Lesson 6: Solid Waste Collection

Where do you think your trash goes?

• Watch this TED Trash Tracker Talk and get a whole new perspective.

Read: Text, Chapter 3, pp. 67 - 91

** Collection accounts for 50-90% of a solid waste management budget! **

• Hauled Container System (HCS) - container is moved to and from the disposal site (commercial, construction, institutions); high gen. rates; 1 driver frequent trips, container size and utilization important;

• Stationary Container System (SCS) - container remains at generation site (residential and commercial)

• Both Vehicles and Containers may be required
  • Review: Text, pp. 71 - 73, 81, 82
• Average life: 5-7 yrs
• HCS - generally handle commercial wastes
  • Hoist truck; small operation, few pickup locations, bulky items (See Text, pp. 81)
  • Tilt frame - large containers, widely used  (See Text, pp. 82)
  • Trash trailers - heavy rubbish (C/D)
• SCS - Residential collection vehicles
  • Packer trucks (SeeText, pp. 70)
    • most have internal compactors
    • Rear loaders - larger hopper not as necessary with the elimination of larger, bulky items
    • Side loaders - 2 person crew (driver and loader)
    • Mechanically loaded - (See: Text, pp. 71)
    • Front Loader, residential waste place in bin then cycled
• SCS - Recycling - compartmentalized truck (See: Text, pp. 97 & 89)
• SCS - Commercial - self loaders (rear, side, front) (See; Text, pp. 81)

Labor

• Labor intensive
• Labor unskilled
• High turn-over rates
• Few prospects for mechanical replacement of manual labor
  • although the use of automated, mechanical equipment for curbside collection is becoming more prevalent
• Injuries and poor working conditions
• Limited career opportunities

Customer Service

• Frequency of service
• Container and storage issues particularly for commercial and industrial
• Location of pickup
• Special wastes

Management and Financing Issues

• Low priority
• Resistance to change and new technologies
• Lack of quality management
• Inflation
• Changing with new regulations

Technological Issues

• Collection of recyclables, yard waste, special wastes -
• Yard waste containers - bagged material must be debagged prior to composting
• Automated collection (still requires an operator) - (See: Text, pp. 71 - 73)
• Development of efficient routes
• Vehicle weight restrictions
• Vehicle turning radius and clearance

Frequency of Collection

Collection frequency has been declining since the 1950s. By the 1970s, once per week (1/wk) collection was common in half of the U.S. This trend continued into the 1980s but at a reduced rate. The south still uses twice a week collection (2/wk) almost exclusively.

 Reasons for declining collection frequency include;

• Proportion of putrescible waste declined (food grinders)
• Better design of collection vehicles controls odors and flies
• Service costs increased
• Time between collection and disposal decreased
• Better management

Advantages and Disadvantages of Different Collection Frequencies

Alternative	Potential Advantages	Potential Disadvantages	Favoring Conditions
Once per week or less	Less expensive, Requires less fuel	Improperly stored waste can create odor and vector problems	Cold to moderate climate
Twice per week	Reduces litter, Reduces storage requirements	More expensive, Requires more fuel	Warm climate
More than twice per week	Reduces litter, Reduces storage requirements	More expensive, Requires more fuel	Dense population

Fixed Factors

• Climate
• Topography
• Layout - container access (alley, curbside, rear of house)
• Available transportation systems, traffic, roads
  • Venice, Italy uses boats
  • In the Bahamas, barges are used to transport collection trucks from island to island to landfills
• Types of wastes collected
• Population density

Variable Factors

• Storage techniques employed
• Recycling
• Collection frequency
• Crew size
• Equipment

Review: Example Problems 3-1, 3-2, 3-3, 3-4, and 3-5
Think: In Example Problem 3-1, is 1400 lb/yd³ a reasonable compacted waste density? Why/Why not?

Rework: Example Problem 3-2, assume that 75 lb of waste is generated per location and the vehicle compacts the waste to a density of 750 lb/yd³. You should get 200 customers.

Rework: Example Problem 3-3, assume that 75 lb of waste is generated per location and the vehicle compacts the waste to a density of 750 lb/yd³. You should get 720 customers. Think: Why didn't the answer change? Think: Estimate the weight and volume of waste collected. (Weight = 240 kN)

Rework: Example Problem 3-4, assume the crew collects waste 5 hours per day. You should get 375 customers per day.