Solid waste collection

1. Collection services: types and methods

2. Vehicle and labor requirements

3. Types of Collection systems (hauled

container system and stationary container
system)
Collection of SW
- 60-80 percent of total SWM costs.

Major problems:
– Poor building layouts
– Road congestion - time cost, leachate, transport
costs.
– Physical infrastructure
– Old containers used (leaky/ damaged)
– Absence of systematic methods (especially at
apartments, markets with large waste volume).
 TYPES OF COLLECTION:
Municipal Collection Services:

Residential: LRD- Curb (or kerb, the raised edge of a raised footpath or
roadway), Alley, Setout-Setback, Setout and Backyard carry.
Curb (Kerb-side)/ Alley collection services
Homeowner is responsible for placing the containers to be
emptied at the curb on the collection day and for returning
the empty containers to their storage location until the next
collection.
Alleys are the part of basic layout of a city or a given
residential area this storage of container used is common.

Setout-set back collection services

Containers are set out from the homeowner’s property and
set back after being emptied by additional crews that work
in conjunction with the collection crew responsible for
loading the collection vehicle
Curbside collection services
 TYPES OF COLLECTION (Cont.)
Setout-set back collection services:
Collectors have to enter property
Set out crew carries full containers from resident storage
location to curb/ alley before collection vehicle arrives.
Collection crew load their refuse into vehicle
Set-back crew return the container to storage area.

Setout collection services:

Same as setout-setback, here homeowner is responsible for
returning the containers to their storage locations.

Backyard collection services:

collection crew is responsible for entering the homeowner’s
property and removing the wastes from their storage location.

House-to-house collection where refuse bags used in 20-30 liter bins.

 TYPES OF COLLECTION (Cont.)

MRD and HRD or High-rise apartment or flats,

specially designed chutes or same as
Commercial-Industrial services.
Commercial-Industrial Collection Services
i. Large movable and stationary
containers
ii. Large stationary compactors (to form
bales)
 Collection Frequency:

- residential areas : everyday/ once in 2 days

- communal/ commercial : daily

- food waste:
• the normal time for the accumulation of
waste to fill a container
• the time for fresh garbage to putrefy and
emit fouls odor
• the length of fly-breeding cycle ( < 7 days).
 Types of collection systems, equipments
and labor requirements:
1. Hauled Container System (HCS)
2. Stationary Container System (SCS)
1. HCS:
 Container is hauled to disposal sites, emptied, and returned to original
location or some other location
 Suitable for areas where higher waste generation
 Types of Equipments:
 Hoist truck : 2 - 10 m3
 Tilt frame container: 10 - 40 m3 –
 Trash trailer - for heavy, bulky rubbish (construction, commercial,
usually open top container);
 Mostly one collector is responsible for deriving the vehicle, loading full
container, unloading empty containers and emptying the contents of the
container at the disposal site.
 In some cases both driver and helper used for loading & unloading and
operating the vehicle respectively.
 TYPES OF COLLECTION SYSTEMS (Cont.)

2. SCS:
 The container used to store waste remain at the point of generation;
except when moved to curb or other location to be emptied.
 Types include:
 Mechanically-loaded system/Self-loading system
 Manually-loaded collection vehicle(more common).
 Used for residential/commercial sites.
 Vehicle with internal compaction mechanism or un-compacted (open
top lorry - side loaded.
 Here deriver often assists the helper in bringing loaded container s
mounted on rollers to the collection vehicle and returning the empty
containers.
 Mostly 1-driver and 2-helpers
 In case of manually loaded system collectors vary from 1-3
depending upon the type of services and the collection equipments.
 ANALYSIS OF COLLECTION SYSTEMS
 Must be optimized to save collection time and costs.
 Important:
 To determine vehicle and labor requirements
 To established vehicle and labor requirements for the various
collection systems & methods. The unit time required to
perform each task must be determined.

 By separating the collection activities into unit operations, it is

possible,
 To develop design data and relations that can be used
 To evaluate both the variables associated with the collection
activities and the variables related to, or controlled by, the
particular location.

 Activities involved 4 unit operation: pick-up, haul, at-site and off-

route.
 Hauled Container System
(Conventional Mode)
Where;
LC = Loaded container,
DEC = Deposit empty contained,
TS = Transfer station
Derive to next
PS = Processing station
Container container
Pick up LC Pick up LC DS = Deposal site
location
n = Number of Containers
Pick up LC
Example below: n = 3
1 n
Truck from Truck to
dispatch LC
DE
LC
DE
LC
DE dispatch
C C C
station- station – End
Beginning of of daily rout
daily rout 2

Haul loaded
container
Schematic of
operational sequence
Haul empty container to TS, PS or DS ( where contents for HCCMS
original pickup location of containers are emptied)
 Hauled Container System (Exchange
Container Mode)
Where;
Pick up LC LC = Loaded container,
Pick up LC
DEC = Deposit empty contained,
TS = Transfer station
Container Deposit EC PS = Processing station
location from previous Pick up LC DS = Deposal site
location n = Number of Containers
Example below: n = 3
1 2 n
Truck with
empty from
DE DE DE
dispatch LC LC LC
C C C
station- Truck with empty container
Beginning of to dispatch station – End of
daily rout daily rout

Haul loaded
container from
location 1 Schematic of
operational sequence
Haul empty container
originally at location 1 TS, PS or DS ( where contents for HCEMS
to location 2 of containers are emptied)
 Stationary Container System
Where;
PLC = Pickup loaded container,
DEC = Deposit empty contained,
Load contents from container (s) at TS = Transfer station
pickup location into collection vehicle PS = Processing station
DS = Deposal site
n = Number of Containers
Container Example below: n = 3
Derive to next
location container Load contents from container (s) at
pickup location into collection vehicle
2
Empty
vehicle from
dispatch LC EC LC EC LC EC n
station-
Beginning of
daily rout 1
Load contents from container (s) at Derive loaded collection
pickup location into collection vehicle vehicle to disposal site

Derive empty collection

vehicle to beginning of
Schematic of
next collection route or operational sequence
return to dispatch station TS, PS or DS ( where contents for SCS
– End of daily rout of containers are emptied)
 ANALYSIS OF COLLECTION SYSTEMS
• Pickup Unit Operation (Pickup Time): p
– HCS (Conventional Mode): Phcs
• Time spent driving to the next container after an empty container
has been deposited,
• pickup loaded container and
• to redeposit the container after it’s contents have been emptied.
– HCS (Ex-change Mode): Phcs
• Time required to pickup a loaded container and
• to redeposit the container at the next location after it’s contents
have been emptied.
– SCS: Pscs
• Time spent for loading the collection vehicles,
• Beginning with the stopping of the vehicle prior to loading the
contents of the first vehicle and
• Ending when the contents of the last container to be emptied have
been loaded
 ANALYSIS OF COLLECTION SYSTEMS
• Haul Unit Operation (Haul Time): h
– HCS (Conventional Mode): Hhcs
• Time required to reach the disposal site, Starting after a container
whose contents are to be emptied has been loaded on the truck
and
• The time after leaving the disposal site until the truck arrives at the
location where the empty container is to be redeposited.

– SCS: Hscs
• Time required to reach the disposal site, Starting after the last
container on the route has been emptied or the collection vehicle
filled and
• The time after leaving the disposal site until the truck arrives at the
location of the first container to be emptied on the next collection
route.
 ANALYSIS OF COLLECTION SYSTEMS
• At-site Unit Operation (At-site Time): s
– The unit operation at-site refers to the time spent at the disposal site
and
– Includes the time spent waiting to unload the collection vehicle.
• Off-route Unit Operation (Off-route Time): w
– The unit operation off-route includes all the time spent on activities that
are non-productive from the point of view of the overall collection
operation.
– Many of the activities associated with off-route times are some time
necessary in the operation. Therefore, the time spent on the off-route
activities are classified into two types.
– Necessary off-route and un-necessary off-route time
• Both are considered because they must be distributed equally over
the entire operation of waste collection.
 ANALYSIS OF COLLECTION
SYSTEMS
• Necessary off-route Time:
• Time spent checking in and out in the morning and at the end
of the day.
• Time spent driving to the first pick up point and/or from the
approximate location of last pick-up point to the dispatch
station at the end of the day.
• Time lost due to unavoidable congestion and
• Time spent for equipment repairs and maintenance etc
• un-necessary off-route Time:
• Time spent for lunch in excess of the sated lunch period and
• Time spent on taking unauthorized coffee breaks, taking to
friends etc
 Factors Affecting SW Collection
Productivity:
a. Service Level Related:
• collection point, frequency, waste material

b. Route related:
• Containers, Distance, topography, Time, road
conditions

c. Collection Methodology Related/Climate

Related:
• Crew size, collection procedures, wind, rain.
 Waste Collection Models

Determination of Vehicle and Labor

Requirements.
 LAY-OUT OF ROUTES:

4-Step Process

1. Prepare location maps:

- with pick-up point locations
- number of containers
- collection frequency
- estimated quantities (in the case of SCS with self-
loading compactors).
2. Data summaries:
- Estimate of wst. each day (from pick-up locations)
- ( for SCS - number of locations for each pick-up
cycle).

3. Lay preliminary collection routes (from different

stations).
- Route should connect all pick-up locations + last
location be nearest to disposal site).

4. Develop balanced route - determine haul distance for

each route
- Determine labor requirements per day, check against
available work times per day - draw master map.
 SOLID WASTE COLLECTION:
Selecting Collection Equipment:
- Changing needs and advances in technology
- Trends - increase use of computer-aided equipment
and electronic control (e.g. on-board computers for
monitoring truck performance and collection
performance).
- Open and close non-compacting trucks:
o Inexpensive to purchase or maintain
o Inefficient for most collection application (small
amt. of waste, have to lift high to dump into the
truck)
o Suitable for yard, bulky wastes, and recyclable
materials, for small communities and rural areas.
 Factors to consider in selection of
vehicle:
1. Waste quantities

2. Truck body or container capacity

a. Regulations regarding truck size and weight,
b. To maximize the amount of wastes that can be collected while
remaining within legal weights for the overall vehicle.

3. Consult with collection crew and drivers.

4. Loading location/ Location of container - determine the type of
vehicles to be used: Front-loading; Side-loading or rear-loading
compactor truck.

5. Physical characteristics of the collection routes/ road width -

e.g. wide street - use side-loading automatic collection system; for
narrow urban streets - use rear loaders.
Factors to consider in selection of
vehicle(Cont.):

6. Residential, commercial or industrial: HCS for large

buildings (e.g. apt., industries,etc.)

7. Safety and comfort - to minimize danger to crews.

– Truck turning radius - be as short as possible.
– Water tightness - to prevent leakages.
– Speed - wide range of speed.
Q___________????

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