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Lesson 2: Characteristics and Quantity of MSW


Objective: To quantify and characterize MSW in the US and Florida and to understand properties commonly associated with MSW.

Goals:

  • Determine why quantification is important
  • Understand the methodology used to quantify MSW
  • Become aware of differences among global production rates
  • Understand factors affecting waste generation rates
  • Become familiar with per capita generation rates
  • Explain why it is important to characterize MSW.
  • Become familiar with MSW descriptors.
  • Understand the methods used to characterize MSW
  • Describe the physical, chemical, and biological properties associated with MSW.
  • Perform calculations using waste composition and properties.

What types of materials are RCRA-Subtitle D wastes (non-hazardous solid wastes)?

  • Municipal Solid Waste (MSW)
  • Household hazardous wastes
  • Municipal sludge - accumulated solids, residues, and precipitates generated as a result of waste treatment or processing
    • Waste water treatment, potable water treatment, air pollution control, mixed liquor from septic tanks, grease traps, privies, etc.
  • Non-hazardous industrial wastes - SW generate by manufacturing. or industrial processes that is not a hazardous waste regulated under Subtitle C.
  • Municipal combustion ash
  • Small quantity generator's hazardous waste
  • Construction and Demolition debris (C&D) - building materials, packaging, and rubble from construction, remodeling, repair, and demolition operations on pavements, houses, commercial buildings, bricks, concrete, soil , rock, lumber, road spoils, rebar, etc.
    • 42 million yd3 from Hurricane Andrew
  • Agricultural wastes - wastes resulting from activities such as planting and harvesting crops, prod of milk, slaughter of animals, and feedlot operations
  • Oil and gas wastes
  • Mining wastes

What is Municipal Solid Waste (MSW) - RCRA Definition?

  • Durable goods - life > 3 yr., appliances, furniture, tires, electronics, oversize, bulky
    • AKA - white goods, inoperative and discarded refrigerators, ranges, water heaters, freezers, and other similar large appliances
    • Florida Definition of special wastes - SW that can require special handling and management, white goods, whole tires, used oil, mattresses, furniture, biol. wastes, lead acid batteries, car parts
  • Non-durable goods - newspaper, clothing, paper towels, cups
  • Containers/Packaging
  • Food wastes
  • Yard wastes - vegetative matter resulting from landscaping, maintenance and land clearing operations
  • Misc. inorganics - stones, concrete, soil, ashes, residues. Clean debris virtually inert and not a pollution threat or fire hazard


MSW - Textbook Definition

  • Mixed household waste
  • recyclables
  • household hazardous waste
  • commercial waste
  • yard waste
  • litter
  • bulky items
  • construction & demolitions waste


Refuse

  • MSW excluding C&D , sludge, bulky items, green waste not derived from homes

What are the sources of RCRA Subtitle-D Wastes?

  • Residential
  • Commercial
  • Institutional
  • Industrial
  • Agricultural
  • Treatment Plants
  • Open Areas (streets, parks, etc.)

 

What is the Nature of Municipal Wastes?

  • Organic
  • Inorganic
  • Putrescible
  • Combustible
  • Recyclable
  • Hazardous - regulated under 40 CFR 261 Subtitle C
    • Regulatory Defn: SW which because of its quantity, concentration, physical, chemical, or infectious character, may cause or significantly contribute to an increase in mortality or an increase in serious, irreversible or incapacitating reversible illness or may pose a substantial present or potential hazard to human health or the environment when improperly transported, disposed of, stored, treated, or otherwise managed.
  • Infectious
    • Disposable equipment, instruments, utensils, or fomites from rooms of patients who have been diagnosed or are suspected of having a communicable disease, laboratory wastes laboratory wastes such as tissues , blood specimens, excreta, and secretions from patients or lab animals, disposable fomites, and surgical op room pathological specimens, fomites and other materials from outpatient areas and emergency rooms

Terminology:

  • Generated Waste = all solid waste materials generated
  • Disposed (collected) Waste = solid waste materials taken to ultimate disposal (landfill or WTE)
  • Diverted Waste = solid waste materials generated but not processed through the normal waste management channels (recycled, composted,....).

 

Important

 

Generated Waste = Disposed (Collected) Waste + Diverted Waste


Importance of Generation Rates

  • compliance with Federal/state diversion requirements
  • equipment selection,
  • collection and management decisions
  • facilities design

Global Production Rates

Municipal Waste Generation Rates of Major Countries

  • US production (avg 4.3 lb/c/d)
  • Chicago - 5 lb/c/d
  • NY - 3.97 lb/c/d
  • Tokyo - 3.04 lb/c/d
  • Hong Kong - 1.87 lb/c/d
  • Hamburg WG - 1.87 lb/c/d
  • Medellin, Colombia - 1.19 lb/c/d
  • Calcutta, India - 1.12 lb/c/d
  • Kano, Nigeria - 1.01 lb/c/d

Comparison of the MSW Generation/Collection Rates for the U.S. and Florida

 

1960

1970

1980

1990

1995

1997

1999

2000

2001

2003

United States, lb/cap/d (generated)

2.68

3.25

3.66

4.51

4.41

4.4

4.6

4.5

4.4

4.5

Florida, lb/cap/d (collected)

--

--

--

8.2

9.6

8.9

8.92

8.8

--

--

United States, population, millions

180

204

227

249

263

270

273

281

285

291

Florida population, millions

4.95

6.79

9.75

12.9

14.1

14.7

15.32

15.98

--

--

Note: Waste quantities are determined locally by load counts and regionally/nationally by a materials balance approach.

Factors affecting generation Rates

  • Source reduction/recycling
  • Geographic location
  • Season
  • Home food waste grinders
  • Frequency of collection
  • Legislation
  • Public attitudes
  • Per capita income
  • Size of households
  • Population density
  • Historically, increases in the generation rate correlate with GNP trend
  • Typically population increase explains 1/3 of increase in MSW generation



Composition Studies

  • Manual sorting of waste components into predefined categories local basis
  • Knowledge of individual components important for
    • recycling impact,
    • calculation of physical properties,
    • combustion characteristics, and
    • landfill requirements
  • Need to be performed seasonally to define
    • equipment needs,
    • management programs, and
    • trends for future planning
  • Examples of seasonal variations in composition include
    • Yard wastes increase in the summer
    • Gift wrap/packaging increase during Christmas and other holidays

What is waste composition like in the U.S.?

Chart: 2001 Total Waste Generation

 

 

 

 

 

 

 

 

 

 

What is waste composition like in other Countries?

  • Food % increases w/ decreasing income
  • Paper % increases w/ increasing income, but
  • Paper % decreases with increased recycling

Physical Properties

Specific weight

  • Values: 600-900 lb/yd3 as delivered
  • Function of location, season, storage time, equipment used, processing (compaction, shredding, etc.)
  • Used in volume calculations

Particle size and distribution

  • Difficult to characterize because of waste heterogeneity
  • Important parameter for waste processing

Geotechnical properties

Soil phase diagram.
Soil Phase Diagram
Vsample=Vsolids+Vliquid+Vgas

Vvoids = Vliquid + Vgas
Wsample=Wsolids+Wliquid (Wgas~0.00)
V=volume, W=weight or mass

Moisture content (MC)

  • Weight or volume based
    • Weight: wt. of water/sample wt.
      • MCwet= Weight water/(Weight water+Weight solids)
      • MCdry= Weight water/Weight solids
    • Volume: volume of water/sample volume
  • Values:
    • For peak methanogenesis: 50-60% (by weight)
    • As placed: 0.036-0.205 cm/cm
    • Field capacity (the amount of water that can be held under free drainage conditions): 0.3-0.4 cm/cm
    • Completely saturated: 0.5-0.6 cm/cm
      • Note: This range corresponds to accepted values for the porosity of MSW
  • Related Concepts:
    • Saturation (Volume of water/Volume of voids)
    • Porosity (Volume of voids/Volume of sample)
    • Void ratio (Volume of voids/Volume of solids)
    • Note: Void space can be occupied by air and/or water

Chemical Composition

Proximate Analysis

  • Loss of moisture (temp held at 105 C)
  • Volatile Combustible Matter (VCM) (temp increased to 950 C, closed crucible)
  • Fixed Carbon (residue from VCM)
  • Ash (temp = 950C, open crucible)

Energy Content

  • Models are derived from physical composition and from ultimate analysis
  • Determined through lab calculations using calorimeters
  • Individual waste component energy content used to determine composite energy content7
  • Empirical Equations
    • Modified Dulong formula (wet basis):

BTU/lb = 145C +610(H2-02/8)+40S + 10N
Where C, H, O, S, and N = percent by weight of each component

    • Model based on proximate analysis

Kcal/kg = 45B - 6W

Where: B = Combustible volatile matter in MSW (%)
W = Water, percent weight on dry basis



Page last updated July 8, 2006 by Dr. Reinhart

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