Solid Waste

1
Solid Waste

• Common household and commercial waste
• Known as refuse, municipal solid waste (MSW)
• Garbage, Trash, Rubbish

2
Solid Waste Hierarchy
Avoidance
Source Reduction
Recycling
Materials recovery
Energy Recovery
Or transform to a product
Landfilling
Lowest in hierarchy
3
Solid Waste Disposal

• Sources
• Disposal Regulations
• Recycling
• Composting
• Collection
• Processing
• Landfilling
• Incineration

4
Sources

• Municipal Wastes 24 lb/capita/day
• metal wastes
• plastic wastes
• food wastes
• Industrial Wastes
• Agricultural Wastes
• Mining Wastes

• paper wastes
• yard wastes
• glass wastes

5
MSW Disposal in US
6
Municipal Wastes

• paper wastes 32
• newspapers, books, magazines, packaging
• good recycling potential
• yard wastes 19
• grass clippings, brush, leaves
• varies seasonally geographically
• glass wastes 7
• bottles, glass jars
• almost all can be recycled

• metal wastes 8
• beverage food containers, scrap appliances
• good recycling potential
• plastic wastes 10
• recycling programs developed
• recycling codes
• food wastes 8
• declined from 15 in 85
• affected by garbage disposals

7
Plastic Recycling Codes

• Polyethylene terephthalate, PETE-1
• High-density polyethylene, HDPE-2
• Polyvinyl chloride, PVC-3
• Low-density polyethylene, LDPE-4
• Polypropelyne, PP-5
• Polystyrene, PS-6
• Other, 7

8
Industrial Classes
US Dept. of Commerce, Standard Industrial
Classification (SIC)
9
SW Regulations

• 1965 Solid Waste Disposal Act
• early recognition of MSW
• promoted better management
• supported RD
• 1970 Resource Recovery Act
• more emphasis on recycling energy recovery
• PHS investigated disposal of hazardous wastes
• 1976 Resource Conservation Recovery Act (RCRA)
• control of hazardous waste storage, treatment and
  disposal
• has been amended and reauthorized many times

10
Functional Elements of a SW Management System
Waste Generation
Recovery or to improve subsequent handling
Waste handling, separation,storage and
processing at the source
Truck routing
Small to large truck
Collection
Separation and processing and transformation of
SW
Transfer Transport
Disposal
11
Recycling
Recycling is the recovery and reuse of a product
which would otherwise be thrown away.
Preliminary steps for a recycling program

• An accurate analysis of the sources and content
  of the solid waste stream.
• Evaluation of any existing recycling programs.
  Existing programs must be integrated into the new
  or expanded program.
• Identification of public attitudes about
  recycling.
• Determine what markets exist for the potential
  recycled materials. (It does no good to collect
  materials for recycling if no market exists for
  their use!)
• Determine the best recycling options.

12
Recycling Options

• Drop-off Centers
• can be staffed or unstaffed
• Curbside Collection
• more effective, but more expensive
• Voluntary vs. Mandatory Recycling
• enforcement?

13
Composting

• controlled aerobic partial degradation of organic
  wastes
• natural microbial processes fungi, bacteria,
  protozoa
• especially useful for leaves that used to be
  burned
• waste volume reductions of 40-75
• wastes placed in windrows which are periodically
  mixed

14
Elements of Composting

• Collection
• curbside, drop-off, required public education
• Preprocessing
• grinding, separating, wetting, screening
• Composting Parameters
• oxygen supplied by natural aeration
• nitrogen C/N ratio varies with season
• temperature heat release
• moisture at least 50

15
Elements of Composting (Cont.)

• Multi-Level Composting
• Minimal-Level 12x24 ft. windrows turned
  annually, center become anaerobic, 3 yrs.
• Low-Level 6x12 ft. windrows mixed monthly to
  quarterly, watered, 1.5 yrs.
• Intermediate-Level same but turned weekly,
  specialized equipment, 5 wks.
• High-Level 10x200 ft., forced air, water N
  added, 2-10 wks., then left for 3-12 month.
• Compost Uses landscaping, gardening, farming

16
Collection
17
Collection Vehicles
Commonly used for trash collection
Also used where recyclables are collected
Compression to 50
See problem 11.1
18
Solid Waste Processing

• Sorting
• at point of generation, transfer station, or at
  landfill
• mechanical or manual
• magnets, compressed air, inertia devices
• Compaction
• low pressure in collection vehicle
• high pressure at transfer station or landfill
• Shredding

19
Landfilling

• The legal and controlled placement of wastes in
  the ground
• Dumping is illegal or uncontrolled
• Material undergoes chemical and biological
  changes
• Water is present which promotes biodegradation
  and carries away dissolved substances Leachate
• Leachate collection and recirculation

20
Leachate Characteristics
Complex Organics
Simple Organics
Acetic Acid
CO2 and CH4
21
Siting Restrictions

• The landfill disposal regulations provide the
  following restrictions on landfill location
• Prohibit the placement of a landfill facility
  near an airport because of dangers from
  scavenging birds.
• Require the landfill to be located outside the
  100 year floodplain or the landfill design must
  prevent the washout of solid waste during a 100
  year flood.
• Prohibit the placement of a new landfill or
  expansion of an existing landfill into or on a
  wetland.
• Prohibit the placement of a landfill within 200
  feet of an earthquake fault.
• Prohibit the placement of a landfill in an area
  with a high probability of a strong earthquake.
• Prohibit the placement of a landfill in an area
  with unstable soil.
• Require existing landfills which cannot meet the
  airport, floodplain, or unstable area
  requirements above, to close within five years.
  The state may grant a maximum of a two year
  extension.

22
Operational Requirements

• Exclusion of hazardous waste from the landfill.
• Provide at least six inches of daily soil cover
  over new solid waste placed in the landfill.
• Control disease vectors such as rodents and
  insects.
• Monitor methane concentrations in the landfill
  and buildings. (Methane is explosive when
  combined with the oxygen in air.)
• Elimination of most open burning.
• Control public access.
• Construct run-on and run-off controls for water.
• Meet water quality discharge requirements (NPDES)
  to surface water.
• Prohibit all liquid wastes except small
  quantities of household liquid wastes.
• Maintain records indicating compliance.

23
Design Requirements

• Synthetic membrane liner at least 30 mils thick
• Soil liner at least 2 ft. thick
• Hydraulic conductivity no more than 10-7 cm/s
• Other state-approved designs possible

24
Landfilling Area Method
From Sincero Sincero, 1996
25
Trench Method
From Sincero Sincero, 1996
26
From Davis Cornwell, 1991
27
(No Transcript)