WASTE MANAGEMENT INTRODUCTION So as to maintain and promote a safe and healthy workplace, efforts should be made to ensure that staff, students and visitors meet government regulations concerning hazardous waste management and worker safety. Wastes, particularly those generated by the laboratories, can pose a significant risk to human health and the environment if not handled correctly. Proper handling and disposal of generated laboratory waste are key elements of these efforts. OBJECTIVE This document provides guidelines to assist staff and students in the proper handling and disposal of waste. Practices and procedures are developed for identifying, segregating, decontaminating, and proper packaging and disposal of chemical, biological, radioactive as well as glassware. SCOPE This document is applicable to all staff and students of the premises of the Department of Medicine. CHEMICAL WASTE 1. Definition Chemical wastes include solids, liquids or gases containing or contaminated with any of the following: Flammable solvents (acetone, alcohol, etc) Corrosives (hydrochloric acid, potassium hydroxide pellets, etc) Reactives such as oxidizers, cyanides, sulphides, explosives, unstable materials and water-reactive materials (sodium metal, benzoyl peroxide, etc) Toxic materials including mutagenic, carcinogenic, acute or chronic toxicity materials (chloroform, ethidium bromide, etc) Polychlorinated biphenyls (> 50 ppm concentration) Non-returnable gas cylinders 2. Guidelines for disposal of chemical waste in the sewer Small amounts of a wide range of chemical residues produced in laboratory operations may be safely disposed of into the sewerage system. However, this method of disposal is not desirable for the following chemicals: Persistent chemicals such as heavy metals (e.g. arsenic, cadmium, lead, mercury, etc) and various organic compounds
Water-immiscible organic liquids such as petroleum hydrocarbons and chlorinated compounds. Compounds which produce toxic vapors, such as cyanide, ammonia, formaldehyde and glutaraldehyde. Strongly acidic or alkaline wastes. Highly reactive chemicals or flammable wastes. Ensure that the chemical is safe for discharge into the sewer. Dilute all chemicals that will be thrown into the sewer. Otherwise, store in empty reagent bottles for processing and disposal by a licensed waste disposal contractor. 3. Waste Avoidance and Waste Minimizing Strategies for avoiding and minimizing production of chemical waste in laboratories: Replace hazardous compounds with less hazardous compounds to minimize the quantity of hazardous materials used. Avoid over-purchasing chemicals, thereby minimizing costly waste disposal. Date containers when received and use older chemicals first. Take periodic inventories of chemicals. Reduce the number of unknowns by labeling all bottles/containers in the laboratory. Prepare only the amount of solutions/mixtures needed for experiments. Provide appropriate handling and safety equipment to make correct waste management easy and convenient. 4. Appropriate Containers All waste must be put into appropriate containers such as glass bottles, plastic containers, or metal containers holding original contents only. Containers must be compatible with the chemical waste being accumulated. Secure tops must be kept on containers at all times unless adding or removing waste. The containers must be filled only to the 80% level with approved solvents and sealed with their original caps. Ensure that there is no leaking vapor, or traces of liquid or contamination on the exterior. Record the identity and the quantity of the waste added on the container's label. Containers with chemical waste must be stored in a designated storage area. Ensure that a licensed waste disposal contractor removes the containers from the waste storage area at appropriate intervals. 5. Packaging Do not package solid chemical waste into biohazard bags, because this incorrectly indicates a hazard that is not present. Waste should be segregated according to compatibility groups such as acids, bases, flammables, oxidizers and water reactives.
Dispose of aging containers promptly. Some chemicals are time sensitive and may degrade into hazardous by-products; e.g., ethers may degrade to form explosive organic peroxides. 6. Labeling All waste must be properly labeled. The label must have the word CHEMICAL WASTE and should contain the name of generator of the waste, date generated, chemical names of the principle components and all minor components. BIOLOGICAL WASTE 1. Definition a. Infectious waste - Cultures, stocks of infectious agents and associated biological, including but not limited to: Regulated medical waste Specimens from medical, pathology and research laboratories Disposable culture dishes Devices used to transfer, inoculate, and mix cultures Wastes from the production of biological materials b. Pathological waste - Human blood, blood products, tissue, organs and body fluids that are removed during surgery, autopsy or other teaching or research procedures including specimens and their containers. c. All sharps (contaminated and uncontaminated) such as: Needles and syringes Scalpels, razors and microtome blades Pasteur pipettes / Transfer pipette tips Slides and cover slips Contaminated broken glass Any object that is capable of penetrating the skin d. Animal carcasses, body parts, and bedding from animals exposed to pathogens in research. e. Other biological waste including but not limited to: Specimen containers Disposable gloves, lab coats, masks and aprons Disposable pipettes All cell culture materials All microorganisms constructed using recombinant DNA
2. Decontamination Procedures a. b. c. Decontamination by Autoclave Autoclaving is the preferred method for sterilizing waste material prior to disposal. The autoclave used must be proven effective against the biological material in question, under the actual conditions of application. Decontamination by Chemicals Chemical decontamination is the preferred method for disinfecting reusable equipment and apparatus. The effectiveness of chemical decontaminating agents must be tested under the same conditions as those under which they will be used in the laboratory, and thereafter used only under conditions demonstrated to allow them to be used effectively. Decontamination by Incineration Incineration is the preferred method of disposal for small animal carcasses, and tissue samples, both human and animal. It is also the preferred method of disposal for sharps. 3. Packaging and Treatment a. General guidelines: The container (box, canister, etc) that are used for collection of solid materials contaminated with biological material, excluding sharps or broken/unbroken glassware, must have easily recognizable and visible approved label. Autoclaving liquid biological waste may cause hazardous situations (explosion, fire, released of toxic gas, etc) due to interaction of autoclave parameters (heat, pressure, etc) with chemicals in the waste. b. Human Blood, Blood Products and Body Fluids: All human tissues must be disposed of by incineration. Incinerate the materials or send them to a commercial rendering plant for disposal. Human blood and body fluids, although they may be considered as human tissues, do not require the same level of decontamination. Where these fluids have been used for research purposes, autoclaving or chemical decontamination is recommended. Add an effective liquid disinfectant such as freshly prepared 10% sodium hypochlorite (household bleach) solution to a final dilution of 1:10 to the flask of liquid biological waste. Let the solution sit for 20 30 minutes and then flush down the laboratory sink with copious amounts of water. Reusable glassware which has been in contact with human blood or body fluids must be autoclaved or disinfected by soaking in an effective disinfectant before being washed and reused. c. Small animal carcasses and tissues, both infected and non-infected, must be disposed of by incineration. d. Autoclaving must be done in an approved autoclave bag, which is in a leak proof container. The material must be placed in the bag in the laboratory, and closed before being transported to the autoclave. The autoclave must be
capable of placing steam, at 121 degrees C, in direct contact with the biological material for the necessary time to achieve sterility. e. Chemical decontamination must be done in the laboratory using either a liquid or gas that has been proven effective in the specific application. f. Glassware for disposal must be separated from plasticware prior to decontamination by autoclave. Contaminated glass may be treated by one of the following two methods: Decontaminate the glass by autoclaving, or by soaking in 10% bleach for 30 minutes, then place in sturdy cardboard box, tape closed, and put the box in the building dumpster; or, contaminated glass may be discarded into a sharps container and handled according to the instructions for "Sharps." g. Sharps (needles, scalpel blades, etc.) must be collected in an approved sharps container. Place intact "sharps," whether contaminated or not, in a puncture resistant "sharps" container. Do not recap, bend, remove, or clip needles. Fill 3/4 full, snap the lid closed and secure with tape. Overfilling or forced filling may result in puncture wounds. h. Reusable glassware, which has been in contact with hazardous biological material, must be decontaminated before being washed and reused. RADIOACTIVE WASTE 1. Definition Radioactive waste is waste material containing radioactive chemical elements that does not have a practical purpose. Their radioactivity is a result of Radioactive decay. The decay process varies from one radioactive element to the next. It might take hours to months or even hundreds and thousands of years. Radioactive waste arises from a wide range of sources and from many activities. Radioactive waste can be categorized in many ways, such as: By state: solid, liquid and airborne waste. By activity concentration: low, intermediate and high activity waste. By half-life: short and long lived (longer than 30 years) waste. 2. Purpose of Radioactive Waste Management The primary purpose of radioactive waste management and disposal is to protect humans and their environment from potential hazards arising from such wastes. Radioactive waste shall be managed in ways that: Limit the radiological risks to humans to an acceptable level. Provide protection of the environment.
3. Types of radioactive waste a. Radioactive dry wastes are dry materials (such as gloves, paper towels, glassware, etc.) that are contaminated with radioactive material. Discarded plastic syringe barrels (without hypodermic needles) that are contaminated with radioactive material may be disposed of as radioactive dry waste. b. Radioactive sharps include hypodermic needles, syringes with attached hypodermic needles, scalpel blades, Pasteur pipettes, and glass or plastic that is broken or is expected to break in the process of storage, processing or disposal. c. Radioactive liquid waste is any freestanding liquid that contains or is contaminated with radioactive material. 4 Waste Storage and Collection a. Work involving radioactive materials should be carefully planned to minimize the volume of waste generated. Care must be exercised to separate radioactive waste from non-radioactive waste as it is generated. b. Radioactive wastes must be stored only in restricted areas where they can be secured against unauthorized removal. c. All radioactive dry waste must be collected by half-life category and sealed in plastic disposal bags provided by the laboratories. These bags must be sealed with tape or twist ties and then placed in a second bag and sealed to ensure contamination control. d. All receptacles for radioactive waste must be clearly labeled with an appropriate radiation warning sign. Each disposal bag should contain waste only contaminated with a single radionuclide and should not have radioactivity quantities exceeding one Licensing Exemption limit (LEL). e. If the radioactive waste contains gamma emitters or high-energy beta emitters, attention should be given to the location of the waste container in the laboratory to minimize radiation exposure of laboratory personnel. Additional shielding may be required. f. Solid and liquid radioactive wastes must be kept separate. The laboratory must have a waste container for dry solid waste and a container for liquid waste. g. Radioactive syringe needles, broken glassware, and other sharps must be packaged in a sharps container, clearly marked for radioactive sharps only. h. All glass should be packaged separately from other dry waste and put into a box with a completed dry solid radioactive waste tag. i. Radioactive aqueous liquids must be collected in plastic containers (with size appropriate to the quantity generated) by half-life category and sealed with lids such that the liquids will not leak. j. Biodegradable scintillation cocktail should be used whenever possible. Liquid scintillation vials will be picked up in the original boxes or in double plastic bags. If bags are used for the vials, the vials must be securely sealed and not more than 200 large vials or 500 small vials placed in a bag. k. Sewer disposal is not to be used as a primary means of disposal. l. The contents of each radioactive material waste container shall be inspected by a laboratory or departmental representative prior to removal from the
laboratory to ensure that the wastes are properly separated and packaged in accordance with applicable procedures. m. All disposals will be done periodically and date of disposal will be informed by the department Safety Committee member for Radiation Safety (SCRS) and arranged by OSHE. Plastic bags with NUS logo and radioactivity hazard symbol, yellow radioactive container labels and Request for Disposal of Radioactive Waste Form (OSHE/F/RS/01) can be obtained from the SCRS. Revised by Safety Website Team Revised on 16 July 2012 Endorsed by Professor Ho Khek Yu Head Department of Medicine