SHORT-TERM COURSEON

“Application of advanced fluidization techniques to waste management and energy production (aaftwmep-2008)”

sponsored by

AICTE

Venue: Department of Chemical Engineering

NIT Rourkela

NITR

Dr. (Mrs.) A. SahooAssitt. professor

Course-coordinator

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TREATMENT TO THE MEDICAL WASTE USING FLUIDIZED BED INCINERATION

Dr. Arvind KumarLecturer

Deptt. of Chemical Engg.NIT Rourkela

E-mail: arvinpch@yahoo.co.in

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INTRODUCTION

• Cultures and stocks of infectious substances• Human Pathological waste• Used Sharps• Contaminated animal wastes• Isolation wastes• Blood and blood products• Unused, discarded sharps

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INTRODUCTION

• Medical waste are very harmful• Degrade the environment severely• Causes several disease like

– AIDS, HBV, SARS, Avian Flue, Malaria, and carcinogenic, mutagenic, and teratogenic

– effects, reproductive system damage, respiratory effects, central nervous system effects,

– and many others – deteriorating quality of potable water

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Public health implications of waste

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MEDICAL WASTE SOLIDIFIER

• The solidification of the medical waste insures – makes the waste easier to handle, – prevents cross-contamination through spills and – minimizes leakage during transportation of the solidified waste to the

disposal location.

• It can be done by– The solidifying agent can be a polymeric compound, frequently referred to

as a superabsorbent compound. Several polymeric compounds which belong to this group include cross-linked acrylics, cross-linked glycolates, starch-graft polymers and cellulose esters.

– The microbicidal agent is typically a chemical compound which, when in contact with an aqueous medium, releases a chemical antimicrobial agent to the medium.

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Characteristics of medical waste suitable for incineration

• Low heating value: above 2000 kcal/kg (8370 kJ/kg) for Starved air incinerators.

• Above 3500 kcal/kg (14640 kJ/kg) for Excess air incinerators.

• Content of combustible matter above 60%.

• Content of non-combustible solids below 5%.

• Content of non-combustible fines below 20%.

• Moisture content below 30%.

• The daily waste generation rate of four hospitals was 985 kg/day, projected to be 1267 kg/day in 2015.

• analysis indicated that the moisture content of wastes was 14,2 % .

• The four hospital wastes consist of 92% combustible wastes and 8% noncombustible wastes by mass.

• The combustible wastes constitute paper (16%), textiles (10,2%), cardboard (4%), plastics (41,2%) and food waste (17%).

Source: S. Altin et al. 2002 Turkey

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Estimatimation the hospital waste generation rateas kg/bed/day

Wday = (Wmed + Wkit) / Np

where;

Wday - waste rate (kg /bed/day-unit)

Wmed - total medical waste (kg/day-unit)

Wkit - total kitchen waste (kg/day-unit)

Np - the number of overnight patients

Predicted waste generation rateWAi = Npi * P * Ap * 365

where:

WAi - total waste of year i

Npi - total number of beds

P - percentage of beds

Ap - waste per patient (kg/day)

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Medical Waste Collection Van of Calcutta Municipal Corporation to find that the rules are being violated at every step

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Objective and Techniques available to MW

Objective: it is necessary to have a appropriate and potentially sound technique to treat them in a proper way

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TECHNIQUES AVAILABLE TO MW

1. STEAM STERILIZATION: This sterilizing equipment sterilizes the waste by exposing it to steam under high pressure, thereby making it free of any contaminants.

Application of Medical Waste Sterilizer/Steam Sterilizers

• Pharmaceutical • Chemicals • Food and Catering • Waste processing Centres

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• GAS STERILIZATION: The gas penetrates the waste and kills infectious agents. Gas sterilization is rarely used to treat medical wastes.

• CHEMICAL DISINFECTION: Primarily through the use of chlorine products, is another method to treat medical waste.

• MICROWAVE: The shredded waste is then mixed with water and subjected to microwaves. The microwaves internally heat the waste, rather than applying heat externally, as in an autoclave.

• IRRADIATION: To sterilize medical equipment or waste is irradiation, generally through exposure of the waste to a cobalt source. The gamma radiation generated by the cobalt source inactivates all microbes

• AUTOCLAVES: Autoclaves are closed chambers that apply both heat and pressure, and sometimes steam, over a period of time to sterilize medical equipment.

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Micro wave-shredding Pyrolysis and oxidation treatment

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Chemical Process

Hydrolysis treatment Eco Cycle

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Thermal inactivation of microbes using:

• Moisture• Heat• Pressure

Pyrolysis• High temperature non-

combustion treatment• Forms glassy aggregate as

residual• Requires energy to operate• Relatively new technology –

requires careful consideration

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1. Currently one of the best available, suitable and technically potential technique for the medical waste treatment. 2. The most widely used treatment technology.

3. It is high-temperature dry oxidation process that reduces organic and combustible waste to inorganic, incombustible matter and

results in a very significant reduction of waste volume and weight.

MEDICAL WASTE INCINERATION

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CHARACTERISTICS OF MEDICAL WASTE SUITABLE FOR INCINERATION

1. Low heating value: above 2000 kcal/kg (8370 kJ/kg) for Starved air incinerators.

2. Above 3500 kcal/kg (14640 kJ/kg) for Excess air incinerators.

3. Content of combustible matter above 60%.

4. Content of non-combustible solids below 5%.

5. Content of non-combustible fines below 20%.

6. Moisture content below 30%.

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WASTE TYPES NOT TO BE INCINERATED

1. Pressurized gas containers.

2. Large amounts of reactive chemical waste.

3. Silver salts and photographic or radiographic wastes.

4. Halogenated plastics such as polyvinyl chloride (PVC).

5. Waste with high mercury or cadmium content, such as broken thermometers, used batteries, and lead-lined wooden panels.

6. Sealed ampoules or ampoules containing heavy metals.

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Fluidized Bed Incinerator

• incinerate means to burn something until nothing is left but ashes

• FBI-An incinerator that uses a bed of hot sand or other granular material to transfer heat directly to destroy slurry and sludge.

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Flue gas treatment with powder activated carbon

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KIND OF INCINERATOR

liquid-waste-incinerator liquid-waste-incinerator

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Fluidized Bed IncineratorFluid: particle motion like fluid

Fluidized bed: If this phenomena is occurring in bed

Incineration: If the particle is contaminated and incinerated in bed

so it is Called

FLUIDIZED BED INCINERATOR

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FLUIDIZED-BED GASIFICATION AND POWER GENERATION

Twin internally Circulating Fluidized-bed Gasifier (TIFG)

The high-efficiency waste-based power generating system

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Process Flow Diagram

Design Temp: 1550o F

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Circulating Fluidized Bed Incinerator

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Outline of Equipment CFBI

• Effectively satisfy the diverse demands made of any sludge incinerators.

• It can accommodate high-calorie sludge, manifold sludge properties, and load changes, and incinerate sludge mixed with other waste materials.

• By operating at a high superficial velocity of 4.0-8.0 m/s, It performs the role of mixing and stirring sludge with the bed material, sand, as well as the role of a heating medium

• High-calorie waste material, a heat exchanger is built into the bottom of the down comer, allowing heat to be recovered inside the incinerator.

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FEATURES

(1) Stable Combustion: temperature inside the incinerator is uniform, temperature control (combustion control) is easy

(2) Low Energy Consumption: The blower required to circulate the sand operates with a low discharge pressure.

(3) Heat Recovery Inside Incinerator

(4) High-Intensity Combustion: superficial velocity range of 4.0-8.0 m/s, the relative speed (slip speed) of gas and particles is maximized

(5) Desulfurization Inside Incinerator: Spraying slaked lime into the furnace enables desulfurization inside the Incinerator, desulfurization efficiency of around 90% can be expected

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PerformanceEPA's proposal, Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources Medical Waste Incinerators

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ADVANTAGES AND DISADVANTAGES OF INCINERATION PROCESS

Advantages• Potentially destroy any

material containing organic carbon including pathogens,

• Typically reduce the volume and mass of material that must be disposed off in landfills by 80–95%, and

• Heat of combustion can be recovered and used to generate steam or hot water.

Disadvantages• Incineration may emit trace

amounts of unwanted pollutants such as the polychlorinated dibenzo dioxins and furans (PCDD and PCDF) and metal particulates if incinerators are not well designed and operated.

• The ash and wastewater produced by the process also contain toxic compounds, which have to be treated to avoid adverse effects on health and the environment.

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Potential incineration emissions

1. Particulate matter

2. Acid gases

3. Trace metals

4. Products of incomplete combustion

5. Polynuclear organic matter (including dioxins and furans, PCDD and PCDF).

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Solid and liquid effluents from incinerators

Organic material:

1. Trace organics (PCDD/PCDF)

2. Pathogens

3. Cytotoxic materials

Inorganic material

1. Toxic and carcinogenic metals

2. Radioactive material.

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But Destruction Isn’t Alwaysthe Best…..

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THANK YOUFor

kind Attention