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Municipal Solid Waste

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					        Review of Module 1
• Definition of solid waste(固体废弃物的定义)
• Impact (pollute, bread)(固体废弃物的危害)
Solid waste management (6 function elements)
  (固体废弃物管理的6个组成因素)
ISWM (Hierarchy: reduction, recycling,
  treatment, disposal)(固体废弃物全过程管理
  的等级顺序)
• Consumption habits(消费习惯对固体废弃物量
  的影响)
       Review of Module 1
Sources and Types of Solid Waste and
 Sources of MSW(固体废弃物的来源与
 类型及城市固体废弃物的来源与类型)
Physical property:Specific Weight,
 Moisture Content, Particle Size and
 Distribution, Field Capacity, Permeability
 (hydraulic conductivity) of Compacted
 MSW(物理性质:比重(密度),含水
 量,粒径及粒径分布,田间持水量,压
 实废物的渗透率(导水率))
       Review of Module 1
Chemical property: Proximate Analysis,
  Fusing point of ash, Ultimate Analysis,
  Energy Content, Essential Nutrients
  ( 近似分析、灰分熔点、元素分析、含
  热量(热值))
• Biological property(生物性质)
• Physical, Chemical and Biological
  Transformations(物理、化学和生物处
  理方法)
Reading in Module 1
 •   P10-17
 •   P40-45
 •   P53-56
 •   P59-64
 •   P69-87
 •   P90-97
            Module 2
Generation, Collection, Transfer and
    Transport of Solid waste
         chapter 6-8,10


Solid Waste Generation and Collection
                Rates
          Chapter 6, p.125
               waste generation


  waste handling & Separation, storage,
  and processing at the sources


                 collection


                              separation and processing
transfer and
                              and transformation of
transport
                              Solid waste


                  disposal
1. Importance of Waste Quantities


 Compliance with federal and state
  waste recycling programs

 Equipment selections
2 Solid Wastes Quantities       30 compartments
                                 300 tons/each
 MSW (Municipal Solid Waste):
 China: 154million tonnes (2008)

   47 Freight trains/day
  Beijing: 6.72million tonnes (2008)


Increasing rate:
        ~4.8%/annum
Household Waste:

 • China:440kg/person/annum
 • England: 520kg/person/ annum
    2008年北京垃圾产生量情况


                年产量    日产量
     垃圾种类
               (万吨)   (吨/天)
 居民和单位生活垃圾      672    18400
建筑垃圾(不含工程槽土)    400    10950
    餐厨垃圾        60     1600
     合计        1132    30950



                               10
3. Measures and Methods Used to Assess
Quantities

 • MSW should be measured as a weight as
   opposed to a volume because the weight
   measurements are consistent and
   reproducible while the volume can vary
   considerably attendant to compaction.
   Ultimately, however, the capacity of a landfill
   is a volume consideration.
 • Units - lb/capita.day (kg/capita.day) for
   residential and commercial
• Estimation of Waste Quantities -
   - Load-count analysis - A landfill without
     scales may estimate the vehicular capacity
     and the number of vehicles of that
     capacity
   - Weight-Volume analysis
   – Material Balance (eq. 6-1, 6-2, 6-3)
Accumulation = inflow - outflow + generation
           dM
                 M in   M out  rw
            dt
Note: Always write rw as positive in the parent
  equation and make a negative substitution
  as required in the final analysis.
example

• Given: Problem 6-1, p153 Note: Paper
  is 32% of the waste produced and 20%
  of it goes to the fireplace except
  magazines.
• Find: Materials flow diagram and
  amount of solid waste disposed of
  during the day
• 6-1 Consider a household that generates a
  certain amount of waste per day. Of this amount,
  bottles and cans represent 20 percent (by weight)
  and are recycled by the family. 20 percent of the
  paper waste(32 percent of total) is burned in the
  fireplace. The remaining paper along with the
  rest of the waste is put into containers for
  collection. On a given day, 20lb of consumer
  goods (food, newspapers, magazines, etc.) are
  brought into the house. The family consumes 7lb
  of food that day, and 5 lb of food is stored. The
  magazines received represent 5 percent of the
  paper wastes of the day, and they are not
  thrown away. Draw a materials flow diagram of
  this problem and calculate the amount of solid
  wastes disposed of during this day.
1. Material Flow Diagram
2. Amount of solid waste disposed of during the day.
a. Waste produced = 20lb in the door -7lb food
   consumed -5lb food stored
    Waste produced = 8 lb/day
b. Bottles and Cans recycled = 8lb/day x .20
   Bottles and Cans recycled = 1.6lb/day
c. Paper goods = 8lb/day x .32
   Paper goods = 2.56lb/day
d. Magazines stored = 2.56lb/day x .05
   Magazines stored = .13lb/day
e. Paper good combusted = 2.56lb/day x .20 (20%
   burned)
   Paper good combusted = .51lb/day
f. solid waste disposed of = 8 lb/day - 1.6lb/day -
   .51lb/day -0.13lb/day
    solid waste disposed of = 5.76 lb/day
• Statistical Analysis –
example
Given: The weekly volume of MSW from
  the local Von's is: 10, 6, 7, 15,10,18,5
  yd3.
Find: Mean, standard deviation, coefficient
  of variation
solution
 1. Mean
 xbar = ∑x/N = (10+6+7+15+10+18+5)/7 = 71/7
 xbar =10.14
 2. Standard Deviation

  s
        ( x  x )2
                      
                        (10  10.14) 2  (6  10.14) 2  ...  (5  10.14) 2
          N 1                                  7
 s = 4.81
 3. Coefficient of Variation (relative measure of dispersion,
    typically 10-60% in solid waste)
 CV = 100s/xbar = 100(4.81)/10.14
 CV = 61.6
4. Generation and Collection Rates

 • Most studies prior to 1990 reflect the
   amount of waste collected as opposed
   to the amount of waste generated. The
   difference may be in recycling, garbage
   disposal, composting, fireplaces, etc.
   The variation may be from 4-15%.
• ≈One ton/capita.year ≈ 2000
  lb/365days/year = 5.48 lb/capita.day.
  More precisely, 3.82 lb/capita.day for
  residential and commercial and 6.16
  lb/capita.day total (T6-3, p138).
• Residential and commercial is typically
  60% of the total.
example
 • Given: The Simi Valley Landfill services
   approximate 50,000 homes.
 • Find: What is the weekly output of
   hazardous waste to the landfill?
 • Assume: 2.35 capita/residence,
 • T6-3, p138
 • hazardous waste=.0063lb/capita.day
solution

• HW = 50,000 residence x 2.35
  capita/residence x .0063lb/capita.day
• HW = 740.25 lb/day x 7 days/wk
• HW = 5181.75 lbs/wk
5. Factor that Effect Generation Rates
  source reduction and recycling activities
  Source Reduction
    Decrease unnecessary or excessive packaging
    Develop and use products with greater
      durability & repairability
    Substitute reusable products for disposable,
      single-use products
    Use fewer resources
    Increase the recycled materials content of
      products
  Extent of Recycling: the existence of recycling
   programs
  public attitude and legislation
  geographic and physical factors
public attitude and legislation
   Public Attitudes
   Legislation
geographic and physical factors
   Geographic Location
   Season of the Year
   Frequency
HOMEWORK

• Read Chapter 6, Solid Waste Generation
  and Collection Rates, pp. 125-157
• P128-134 p142-146
• Problems, p.152, 6-2, 6-7A
   Waste Handling and Separation
Storage and Processing at the Source

          Chapter 7, p.159
           waste generation


  waste handling & Separation, storage,
  and processing at the sources


               collection


                            separation and processing
transfer and
                            and transformation of
transport
                            Solid waste


                disposal
1. Handling and Separation at the Source

 • Handling refers to activities associated
   with MSW before they are placed in a
   collection container
 • May also include handling the collection
   container to and from the collection
   point
 • Source recovery is one of the most
   effective ways to recycle: aluminum
   cans, newspaper, plastic soda and milk
   bottles.
2. Storage of SW at the Source
  Effects of Storage
 • Putrefaction - Microbial decomposition via
   bacteria and fungi leading to vermin and
   odors.
 • Absorption of Fluids - If more than a week,
   the water will become equally distributed,
   primarily moisture from food and garden
   material moving into the paper.
 • Contamination - A small volume of paint had
   great potential to contaminate a great deal of
   plastic of recyclables.
3. Processing at Dwellings
 • Grinding of food - No significant
   decrease in the weight or volume of the
   MSW
 • Separation - very effective if you can
   engender meaningful participation.
 • Compaction - individual units under the
   counter, collection and processing by
   large units. also, compaction may foster
   contamination.
4. Composting
 • The biological conversion of the
   biodegradable organic fraction of the MSW
   resulting in a volume reduction and producing
   a useful by-product
 • Isolate a 3ft square area with chicken wire
   and dump the yard wastes. Food wastes
   may be stirred into the mix if odor and
   vermin problems can be obviated.
 • Water and turn occasionally, once/week.
   Perhaps ready to use after 1 year, put in at
   top, take out at bottom.
 • Produces a humus-like material which is a soil
   conditioner, not a fertilizer.
HOMEWORK


• Read Chapter 7, Waste Handling and
  Separation, Storage, and Processing at
  the Source, p.159-191
Collection of Solid Waste

     Chapter 8, p.193
               waste generation


  waste handling & Separation, storage,
  and processing at the sources


                 collection


                              separation and processing
transfer and
                              and transformation of
transport
                              Solid waste


                  disposal
1. Waste Collection
 A. General
 • Major cost element of solid waste
   disposal - typically 50-70% of the total
   and therefore, demands major attention
   especially with final disposal.
 • Collection includes:
   – picking up MSW from sources
   – hauling to the emptying location
   – emptying of the truck or container
B. Collection of Commingled Wastes, Low Rise,
  Detached
 The waste is commingled or heaped together
  as opposed to source separation
 Collection services:
  Curb-(manual or mechanical) most common,
   homeowner moves the container back and forth
   between the curb from the storage location.
  alley - Narrow utility thoroughfare in the rear of
   residences; not uncommon in older communities
  backyard carry - collectors retrieve the container
   from the storage location, empty it and return the
   container to the storage location.
Curb collection service
Manual methods of collection:
direct lifting and carrying
rim roll
small lifting devices
satellite vehicles
Satellite vehicle collection system
C. Collection of Commingled Wastes, Others
   From Low-and Medium Rise Apartments—
    Curbside
   From high-rise apartments—large containers are
    used, then may be hauled to an off-site location.
   From commercial-industrial Facilities—movable
    containers, large stationary compactors, large-
    capacity open-top containers

Much collection is done at night and very early
 morning to avoid the traffic.
D. Equipment
Evolution of vehicles
of waste collection
Residential or commercial
typical storage container (SCS)
1)Residential collection vehicle (SCS) -
  packer truck




   (a)Side loaders        (b)Rear loaders
Residential collection vehicle (SCS) -Mechanically
                        loaded




     Typical example of mechanically loaded collection vehicle
       2) Recycling collection vehicle -
            compartmentalized truck




Specially designed vehicles for the collection of source-separated wastes
3)Commercial collection vehicle (SCS) - self
   loaders




  Self-loading collection vehicle equipped with internal compactor
4)Commercial (HCS)




          Large open-top container
4)Commercial collection vehicle (HCS)




            Hoist truck
4)Commercial collection vehicle (HCS)
                          Tilt frame
4)Commercial collection vehicle (HCS)




              Trash trailers
Crushing and Compacting Type   Multi-Chamber Separation and
Refuse Collector               Classification Recyclables Collector
Separation and Classification Type   Demountable Container
   Can Compacting Collector          Carrier Truck
Review
Module 1 review
• Importance of Wastes Quantities
Measures and Method Used to Assess
  Quantities
  Load-count analysis
  Weight-volume analysis
  Material Balance analysis
2. Types of Collection Systems(T8-3, p.205)

 HCS (hauled container systems拖曳容器
  系统)
  the container is carried to and from the
  disposal area
 SCS (stationary container systems固定
  容器系统)
  the container is emptied into a truck
  and the truck travels to and from the
  disposal area.
A. Hauled Container Systems
Container is moved to disposal site
One drive and frequent trips
Types:
Hoist truck
Tilt-frame
Trash-trailer
Advantages:
 Useful when the generation rate is high
  and the containers are large.
 May eliminate spillage associated with
  multiple smaller containers.
 Flexible. Containers of many different
  sizes and shapes are available for the
  collection of all types of wastes.
Disadvantage:
 If the containers are not filled, low
  utilization rate.
B. Stationary Container System
   container remains at site
   May be manually or mechanically loaded

  Types:
   Manually loaded.
   Mechanically loaded.
   Almost all contain internal compaction
    equipment
Advantage:
 the vehicle does not travel to the disposal
  area until it is full yielding higher utilization
  rates.
Disadvantages:
 The system is not flexible in terms of picking
  up bulky goods.
 Wastes e.g. demolition, that make damage
  the relatively delicate mechanisms.
 3 Analysis of collection systems




Schematic diagram of operational sequence for
           HCS—conventional mode
                     1、牵引车从
                     调度站出发到
                     此收集线路一
                     天的工作开始
                     2、拖曳装满
                     垃圾的垃圾桶
                     3、空垃圾桶
                     返回原放置点
                     4、垃圾桶放
                     置点
  拖曳容器系统 (a)简便模式
5、提起装了垃圾的垃圾桶6、放回空垃圾桶 7、开车
至下一个垃圾桶放置点 8、牵引车回调度站 9、垃圾
处理场或转运站加工场
3 Analysis of collection systems




     Schematic fig. of operational sequence for
          HCS—exchange container mode
                      1、垃圾
                      桶放置点
                      2、从调
                      度站带来
                      的空垃圾
                      桶,一天
                      收集线路
                      的 开 始 3、
                      从第一个
                      垃圾桶放
                      置点拖到
图2—2 拖曳容器系统 (b)交换模式   处置场
4、处置场 5、出空垃圾桶送到第二个垃圾桶放置点
6、放下空垃圾桶再提起装了垃圾的垃圾桶 7、牵引
车带着空垃圾桶回调度站
 3 Analysis of collection systems




Schematic diagram of operational sequence for
                     SCS
1、垃圾桶放置
点 2、垃圾车辆
从调度站来,开
始收集垃圾 3、
收集线路
4、放置点中垃
圾桶出空到垃圾
车上 5、垃圾车
驶往下一个收集
点 6、处
置场或中继站、
加工场 7、垃圾
车回调度站      图2-3固定容器系统示意图
A. Definition of Terms
  1.) Pickup (Phcs or scs)拾取时间
   Phcs (conventional) –Time spent
      Driving to next site after depositing empty container
      Picking up loaded container
      Depositing empty container
   Phcs (exchange/swap) - not common –Time spent
      Picking up loaded container
      Re-depositing empty container
   Pscs -Time spent
      loading containers from first container till last container
       loaded, mechanical or manual.
2.) Haul (h) 运输时间
   Haul time (h), may be one-way or round-trip
 HCS
  h= time to reach disposal site and return to
   container location (not including time spent at
   disposal site)
 SCS
  h= time to reach disposal site after last container
   on route emptied plus time to reach first container
   on next route
3.) At-Site (s) 在处置场花费的时间
• The time spent at the site (landfill, MRF,
  transfer station) where the system is
  unloaded including waiting time.
4.) Off-Route (W) 非生产性时间
   Range: 10%-25% typically: 15%
   Types of off-route (non-productive) time
   Necessary
        Check in/out
        Lost to traffic congestion
        Equipment repairs, maintenance, etc.
        Lunch time
   Unnecessary
      Excessive lunch time
      Unauthorized coffee breaks
      Talking
• B. Hauled Container System Analysis
  Equations
             Thcs = (Phcs + s + h)
• Where
   Thcs = time per trip for hauled container system, h/trip
   Phcs = pickup time per trip for hauled container system,
    h/trip
   s = at-site time per trip, h/trip
   h = haul time per trip, h/trip
                        h = a + bx
h= total haul time, h/trip
a= empirical haul-time constant, h/trip
b= empirical haul-time constant, h/mi
x= average round-trip haul distance, mi/trip


                 Phcs = pc + uc + dbc
pc= time required to pick up loaded container, h/trip
uc= time required to unloaded empty container, h/trip
dbc= time required to drive between container locations, h/trip
              Hau-speed constants

Speed limit (mi/h)   a(h/trip)      b(h/mi)

       55             0.016         0.018

       45             0.022         0.022

       35             0.034         0.029

       25             0.050         0.040

       15             0.060         0.067
         Nd = [ H ( 1-W ) - ( t1 + t2 ) ] / Thcs
Nd =number of trips per day, trips/d
H = length of work day, h/d
W= off-rout factor, expressed as a fraction
t1= time to drive from dispatch station (garage) to
  first container location to be serviced for for the
  day, h
t2= time to drive from the last container location to
  be serviced for the day to the dispatch station
  (garage), h
Thcs = time per trip, h/trip
C. Stationary Container System Analysis
• Equations
                Tscs = (Pscs + s + a + bx)
• Where
   Tscs = time per tip for stationary container system, h/trip
   Pscs = pickup time per trip for stationary container
    system, h/trip
   s = at-site time per trip, h/trip
   a= empirical haul-time constant, h/trip
   b= empirical haul-time constant, mi/trip
   x= average round-trip haul distance, mi/trip
             Pscs = Ct(uc) + (np-1)(dbc)

Pscs = pickup time per trip for stationary container system,
   h/trip
Ct= number of containers emptied per trip, h/container
uc = average unloading time per stationary container for
   stationary container systems, h/container
np= number of container pickup locations per trip,
   locations/trip
dbc=average time spent driving between container locations,
   h/location
• Example
• Solid waste from a new industrial park is to be
  collected in large containers(drop boxes,using
  stationary compactors). Based on traffic studies at
  similar parks, it is estimated that the average time to
  drive from the garage to the first container location(t1)
  and from the last container location(t2) to the garage
  each day will be 15 and 20min, respectively. If the
  average time required to drive between containers is 6
  min and the one-way distance to the disposal site is
  15.5mi(speed limit:55mi/h).
• determine the number of containers that can be
  emptied per day, based on an 8-h workday. Assume
  the off-rout factor, W, is equal to 0.15.
Solution
 1.Determine the pickup time per trip using Eq. (8-4).
  Phcs=pc+uc+dbc
  Use pc+uc=0.4h/trip( see table 8-5)
  Dbc=0.1h/trip(given)
  Phcs=(0.4+0.1)h/trip = 0.5h/trip
 2. Determine the time per trip using Eq. (8-3)
  Thcs=Phcs +s+a+bx
  Phcs=0.5h/trip (from step 1) s=0.133h/trip (see
    table 8-5)
  a=0.016 h/trip (see fig. 8-16)    b=0.018h/trip (see
    fig. 8-16)
  Thcs=[0.5+0.133+0.016+0.018(31)]h/trip =
    1.21h/trip
3.Determine the number of trips that can be
  made per day using Eq. 8-5
 Nd=[H(1-W)-(t1+t2)]/Thcs
 Use H=8h(given) W=0.15h(given)
  t1=0.25h(given) t2=0.33h(given)
  Thcs=1.21h/trip
 Nd=[8(1-0.15)-(0.25+0.33)]/1.21 =(6.8-
  0.58)/1.21 =5.14trips/d
 Use Nd=5.0trips/d
4. Determine the actual length of the workday
 5 trips/d=[H(1-0.15)-0.58]/1.21 H=7.80h
  (essentially 8h)
4. Collection Routes
 A. General
 Use a common sense, trial and error
   approach consistent with the philosophy
   of collecting the most waste with least
   resources in the context of constraints
   such as equipment breakdowns,
   holidays and vacations, good labor
   practices and the following guidelines:
 - Crew size and vehicles must be known and
  coordinated.
 - Routes should begin and end near arteries
 - Topographic and physical boundaries should be
  route boundaries.
 - Start at the top of a hill and work downward.
 - Last collection point should be near disposal site.
 - Traffic problems should be dealt with early in the
  morning.
 - Extremely large load should be dealt with early in
  the morning.
B. Layout of Collection Routes
The general steps:
 Step 1: preparation of location maps showing
  pertinent data and information concerning the
  waste generation sources including location,
  collection frequency, number of containers
 Step 2: data analysis and, as required,
  preparation of information summary tables
 Step 3 preliminary layout of routes
 Step 4 evaluation of the preliminary routes
  and development of balanced routes by
  successive trials.
Review
 Factors that effect generation rates
   Source reduction and recycling activities
   Public attitude and legislation
   Geographic and physical factors
 Waste handling and separation at the
  source
   – Grinding of food, separation, compaction,
     composting
 • Collection service
   – Curb, alley, backyard carry
 • Collection Vehicles
Review
 Types of Collection Systems
 Hauled Container System Analysis
 Stationary Container System Analysis
   Terms
   Equations
 • Collection Routes
   – Factors considered
   general steps in layout of collection routes
• Example 3
• The industrial service area is shown in the
  accompanying map. There are, as shown on the
  map, a total of 28 pickup locations and 32
  containers. The total quantity of waste to be
  collected each week is 277yd3. The map and the
  information it contains would be prepared as
  the first step in the layout of collection routes.
  Lay out collection routes for both a hauled
  container and a stationary container collection
  system.
• Assume the following conditions apply:
1. Containers with a collection frequency of
  twice per week must be picked up on
  Tuesday and Friday.
2. Containers with a collection frequency of
  three times per week must be picked up on
  Monday, Wednesday, and Friday.
3. Containers may be picked up from any side
  of the intersection where they are stationed.
4. Start and finish each day at the dispatch
  station site A.
• Assume the following conditions apply:
5.From the hauled container system, collection
  will be provided Monday through Friday.
6.Hauled container system are exchanged mode.
7. For the stationary container system, collection
  will be provided only 4 days/wk (Monday,
  Tuesday, Wednesday, and Friday) with only 1
  trip/day.
8.For the stationary container system, the
  collection vehicle will be a self-loading
  compactor with a capacity of 35yd3 and a
  compaction ratio of 2.
• Solution
1. HCS
(1)Set up a summary table (step 2)
The summary table is
(2)Layout balanced collection routes for each day
  of the week by successive trails(step 3 and 4)
   The rout will vary from one solution to another.
   The optimum solution will be to have an equal
  number of containers as well as equal distances
2. SCS
(1)Set up a summary table (step 2)
as follows:
(2) Layout balanced collection routes by successive trials
   in terms of quantity of wastes collected (step 3,4)
    Collection routes will vary
    The optimum solution will be to have an equal amount
   of waste collected as well as equal distances.
5 Vacuum Type Refuse Collecting and
Transporting System
  Refuse is disposed of via an indoor disposal
   chute provided on each floor of a building or
   outdoor disposal posts in front of the building
   and then temporarily stored in underground
   storage tanks.
  The stored refuse is loaded, by utilizing
   vacuum suction force, into a refuse collecting
   vehicle through an underground pipe network
   and a loading station.
Microcomputer-controlled vacuum
  type refuse collecting vehicle   Input post
Refuse storage bin   Pipe line
• FEATURES
Improved working condition
Reduced collecting costs
Satisfactory customer service
Good urban landscapes
Low maintenance costs
HOMEWORK


• Read Chapter 8, Collection of Solid
  Waste, pp. 193-245
• P204-215 p218-220 p228-235
• Problems, p.238 8-8, 8-15
• Project 2
Transfer and Transport

    Chapter 10, p.325
               waste generation



  waste handling & Separation, storage,
  and processing at the sources


                 collection


                              separation and processing
transfer and
                              and transformation of Solid
transport
                              waste


                  disposal
1.Need for Transfer Operations
 A. General
     Used when:
  Remote disposal sites >10 mi.
  Small capacity collection vehicle <20 yd3
  Low density residential areas
  Widespread use of medium sized
     commercial containers
 - Direct hauling to the processing center or
     disposal site is no long economically feasible.
B. Benefits
 Large vehicles replace several collection
  vehicles, reducing collection vehicle and crew
  route time
 Paved roads at transfer station reduce
  maintenance costs, time spent stuck at landfills;
  75-90% of flat tires occurred at the LF in one
  study
 Opportunity for baling or recycling; may
  increase operational cost at TS but decrease
  LF costs
 Easy use of multiple disposal sites
2. Types of Transfer Stations (Self-study)
(Fig.10-1, p.329)
 • Three types: direct-load, storage-load,
   combined direct-load and discharge load.
 A. Direct-Load Transfer System
 • The wastes in the collection vehicles are
   emptied directly into:
     - the vehicle that will transport the wastes to the
      final disposal site
     - facilities to compact the wastes into transport
      vehicles or
     - waste bales.
B. Storage-Load Transfer System
 • Wastes are dumped into a pit or
   unloading area as opposed to the
   transfer vehicle. The pit is typically a
   larger area and thus facilitates
   unloading of collection vehicles and
   shortens waiting time. Auxiliary
   equipment such as payloaders move
   the material from the storage area into
   the transfer vehicle. The storage time is
   typically 1-3 days.
C. Combined Direct-Load and Discharge
Load Transfer Stations


 • Usually a multipurpose facility: perhaps
   a transfer station and a MRF.
Review
 • Collection Routes
   – Factors considered
   general steps in layout of collection routes
 • Vacuum Type Refuse Collecting and
   Transporting System
 • Transfer and Transport
   – When needed
   – Benefit
   – Types
3. Transport Means and Methods
(self Study)

 A. Motor Vehicle Transport (T10-1,2,
   p.346)
 • Used where roads are available and
   include:
 • - trailers
 • - semi-trailers
 • - compactors
Transport vehicles
(a) truck(also truck
   chassis with
   detachable body)
(b)truck-trailer
   combination
(c)tractor-semitrailer
   combination
(d)tractor-semitrailer-
   pull trailer
   combination
• Unloading methods:
 self-emptying (Fig. 10-19, p.347)
  – hydraulic dump beds
  – powered internal diaphragms, most
   common
  – moving floors,
Unloading semitrailers: (a) equipped with movable internal
    diaphragm (b)equipped with continuous moving drag
                           conveyor
auxiliary equipment
  – pull-off type - wastes are pulled out of the
    truck by either a movable bulkhead or wire
    cables slings placed forward of the load.
  – hydraulically operated tipping ramps.
B. Rail Transport
 • Seattle to Columbia Ridge model. A
   distance of 300 miles in which 25-28
   tons are compacted into a 40' shipping
   container.

 • Interesting modifications possible:
   – Special fork lifts to load the containers.
   – rail cars also equipped with set down tires
    which will allow road transport
C. Water Transport




 • Barges, scows and special boats have
   been around a long time.
D. Pneumatic, Hydraulic etc.
 • Largest pneumatic system at Disney
   World in Florida. May be suitable for
   high density areas feeding a central
   collection point. Complex control valves
   and isolation equipment.
 • Hydraulic system - Macerate the waste
   and pipe it to a remote location.
   Potential for great economies except
   scarcity of water.
   Ocean water? Must the transport water
   be treated?
4. Transfer Station Design Requirements
(self study)
 • Type - The key element is will the
   waste be merely taken from one truck
   to another or will waste recovery
   operations such as recycling,
   composting, diversion be incorporated
   into the design.
 • Capacity - Waiting time for unloading
   vehicles
5. Location of Transfer Stations
 (self study)

 • Near as possible to the center of the
   service area.
 • Near highways, close to access avoid
   houses.
 • Minimum public environmental
   objections
 • Economical construction and operation
HOMEWORK


• Read Chapter 10, Transfer and
  Transport, pp. 325-360
• Problems, p.358 10-14
• P328-343

				
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