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SKKK 3413

Environmental Engineering and

Sustainability

Incineration

Technology and

Emission

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Incineration is a waste treatmenttechnology that involves burning

commercial, residential and hazardous

waste.

Incineration converts discarded materials,

including paper, plastics, metals and food

scraps into bottom ash, fly ash,

combustion gases, air pollutants,wastewater, wastewater treatment sludge

and heat.

Introduction

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Incinerators are often located in or nearurban areas.

Most of them are used to generate

electricity.

Modern incinerators are equipped with

rigorous pollution control technologies to

decrease the emissions of potentially

toxic chemicals. Emitted particulatesare widely dispersed

in the environment, and do not

depositlocally in significant amounts.

Background of The Study

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Issue 1: Modern incinerators areexpensive and produce more carbon

dioxide than alternatives.

Incinerators are the most expensive

method to generate energy and to

handle waste

Incinerators emit more carbon dioxide

(CO2) per unit of electricity (2988lbs/MWh) than coal-fired power plants.

(2249 lbs/MWh).

Overview

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Issue 2: Modern European incineratorscaused pollution

A recent public health impacts report

states that modern incinerators in the

EU are a major source of ultra-fine

particulate emissions.

The emission of incinerator caused

significant public health risk

Overview

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Overview of Waste Incineration

in Malaysia

Local community produced about 17,000 tonnes ofmunicipal solid waste (MSW) per day

Types of waste are municipal wastes, hazardous wastes(schedule wastes) and clinical wastes

MSW incinerators with 5 to 20 ton/day capacity to beoperated on islands of Pangkor, Labuan, Langkawi andTioman

Incineration plant in Bukit Nenas, Negeri Sembilan is the

only off-site incinerator in the country handles majorityof schedule wastes

In planning, Kepong(mid 2015), Bukit Payung, Johor andSungai Udang, Malacca

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Sources of Pollutants Emissions

Dioxins and Furans

Carbon Monoxide (CO)

Carbon dioxide (CO2)

Nitrogen Oxides, Nox

Sulphur Oxides, Sox

Hydrogen Chloride, HCl and

Hydrogen Fluoride, HF

Mercury and Mercury Compounds

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Emissions of Pollutants

from Incinerator

Reduces the waste to 1/3 of its mass and to1/10 of its volume

During the incineration process, smallparticulates are entrained into the flue gases

EPA (2012) that the safe limit for human oralconsumption is 0.7 picograms ToxicEquivalence (TEQ) per kilogram bodyweightper day, which works out to 17 billionths of agram for a 150 lb person per year.

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All of the carbon content in the waste is emitted as CO2to the atmosphere, contributing to

the enhancement of Earth's greenhouse effect. As a relatively small contributor to the total

emissions of carbon dioxide from any municipal area, so no attempts are made

SO2& NOxcontribute to the deposition of acidifying substances from the

atmosphere, e.g. acidic precipitation. Within limits, sulfur dioxide and oxidesof nitrogen can be removed from the waste gases of incinerators.

Fly ash and bottom ash produced when coal is combusted. Fly ashcontains high concentrations of heavy metals such as Pb, Cd, Cu, Zn and

small amounts of dioxins and furans. The bottom ash seldom contains a

significant level of heavy metals.

Due to its toxicity and high volatility, Hg is vaporized during incinerationand enters the flue-gas stream. Absorption of fine activated carbon,

removed by particulate control technology

Formed during combustions involving chlorine-containing organic materials(PVC, PCB), efficient at (300

500C) when Cu, Al, and Fe catalysts present.

The steam content in the flue may produce visible, which can be perceived as a visual

pollution, avoided by flue-gas condensation & reheating, or by increasing the flue gas exit

temperature well above its dew point, allows the latent heat of vaporization of the water to

be recovered, subsequently increasing the thermal efficiency of the plant.

Dioxin &

Furans

Mercury

CO2

SO2& NO

x

Fly ash &

bottom ash

Steam

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Flue Gas Cleaning

Each ton of incinerated waste produces solidpollutants, such as

dust and heavy metals, and

flue gases, mainly carbon monoxide (CO),nitrogen oxide (NO), sulphur dioxide (SO),

nitrous oxide (NO), hydrogen chloride (HCl) and

hydrogen fluoride (HF).

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Particle Removal

The first step of the flue gas treatment is toremove the solid particles, which size rangesfrom 1mto 1mm.

Common removers are cyclone, electrostaticprecipitator or fabric filter.

Electrostatic precipitators and fabric filtershave a similar operational area, with the

fabric filters showing a slightly betterperformance for particles smaller than 1m.

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Gaseous Contaminants Removal

Gaseous contaminants removal is based on

either absorption or adsorption.

Absorption means that the flue gas is mixed with

additives that react with the contaminant gasesand transform them into non-polluting products.

In adsorption processes, the molecules of the

contaminants attach to the surface ofadsorbents and the non-polluting air is allowed

to pass through.

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Optimization of Flue Gas Cleaning

Systems

To increase the collection efficiency of existing flue gas

cleaning systems,

The potential of lime based systems is to increase the

relative humidity, for examples recuperative gas cooling

with a heat exchanger, water injection in a cooling tower

associated with a steam cooling system, and steam

injection.

The potential of sodium bicarbonate systems can be

increased by ensuring sufficiency of high temperature,

warranty of a homogeneous distribution, realisation of

sufficient residence time, and high surface or small particle

sizes.

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Conclusions

Effective flue gas treatment system is vital to theoperation of a clean and efficient waste-to-

energy incineration plant.

Important to understand its efficiency andoptimize the flue gas cleaning system

Reduce emission of toxic chemicals and

pollutants into the atmosphere

The process of waste incineration will not affect

human health and the environment

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