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Website download address Air Pollution http://www.public.iastate.edu/~sung/ce326/air.ppt Solid Waste Management http://www.public.iastate.edu/~sung/ce326/msw.ppt Hazardous Waste Management http://www.public.iastate.edu/~sung/ce326/hwm.ppt Scope of Hazardous Waste (HW) Problem

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website download address
Website download address
  • Air Pollution

http://www.public.iastate.edu/~sung/ce326/air.ppt

  • Solid Waste Management

http://www.public.iastate.edu/~sung/ce326/msw.ppt

  • Hazardous Waste Management

http://www.public.iastate.edu/~sung/ce326/hwm.ppt

slide2
Scope of Hazardous Waste (HW) Problem

1985 EPA Survey 2,959 facilities managing 247 mil. tons of HW

Chemical Manufacturers surveyed 681 industrial plants – 213 mil. Tons (approx. Assoc. (CMA) 1985 48 - 68% of total HW generation)

Congressional Budget 223 – 308 mil. Tons Office (1982)

Office of Technology 255 – 275 mil. Tons Assessment

EPA National Biennial 20,233 generators and 3078 Treatment, Storage or Hazardous Waste Disposal Facilities (TSDFs) Report 60 TSDFs managed 93% of HW

slide3
Breakdown of the major HW are as follows:

51% Chemical Products

7% Transportation Equipment

9% Petroleum and Coal Products

9% Electronics

8% Primary Metals

16% All other industries

slide4
Overview of Hazardous Waste Management

General definition of “hazardous:

  • Potentially dangerous or harmful to human health or environment
  • Capable of causing adverse physiological effects
  • Statutes that primary address hazardous wastes are the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).

RCRA is focused on the existing, active and future hazardous waste sites and management

CERCLA is focused on inactive hazardous waste disposal sites (Superfund)

slide5
General Description of CERCLA

The Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) was enacted by Congress on Dec. 11, 1980. CERCLA is commonly known as “Superfund”. This law gives the Federal Government authority to respond to:

(a) Emergencies involving immediate and uncontrolled release of HW whether on land or in navigable waters

(b) Identify uncontrolled and abandoned HW sites and ensure clean-up of the worst HW sites

(c) Compel those responsible for the problem to clean-up the HW sites at their own expense or to recover the costs of federal actions

slide6
General Description of CERCLA (continued)

CERCLA created a “Hazardous Substances Release Trust Fund” from taxes on the chemical and petroleum industries. Funds collected are used for the clean up of abandoned or controlled HW sites.

CERCLA was amended in Oct 17, 1986 by the Superfund Amendments and Reauthorization Act (SARA). SARA significantly increase the size and scope of CERCLA program.

CERCLA also established a priority list of abandoned or inactive HW sites for cleanup – called the National Priority List (NPL)

slide7
RCRA Introduction and History:
  • Enact in 1976 to fill the regulatory pollution control gap between the Clean Air Act (1970) and the Clean Water Act (1972)
  • Enacted as an amendment to the Solid Waste Disposal Act – delegated US EPA the task of defining what substances are “hazardous wastes” and how these wastes should be regulated in order to prevent harm to human health or the environment
  • In 1984, Congress amended RCRA through the Hazardous and Solid Waste Amendments (HSWA). Amendments were made in response to EPA’s inability over the previous eight years to promulgate effective and satisfactory regulations. HSWA gave more specific guidelines for regulations, timetable for promulgation of regulations by installing minimum regulatory controls or hammers to promote rapid promulgation of regulations.
  • Sections of RCRA that are important are Subtitle C of RCRA which establish a program to manage HW from cradle-to-grave and a program for identifying and listing HW
slide8
Identifying Hazardous Waste

RARC Sec. 1004 (5) defines a hazardous waste as:

….. A solid waste, or a combination of solid wastes, which because of its quantity, concentration, or physical, chemical or infectious characteristics may (a) cause, or significantly contribute to an increase in mortality or increase in serious irreversible, or incapacitating reversible illness or (b) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported or disposed of or otherwise managed.

By definition, all “hazardous waste” it must first be a solid waste. (Therefore, hazardous waste is a subset of solid wastes.)

slide9
Statutory definition of solid waste:

“…. Garbage, refuse, sludge from a waste treatment plant, water supply treatment plant, or air pollution control facility and discarded materials including solid, liquid, semi-solids or contained gaseous materials resulting from industrial, commercial, mining and agricultural operations, and from community activities but does not include solid or dissolved materials in domestic sewage, or irrigation return flows or industrial discharges which are point sources, special nuclear or by-product material as defined by the Atomic Energy Act of 1954.

slide10
A “Solid Waste” is a Discarded Material
  • Under RCRA, a material must be discarded before it becomes a solid waste. RCRA was not intended to regulate raw materials or products, regardless of their hazardous characteristics, unless they have been discarded.
  • The cradle-to-grave concept regulate the HW generators, transporters, and TSDFs and involves EPA, State and local regulatory agencies. The cradle-to-grave concept requires generators, transporters and TSDFs:

- to obtain an EPA Indentification Number

- to use an uniform HW manifest that contains information on the generator, transporters, and TSDFs to track and manage HWs

- to adopt DOT regulations for proper packaging and identification of HW during shipment

- to provide guidelines for the safe disposal of HW by TSDFs

tsdfs
TSDFs

Treatment, Storage or Disposal Facilities (TSDFs) include

  • landfills,
  • above ground tank systems,
  • surface impoundments,
  • waste piles,
  • land treatment,
  • incinerators,
  • other thermal treatment units,
  • chemical, physical and biological treatment units and
  • underground injection wells.
slide13

Cradle-to-Grave Concept

- Manifest System

Transporters

TSDFs

Generators

EPA

State

slide14
When is a “Solid Waste” a “Hazardous Waste”

A waste may be classified as a hazardous waste if the waste meets the criteria for any of the following categories:

  • Listed Waste

F, K, P or U wastes

2. Characteristics Wastes

Ignitability, Corrosivity, Reactivity, or Toxicity

  • “Mixed Wastes” and “Derived From” Rules (not discuss in this class)
slide15
Listed Hazardous Wastes

US EPA idenfied specific solid wastes that are hazardous wastes because of known hazardous characteristics. These lists consist of:

F Waste (40 CFR 261.32) – manufacturing wastes from nonspecific sources, eg., spent solvents, electroplating wastes, wood preserving wastes (tetrachloroethylene, trichloroethylene)

K Waste (40 CFR 261.32) manufacturing wastes from specific industrial processes, eg., wastes from wood preserving and petroleum refining industries (eg., distillation bottoms from production of acetaldehyde from ethylene)

P Waste (40 CFR 261.33(3)) discarded chemical products or intermediates that are acutely toxic wastes

U Waste (40 CFR 261.33(f)) discarded chemical products or intermediates that present risks of chronic toxicity from exposure

P and U wastes contain specific chemicals such as organics, pesticides and acids (eg., acetone, aldicarb)

slide16
2. Characteristic Wastes

Waste may be regulated for exhibiting one of the following characteristics of a hazardous waste as determined by the EPA:

Ignitability

  • Liquid except aqueous solutions containing less than 24% alcohol, that has flash point less than 60oC
  • Nonliquid capable, under normal conditions of spontaneous and sustained combustion
  • Ignitable compressed gas under DOT regulations
  • Oxidizer under DOT regulations

Corrosivity

  • Aqueous material with pH less than or equal to 2 or greater than or equal to 12.5
  • A liquid that corrodes steel at a rate greater or equal than ¼ inch per year at a temperature of 55oC
slide17
Characteristic Wastes (continued)

Reactivity

  • Normally unstable and readily undergoes violent change without detonating
  • Forms potentially explosive mixtures with water
  • When mixed with water, it generates toxic gases, vapors, or fumes in a quantity sufficient to present a danger to human health or the environment.
  • It is a cyanide or sulfide bearing waste which exposed to pH conditions between 2 and 12.5 can generate toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment.
  • It is capable of detonation or explosive reaction if subjected to a strong initiating source or if heated under confinement.
  • It is readily capable of detonation or explosive decomposition or reaction standard temperature and pressure
  • It is a forbidden explosive as defined in DOT regulations
slide18
Characteristic Wastes (continued)

Toxicity

  • Using an approved extraction method – Toxicity Characteristics Leaching Procedure (TCLP), the extract from the waste contains any of the contaminants with a concentration equal to or greater than the values listed in the Table 10-10 (see Text page 841)

TCLP test procedures:

  • Solid material crush to particle size < 9.5 mm
  • Weak acetic acid addition acid : solid = 20 : 1 by wt.
  • 18 hrs 30 rpm at 22oC
slide19

Table 10-10 p841

Toxicity characteristic

constituents and

regulatory levels

slide20
Treatment Technologies for Hazardous Wastes
  • Biological treatment, eg., use of conventional biological treatment processes such as activated sludge system and trickling filters to treat hazardous organic compounds
  • Chemical Treatment for detoxifying HW include neutralization using acid or bases; oxidation using chlorine, hydrogen peroxide and ozone; and chemical precipitation; adsorption using granular activated carbon or ion exchange resin; and stabilization/solidification
  • Physical Treatment – separation or concentration of HW using distillation, filtration, membrane processes such as reverse osmosis
  • Thermal Processes – destruction of waste by high temperature, eg., incineration
  • Land Disposal – such as deep well injection, landfills, and surface impoundments
slide22
Destruction & Removal Efficiency (DRE)

DRE of 4”9s” means 99.99%

Example:

An initial concentration of contaminant is 100 mg/L

The concentration after treatment is 0.1 mg/L

DRE = (100 – 0.1)/100 = 0.999 = 99.9%

=> 3”9s” or 3 log reduction

polychlorinated biphenyl pcb

Cl

3-chlorobiphenyl

polychlorinated biphenyl (PCB)
  • over 200 isomers
  • different chlorine composition (Araclor 1248)
  • virtually indestructible - useful as transformer fluid (in every transformer: 1930 - 1970)
  • toxic effects to exposed workers noted in 1937
  • environmental contamination realized in 1969
dioxin

Cl

Cl

Cl

o

Cl

2,3,7,8 TCDD

dioxin

o

  • dibenzo -  - dioxin
  • over twenty different isomers
  • byproduct of herbicide/pesticide manufacture
  • created during incineration of hazardous wastes
  • contaminant in 2,4-D, agent orange and others
  • carcinogenic, teratogenic, mutagenic, embryo-toxic in animal studies
  • bioaccumulates in fatty tissue
  • no known link to human effects
slide25

Calculating Cancer Risk for Carcinogen

Where:

TR = Target cancer risk (dimensionless)

Cw = Concentration of chemical of concern in water (mg/L)

IR = Ingestion rate of water (L/day)

EF = Exposure frequency (days/yr)

ED = Exposure duration (yr)

BW = Body weight (Kg)

ATc = Averaging time (life expectancy) for cancer (days)

SF0 = Oral cancer slope factor (Kg*day/mg)

slide26

Slope Factor

Dose – response curve

Risk,

dimensionless

x

x

x

x

x

x

x

x

x

x

Slope at response of 1x10-6 = Slope factor (Kg*day/mg)

1x10-6

Dose, mg/Kg*day

EPA accept Linearized multistage extrapolation method

to estimate SF

slide27
Generally, lifetime cancer risk is calculated by assuming EF x ED = ATc

This simplifies the equation to:

Some Oral Slope Factor:

Chemical SF0 (Kg*day/mg)

Arsenic (inorganic) 1.7500

Benzene 0.0290

Chloroform 0.0061

Hexachlorobenzene 1.6000

Hydrazine 3.0000

slide28

Example Problem 1:

Determine the lifetime risk of cancer from drinking well water

contaminated with 0.5 mg/L benzene for five years.

Assume:

IR = 2.0 L/day

BW = 70 Kg

ATc = (70*365) = 25,550 days

About 1 in 100,000

slide29

Example Problem 2:

Determine the lifetime risk of cancer from drinking a water

source that contains the MCL for benzene.

MCL: maximum contaminated level

MCL for benzene = 0.005 mg/L (Text page 218 Table 4-7)

About 1 in 1,000,000

slide30
Flash Point: The temperature at which a liquid or volatile solid gives off vapor sufficient to form an ignitable mixture with air

Back

slide31
Chemical Precipitation for Heavy Metals Removal

Example:

What is the minimum pH to have a Ca(OH)2 solution with Cu2+ ion conc. < 0.5 mg/L?

Ksp = 2 x 10 -19 = [0.5 mg/L / (1000 mg/g x 63.54 g/mole)] x [OH-]2

[OH-] = 1.59 x 10-7

Kw = [H+] [OH-] = 1 x 10-14

Therefore [H+]=10-14 / 1.59 x 10-7 = 6.28 x 10-8

=> pH = -log [H+]= 7.2

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