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Prof. M.R.Ezhilkumar
Assistant Professor
Department of Civil Engineering
Sri Krishna College of Engineering and Technology
Coimbatore
ezhilkumar@skcet.ac.in
I only feel angry when I see waste.
When I see people throwing away
things we could use. – Mother
Teresa
1
17CE413
SOLID AND HAZARDOUS
WASTE MANAGEMENT
2.4 – Types of Collection system & its
Analysis

SHWM – Module 2 – MUNICIPAL OF SOLID WASTES HANDLING AND MANAGEMENT  Mr.M.R.Ezhilkumar 2
Learning Outcomes
☼ Basic collection system
☼ Types of collection system
☼ Analysis using collection systems
2.4 – Types of Collection system & Collection Routes

Video Session

SHWM – Module 2 – MUNICIPAL OF SOLID WASTES HANDLING AND MANAGEMENT  Mr.M.R.Ezhilkumar
The process of refuse collection should be thought of as a multiphase process, and it is
possible to define at least five separate phases
4
MSW Collection System

 The most common system of getting the solid waste into the truck was the collectors
going to the backyard, emptying the garbage cans into large tote containers, and
carrying these to the waiting truck.
 This system was not only expensive in cost to the community, but it was expensive in
terms of the extremely high injury rate to the collectors.
 The traditional trucks used for residential and commercial refuse collection are rear-
loaded and covered compactors called packers, and vary in size and design with 12
and 15 m3 loads being common.
5

A rear-loading packer truck for collecting residential solid waste
6

 The truck size is often limited not by its ability to store refuse but by its wheel weight.
 Residential streets are not designed to carry large wheel loads, and refuse trucks can
easily exceed these limits.
 Commonly, the refuse is emptied from garbage cans into the back of the packers
where it is scooped up by hydraulically operated compaction mechanisms that
compress the refuse from a loose density of about 60 to 120 kg/m3 to about to 360 to
420 kg/m3.
7

 The compaction (packing) mechanism of one manufacturer is shown below.
 To reduce injuries and to speed up collection, some solid waste collection companies
are changing from rear loaders to side loaders.
8
Compacting mechanism for a packer truck Side-loading packer truck.

 Two revolutionary changes during the 1990s had a great impact on both the cost of
collection as well as the injury rate of the collectors.
 The first is wide acceptance of the Can-on-Wheels idea, known as waste wheelers.
 The resident fills a large plastic container on wheels and then pushes it to the curb for
collection.
 These containers can be used for mixed refuse, recyclables, and/or yard waste.
9

 The collection vehicles are equipped with hydraulic hoists that are used to empty the
contents into the truck.
 The collectors do not come into contact with the refuse, avoiding dangerous materials
that can cut or bruise.
 This system, referred to as semi-automated collection, typically requires a driver
and one or more collectors.
10

 A further development in solid waste collection technology
is the can snatcher, trucks equipped with long arms that
reach out, grab a can, and lift it into the back of the truck.
 Such systems, called fully automated collection, are
especially useful where the street layout includes alleys
behind the houses.
 Communities that have converted from the manual
system to the fully automated system have saved at least
50% in collection costs, much of it in reduced medical
costs.
11

 The second revolutionary development in solid waste
collection is the widespread use of plastic bags.
 Many communities now insist that all refuse be packaged in the
plastic bags and that these be taken to the curb for collection.
 While the collectors still have to lift the bags to the truck, the
bags do not weigh very much, and injuries due to strains are
almost eliminated.
 In some communities, the cans are no longer used, and the bags
are left on the curb for collection.
12

 Plastic bags, of course, have some serious disadvantages.
 Bags can rip while they are transported to the curb, and can be torn apart by small
animals seeking food, resulting in the garbage being spread all over the sidewalk or
alley.
13

TYPES OF COLLECTION SYSTEM
 Over the past 20 years, a wide variety of collection systems and equipment have
been used for the collection of solid wastes.
 When considering collection technology, the basic components are surface streets
and roadways, over-the-road trucks, and sturdy containers for storage.
 There have not been dramatic changes to these components since motor-driven
vehicles replaced horse-drawn carts (Merrill, 1998).
 Technology changes will make the truck and labor more efficient, but the basic
collection truck will be used for many more years.
14

TYPES OF COLLECTION SYSTEM
 Solid waste collection systems may be classified from several points of view, such as
the mode of operation, the equipment used, and the types of waste collected.
 The two principal types of collection systems now used are according to their mode of
operation:
1. Hauled container systems
2. Stationary container systems
15

1. Hauled container systems (HCS)
 These are collection systems in which the containers used for the storage of wastes
are hauled to a materials recovery facility (MRF), transfer station, or disposal site,
emptied, and returned to either their original location or some other location.
 Hauled container systems are ideally suited for the removal of wastes from sources
where the rate of generation is high because relatively large containers are used.
 The operational sequence in HCS is further classified into two types of operation, (1)
Conventional mode and (2) Exchange container mode.
16

17
Containers used for the storage of
wastes are hauled to an MRF,
transfer station, or disposal site,
emptied, and returned to their
original location

18

19
Containers used for the storage of wastes
are hauled to an MRF, transfer station, or
disposal site, emptied, and returned to a
different location in the exchange mode of
operation.
The exchange mode works best when the
containers are of a similar size.
In the exchange mode, the driver must begin
the collection route with an empty container
on the vehicle to be deposited at the first
collection site.

20

 The use of large containers eliminates handling time as well as the unsightly
accumulations and unsanitary conditions associated with the use of numerous
smaller containers.
 Another advantage of HCSs is their flexibility: Containers of many different sizes and
shapes are available for the collection of all types of wastes.
 Because containers used in this system usually must be filled manually, the use of
very large containers often leads to low-volume utilization unless loading aids, such
as platforms and ramps, are provided.
21

 HCSs have the advantage of requiring only one truck and driver to accomplish the
collection cycle, each container that is picked up requires a round trip to an MRF,
transfer station, or disposal site.
 Therefore, container size and utilization are of great economic importance.
 Further, when highly compressible wastes are to be collected and hauled over
considerable distances, the economic advantages of compaction are obvious.
22

 There are three main types of HCSs:
I. Hoist truck
II. Tilt frame container
III. Trash trailer
23

(i) Hoist-truck systems
 These types of collection trucks are widely used with
containers of size ranging from 1.5 to 8.0 m
 For the collection of wastes by a collector who has a
small operation and collects from only a few pickup
points at which a considerable amount of wastes are
generated.
 For the collection of bulky items and industrial rubbish
not suitable for collection with compaction vehicles.
24

(ii) Tilt-frame container
 Systems that use tilt-frame-loaded vehicles and large
containers, often called drop boxes or roll-off containers,
are ideally suited for the collection of all types of solid
waste and rubbish from locations where the generation
rate warrants the use of large containers.
 Because of the large volume that can be hauled, the use
of the tilt-frame HCS has become widespread, especially
among private collectors servicing commercial accounts.
25

(ii) Trash trailer
 The application of trash trailers is similar to that for tilt-
frame container systems.
 Trash trailers are better for the collection of especially
heavy rubbish, such as sand, timber, and metal scrap,
and often are used for the collection of demolition
wastes at construction sites.
26

27

2. Stationary container systems (SCS)
 In the SCSs, the containers used for the storage of wastes remain at the point of
generation, except when they are moved to the curb or other location to be emptied.
 Stationary container systems may be used for the collection of all types of wastes.
 The systems vary according to the type and quality of wastes to be handled, as well
as the number of generation points.
 The operational sequence for the SCSs is schematically shown in next slide.
28

29
Containers used for the storage of
wastes remain at the point of
generation, except when they are
moved to the curb or other location to
be emptied.
The collection vehicle is driven from
pickup location to pickup location until it
is loaded fully.

30

 There are two main types:
1. Systems in which mechanically loaded
collection vehicles are used
2. Systems in which manually loaded
collection vehicles are used
31

 Because of the economic advantages involved, almost all of the collection vehicles
now used are equipped with internal compaction mechanisms, especially where long-
haul distances are involved.
 To optimize the payload, many newer collection vehicles contain onboard scales,
including load cells on the arms of mechanical lifting devices (to weigh individual
containers) and/or load cells on the truck chassis (to weigh the loaded material).
32

(1) Systems in which mechanically loaded collection vehicles are used
 Container size and utilization are not as critical in SCSs using collection vehicles
equipped with a compaction mechanism as they are in hoist-truck systems.
 Trips to the disposal site, transfer station, or processing station are made after the
contents of a number of containers have been collected and compacted, and/or the
collection vehicle is full.
 For this reason, the utilization of the driver in terms of the quantities of wastes hauled
is considerably greater for these systems than for HCSs.
33

 A variety of container sizes are available for use with these systems.
 They vary from relatively small sizes (1 yd3) to sizes comparable with those handled
with a hoist truck.
 The use of smaller containers offers greater flexibility in terms of shape, ease of
loading, and special features available.
 By using small, easier-to-load containers, utilization of containers can be increased
considerably.
34

 These systems can also be used for the collection of residential wastes where one
large container can be substituted for a number of small containers.
 Because truck bodies are difficult to maintain and because of the weight involved,
these systems are not ideally suited for the collection of heavy industrial wastes and
bulk rubbish, such as that produced at construction and demolition sites.
 Locations where high volumes of rubbish are produced are also difficult to service
because of the space requirements for the large number of containers.
35

(2) Systems with Manually Loaded Collection Vehicles
 The major application of manual loading methods is in the collection of residential
source-separated and commingled wastes and litter.
 Manual loading is used in residential areas where the quantity picked up at each
location is small and the loading time is short.
 In addition, manual methods are used for residential collection because many
individual pickup points are inaccessible to mechanized mechanically loaded
collection vehicles.
36

(2) Systems with Manually Loaded Collection Vehicles
 Special attention must be given to the design of the collection vehicle intended for
use with a single collector.
 At present, it appears that a side-loaded compactor equipped with stand-up right-
hand drive, is best suited for curb and alley collection.
37

Personnel Requirements
38

 Hauled Container System – HCS
 Stationary Container System – SCS
 Pick up – P
 Haul – h
 At site – s
 Off Route – W
39
Analysis of a Collection System

Hauled container systems (SCS)
Thcs = Phcs + s + h ---------- (1)
(h/trip) (h/trip) (h/trip) (h/trip)
h = a + b . x ---------- (2)
(h/trip) (h/trip) (h/km) (km/trip)
Thcs = Total haul time per collection trip Phcs & s are relatively constant
a & b are empirical constants derived from analysis of haul speed & distance
X = average round trip haul distance

From equ. (1) & (2)
Thcs = Phcs + s + (a + bx) ---------- (3)
Phcs = pc + uc + dbc ---------- (4)
(h/trip)
pc = time required to pickup loaded container (h/trip)
uc = time required to unload empty container (h/trip)
dbc = time required to drive between container locations (h/trip)

If Nd = No. of trips / day
H = length of work (in hours) / day
W = off-route factor (0.1 to 0.4) [0.15 (typ.)]
Nd = [ H ( 1 – W ) – ( t1 + t2 ) / Thcs ] ---------- (5)
t1 – time of travel from garage to Ist container (hours)
t2 – time of travel from last container to garage (hours)

Also, Number of trips required per day (or week)
Nd =
Va
c ∗ f
---------- (6)
Vd = average quantity of waste to be collected (m3/d)
c = average container size (m3/trip)
f = weighted average container utilization factor
Number of trips required = Number of containers collected

Stationary container systems (SCS) {Mechanically loaded}
Tscs = Pscs + s + (a + bx) ---------- (7)
(h/trip) (h/trip) (h/trip) (h/trip) + (h/km) (km/trip)
Pscs = Ct (uc) + (np – 1) dbc ---------- (8)
(h/trip)
Ct = no. of containers emptied / trip
uc = avg. unloading time per stationary container
np = no. of pickup locations / trip
dbc = avg. time spent to drive between container locations

Stationary container systems (SCS) {Mechanically loaded}
Ct = (v . r) / (c . f) ---------- (9)
Number of trips that can be made by a vehicle per day
Nd = [ H ( 1 – W ) – ( t1 + t2 ) / Tscs ] ---------- (10)
Number of trips required per day (or week)
Nd =
Vd
v ∗ r
----------- (11)
v = Volume of collection vehicle
r = Compaction ratio
c = Container volume
f = Weighted container utilization factor
Vd = average daily quantity of waste collected

Stationary container systems (SCS) {Manually loaded}
H = [ (t1 + t2) + Nd (Tscs)] / (1 – W)
Np = ( 60 * Pscs * n ) / tp
Np = number of pickup locations / trip
60 = conversion factor from h to min
Pscs = pickup time / trip (h / trip)
n = number of collectors
tp = pickup time / pickup location (collection-min/location)

Stationary container systems (SCS) {Manually loaded}
tp = dbc + k1Cn + k2 (PRH) = 0.72 + 0.18 Cn + 0.014 (PRH)
Then proper size of collection vehicle (m3/trip)
v = ( Vp . Np ) / r
Cn = average no. of containers / pickup location
PRH = rear of house pickup location (%)
Vp = Volume of solid wastes collected / pickup location
Np = No. of pickup locations / trip
r = compaction ratio

Assessment Time
Review
Question
Solid waste from a new industrial park is to be collected in large containers
(drop boxes), some of which will be used in conjunction with 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 (t2) to the garage each day will be 15 and 20 min,
respectively. If the average time required to drive between containers is 6
min and the one-way distance to the disposal site is 15.5 km(Speed Limit =
55 km/h), determine the number of containers that can be emptied per day,
based on an 8-h workday. Assume the off-route factor, W, is equal to 0.15.
Use pc + uc = 0.4 h/trip; s – 0.133h/trip; a – 0.016 h/trip; b – 0.018 h/trip;

End of this topic

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