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Waste Collection : Waste Collection


Lesson Objectives : Lesson Objectives Understand problems and concerns associated with MSW collection. Compare and contrast privately and publicly operated systems. Understand the types of collection systems Identify the benefits associated with the use of transfer stations Prepare an economic analysis of transfer stations Understand the design issues associated with transfer stations


Slide3 : Collection accounts for 50-70% of a SW budget!


History of Waste Collection Vehicles : History of Waste Collection Vehicles Covered Body (Early 1920’s) External Hopper (Mid 1920’s) Rotary Loader (late 1920’s) Rear Loader Compactor (1938) Side Loader Compactor (1947) Front End Loader (1955)


Types of Waste Collection Systems : Types of Waste Collection Systems Refuse Collection Systems (residential) Commercial Waste Collection Recyclable Material Collection 179,000 trucks in the US (most diesel powered)


Refuse Collection (Residential) : Refuse Collection (Residential) Stationary container emptied into truck Manually High injury rates (heavy containers, broken glass/sharp objects) Temporary containers that fall apart Automatic


Rear Loading Compactor : Rear Loading Compactor


Side Loader : Side Loader


Commercial Waste Collection : Commercial Waste Collection Mechanically front loaded Hoist trucks Tilt Frames Trash Trailers


Front Loading Compactor : Front Loading Compactor


Collection with Recycling : Collection with Recycling Collection of mixed MSW with sorting at MRF (single stream) Collection of separated recyclables and MSW (dual stream) Hand sorting of recyclables at MRF Hand sorting at point of collection (multi-compartment trucks) Collection of separate yard waste Bags, bins, or carts (require automation) Vacuum collection Dual compartment collection vehicle Curbside collection costs are $15/ton lower for single-stream than for separated


Recycling Hauler : Recycling Hauler


Split Body Rear Loader : Split Body Rear Loader


Vacuum Collection : Vacuum Collection


New Trends in Collection : New Trends in Collection Automated Collection Underground Collection and Storage Pay-As-You-Throw


Automatic Collection : Automatic Collection Usually only one driver required 18% of trucks are automated side loaders (> initial and maintenance cost) Use 60-90 gal containers usually provided by community


Automated Collection : Automated Collection


Advantages : Advantages Increased efficiencies in routing and collection Reduced costs Reduced driver shortages Less worker strain and injury Improves quality of life for workers (don’t smell as bad!, less soreness) Career opportunities for women


Disadvantages : Disadvantages More maintenance; need commitment to preventative maintenance Greater upfront cost (trucks, carts, community education) Cannot use with on-street parking, low hanging wires, narrow streets Need commitment to educating public Drivers get lonely


Underground Storage : Underground Storage Used by 15 million people in Europe Vertical containers installed in ground greater capacity cooler increased compaction decreased odor


Underground Collection : Underground Collection Motivation Increased waste generation Increased traffic Reduced availability of land Short distances of waste transport > number of containers for recyclables Collector safety Used in: Barcelona Stockholm Vittoria, Spain


Slide24 : Vittoria, Spain Vacuum Collection


Pay-As-You-Throw : Pay-As-You-Throw > 6000 in US Why? Tight landfill capacity Meet state/local recycling goals Environmentally sound Residents charged for collection of MSW based on the amount they throw away Proportional: residents are charged the same amount of money for each unit set out for collection Variable: Residents are charged a different amount per different sized units of garbage Multi-tiered: Flat fee for basic level of service, pay a second tier fee based on amount of waste


Examples : Examples Gainesville Since 1994 18% decrease in the amount of MSW 25% increase in the amount of recycling Tacoma, WA Costs decreased by 50% Recycling tripled


Collection Options - Public Collection : Collection Options - Public Collection Advantages More control over collection City owned and operated equipment City manages personnel Funded from tax, fees, or bills Disadvantages Less efficient Hard to raise capital Public control over waste disposal


Collection Options - Private Collection : Collection Options - Private Collection Non-Exclusive Franchise Exclusive Franchises Advantages No capital outlay for cities Decreased costs If exclusive, cans on the street only 1-2 times/wk Disadvantages Large haulers take over less competitive Over site by city required


Labor Issues : Labor Issues Labor intensive Labor is unskilled High turn-over rates Few prospects for mechanical replacement of manual labor Injuries and poor working conditions Limited career opportunities


Customer Service : Customer Service Frequency of service Container and storage issues particularly for commercial and industrial Location of pickup Special wastes


Management and Financing Issues : Management and Financing Issues Low priority Resistance to change and new technologies Lack of quality management Inflation Changing with new regulations


Technological Issues : Technological Issues Collection of recyclables, yard waste, special wastes Yard waste containers - bagged material must be debagged prior to composting New Trends Development of efficient routes Vehicle weight restrictions Vehicle turning radius and clearance


Reasons for declining collection frequency include: : 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


Safety : Safety Third most dangerous job behind fishing and timber cutting Falls off trucks Hit by cars Inappropriate disposal of wastes Lifting injuries


Fixed Factors Affecting Design and Cost : Fixed Factors Affecting Design and Cost Fixed Factors Climate Topography Layout - container access (alley, curbside, rear of house) Available transportation systems, traffic, roads (Venice uses boats) Types of wastes collected Population density


Variable Factors Affecting Design and Cost : Variable Factors Affecting Design and Cost Storage techniques employed Recycling Collection frequency Crew size Equipment


Collection Cost Calculations : Y = a + b + c(d) + e + f + g Where: Y = total collection time/day or week a = garage to route time/day or week b = actual time collecting waste/day or week c = number of trips to disposal site/day or week d = time to drive fully loaded truck to disposal facility, unload and return to collection area/trip e = time to drive to garage at the end of the trip/day or week f + g = off route time, can be expressed as a fraction of Y/day or week Collection Cost Calculations


Hauled Container System : Hauled Container System 1 2 3 4 5 Disposal Site Number of Containers = n Example below: n=5 The number of drive between Containers (dbc) = n-1 Example: n = 5 dbc = 4


Return to Home page : Return to Home page Updated October 31, 2007