DEDEA Environmental Plans –
Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment
Methods and Processes
Literature Study
DRAFT FOR REVIEW
J29119
November 2009
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Methods and Processes
Literature Study - DRAFT
CONTENTS
Chapter
Description
1
INTRODUCTION TO THE DOCUMENT
1
1.1
Background
1
1.2
What are the report objectives?
1
1.3
Who would benefit from reading the report?
1
1.4
Structure of this document
1
2
Page
DEFINITION, PRINCIPLES, CLASSIFICATION AND RATING
2
2.1
What is the definition of hazardous waste?
2
2.2
What is the Waste Management Hierarchy?
2
2.3
On what core principles is waste management based?
2
2.4
What does delisting of waste mean?
2
2.5
What are the classes of hazardous waste?
3
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
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2.6
3
4
5
6
7
What is a Hazard Rating?
3
INTRODUCTION TO TREATMENT OPTIONS AND PROCESSES FOR DISPOSAL
5
3.1
What are the basic treatment categories for hazardous waste?
5
3.2
How to choose an appropriate and effective hazardous waste treatment/disposal option? 5
PHYSICAL TREATMENT
6
4.1
What does it mean?
6
4.2
How does it work and what is it typically used for?
6
PHYSICAL TREATMENT – SILICA MICRO ENCAPSULATION
7
5.1
What does it mean?
7
5.2
How does it work and what is it typically used for?
7
CHEMICAL TREATMENT
8
6.1
What does it mean?
8
6.2
How does it work and what is it typically used for?
8
6.3
What are the pros and cons?
8
CHEMICAL TREATMENT – DEHALOGENATION / DECHLORINATION
9
7.1
What does it mean?
9
7.2
How does it work and what is it used for?
9
7.3
What are the pros and cons?
9
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Overview of Hazardous Waste Treatment Options – Draft
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9
CHEMICAL TREATMENT – CATALYTIC DETOXIFICATION
10
8.1
What does it mean?
10
8.2
How does it work and what is it used for?
10
8.3
What are the pros and cons?
10
BIOLOGICAL TREATMENT / BIOREMEDIATION
11
9.1
What does it mean?
11
9.2
How does it work and what is it typically used for?
11
10
BIOREMEDIATION – IN-SITU
12
11
BIOREMEDIATION – IN-SITU PHYTOREMEDIATION
13
12
BIOREMEDIATION – EX-SITU TREATMENT
14
13
BIOREMEDIATION – EX-SITU BIOREACTORS
15
14
RE-USE, RECOVERY AND RECYCLING
16
14.1
What does it mean?
16
14.2
Why should we recycle?
16
14.3
How is it implemented in South Africa?
16
14.4
What about hazardous waste?
16
14.5
Which hazardous wastes are typically recycled?
16
14.6
Where can I read or find out more?
16
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
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16
17
18
THERMAL PROCESSES AND ENERGY RECOVERY
17
15.1
What does it mean?
17
15.2
How does it work and what is it typically used for?
17
15.3
What are the pros and cons?
17
LANDFILLING
18
16.1
What does it mean?
18
16.2
What are the types of landfills?
18
COMPLEX COMBINATION TREATMENT PROCESSES
19
17.1
What does it mean?
19
17.2
What are typical examples of this application?
19
REFERENCES
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
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1
INTRODUCTION TO THE DOCUMENT
1.1
Background
1.2
What are the report objectives?
The
Department
of
Economic
Development and Environment Affairs
(DEDEA) Eastern Cape appointed GIBB
to undertaken a Hazardous Waste
Management Plan for the province. In
addition
DEDEA
requested
the
compilation of basic “guidelines for the
treatment and disposal of Hazardous
Waste”.
The main objective of the report is to
provide DEDEA officials and other
stakeholders with a basic overview of
what hazardous waste management and
treatment methods and processes
typically entail and how they are applied.
With this objective in mind the report
provides
a
brief
and
simplistic
introduction and overview on:
A Water Research Commission Report
(No 1548/1/06) by James Brice et al with
the title “Guidance for the Classification,
Rating and Disposal of Common
Hazardous
Waste
Streams”
was
published in 2006 (Brice, 2006). Since
GIBB considers the mentioned report to
be relatively comprehensive and userfriendly, it was deemed unnecessary to
repeat this effort.
•
•
•
•
•
Instead, GIBB compiled this ‘literature
study’ to provide a brief overview of a
selection of definitions and concepts as
well as best practice methods and
processes which are typically applied to
manage and treat hazardous waste. The
main focus is thus on methods and
processes of treatment opposed to how
to treat a specific hazardous waste.
In as much, this document is thus
considered complimentary to the Bricereport.
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Definition of hazardous waste
Delisting of hazardous waste
SANS 10228 classification
Hazard Rating
Methods and processes for the
disposal of hazardous waste.
A few examples of application and some
pros and cons of the various methods
and processes are also briefly discussed.
However, it is important to note that the
advantages and limitations of different
treatment techniques is often case
specific. A detailed specialist study of
the specific waste stream would thus be
needed
to
fully
assess
the
appropriateness of a disposal option.
1.3
Who would benefit from reading
the report?
Gaining a basic understanding of options
and processes for hazardous waste
treatment would benefit officials who deal
with:
•
•
•
1.4
Licence applications for hazardous
waste treatment, disposal and other
management infrastructure and
activities
Evaluation of selection of hazardous
waste treatment options
Monitoring of hazardous waste
activities.
Structure of this document
Section 2 explains a number of
important definitions and concepts in
hazardous waste management, while
Section 3 gives an introduction to the
treatment options and processes that are
unpacked in more detail in the sections
that follow.
References to other
important documents are included for
further reading.
Since this document intends to provide a simplistic
overview it should not be regarded or used as a
d t il d
d i
t h i ld
t
1
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2.1
DEFINITION, PRINCIPLES, CLASSIFICATION AND RATING
What is the definition of
hazardous waste?
2.3
The
National
Environmental
Management: Waste Act, Act 59 of 2008,
(Waste Act) defines Hazardous Waste as
“any waste that contains organic or
inorganic elements or compounds that
may, owing to the inherent physical,
chemical or toxicological characteristics
of that waste, have a detrimental impact
on health and the environment”.
2.2
What is the Waste Management
Hierarchy?
South Africa supports the waste
hierarchy in its approach to waste
management, by promoting cleaner
production, waste minimisation, reuse,
recycling and waste treatment with
disposal seen as a last resort.
On what core principles is waste
management based?
The South African National Waste
Management Strategy defines these as:
•
•
•
•
•
•
•
•
•
•
•
•
Accountability
Affordability
Cradle to Grave Management
Equity
Integration
Open Information
Polluter Pays
Subsidiarity
Waste Avoidance and Minimisation
Co-operative Governance
Sustainable Development
Environmental Protection and Justice
(DEAT, 1999/2000)
2.4
What does delisting of waste
mean?
Delisting of waste is a procedure
whereby it is proven that a specific waste
is inherently or can be treated to be
reclassified for disposal at a landfill site
with a category for lesser hazardous
waste. This is done through tests and
risk analysis that show that the lower
category of landfill would effectively
contain and mitigate the environmental
impacts that result from this disposed
waste. The waste would typically be less
corrosive, toxic or mobile than what the
waste had originally been classified for.
Delisting is generally pursued to reduce
landfilling costs.
Refer to Section 16 for landfills types.
Waste Management Hierarchy
Cleaner
Production
Refer to Figure 1 for an illustration of the
Waste Management Hierarchy.
Prevention
Minimisation
Order of
Prioritisation
Re-use
Figure 1: Waste Management Hierarchy
Recycling
Sources: South African Waste Information Centre
(SAWIC, 2008) and Management Strategy
(NWMS, DEAT, 1999/2000)
Recovery
Composting
Physical
Treatment
Chemical
Destruction
Disposal
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
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Landfill
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2.5
What are the classes of
hazardous waste?
Figure 2: Nine Hazardous waste classes
The
SANS
10228
classification, which has been
adopted as the SA standard,
defines
nine
types
of
hazardous waste as illustrated
in Figure 2.
Some of the classes are
further subdivided.
For
example,
explosives
are
classified as Class 1 and are
further sub-divided according
to type of hazards, e.g. mass
explosion, projection, fire or
minor
hazard.
Hazardous
waste gasses are classified as
Class 2 and are sub-divided
into flammable, non-flammable
and
poisonous
gasses.
Flammable
liquids
are
classified as Class 3 and are
sub-divided into specified low,
intermediate
and
high
flashpoint ranges.
In turn,
flammable
solids
or
substances are listed under
Class 4 and are sub-divided
into
flammable
solids,
substances
liable
to
spontaneously combust and
substances emitting flammable
gasses when wet.
2.6
In 2005 the Department of
Water Affairs (formerly DWAF)
published the 3rd edition of the
Minimum Requirements for the
Handling, Classification and
Disposal of Hazardous Waste.
The document details how to
systematically identify, classify
and rate hazardous waste.
1.
Explosives
2.
9.
Miscellaneous
dangerous
substances &
goods
Gases
3.
8.
Flammable
liquids
Corrosives
Hazardou
s
Waste
7.
4.
Radioactive
material
Flammable
solids
6.
Toxic and
infectious
substances
What is a Hazard Rating?
5.
Oxidising
substances &
organic
peroxides
While the SANS10228 classes
group waste according to the
nature of the waste, the Hazard
Rating
(HR)
differentiates
between the level of risk
associated with the hazardous
nature of the waste. The HR
determines amongst others the
type of landfill to be used and
the permitted* on-site storage
level as indicated in Table 2.
The HR of a specific waste is
based on:
•
•
•
•
•
Carcinogenicity
Toxicity
Ecotoxicity
Biodegration
Accumulation and
persistence potentials
Concentration of organic and
inorganic substances.
The SANS 10228 classification determines the type o
hazardous waste
•
Schedule 1 of the Waste Act list waste managemen
activities in respect of which a waste managemen
* Broadly, there are three types of
landfills, namely ‘general’ (G), ‘low
hazardous’ (H:h) and ‘high hazardous’
(H:H) (Refer to Section 16).
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Overview of Hazardous Waste Treatment Options – Draft
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Table 1: Examples of Type of Waste per Waste Class
Class 1: Explosives
•
•
•
•
•
ammonium
perchlorate
ammunition
explosive articles
cyclonite
• dinitrophenol
• nitrocellulose
• hexanitrodiphenylamine
Class 4: Flammable solids
• white phosphorus
• yellow phosphorus
• alkali metals
•
•
•
•
•
• Uranium
•
•
•
•
•
compressed oxygen
aerosols
butane
compressed helium
ammonia
Class 5: Oxidising substances and
organic peroxides
•
•
•
•
Class 7: Radioactive material
Class 3: Flammable liquids
Class 2: Gases
• peracetic acid
sodium peroxide
potassium super oxide
potassium permanganate
tertiary-butyl peroxide and
• butaldehyde
Class 6: Toxic and infectious
substances
• arsenic
• clinical Waste
Class 9: Miscellaneous dangerous
substances and goods
Class 8: Corrosives
•
•
•
•
acetone
alcohol
ethyl ether
aviation gasoline
brake fluid
mineral acids
organic acids
acetic acid
strong bases
• Environmentally hazardous chemicals
Source: SANS 10228 and various others from Reference List
Table 2: Hazard Rating
Hazard Rating
Risk
Acceptable Landfill Type
HR 1
HR 2
HR 3
HR 4
No Rating
(for General Waste)
Extreme Risk
High Risk
Moderate Risk
Low Risk
Minimal Risk
H:H
H:H
H:H or H:h
H:H or H:h
General
On-site Storage Limit
10 kg
100 kg
1 000 kg
10 000 kg
No limit,
but must be temporary storage
Source: Brice, 2006
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3
INTRODUCTION TO TREATMENT OPTIONS AND PROCESSES FOR DISPOSAL
3.1
What are the basic treatment
categories for hazardous waste?
3.2
Hazardous waste treatment can be
categorised in a number of ways.
Categorisation could
treatment method:
•
•
•
relate
to
the
Physical
Chemical
Biological
Often waste is subjected to a
combination of these methods for
effective and safe disposal. The way in
which different methods are combined
and ‘stringed together’ for treatment is
referred to as a ‘process’. A technical
illustration of the process is referred to as
a ‘process flow diagram’.
Another hazardous waste treatment
categorisation could be linked to the
Waste Management Hierarchy:
•
•
•
•
Re-use, reconditioning and recovery
Recycling and energy recovery
Treatment
Disposal – landfill.
The sections below describe these
treatment approaches in further detail.
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
How to choose an appropriate
and effective hazardous waste
treatment/disposal option?
Treating hazardous waste
complex and expensive.
can
Figure 3: Pesticides stored inappropriately
outdoors
be
For
certain
common
hazardous
substances best practice treatment has
already been well established through
research and practical experience. For
such substances treatment options are
generally easily determined and applied.
However, for a number of more uncommon or problematic wastes and/or
mixtures of contaminants, specialist
experts may need to identify or develop
an appropriate treatment option/process.
Image Source: WRC, 2001
Figure 4: Obsolete pesticides cleanup
operation outdoors
Some contaminants may be so complex
and/or difficult to treat that the best option
remains to safely store the waste until
shipment to an appropriate treatment
facility in South Africa or abroad. Safe
storage and transportation in itself may
be complex and specialised.
Often Material Safety Data Sheets
(MSDSs) of the products that resulted in
the waste may be a good starting point
for the treatment investigation. However,
MSDSs may need to be specifically
developed for hazardous waste before it
is stored, treated, shipped or disposed.
5
Image Source: WRC, 2001
In November 1999, about 740 tons of highly
toxic obsolete pesticides were exported to
Wales at Shanks to be incinerated. The
remaining 250 tons less toxic pesticide waste
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PHYSICAL TREATMENT
4.1
What does it mean?
A waste is subjected to physical methods
or processes so as to contain the hazard,
to
immobilise
the
hazardous
component(s) or substance(s) and/or to
prepare it for further treatment, recycling
or landfill.
“Physical methods don’t destroy wastes,
instead, they change them into forms that
are easier to treat further or to dispose.
Traditional physical methods include
carbon adsorption, filtration, flocculation,
distillation, reverse osmosis and ion
exchange.” (WRC, 2001)
4.2
How does it work and what is it
typically used for?
Encapsulation
Encapsulation involves immobilising or
reducing the toxicity of hazardous
materials by either containerisation or
stabilisation and incorporation within a
solid water-resistant matrix such as
Portland cement, asphalt or proprietary
organic polymers prior to landfilling.
Examples:
• Double bagging of asbestos waste
• Sulphur polymer stabilisation/
solidification of mercury compounds
(also forms highly insoluble HgS)
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
•
•
•
Stabilisation of metal hydroxide
sludge, sulphuric acid plating waste
and oily metal sludge with a sludge
mixture of lime, fly-ash and bentonite
Encapsulating beryllium or
polychlorinated biphenyls (PCBs) in
concrete blocks
Contaminated soil mixed into asphalt.
Thermal encapsulation is the term used
when heat is applied to melt
encapsulation products like asphalt,
plastics or waxes in the encapsulation
process.
Another form is micro-encapsulation,
which
entails
the
permanent
encapsulation (trapping) of hazardous
molecules within the molecular structure
of an inert material like silica and sulphur
polymer cement.
More information
thereon is provided in Section 5.
Wetting
Wetting is a method whereby water is
used to suppress the spreading of
hazardous dust or fibres. In some cases
chemicals, such as detergents, are
added to the water to enhance the
wetting of the substance.
Examples:
• Wetting of asbestos fibres
• Sprinkler systems on ash waste piles
and mine tailings dams.
6
Physical Separation Filtration/
Centrifuging/ Distillation/ Reverse
Osmosis/
Ion
Exchange
and
flocculation
This approach involves physically
separating
phases
which
contain
hazardous substances from other nonhazardous constituents which form part
of the waste stream.
Examples:
• Separation of oils from ship bilge
waters
• Wastewater treatment (e.g. ion
exchange treatment of perchloratecontaminated waters.)
Mechanical
Breaking/
Ripping/ Pelletising
Shredding/
Such methods are used to physically
break-up the waste to either prepare it for
further treatment or recycling; to reduce
the physical hazard; and/or to reduce the
volume of waste for airspace and cost
saving purposes.
Examples:
• Waste tyres are shredded and
pellitised into small rubber pellets for
shipment to a rubber recycler
• Neon light tubes are broken under
controlled condition to render it
physically safe and release or recover
the mercury containing substances.
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PHYSICAL TREATMENT – SILICA MICRO ENCAPSULATION
Sources: Mbhele, 2007; Sala et al, 2000; Singal
et al, 2000; TEPCO Products, 2009
5.1
5.2
What does it mean?
With the application of this technology
and silica reagents developed by Klean
Earth Environmental Company (KEECO),
SME usually achieves control of
contaminants in a single step. Thus
without the need for pre-treatment with
chemicals or post-treatment flocculation
or filtration. The silica reagent is simply
mixed with the contaminated water or
liquid where after the ‘sand’ readily
settles out. Soil can be treated ‘in-situ’
by mixing or ‘ploughing’ the reagent in, if
the contaminated layer is shallow. For
deeper layers of contaminated soil the
soil is excavated, then mixing with the
reagent ‘ex-situ’ where after the soil (with
the silica product) is returned to the site.
In Silica Micro Encapsulation (SME),
hydrocarbon, chemical, heavy metal
and/or radioactive contaminants are
encapsulated (trapped / stabilised) within
an impervious silica matrix, thereby
completely and permanently isolating it
from the environment. This essentially
means permanently locking contaminants
up in very small grains of sand. Silica is
one of the most inert natural substances
and with the hazardous contaminant
being entrapped in the silica matrix
contaminants
are
prohibited
from
migrating or leaching out. The silica
grain typically does not degrade and
generally strengthens over time.
Figure 6: Schematic illustration of organics
are entrapped in the silica matrix
How does it work and what is it
typically used for?
Figure 5: Electro-microscope image
showing the cavities within the
silica molecular structure magnified
2000 fold
“SME is a very robust technology which
has been demonstrated to work
effectively on heavy metals (such as
chromium, copper and zinc), metalloids
(such as arsenic), and radionuclides
(such as uranium). It can be applied to
wastewaters, sediments, sludges, soils,
mine tailings, and other complex media.
In addition to the control of metals, SME
chemicals have been shown to reduce
dissolved solids (such as sulphates) and
to break down hydrocarbons (such as
gasoline and fuel oil) and other organic
chemicals
through
a
high-energy
oxidation process.” (Sala et al, 2000)
Figure 7: Polarised light
image showing how oil is
entrapped within the silica
grain at magnified 10 fold
Image Source: TEPCO Products, 2009
Some points of note
• The silica coating is resistant to
degradation even under extreme
environmental conditions (acid,
base, temperature)
• SME has most extensively been
applied in treatment of mine
tailings
• Studies show that extractable
hydrocarbons in soil polluted with
diesel oil were reduced by 70 to
100%
• Various factors such pH, type of
soil, size of metal ions and the
presence of hydrocarbons when
removing heavy metals can affect
the efficiency of remediation
• The efficiency is enhanced in
sandy soil as opposed to clay soil
• For
certain
applications
surfactants (soaps) are added to
improve
the
encapsulation
efficiency
Image Source: TEPCO Products,
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CHEMICAL TREATMENT
Sources: New Zealand Institute of Chemistry,
2002; WRC,2001
6.1
What does it mean?
“Chemical treatment methods use
different properties of a chemical to alter
its hazardous elements. Chemical
reactions alter the chemicals, destroying
the hazardous elements or producing
new compounds that are easier to treat
or dispose of.” (WRC, 2001) This specific
treatment thus uses a chemical reaction
or process to render the waste nonhazardous or less hazardous.
6.2
•
How does it work and what is it
typically used for?
Chemical reactions or processes could
for example chemically neutralise,
oxidise, reduce, hydrolyse, precipitate,
dechlorinate and/or catalytically detoxify
the component that renders the waste
hazardous.
Neutralisation
In this situation, a substance or solution
with a high acidity (low pH) or high
alkalinity (high pH) is treated to become
more neutral (thus closer to a pH of 7). A
waste acid is reacted with an alkali and a
waste alkali with an acid.
Example:
DEDEA Environmental Plans – Hazardous Waste Management Plan
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H2SO4 +
•
Hydrolysis
Sulphuric acid waste with sodium
carbonate (soda ash)
CO32-
→
SO42-
Decomposition of hazardous organic
substances, e.g. decomposing certain
organophosphorus
pesticides
with
sodium hydroxide (caustic soda).
+ CO2 + H2O
Lime or calcium carbonate*
neutralisation of mine acid-water
Precipitation
* Note: A new cost-effective form of acidwater neutralisation was developed by the
CSIR. It uses the calcium carbonate byproduct of the paper industry, instead of the
traditional lime, for neutralisation. (Patel, 2006)
This technique is particularly useful for
converting hazardous heavy metals to a
less mobile, insoluble form prior to
disposal to a landfill.
Oxidation
Example:
• Precipitation of cadmium as its
hydroxide by the use of sodium
hydroxide. (E.g. removal of cadmium
from metal finishing waste water)
In this process a common oxidising
substance such as hydrogen peroxide or
calcium hypochlorite is used to oxidise a
hazardous compound.
Examples (Also refer to Section 8):
• Cyanide waste (e.g. from metal
finishing and gold process tailings)
reacted with calcium hypochlorite.
Cd2+(aq) + 2OH- → Cd(OH)2(s)
Dechlorination
detoxification
CN- + OCl- → OCN- + ClOCN- + H3O+ → CO2 + NH3
Reduction
Example:
• Reduction of chrome [Cr(VI) to Cr(III)]
by the use of ferrous sulphate. (E.g.
chrome waste from metal plating)
+
2-
2+
14H + Cr2O7 + 6Fe →
6Fe3+ + 2Cr3+ + 7H2O
8
catalytical
(Refer to Section 7 and Section 8)
6.3
In this case an inorganic substances is
converted to a less mobile and toxic form
using a reducing agent.
and
What are the pros and cons?
Pure chemical processes are useful
primarily when a single chemical is
involved or a few chemicals with similar
properties. When applied to waste
mixtures, side reactions interfere with the
desired reactions. Methods are however
improving and are often used in
combination with non-chemical methods.
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CHEMICAL TREATMENT – DEHALOGENATION / DECHLORINATION
Source: WRC,2001; Rahuman, 2000
7.1
What does it mean?
“Chemical dechlorination is a chemical
process that removes chlorine from a
substance
rendering
the
original
chemical less toxic.” (WRC,2001)
7.2
How does it work and what is it
used for?
“Although dechlorination processes has
been known for over 75 years, only in the
past decade have researchers begun to
look
at
its
potential
to
treat
polychlorinated biphenyl (PCB) and
dioxin
contaminated
materials.”
(WRC,2001)
“Chemical dehalogenation technologies
are applicable to halogenated aromatic
compounds, including PCBs, PCDDs,
PCDFs, chlorobenzenes, chlorinated
phenols,
organochlorine
pesticides,
halogenated herbicide, and certain
halogenated aliphatics (e.g. ethylene
dibromide,
carbon
tetrachloride,
chloroform, and dichloromethane). If
other volatile organic, semivolatile
organic, or metal contaminants are
present, chemical dehalogenation can be
used
in
conjunction
with
other
technologies, such as low-temperature
thermal desorption, solvent extraction, or
biodegradation.” (Rahuman, 2000)
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This process uses glycols, alcohols, and
water as their primary reagents. The two
most common versions of chemical
dechlorination are:
Glycolate dehalogenation
Note:
Chlorine is
a halogen.
The alkali metal hydroxide portion of the
reagent reacts with chlorine in the
contaminant and forms a non-toxic salt.
This process consists of five steps:
prepare, react, separate, wash, and
dewater. During preparation step, the
contaminated waste/soil is excavated
where after it is mixed with the reagent in
a large heated container (reactor).
Base-catalyzed decomposition
7.3
What are the pros and cons?
Pros:
• Treat contaminated material on-site
• Use of an enclosed vessel at mild
temperature and pressure results in
no air emissions or water discharges
• Produced off-gases are collected and
recovered for treatment
• Some costs can be recovered by
recycling reagents.
Cons:
• Lack of information on the toxicity of
the reagents, polyethylene glycol and
dimethyl sulfoxide.
Figure 8: PCB contaminated transformers
During the late 1980’s and early 1990’s
the
United
States
Environmental
Protection Agency (USEPA) developed
this inexpensive process to remediate
liquids, sludge, soil and sediment
contaminated with chlorinated organic
compounds. Such compounds include
PCBs, pesticides, herbicides and dioxins.
In the process, contaminated soil is
mixed with sodium bicarbonate. This
mixture is then heated in a reactor to
evaporate and thereby separate the
chlorinated compounds from the soil. The
condensed contaminants are then
dechlorinated by reaction with several
chemicals, including sodium hydroxide, in
a heated reactor.
9
Image Source: US EPA, 2009
The
halogen
process
was
successfully
demonstrated at the Wide Beach Superfund site
USA in 1991. Approximately 42,000 tons of
stockpiled soil contaminated with PCBs at
Arcus GIBB
November 2009
8
CHEMICAL TREATMENT – CATALYTIC DETOXIFICATION
Sources: WRC,2001; Schwinkendorf, 2001
8.1
What does it mean?
A catalyst is a substance that modifies
reactions and increases reaction rate
without being consumed in the process.
Usually only a small amount of catalyst is
required relative to the reactants.
The Delphi Research DETOX System is
a catalysed wet oxidation process. It
chemically and non-thermally breaks
down organic wastes into carbon dioxide
and water and is discussed by way of an
example in this section.
8.2
It was primarily developed to treat PCB
wastes, but can destroy all organics
except for fluoropolymers.
Nonchlorinated
organics
are
typically
destroyed at an efficiency of almost
100% while PCBs are destroyed at an
efficiency of 98%.
It is best applied to bulk organic wastes
containing toxic and/or radioactive
metals.
Dioxins,
polychlorinated
biphenyls, volatile and semi-volatile
organic compounds, heavy metals,
radioactive metals, and pesticides can all
be treated by this system.
How does it work and what is it
used for?
Other Chemical Processes
This catalytic aqueous detoxification
process with ferric chloride (FeCl3) and
hydrochloric acid (HCl) at 1000C to 2000C
is a complex process as illustrated by the
flow diagram in Figure 9. Basically,
waste and oxygen are fed into a reactor
where organic compounds are destroyed
and toxic metals are concentrated and
recovered, or disposed.
MEO makes use of silver, cerium
or cobalt compounds in nitric acid
as oxidizing agents at room
temperature and pressure. While
the process is being further
developed, it is applied in the UK
to treat ion exchange resin, dry
active waste, chemical munitions
and for plutonium recovery. MEO
oxidises many different organic
materials (solids and liquids).
The system is designed to handle soil,
sludge (not municipal sewage sludge),
solids, sediment, off-gases from primary
treatment technologies, and mixed
wastes.
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Mediated Electrochemical
Oxidation (MEO)
8.3
What are the pros and cons?
Pros:
• No dioxins, furans, or volatile metals
are produced due to the low
temperature inputs and nature of the
catalyst solution
• Less need for off-gas treatment
• The process doesn't need fuel to
operate.
Cons:
• Not very efficient in treating great
amounts of soils and waters with
small amounts of contaminants
• Does not destroy toxic metals
• Corrosion, materials compatibility and
leaks are issues of concern
Figure 9: Illustration of the Detox wet oxidation process
Direct Chemical Oxidation
(DCO)
DCO is the least corrosive of the
chemical oxidation processes.
The oxidant is regenerated
electrochemically, but the process
has not been demonstrated.
Image Source: Borduin, 1998
10
Arcus GIBB
November 2009
9
BIOLOGICAL TREATMENT / BIOREMEDIATION
Sources: UWC, 2008; Maila et al, 2004; WRC,
2001; Singh, 2009
9.1
Figure 10: Illustration of bioremediation
types
Contaminated
Site
What does it mean?
In Situ
Biological treatment, which in the context
of hazardous waste treatment is more
commonly referred to as bioremediation,
is a process whereby waste materials are
biologically degraded under controlled
conditions.
9.2
How does it work and what is it
typically used for?
Naturally
occurring
or
synthetic
genetically engineered bacteria are
applied or their growth conditions
enhanced to break down specific
chemicals or chemical mixtures. The
hazardous component of the waste is
thereby converted to an innocuous state
or to levels below concentration limits
established by regulatory authorities.
Depending on the process, bacteria may
be applied directly on contaminated soil,
placed in ponds, lagoons or holding tanks
or added to groundwater. As illustrated
in Figure 10, a variety of technologies
can be broadly categorised into ‘in-situ’
and ‘ex-situ’ or ‘excavated’ processes.
Bioremediation may be employed in
order to attack specific contaminants,
such as chlorinated pesticides that are
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Bioventing
Excavated
Treated on
site
Bioprocesses can take place under
aerobic or anaerobic conditions.
Treated off
Site
Stimulation &
Augmentation
Land Farming
Land Farming
Biosparging
Composting
Composting
Phytoremedia
tion
Biopile
Biopile
Bioreactor
Bioreactor
Pump & Treat
Pump & Treat
Phytoremedia
tion
Source: UWC, 2008
‘In-situ’ means that contaminated
sites/areas are treated at the area of
initial contamination without removal
of contaminated soil, water or other
substance
‘Ex-situ’ or ‘Excavated’ means
removal of the contaminated soil,
water or other substance from the
area where contamination originally
took place and treating the substance
it
t k
ff it t b t t d
11
degraded by bacteria. Some examples
of bioremediation technologies are
bioventing, land farming, bioreactors,
composting,
bioaugmentation
and
biostimulation.
‘Aerobic’ means that oxygen is
present in the environment where a
reaction takes place and therefore
‘Anaerobic’ means that the
environment in which the reaction
takes place lacks oxygen, and
Aerobic conditions are important for
degradation of reduced hydrocarbons.
On the other hand benzene and alkylated
and oxygenated aromatics can be
degraded
anaerobically,
provided
nitrates, iron and sulphate are present to
act as terminal electron acceptors.
Since bioremediation involves the use of
biological species to break down the
hazardous substances, it is important
that the growth medium includes the
necessary nutrients. Essential nutrients
include nitrogen (N) and phosphorous
(P).
Biodegradation rates can be
increased by adding nitrogen fertilisers
which typically is 100:10:1 C:N:P.
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November 2009
10
BIOREMEDIATION – IN-SITU
Sources: UWC, 2008; Maila et al, 2004; WRC,
2001; ITRC, 2007; Singh, 2009
Bioventing
Bioventing is an in-situ treatment which
combines an increase of oxygen (O2)
(and nutrients) with vapour extraction.
Figure 11: Illustration of a typical
bioventing process
Biostimulation
Fixed Biobarriers / Biowalls
Biostimulation refers to the modification
of contaminated areas to enhance the
growth of indigenous microbes already
present.
This process may include
utilising fertilisers and other nutrients to
stimulate the microbes. This method
presumes that the correct microbes are
present.
The US Interstate Technology &
Regulatory Council provides this cited
overview: “Fixed biobarriers use solid or
viscous amendments placed across the
flow path of contaminated groundwater to
form a permeable reactive barrier.
Groundwater flows to, through, and past
the fixed amendment. The fixed
biobarrier approach can use engineered
trenches or barriers containing solidphase, slow-release substrates or
viscous substrates placed crossgradient
via direct-push injections.”
Biosparging
This approach aims to increase biological
activity of the soil by increasing the O2
supply. Air is initially injected through
wells, where after pure O2 is injected.
Figure 12: Illustration of bioventing
process
“In situ enhanced bioremediation in the
form of a fixed biobarrier is a suitable
technology for large plumes having
poorly defined, widely distributed, or
inaccessible source areas.” (ITRC, 2007)
Figure 13: Illustration of biowall process
Source: UWC, 2008
Bioaugmentation
Bioaugmentation refers to the addition of
naturally
occurring
microbes
to
contaminated materials and sites in order
to achieve bioremediation. The process
insures that the correct microbes are
added in sufficient quantities.
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Image Source: UWC, 2008
Image Source: ITRC, 2007
12
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November 2009
11
BIOREMEDIATION – IN-SITU PHYTOREMEDIATION
Sources: UWC, 2008; Maila et al, 2004; WRC,
2001; ITRC, 2007; Singh, 2009
Phytoremediation
Phytoremediation is the use of ‘higher
than micro-organism’ plants for removal
of contaminants from soil or water.
Contaminants are fixed in the ground,
accumulated in the plant tissue or
released to the atmosphere.
Figure 14: Illustration of a
phythoremediation process
Constructed / Artificial Wetlands
Wetlands constructed for remediation
purposes
are
examples
of
phytoremediation.
“Constructed
wetlands have been used for decades for
the management and treatment of many
wastewaters, including municipal, acid
mine drainage, agriculture, petrochemical
and textile industries, and storm water.
Increasingly,
however,
constructed
wetlands are being used for the
remediation of groundwater for surface
water impacted by industrial chemicals
and wastes such as landfill leachate and
explosives such as TNT or RDX. The
trend
toward
increased
use
of
constructed wetland technology relates to
the low capital and operating and
maintenance costs associated with this
mostly passive technology.” (ITRC, 2007)
Figure 15: Constructed wetland in
Pennsylvania
Image Source: Princeton, 2009
“Wetlands are usually constructed using
limestone drains aid in neutralizing acid
from acid mine drainage.” (Princeton, 2009)
Figure 16: Illustration of a typical
constructed wetland
Image Source: UWC, 2008
Sections 35 to 41 of the Waste Act deals wit
matters related to contaminated land. It cover
historically contaminated land. The Minister o
relevant MEC might give orders for investigatio
d/
di i
f
i
dl d
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Image Source: Princeton, 2009
13
Arcus GIBB
November 2009
12
BIOREMEDIATION – EX-SITU TREATMENT
Biopile / Biocells / Bioheaps
Sources: UWC, 2008; Maila et al, 2004; WRC,
2001; ITRC, 2007
Landfarming
Figure 17: Illustration of ‘Hot Spot’ ex-situ
bioremediation of perchlorate
Landfarming refers to a ‘low tech’
biological treatment which involves the
controlled application and spread-out of a
more-or-less
defined
organic
bioavailable waste on the soil surface, and
the incorporation of the waste into the
upper soil zone. It is typically used for
biological removal of petroleum products
from contaminated soil.
Biopiles are essentially heaps of
contaminated soil placed on lined areas
to prevent leaching. They are typically
covered with plastic and liquid nutrients
are applied. Aeration is improved by
applying suction to the base of the pile.
Leachate is collected by pipes at the
base.
Figure 19: Illustration of biopiling
Composting
Due to its common use for household
garden waste, this is the well known
controlled biological decomposition of
organic material in the presence of air to
form a humus-like material.
Methods
of
composting
include,
mechanical
mixing
and
aerating,
ventilating the materials by dropping
them through a vertical series of aerated
chambers, or placing the compost in piles
out in the open air and mixing it or turning
it periodically.
Image Source: UWC, 2008
Figure 18: Illustration of ex-sito anaerobic
bioremediation in bags at an industrial site
Image Source: ITRC, 2007 (Source: Geosyntec Consultants)
Earth worms
Studies have shown that: “Earthworms burrow through the soil thereby accumulating many
lipophilic organic pollutants from the surrounding environment, so they could be used to
remove polycyclic aromatic hydrocarbons (PAHs) from soil. The microorganisms in the gut of
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
14
Image Source: ITRC, 2007
Arcus GIBB
November 2009
13
BIOREMEDIATION – EX-SITU BIOREACTORS
Sources: UWC, 2008; WRC, 2001; ITRC, 2007
Bioreactors
Figure 19: General structure of batch
type stirred tank bioreactor
Figure 20: The GenCorp Aerojet Fluid Bed
Reactor Facility in Sacramento, California
– the world’s first groundwater treatment
system for perchlorate.
A bioreactor refers to any device,
container or system that supports a
biologically
active
and
controlled
environment for bioremediation. This exsitu biological treatment process depends
on maintaining a high active biomass
concentration
in
the
reactor.
Bioremediation reactors can be classified
as follows:
•
•
Suspended-growth reactors –
active biomass is suspended as free
organisms or microbial aggregates
(i.e. Continuous Stirred Tank
Reactors (CSTR))
Supported-growth or fixed-film
reactors – growth occurs on or within
a solid medium or a biomass granule
or pellet (i.e. Fluidised Bed Reactors
(FBR) and Packed Bed Reactors
(PBR))
CSTRs are typically used for treatment of
high strength contaminated wastewater
at low flow rates and are as such often
used for treating industrial wastewater
streams. In turn, FBRs and PBRs find
their application in treatment of lower
strength streams at high flow rate such
as may be required for groundwater and
water treatment.
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Image Source: Yassine Mrabet, 2009
“CSTR means that the biomass is
suspended in the treated water and
not attached to the media surfaces
to keep them in the reactor. The
biomass continually reproduces at a
high rate so that a constant
A key step in the design of any biological
process is the selection of the
appropriate reactor configuration.
Bioleaching
In bioleaching, bioremediation of heavy
metal contaminated soil is achieved
using acidophilic bacteria that oxidize
reduced sulphur compounds to sulphuric
acid. The process makes use of either a
slurry or a heap leaching system.
15
Image Source: ITRC, 2007
“The FBR is a reactor column that
fosters the growth of microorganisms
on a hydraulically fluidized bed of
media, usually sand or activated
carbon. The fluidized medium
selected provides a large surface
area on which a film of
i
i
th
“As with the FBR, the PBR is a fixed
film–based bioreactor in which the
sand, carbon, or plastic media is
stationary. As in the FBR, the
microorganisms attach to the media
in the reactor. Unlike the FBR, PBRs
b d i
di i h
fl
Arcus GIBB
November 2009
14
RE-USE, RECOVERY AND RECYCLING
14.1
What does it mean?
14.2
The Waste Act defines reduce, reuses,
recycle and recovery as follows:
means the avoidance of the amount
and toxicity of waste that is
generated and in the event where
waste is generated, the reduction of
h
d
i i
f
means the continuous application of
integrated preventative
environmental strategies to
processes, products and services to
increase overall efficiency and to
d
th i
t f
h
"recovery" means the controlled
extraction of a material or the
retrieval of energy from waste to
14.5
Continuous production
of vast amounts waste
is
unsustainable.
Recovering and reutilising products from
waste expands the
product lifecycle and
thus reduces waste
and environmental impact.
"waste minimisation" (reduce)
"cleaner production" (reduce)
Why should we recycle?
14.3
Examples of recyclable hazardous waste
include:
•
•
How is it implemented in South
Africa?
Section 17 of the Waste Act provides a
framework for recovery, reuse and
recycling.
14.4
"re-use" means to utilise articles
from the waste stream again for a
similar or different purpose without
changing the form or properties of
"recycle" means a process where
waste is reclaimed for further use,
which process involves the separation
of waste from a waste stream for
further use and the processing of
h
d
i l
d
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Which hazardous wastes are
typically recycled?
What about hazardous waste?
Re-use, recovery and recycling of useful
products from hazardous waste is often
problematic and costly. This is due to the
sophisticated
health,
safety
and
environmental
precautions
required
and/or the complexity of treatment
processes that are required.
While certain hazardous wastes or
components thereof are re-useable the
focus
should
remain
on
waste
minimisation and cleaner production as
the most important objective. Cleaner
production may include recycling.
16
14.6
Toxic lead and sulphuric acid are
recovered from car batteries
Used lubricating motor and other oils
are refined for recycling.
Where can I read or find out
more?
The Institute of Waste Management South
Africa (IWMSA)
http://www.iwmsa.co.za
Responsible Container Management
Association of South Africa (RCMASA)
http://www.rcmasa.org.za/
e-Waste Association of SA: www.ewasa.org
ROSE Foundation:
www.rosefoundation.org.za
National Recycling Forum:
www.recycling.co.za
Source: Rose Foundation, 2009
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November 2009
15
THERMAL PROCESSES AND ENERGY RECOVERY
Source: WRC, 2001; Singh, 2009; Scminkendorf,
2001
15.1
What does it mean?
In thermal processes heat is applied to
remove, break down or treat the
hazardous waste.
15.2
How does it work and what is it
typically used for?
“Most thermal destruction methods use
high temperatures (416°C to 1648°C) to
break down organic chemicals into more
simple, less toxic forms in systems with
oxygen (incineration) or without oxygen
(pyrolysis) present. Wastes are typically
combusted in 2 stages during pyrolysis.
The first stage occurs in the main
chamber. The next stage occurs in the
secondary chamber, where gases formed
in the main chamber are burned at 976
°C – 1648 °C. In theory, this second
chamber burns off carbon monoxide and
organic vapours generated in the first
chamber, and avoids vaporization of
inorganic
material.
Inorganic
compounds, which include heavy metals,
form an insoluble residue, which is not
destroyed by incineration and has to be
disposed of. One of the advantages that
the pyrolysis process has over the
incineration process, is the reduction in
the production of unwanted by-products
like dioxin (USEPA, 1998)” (WRC,2001)
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Thermal Desorption
15.3
Hazardous waste or contaminated soils
are heated to about 6000C to evaporate
(separate)
volatile
contaminants.
Thereafter contaminants are removed
from the evaporation by condensation,
scrubbing, filtration or destruction.
What are the pros and cons?
Vitrification is a technology whereby
contaminated soil is heated to a
temperature even higher than for
incineration processes to ‘melt’ the soil
into a monolithic glassy product.
“Incinerators are the preferred method of
destruction of waste materials and is
regarded by the USEPA as the Best
Available Control Technique (BACT).
However, this technique of removal has
received considerable opposition from
environmental groups, the public and
some governments.
The opposition
arose from the quantities and types of
chemicals in the incinerator stack
emissions. In general, well operated
incinerators, designed for the destruction
of hazardous waste will have lower
emissions than older and less efficiently
operated
facilities.”
Technologies
designed to remove chemicals from the
flue gases include: scrubbing, wet or dry
spray sorption systems and sorption of
the organic products of incomplete
combustion onto beds of activated
carbon or other effective sorptive
material. (WRC,2001)
Wet and Supercritical Oxidation
Figure 21: Cement Manufacturing Facility
Wet oxidation of contaminants is
promoted in the water phase at high
temperature and pressure, but below the
supercritical temperature and pressure of
water. In turn, supercritical oxidation is
similar to wet oxidation but in this
process temperatures and pressures are
raised to a supercritical lever, which
enhances the oxidation rate.
Image Source: PPC, 2009
Incenaration
Hazardous wastes are incinerated by
heating to a high temperature of between
880
and
12000C,
whereby
the
contaminants are either destroyed or
detoxified. Cement kilns are often used.
Vitrification
17
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November 2009
16
LANDFILLING
Source:
DWAF, 2005; Freudenrich, 2000;
Enviroserv, 2009
16.1
What does it mean?
The term ‘landfill’ refers to the physical
facility, which has been specifically
designed, constructed and operated for
the disposal of waste on land.
16.2
What are the types of landfills?
The principal types of landfills are
grouped into two classes: General and
Hazardous.
General Waste Sites (landfills) can only
receive waste that does not pose any
significant threat to public health or the
environment if properly managed.
Examples include commercial, domestic
waste and builders rubble.
Hazardous Landfills are the only landfill
facilities that are allowed to accept
hazardous waste and have high design
standards and licensing requirements.
General Waste Landfill Sites
General Waste Landfill Sites are
classified in four categories, namely:
•
•
•
•
Communal <1 tonnes/day (GC)
Small 1 to 25 tonnes/day (GS)
Medium 25 to 500 tonnes/day (GM)
Large >500 tonnes/day (GL).
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Figure 22: This cross-section drawing shows
the structure of a solid waste landfill.
General Waste Sites (landfills) can only
receive waste that does not pose any
significant threat to public health or the
environment if properly managed.
Unless
in
small
quantities
or
encapsulated, these sites are generally
not used for disposal of hazardous
waste.
Hazardous Waste Landfill Sites
Hazardous Waste Landfill Sites fall into
two categories:
•
•
H:H Landfills - high hazardous waste
H:h Landfills - low hazardous waste
There are only three licensed H:H landfill
sites in South Africa, namely: Holfontein
at Springs, Vissershok close to Cape
Town, Aloes at Bedfordview.
“Certain wastes are prohibited for
disposal to landfill. These wastes
may be categorised as: Explosives,
Gasses, Radioactive Substances and
S l t dO
i ” (E i
“Co-disposal is the most common
form of disposal for Hazardous
Waste in South Africa. Objective of
Co-disposal is to absorb, dilute and
neutralise any liquids and to
18
Typical
structure
and basic
Image
Source:
Freudenrich,
2000
components of a hazardous landfill:
• Bottom liner system - separates waste
and subsequent leachate from groundwater
(see C in figure above)
• Cells (old and new) - where the waste is
stored within the landfill
• Storm water drainage system - collects
rain water that falls on the landfill
• Leachate collection system - collects
water that has percolated through the
landfill itself and contains contaminating
substances (leachate). See F and G in
figure above.
• Methane collection system - collects
methane gas that is formed during the
breakdown of trash
• Covering or cap - seals off the top of the
landfill.
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November 2009
17
COMPLEX COMBINATION TREATMENT PROCESSES
17.1
What does it mean?
Often
effective
hazardous
waste
treatment is highly complex and may
require a complex treatment approach
and process. Such a process may
require a combination of physical,
chemical, biochemical and other methods
to stabilize, neutralise or detoxify a
waste.
Complex
combination
treatment
processes are often required if a waste
stream consists of a ‘cocktail’ of
hazardous compounds. Over the years a
number of specific best practices
processes have been developed for
treatment of complex and very toxic
substances.
In such cases, suitably
qualified professionals should manage
the development of suitable and effective
treatment processes.
17.2
What are typical examples of this
application?
Closed Loop Detoxification
Source: WRC, 2001
Closed
loop
detoxification
is
thermochemical reduction process.
a
Waste streams containing halogenated
or chlorinated organics are subjected to
catalytic stream gasification.
DEDEA Environmental Plans – Hazardous Waste Management Plan
Overview of Hazardous Waste Treatment Options – Draft
Used Lubricating Oil Refining
In the closed loop detoxification process
steam reacts with the carbon based
material to form carbon dioxide and
hydrogen.
The
organic
materials
decompose
thermally
and
react
chemically before further treatment in a
reactor for complete contaminants
conversion. Thereafter it is cooled to
about 470°C and sent to a cyclone
separator to separate the gases and
solids.
A cyclone makes use of a
spinning motion for separation.
The
gases, carbon dioxide and hydrogen, are
then scrubbed (‘washed in sprinkled or a
film of water) and recycled. The liquid
phase contains the sodium chloride,
which is removed, and water, which can
be recycled and used as steam. The ash
residue can be landfilled or processed
further.
Figure 23: Refinery for used oil
Examples:
Detoxification
of
the
following
substances:
• Metallic (in)organic
• Radioactive substances
• Solvents
• Herbicides
• Pesticides and other chemicals;
including highly toxic compounds
such as trichloroethylene (TCE),
various polychlorinated biphenyls
(PCBs), the herbicides 2,4dichlorophenoxyacetic acid (2,4-D)
and 2,4,5-trichlorophenoxyacetic acid
(2,4,5-T), and dioxin.
Image Source: FFS
19
Source: FFS, 2009
This process utilises a full range of
technologies from thermal evaporation,
static separation, low and high-speed
centrifugation,
filtration,
blending,
distillation, hydrogenation and cracking in
order to achieve a wide range of products
to exacting specifications. One of South
Africa’s leading used oil refiners, FFS
Refiners (Pty) Ltd, supplies more than
300 000 tons of industrial heating fuels
annually to its customers. These
customers use these fuels for glass
making, brick making, steam raising in
boilers,
billet
re-heating,
baking,
incineration, laundry, road-mix heating,
lime kilns, sand and stone drying.
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November 2009
18
REFERENCES
Brice, James et al. July 2006. Guidance for
the Classification, Rating and Disposal of
Common Hazardous Waste Streams. Water
Research Commission Report No 1548.
Compiled
by
Environmental
Business
Strategies (Pty) Ltd. Url:
http://www.envirobiz.co.za/docs/EBS%20%20
WRC%20%20Guidance%20on%20Common%20Indust
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