Treatment technologies and Common Bio-medical Waste ...

Treatment technologies and Common Bio-medical Waste Treatment Facility
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Introduction
A common bio-medical waste treatment facility (CBWTF) is a set up where biomedical waste, generated from a number of healthcare units, is treatedcentrally.A CBWTF should have all the required technologies to collect, treat and dispose Bio- medical waste.
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Draft Guidelines for CBWTF
The guidelinesare laid by Central Pollution controlboard.Salient features:Every CBWTF must have treatment equipments like incinerator, autoclave or microwave, shredder and effluent treatment plant as a part of treatment, prior to commencement of itsoperation.It should collect, transport, treat and dispose segregated Bio medical waste of all Healthcare Facilities within 75 km range.Operator of a CBWTF should maintain a record of recyclable wastesTherecord shall be open for inspection by the prescribedauthoritiesIt shall allow visit by any occupierBar code and global positioning system should be used byCBWTFAll the CBWTF vehicles should be labeled as given in part ‘A’ of the Schedule IV of the Bio-medical waste managementRules
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Technologies used in a CBWTF
AutoclaveIt isa low heat thermal process and it uses steam for disinfection of waste.It uses differenttemperature, pressure and time combinations for a treatmentcycle.
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Types of Autoclave
Air is an effective insulator, thus complete disinfection demands removal of air from the chamber. Two methods of removing air are:Gravity displacementPre-vacuum
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Stages in autoclave operation
Pre-heatingLoading of waste with an indicatorAir evacuationSteam treatmentSteam dischargeUnloadingMechanical treatment
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Standards for waste autoclaving
Dedicated autoclave for waste treatmentTime, temperature and pressure to themaintainedGraphic/computer recording devicesValidation test: Spore testing (bacillusstearothermophiluswithatleast1x104spores/ml)Routine test: chemical indicator strip/tape which iscoloursensitive.Operating parametersGravity flow:121oC, 15psi, 60`; 135oC,31psi,45`; 149oC, 52psi, 30`Pre-vacuum:121oC, 15psi, 45`; 135oC,31psi, 30`
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Types of waste allowed/ disallowed
Waste AllowedYellowCategory waste: Under this, soiled waste: items contaminated with blood and body fluids, including cotton dressings, soiled plaster casts, linen, beddings, etc.RedCategory – Contaminated Waste (Recyclables) - waste generated from disposable items other than the waste sharps, such astubings, catheters, intravenous sets, syringes (without needles or fixed needles syringes),vaccutainerswith their needles cut etc.WhiteCategory (Translucent) - Waste sharps including metals: needles, syringes, scalpels, blades, glass etc. that may cause puncture and cuts. This includes both used and unused sharps.BlueCategory – Glassware – Broken or discarded & contaminated glass including medicine vials and ampoules except those contaminated withcytotoxicwastes.Not to be treated:Volatile and semi-volatile organic compoundsChemotherapeutic wastes, mercury and other hazardous chemical wasteRadiological waste, Sealed heat resistant containersHuman/ Animal Anatomical WasteMicrobiological/Biotechnological WasteHuge and bulky bedding material
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Points to remember
Segregated waste is a mustAir evacuation is necessaryPlace bags in multi-load traysProper ventilation to avoid odorsThermocouples and pressure gauges should be checked frequently
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Microwaves: action mechanism
Disinfection by moist heat and steam generated by microwave energyMagnetrons convert high voltage electrical energy into microwave energyThe microwaves create an electromagnetic fieldWater and other molecules in waste try to align in the field and in the process they vibrateVibration of the molecules produces heat
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Microwaves: action mechanism
Microwave kills by two mechanisms:By heat energy from the steam generatedChanging the biological molecular structure of proteinsMicrowaves are high frequency (2450+50mhz) radio waves capable of creating electromagnetic fieldTemperatures reached are around 97-100oC. In some new systems, steam under pressure is passed, to achieve temperatures>135oC.Cycle time is around 25`Typically, around 2-6 magnetrons are used with an output of about 1.2KW each
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Stages in microwave operations
Waste loadingSteam injection in the hopperInternal shreddingMicrowave treatmentDisinfection cycleOptional secondary shreddingDischargeCategory of waste that can be and cannot be treated is similar to the autoclave. Emission parameters are also similar
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Advantages and disadvantages
AdvantagesIn use for more than a decadeMinimal emissions if no hazardous waste fedAutomated systemNo liquid effluentDisadvantagesRelatively high capital costToxic emissions if hazardous waste fedAny large metal item can damage shreddersOdourproblemsProbability of microwave energy leakage
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Standards for microwaves
Not to be used forcytotoxic, hazardous or radioactive wastes, contaminated animalcarcasses, body parts and large metal itemsShould comply with efficacy and routine testsandshould consistently kill bacteria and otherpathogenicorganismsBiological indicator: bacillussubtilisspores(using strips/vials of 1x104spores/ml)
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Hydroclave
Hydroclaveis steam treatment with fragmentation and drying of wasteIt hasadouble walled chamber with an agitator insideSteam is injected into this wall (jacket) and waste is loaded in the inner chamberThe agitator fragments and turns waste
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Hydroclave: treatment mechanism
The moisture in the waste turns tosteam and exertspressure on the inner walls. If thispressureis not sufficient, additional steammaybe injected inside.Cycle runs at 132oC for 15`/ 121oC for 30`Finally the steam is vented through a condenser while maintaining heat input, causing the waste to drySteam is shut off, discharge door is opened and agitator runs in reverse rotation to place the waste on a conveyor belt/ container
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Advantages and disadvantages
AdvantagesShredded, dry wasteInternal mixing improves transfer of heatDisadvantagesClogging of agitator blades with wasteMixed shredded waste makes recycling difficult
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
PlasmaPyrolysis& Gasification: Action Mechanism
This process convertsorganic matter into synthetic gas, electricity, and slag using plasma.Aplasma torch powered by an electric arc, is used to ionize gas and catalyze organic matter into synthetic gas and solid waste (slag)Astrong electric current under high voltage passes between the two electrodes as an electric arc.Pressurizedinert gas is ionized passing through the plasma created by the arc. The torch's temperature ranges from 4,000 to 25,000 °F (2,200 to 13,900 °C).Thewaste is heated, melted and finallyvaporised.
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Dry HeatSterilization: Action Mechanism
This system usesheated air at high speed.Afterthe waste is loaded, it is shredded and then transferred to a treatment chamber.Hotair is directed in a way that causes the waste particles to rotate turbulently around a vertical axis in atorroidalmixing action.Thiscauses high rates of heat exchange and within four to six minutes, dryunrecognisablewaste is ejected.Thetype of waste to be treated and emission problems with this system are similar to those of autoclaves.This technology requires a temperature of 185°C for a residence time of 150 minutes, with a sterilization period of 90 minutes.
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Incineration
Incineration is a burn technology and high temperatures are used to kill the pathogens and, in the process, destroy the materials on which they reside.Duringincineration and post combustion cooling, waste components dissociate and recombine, forming hundreds and thousands of new molecules, which are referred to as products of incomplete combustion (PIC).Theoretically, an incinerator would change all hydrocarbons to carbon- dioxide and water, but this does not happen in practice
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Incineration Standards
TemperaturePrimary Chamber-800+/-50oCSecondary Chamber- 1000+/-50oCSecondary chamber gas residence timeatleast2 seconds, with minimum 3% oxygen in the stack gasMinimum Stack height shall be 30 meters above groundVolatile organics in ash not more than 0.01%Suitable pollution control equipment to achieve emission levels
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Dioxins: where do they come from?
Are an unintentional by product of waste incineration, as well as certain chemical and manufacturing processes;Are toxic at very low levels of exposureAre persistent in the environmentBio-accumulateHave a half-life of approximately 7 years in humans, 100 years in sub-surface soil and over 50 years in water bodies and sediments
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Medical waste incineration and dioxins
Medical waste incinerators are a major source of dioxins in the global environmentBurning of chlorine-containing material such as chlorinated plastics result in dioxinsDioxins are formed after combustion, during the cooling of the exhaust gasesPolyvinyl chloride (PVC) is a major source of chlorine in medical waste
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Human health effects of dioxin
Cancerincreased cancer mortalityNeo-natal abnormalitieschange in Sex Ratioaltered level of thyroid hormoneSkin disordersporphyriacutaneatardachloracne
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers
Human health effects of dioxin
Immune systemChanges/suppression in immune systemEndocrine (hormone) system effectsLow levels of testosteroneIncrease in glucose toleranceDecreased estrogen and estrogen-receptor levels afterfoetalexposure
Ash
Incinerator ash is hazardous wasteNeeds to be disposed in secured landfillsProblems are:Contamination with heavy metals (lead, cadmium and mercury)Loaded with dioxins and furansPollution control equipment increase toxicity of ash
Understanding and Simplifying Bio-medical Waste ManagementA training manual for trainers