are detergents and masonry cleaners. If you use such products, look for alternatives that are more environmentally friendly. If you are using these materials outdoors, also remember never to let any water enter drains located outside. These drains are connected to the storm water system, which drains directly to the Huron River without any treatment.

Photo Processing Wastes
What do I do with photo processing wastes?
Spent fixer, spent developer, and other used chemicals should be collected for disposal by the OSEH Hazardous Materials Management program. Wash-water generated from photo processing contains silver and other chemicals. Improper disposal of this waste can damage building piping. Even small quantities of metals in the wash-water can be harmful to both the WWTP and the Huron River.

If your dark room does not have silver recovery, collect the processing wastewater that contains silver during photo development and then call OSEH-HMM for proper disposal at 734-763-4568. With pretreatment systems, silver can be recovered from the photo development wash-water prior to draining. Metal recovery companies can supply silver recovery systems, provide maintenance and remove the collected silver on a routine basis. Call OSEH for more information regarding silver recovery.

Stains
What about stains?
Never flush solutions containing stains such as ethidium bromide (EtBr) or Coomassie blue dye down the drain. Stains such as Coomassie blue dye and EtBr can be removed from solution using charcoal filters. These filters should then be collected for disposal by OSEH. Contact OSEH for information about obtaining filters. Fluorescent dye used in automated DNA sequencing is not hazardous and has no special disposal requirements.

Unused Chemicals
What do I do with leftover, unused chemicals?
Unopened chemicals that are "leftover" after the completion of individual protocols or when research practices are changed can be redistributed throughout the UM. These materials should not be disposed of as waste; please contact the Office of Campus Sustainability for pickup as part of the Chemical Reuse Program. OSEH HMM will also pick up open or contaminated chemicals. Contact Hazardous Materials Management at 734-763-4568 to arrange pickup.

WWTP
How is sanitary wastewater treated?
Treatment occurs at the WWTP through a series of chemical, biological, and physical methods. Wastewater passes through several phases of treatment before it meets state and federal discharge requirements; to be certain it meets these requirements, the treatment process is continuously monitored and the water is sampled as it enters and leaves the plant. The treatment process consists of the following steps:

  • Preliminary Treatment – Screen mechanisms physically remove large solids and heavy particles from the liquid waste stream.
  • Primary Treatment – Suspended solids "settle out" as the sewage travels through a series of settling tanks. Chemicals may be added to enhance the process.
  • Secondary Treatment (Aeration and Clarification) - The wastewater is mixed with microorganisms that digest organic matter. Air is added to the mixture to stimulate microbiological growth. The water is then sent to clarifying tanks where the microorganisms and remaining waste settle out.
  • Tertiary Treatment - High levels of phosphorus and nitrogen harm fish, so these nutrients are stripped from the effluent.
  • Final Step - The water is sterilized using ultraviolet irradiation before it is discharged into the Huron River.
  • Solid Treatment – Solids collected at all phases of treatment are sent to digesters where they are treated by a biological process, followed by application on farmland or disposal at a landfill.