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 Industrial Wastes
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% metal wastes: 8% yard wastes: 19%
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 R&D
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 Preliminary steps for a recycling program:
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 Curbside Collection
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 Compression to 50%
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