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Application of treatment and disposal methods
9 Application of treatment and
disposal methods tohealth-care waste categories Suitable treatment and disposal methods for the different categories ofhealth-care waste are summarized in Table 9.1 and discussed in moredetail in this chapter.
Infectious waste and sharps
Within the limitations mentioned in the relevant sections, almost all thetreatment methods outlined in Chapter 8 are suitable for infectiouswaste and sharps, except “inertization.” The treatment option should bechosen according to the national and local situation.
Destroying infectious microorganisms—by heat, by chemical means, orby microwave irradiation—is relatively easy. Highly infectious waste,such as cultures and stocks of infectious agents from laboratory work,should be sterilized by wet thermal treatment (e.g. autoclaving) at theearliest stage possible. For other infectious health-care waste, disinfec-tion is adequate.
Sharps should undergo incineration whenever possible, and can be incin-erated together with other infectious waste. Encapsulation is also suit-able for sharps. After incineration or other disinfection, the residues maybe landfilled.
In exceptional emergency situations, such as outbreaks of communicablediseases, burning of infectious health-care waste in open trenches mayalso be envisaged if it is not possible to use any of the treatment optionsdescribed in Chapter 8 (see also Chapter 16).
Unless there is an adequate wastewater treatment plant, blood should bedisinfected before discharge to a sewer; it may also be incinerated.
Pharmaceutical waste
Sound management of pharmaceutical products facilitates waste mini-mization (see section 6.1) and is of prime importance to better wastemanagement in general. Disposal of small amounts of chemical or phar-maceutical waste is easy and relatively cheap; large amounts require theuse of special treatment facilities.
Disposal of small quantities of pharmaceutical waste The disposal options for small quantities of pharmaceutical waste in-clude those outlined in the following paragraphs.
Safe management of wastes from health-care activities
Table 9.1
Overview of disposal and treatment methods suitable for differ-ent categories of health-care waste Small quantities of pharmaceutical waste produced on a daily basismay be landfilled provided that they are dispersed in large quantitiesof general waste. Cytotoxic and narcotic drugs, however, should neverbe landfilled, even in small quantities.
Small quantities of pharmaceutical waste may be encapsulated, to-gether with sharps if appropriate.
• Safe burial on hospital premises Safe burial of small quantities of pharmaceutical waste prevents scav-
enging and may be an appropriate disposal method for establishments
applying minimal programmes.
Moderate quantities of relatively mild liquid or semi-liquid pharma-ceuticals, such as solutions containing vitamins, cough syrups, intra-venous solutions, eye drops, etc. (but not antibiotics or cytotoxic drugs),may be diluted in a large flow of water and discharged into municipalsewers. It is not acceptable, however, to discharge even small quanti- Application of treatment and disposal methods
ties of pharmaceutical waste into slow-moving or stagnant waterbodies.
Small quantities of pharmaceutical waste may be incinerated togetherwith infectious or general waste, provided that they do not form morethan 1% of the total waste (in order to limit potentially toxic emissionsto the air).
Disposal of large quantities of pharmaceutical waste Large quantities of solid pharmaceutical waste may have to be dealt withif a pharmacy closes down, for example, or after emergencies (see alsoGuidelines for safe disposal of unwanted pharmaceuticals in emergenciesand difficult circumstances1). The treatment methods outlined in thefollowing paragraphs are suitable.
Incineration is the best way to dispose of pharmaceutical waste. Thewastes should be mixed with their cardboard packaging, and possiblywith other combustible material and infectious waste, to ensure opti-mal combustion conditions. Low-temperature incineration (<800 °C),however, provides only limited treatment for this type of waste; it isnot recommended unless it is followed by combustion in a secondchamber, operating at temperatures about 1000 °C, to burn off poten-tially toxic exhaust gases that may be produced. Ideally, largeamounts of pharmaceuticals should be treated in incinerators de-signed for industrial waste (including rotary kilns), which can operateat high temperatures (>1200 °C). Cement kilns are also particularlysuited to the treatment of pharmaceuticals; in many countries, cementproducers accept pharmaceutical waste as an alternative fuel, thusreducing fuel costs. As a “rule of thumb”, however, it is suggested thatno more than 5% of the fuel fed into the furnace at any time ispharmaceutical material.
Solid, liquid, and semi-liquid waste can be encapsulated in metaldrums (see section 8.5).
Landfilling of large quantities of pharmaceuticals is not recommendedunless the waste is encapsulated and disposed of in sanitary landfillsites, where the risk of groundwater contamination is minimized. Largeamounts of pharmaceutical waste should not be disposed of with generalhospital waste, nor should they be diluted and discharged into sewers(except for certain very mild solutions, such as vitamin preparations).
Intravenous fluids and glass ampoules are special cases. Intravenousfluids (salts, amino acids, lipids, glucose, etc.), which are relatively harm-less, can be disposed of to a landfill or discharged into a sewer. Ampoulesshould be crushed on a hard, impermeable surface; workers should wearprotective clothing, eye protection, gloves, etc. The glass should then be 1 Disposal of unwanted pharmaceuticals in emergencies and difficult circumstances. Geneva, World Health Organization (unpublished document, in preparation; will beavailable on request from Department of Essential Drugs and other Medicines, WorldHealth Organization, 1211 Geneva 27, Switzerland).
Safe management of wastes from health-care activities
swept up, collected, and disposed of with sharps. Ampoules should not beincinerated as they may explode, damaging the incinerator or injuringworkers.
Cytotoxic waste
Cytotoxic waste is highly hazardous and should never be landfilled ordischarged into the sewerage system. Disposal options include thefollowing: Safely packaged but outdated drugs and drugs that are no longerneeded should be returned to the supplier. This is currently the pre-ferred option for countries that lack the facilities for incineration.
Drugs that have been unpacked should be repackaged in a manner assimilar as possible to the original packaging and marked “outdated” or“not for use”.
• Incineration at high temperatures Full destruction of all cytotoxic substances may require temperaturesup to 1200 °C; Table 9.2 gives the minimum temperatures necessary todestroy common cytotoxic products. Incineration at lower tempera-tures may result in the release of hazardous cytotoxic vapours into theatmosphere.
Modern double-chamber pyrolytic incinerators are suitable, providedthat a temperature of 1200 °C with a minimum gas residence time of2 seconds or 1000 °C with a minimum gas residence time of 5 secondscan be achieved in the second chamber. The incinerator should be Table 9.2
Minimum temperatures for destruction of cytotoxic drugs, forconventional residence times, according to different authors aAllwood & Wright (1993); bLee (1988); cWilson (1983).
Note: The data included in this table were the most recent data available at the time of preparation of this handbook, but no information has been provided as to the scientific background whichled to these proposals. The Agence de I’Environnement et de la Maîtrise de I’Energie(ADEME) (contact address: Centre de Sophia Antipolis, Département Toxicologie etExotoxicologies, 500 route des Lucioles, 06560 Valbonne, France) is investigating the effi-ciency of incineration of a number of individual drugs and the genotoxic risk of the outgoingresidues.
Application of treatment and disposal methods
fitted with gas-cleaning equipment. Incineration is also possible inrotary kilns designed for thermal decomposition of chemical wastes, infoundries, or in cement kilns, which usually have furnaces operatingwell in excess of 850 °C.
Incineration in most municipal incinerators, in single-chamber incin-erators, or by open-air burning is inappropriate for the disposal ofcytotoxic waste.
Chemical degradation methods, which convert cytotoxic compoundsinto non-toxic/non-genotoxic compounds, can be used not only for drugresidues but also for cleaning of contaminated urinals, spillages, andprotective clothing. The methods are appropriate for developing coun-tries. Drugs for which chemical degradation methods are available arelisted in Box 9.1. Most of these methods are relatively simple and safe;they include oxidation by potassium permanganate (KMnO ) or sulfu- ric acid (H SO ), denitrosation by hydrobromic acid (HBr), or reduction by nickel and aluminium. They are described in detail in Annex 2. TheInternational Agency for Research on Cancer (IARC) may be contactedfor further information.1 The methods are not appropriate for thetreatment of contaminated body fluids.
It should be noted that neither incineration nor chemical degradationcurrently provides a completely satisfactory solution for the treatmentof waste, spillages, or biological fluids contaminated by antineoplasticagents. Until such a solution is available, hospitals should use the utmostcare in the use and handling of cytotoxic drugs.
Where neither high-temperature incineration nor chemical degradationmethods are available and where exportation of cytotoxic wastes foradequate treatment to a country with the necessary facilities and exper-tise is not possible, encapsulation or inertization may be considered as alast resort.
Cytotoxic drugs for which chemical degradation
methods exist
a1-(2-Chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea.
1 International Agency for Research on Cancer, Unit of Gene–Environment Interactions, 150 Cours Albert-Thomas, 69372 Lyon Cedex 08, France.
Safe management of wastes from health-care activities
Chemical waste
As for pharmaceutical waste, improving the management of chemicalwaste starts with waste minimization efforts (see section 6.1).
Disposal of general chemical waste Non-recyclable, general chemical waste, such as sugars, amino acids, andcertain salts (see also section 2.1.7), may be disposed of with municipalwaste or discharged into sewers. The discharge into sewers of aqueouschemical wastes that arise in health-care establishments, together withtheir associated suspended colloidal and dissolved solids, has tradition-ally been accepted by sewerage authorities in many countries. However,official permission from the appropriate authority may be required andthe types and quantities of material that can be discharged may belimited. Generally, conditions for discharge may include restrictions onpollutant concentrations, content of suspended solids, temperature, pH,and, sometimes, rate of discharge. Unauthorized discharge of hazardouschemicals can be dangerous to sewage treatment workers and may ad-versely affect the functioning of sewage treatment works.
Petroleum spirit, calcium carbide, and halogenated organic solventsshould not be discharged into sewers.
Disposal of small quantities of hazardous chemical waste Small quantities of hazardous chemical waste, e.g. residues of chemicalsinside their packaging, may be dealt with by pyrolytic incineration,encapsulation, or landfilling.
Disposal of large quantities of hazardous chemical waste There is no way to dispose both safely and cheaply of significant quanti-ties of hazardous chemical waste. The appropriate means of disposal isdictated by the nature of the hazard presented by the waste.
Certain combustible wastes, including many solvents, may be inciner-ated. However, incineration of large quantities of halogenated solvents(containing chlorine or fluorine for instance) should not be undertakenunless facilities have adequate gas-cleaning equipment. Any waste thatcannot be safely and efficiently incinerated should be handled and dis-posed of by an organization or company specifically authorized to managehazardous waste. This organization may eliminate the wastes in a rotarykiln, treat them chemically, or store them in a safe disposal facilityengineered for hazardous chemicals.
Other possibilities for disposing of hazardous chemicals include return tothe original supplier, who should be equipped to deal with them safely.
Where such an arrangement is envisaged, appropriate provisions shouldbe included in the original purchase contract for the chemicals. Thewaste could also be exported to a country with the expertise and facilitiesto dispose safely of hazardous waste. Shipment for this purpose shouldcomply with international agreements, such as the Basel Convention (seesection 4.1). Use of certain products for non-medical purposes may also beconsidered; for example, use of outdated disinfectants to clean toilets isoften acceptable.
Application of treatment and disposal methods
The following additional measures are also recommended: • Hazardous chemical wastes of different composition should be stored separately to avoid unwanted chemical reactions.
• Hazardous chemical waste should not be discharged into sewerage • Large amounts of chemical waste should not be buried as they may • Large amounts of chemical disinfectants should never be encapsulated as they are corrosive and sometimes flammable.
Wastes with high heavy-metal content
Wastes containing mercury or cadmium should never be burned or incin-erated because of the risk of atmospheric pollution with toxic vapours,and should never be disposed of in municipal landfills as they maypollute the groundwater.
In countries with “cottage” industries specializing in the recovery ofheavy metals, mercury- and/or cadmium-containing waste can be sentto these facilities for recovery of the valuable materials. It may also bepossible to send back the waste to the suppliers of the original equip-ment, with a view to reprocessing or final disposal, but this is unusualbecause suppliers are generally reluctant to accept these wastes. Thesituation should be checked before dispatch of wastes. Exporting thewaste to countries with the expertise and facilities for its adequatetreatment should also be considered.
If none of the above options is feasible, the wastes may be disposed of in
a safe storage site especially designed for the final disposal of hazardous
industrial waste. Establishments that apply minimal programmes
may also consider encapsulation, followed by disposal in an impermeable
landfill (if available).
Where the production of waste with high heavy-metal content is minimal(e.g. in similar quantities to that present in municipal waste) and thereare no facilities for recovery of heavy metals within the country, thiswaste may join the municipal waste stream.
Pressurized containers
Incineration or burning is not a disposal option for pressurized contain-ers or aerosol cans because of the risk of explosion. The best disposaloptions are recycling and reuse; most undamaged pressurized containersmay be sent back to the gas suppliers for refilling. Appropriate arrange-ments for the return of containers should be included in the originalpurchase contracts. Halogenated agents in liquid form, supplied in glassbottles, should be handled as hazardous chemical waste and disposed ofas such (see section 9.4).
The following containers should be returned to the supplier: Safe management of wastes from health-care activities
— nitrous oxide cartridges or cylinders attached directly to the — ethylene oxide cartridges or cylinders, which are usually attached — pressurized cylinders for other gases, such as oxygen, nitrogen, carbon dioxide, compressed air, cyclopropane, hydrogen, petroleumgases (for heating and cooking), and acetylene (for welding).
Pressurized containers that have been damaged and are unsuitable forrefilling may be crushed after being emptied completely; they can thenbe disposed of in any landfill. This option may also be selected whenthe return of empty containers to the gas suppliers is uneconomical.
“Cottage” industries specializing in recovery of metals may also acceptdamaged pressurized containers. In extreme cases, where containershave corroded valves and still have residual pressure, the only safesolution is to assemble them at a safe location (e.g. a military trainingarea) and arrange for qualified specialists to destroy them by con-trolled explosion.
Small aerosol cans should be collected and disposed of with generalwaste in black waste bags, but only if this waste is not destined forburning or incineration. They should never be placed in yellow bags,which will go for incineration. Large quantities of disposable aerosolcans may be returned to the supplier or sent to waste recycling plantswhere possible.
Radioactive waste
Note: A number of specific terms used in this section are explained in the The safe management of radioactive waste should ideally be thesubject of a proper national strategy with an infrastructure that includesappropriate legislation, competent regulatory and operational organiza-tions, and adequately trained personnel. The national strategy shouldalso determine whether there will be centralized waste management orwhether waste will be managed entirely at source (e.g. at the health-careinstitutions). This decision will be based on the quantity and activitylevels of the waste generated and on the outcome of a cost–benefitanalysis.
Each hospital or laboratory that uses unsealed radioactive sources fordiagnostic, therapeutic, or research purposes should designate a trainedRadiation Officer who will be responsible for the safe use of radioactivesubstances and for record-keeping. Properly calibrated instrumentsshould be available for monitoring dose rates and contamination. Asuitable record system that will ensure the traceability of radioactivewaste transferred or disposed of locally should be established and kept upto date at all times.
Note: The classification of radioactive waste and the clearance levels should be established by the regulatory authority. Table 9.3 and Application of treatment and disposal methods
Table 9.3
Materials containing levels of radionuclides at concentrations less than those expressed in Annex 3 (Tables A3.1–A3.3) Low-level radioactive waste containing short-lived radionuclides only (e.g. with half-lives less than 100 days), that will decay toclearance levels within 3 years of being produced Waste that will not decay to clearance levels within 3 years, containing b- and g-emitting radionuclides with half-lives less than 30 years and/or a-emitting radionuclides with an activityless than 400 Bq/g and a total activity of less than 4000 Bq ineach waste package Radioactive waste that contains radionuclides at concentrations above those for LILW-SL but with heat-generating capacity not Radioactive waste that contains radionuclides at concentrations above those for LILW-SL and with heat-generating capacityabove 2 kW/m3 of waste Annex 3 provide examples of waste classification and clearancelevels.
Radioactive waste should be classified in accordance with national legis-lation and according to the activity levels and half-lives of the radio-nuclides present, as shown in Table 9.3.
Radioactive waste segregation and characterization Radioactive waste should be categorized and segregated on the basis ofthe available options for treatment, conditioning, storage, and disposal.
Possible categories are: • half-life—for instance, short-lived (e.g. half-life <100 days), suitable for — liquid: aqueous and organic— non-homogeneous (e.g. contain sludges or suspended solids)— solid: combustible/non-combustible (if applicable) and compactable/ • sealed/non-sealed sources—for instance, spent sealed sources; • waste content—for instance, waste containing hazardous (e.g. patho- After segregation, each category of waste should be kept separately, i.e.
in separate containers. The waste containers should: • bear a radiation trefoil symbol when in use; • be compatible with the waste contents; • be capable of being filled and emptied safely.
The following information should be recorded for each waste container: Safe management of wastes from health-care activities
• activity (if measured or estimated) and date of measurement; • origin (room, laboratory, individual, etc. if applicable); • potential/actual hazards (chemical, infectious, etc.); • surface dose rate and date of measurement; Containers for solid wastes should be lined with a durable transparentplastic bag which can be sealed (tied with plastic adhesive tape or heat-sealed).
Liquid waste should be collected in suitable containers according to itschemical and radiological characteristics, volume, and handling andstorage requirements.
Spent sealed sources should be kept under shielding.
Containers should be checked for radioactive contamination; loose con-taminating material should be removed before containers are reused.
Characterization of radioactive waste in terms of activity, radionuclidecontent, physical and chemical form, and associated hazards can beachieved by a combination of quality assurance (records of radionuclideinventory, activity decay, composition of materials used, etc.) and directmeasurement techniques. Waste of unknown origin and composition willrequire detailed analysis. This may be complex and expensive.
Management options for radioactive health-care waste A range of options may need to be considered for dealing with radioactivewaste generated by health-care activities, depending on the amount andcharacteristics of the waste.
The waste may be suitable for release from regulatory control immedi-ately or after a period of decay storage, which may vary from some daysto a few years. Such waste may be released in quantities or at activitylevels established by the regulatory authority. The recycling or reuse ofradioactive materials is also possible if the regulatory authority hasapproved such an option.
If release is not a feasible option, return of the waste to the producer/supplier of the original material should be considered. This is of particu-lar importance for large sealed sources and sources containing long-livedradionuclides.
For waste that can neither be released from regulatory control nor re-turned to the producer/supplier, an acceptable destination will need to beidentified. This could be either a disposal facility or a facility for long-term storage pending future disposal. In both cases, prior treatment orconditioning of waste may be needed.
Decisions on waste management have significant financial implicationsthat have to be addressed, since the waste generator is responsible forthe waste. In developing its strategy, the national government maychoose to undertake essential waste treatment, conditioning, storage, Application of treatment and disposal methods
and/or disposal if it is in the public interest to do so. In such cases, thefunction of the regulatory authority should be clearly separate and inde-pendent from that of the operating organizations.
Exemption and clearance
Some radioactive wastes can be exempted, or released, from regulatory
control, because they represent a negligible radiological hazard. The
radioactivity of materials released to the environment should be below
the clearance levels established by the regulatory authority (examples
are given in Tables A3.1–A3.3 of Annex 3). The discharge or release
of the radioactive material should be monitored and recorded with
sufficient detail and accuracy to demonstrate its compliance with the
regulations.
Radioactive waste containing short-lived radionuclides should be storedfor decay to the clearance levels.
Exemption of radioactive health-care waste from regulatory control isunlikely to mean that it is also exempt from regulatory control of otherhazards.
Recycling and reuse
Recycling and reuse of radioactive materials should be considered as an
alternative to disposal, if circumstances permit. Possibilities include:
• decontamination and reuse of equipment and protective clothing; • reuse of dilute waste streams (for rinsing and washing of waste tanks that contained liquid waste with higher radioactivity content).
The reuse and/or recycling of radioactive materials should be subject toapproval by the regulatory authority. Special attention should be givenboth to the implications of producing secondary waste streams, and to theneed to ensure that sealed sources are in a serviceable condition andsuitable for the intended application.
Spent sealed sources should not be recycled by the health-care institu-tions.
Return to supplier
If at all possible, spent sealed sources should be returned to suppliers.
This is particularly important for sources with high activity and those
containing long-lived radionuclides.
The high-activity radionuclides, usually of long half-life, used for thera-peutic purposes are conditioned as sealed sources, in the form of pills,seeds, ribbons, capsules, tubes, or needles. Brachytherapy sources arerecovered after use, washed, disinfected, and stored under lead shieldinguntil needed for other patients. These items may become waste if theirconditioning is damaged, the activity has decayed, or they are no longerrequired. Spent sources for teletherapy also become waste. In countriesthat lack a nuclear industry equipped to dispose of spent sealed sources,hospitals should return these items to their original containers or other-wise package them appropriately (see Chapter 7) and send them back tothe supplier for reprocessing, recycling, or safe disposal. Where a nuclearindustry with appropriate capabilities exists, hospitals may send non- Safe management of wastes from health-care activities
recyclable spent sealed sources to an authorized facility or to the nationalagency designated for radioactive waste disposal.
Any health-care institution proposing to import a sealed source contain-ing radioactive material that will have an activity greater than 100 MBq10 years after receipt is recommended to: • require the supplier to accept the source back after expiry of its useful lifetime, within 1 year of such return being requested, on conditionthat the user undertakes to return the source to the supplier not laterthan 15 years after receiving it; • submit to the regulatory authority a copy of relevant parts of the contract (if the source is purchased) or acceptance document (if thesource is donated) and obtain the written agreement of the authoritybefore purchasing or accepting the source. Storage
Storage facilities may be required for untreated, treated, and conditioned
radioactive health-care waste; special care is needed for the storage of
unconditioned waste in order to limit the risk of dispersion. Storage
facilities should be designed to provide physical security, retrievability,
and radiological protection. Radioactive waste must be stored in such a
way that human health and the environment are protected; it must not
be stored in the vicinity of corrosive, explosive, or readily flammable
materials.
Where activity limits for immediate or simple discharge/disposal meth-ods cannot be met, health-care establishments should segregate radioac-tive waste and store it for the time required for the activity to decay toclearance levels. Since the half-life of most radioactive materials usedin hospitals is of the order of hours or days, storage for at least 10 half-life periods can be followed by disposal to the ordinary waste system(with appropriate monitoring). Decayed, non-infectious radioactive wasteshould be placed in transparent bags to facilitate visual inspection (if thewastes are to be landfilled). Decayed but infectious radioactive wasterequires disinfection before disposal and is therefore collected in yellowplastic bags.
All radioactive waste that is to be stored during decay should be kept insuitable containers that prevent dispersion of their content. A plastic bagin an easy-to-handle can or drum should be used. Containers used for thestorage of radioactive waste should be clearly identified (marked with thewords “RADIOACTIVE WASTE” and the radiation symbol), and labelledto show the activity of the radionuclide on a particular date, period ofstorage required, origin of the waste, surface dose rate on a particulardate, quantity, and responsible person. The containers should be storedin a specially designated area in storage rooms—lead-shielded if neces-sary—designed for radioactive substances or waste. The storage recordshould be clearly endorsed to indicate the items that are “radioactivewaste”.
Facilities or areas for radioactive waste must be clearly demarcated, withcontrolled access, and should have the characteristics listed in Box 9.2.
Areas for untreated (raw) waste should be separate from those for condi-tioned waste.
Application of treatment and disposal methods
Characteristics of storage facilities/areas for
radioactive health-care waste
• Sufficient capacity to accommodate all waste generated before discharge, treat- • Simple construction, with non-flammable walls and floors that may be easily • Impermeable floor covering, with a containment edge and slight slope to a • Air sampling and radiation alarms (as required by the regulatory authority).
• Fire detection/control equipment (as required by the regulatory authority).
• Compartments to allow separation of different kinds of waste (e.g. to facilitate the safe storage of materials presenting particular hazards—volatile, pathogenic,infectious and putrescible, chemically reactive).
• Demarcation as radiologically controlled areas.
• A log-book, listing the number of containers, entry date, waste types, activity, etc., which should be kept outside, but near, the storage room or area.
• Protection from the environment (weather), including extremes of temperature.
• Protection against unauthorized entry and against the intrusion of animals, in- • Movable radiation shielding (placed as appropriate to protect workers from Treatment and conditioning
Radioactive health-care waste should be treated and conditioned in ac-
cordance with the national radioactive waste management strategy and,
in particular, to meet any waste acceptance criteria laid down by the
regulatory authority. Treatment and conditioning should be undertaken,
when necessary, to improve the characteristics of waste before interim
storage and/or disposal.
Treatment includes operations intended to improve safety or economy bychanging the characteristics of the radioactive waste. The basic objec-tives are: — for solid waste: shredding, low-force compaction, and controlled — for liquid waste: evaporation under controlled conditions.
Safe management of wastes from health-care activities
— for solid waste: decontamination;— for liquid waste: ion exchange.
— for liquid waste: precipitation/filtration.
It is important to be aware that treatment processes may result in theproduction of secondary radioactive waste streams (contaminated filters,spent resins, sludges, ash), which also need to be appropriately managed.
Conditioning involves those operations that convert radioactive wasteinto a form that is more suitable for handling, transportation, storage,and disposal. The operations may include immobilization of radioactivewaste in concrete, placing the waste in suitable containers, and providingadditional packaging. In many instances, treatment and conditioningtake place in close physical conjunction with one another.
Discharge/disposal
Although management may involve the concentration and containment
of radioactive waste, it may also involve the discharge of effluents (for
example, of liquid and gaseous waste) into the environment. This may be
done only within the limits authorized by the regulatory authority, and
should take into account subsequent dispersion. For all practical pur-
poses this is an irreversible action and is considered suitable only for
limited amounts of certain radioactive wastes.
The health-care institution should ensure that radionuclides are notreleased to the environment unless: • the activity released is confirmed to be below the clearance levels; or • the activity of the liquid or gaseous effluents discharged is within limits authorized by the regulatory authority.
Any health-care institution wishing to release to the environment solid,liquid, or gaseous radioactive waste with activity above the clearancelevels should apply for an authorization. It should also: • keep all radioactive discharges or releases as far below the authorized • monitor and record the discharges or releases of radionuclides with sufficient detail and accuracy to demonstrate compliance with theauthorized discharge limits; • report discharges to the regulatory authority at whatever intervals are • report promptly to the regulatory authority any discharges or releases Whether radioactivity is released within the clearance levels or underauthorization, the non-radiological hazards of the release must also beconsidered and the requirements of any regulations governing thosehazards should be met.
Disposal is the final step in the management of radioactive waste. Essen-tially, it involves the placement of radioactive waste in a disposal facilitythat provides reasonable assurance of safety; in general there is nointention of retrieval, and no long-term surveillance or maintenance of Application of treatment and disposal methods
the disposal site. The establishment of an engineered disposal facility(repository) is thus a complex and costly undertaking.
When radioactive waste is not suitable for discharge or release to theenvironment or for clearance within a reasonable time, the health-careinstitution should submit its proposals for disposal to the regulatoryauthority. It should then ensure that the criteria set by the regulatoryauthority for acceptance of the waste at any repository or by any nationalwaste management organization are met.
Additional remarks
• Disposable syringes containing radioactive residues should be emptied in a location designated for the disposal of radioactive liquid waste.
They should then be stored in a sharps container to allow decay of anyresidual activity, before normal procedures for disposal of syringes andneedles are followed.
• It is not appropriate to disinfect radioactive solid waste by wet thermal • Solid radioactive waste such as bottles, glassware, and containers should be destroyed before disposal to avoid reuse by the public.
• The drains that serve sinks designated for discharge of radioactive liquids should be identified. If repairs become necessary, radiationlevels should be measured as the drain or sewer is opened up, andappropriate precautions should be taken.
• Liquids that are immiscible with water, such as scintillation counting residues, should not be discharged to sewers but treated by an alterna-tive method, e.g. incineration, absorption.
• Higher-level radioactive waste of relatively short half-life (e.g. from iodine-131 therapy) and liquids that are immiscible with water, suchas scintillation counting residues and contaminated oil, should bestored for decay in marked containers, under lead shielding, untilactivities have reached authorized clearance levels. Water-misciblewaste may then be discharged to the sewer system and immisciblewaste may be disposed of by the methods recommended for largequantities of hazardous chemical waste.
• Radioactive waste resulting from cleaning-up operations after a spill- age or other accident should be retained in suitable containers, unlessthe activity is clearly low enough to permit immediate discharge. Ifexcessive activity enters the sewer accidentally, a large volume ofwater should be allowed to flow to provide dilution to about 1 kBq perlitre. The relevant governmental agency must be informed urgentlyif radioactive waste in excess of the permitted amounts has beendischarged to sewers, the atmosphere, or otherwise into the environ-ment. After the emergency period, the activity of the resulting wasteshould be assessed and the relevant ministries should be informed ofthe circumstances that gave rise to the incident.
• It is not usually necessary to collect and confine patients’ excreta after diagnostic procedures, although ordinary toilets used by such patientsshould be checked regularly for radioactive contamination by compe-tent staff (e.g. the Radiation Officer). In the case of therapeutic proce-dures involving radionuclides, hospital toilets must be checked forradioactive contamination after each use by patients, unless everypatient has an individual toilet. Some countries require the use ofseparate toilets equipped with delay tanks and/or special treatmentsystems for patients undergoing radiotherapy.
Safe management of wastes from health-care activities
• Radioactive gases, deriving mainly from research and radioimmunoas- says, should be discharged directly to the atmosphere for dilution bydispersal (within the authorized limits). In general, all gaseous wastedischarges, including exhausts from stores and fume cupboards,should be designed and sited to prevent re-entry into any part of thepremises. Radiation and contamination levels near discharge pointsshould be checked periodically by the Radiation Officer. The WHO airquality guideline value for atmospheric radioactivity is 1 Bq/m3.
References and suggested further reading
Allwood M, Wright P, eds (1993). The cytotoxic handbook. Oxford, Radcliffe Barek J et al. (1987). Method for efficient degradation of melphalan into non- mutagenic products. Microchemical journal, 36:192–197.
Bisson M et al. (1995). Elimination par incinération des déchets liés à l’utilisation de médicaments anticancéreux. Rapport final. [Elimination of wastes relatedto the use of anti-cancer drugs by incineration. Final report.] Valbonne,Agence de l’Environnment et de la Maîtrise de l’Energie.
Bisson M (1996). Elimination par incinération des déchets liés à l’utilisation de médicaments anticancéreux: optimisation couple température-temps.
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