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.?

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.

V_sample=V_solids+V_liquid+V_gas

V_voids = V_liquid + V_gas
W_sample=W_solids+W_liquid(W_gas~0.00)
_{V=volume, W=weight or mass}

Moisture content (MC)

Weight or volume based

Weight: wt. of water/sample wt.

MC_wet= Weight water/(Weight water+Weight solids)
MC_dry= 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

Used primarily for combustion and waste to energy (WTE) calculations but can also be used to estimate biological and chemical behaviors
Waste consists of combustible (i.e. paper) and non-combustible materials (i.e. glass)
Typical Data on the ultimate analysis of combustible components of MSW
Ultimate Analysis

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