Collection of Solid Waste, Transferand TransportEnvironmental Engineering (VCB 3033)

CO2: To develop integrated solid wastemanagement system

Nurul Izma MohammedCivil and Environmental Engineering Department

Universiti Teknologi PETRONAS

Unit objectives

At the end of this session you will be able to:

• Assess the importance of waste collection,transfer and transport

• Identify and compare types of collectionand transport systems

• Analysis the collection routes andalternative techniques

Unlike wastewater that is normallytransported in the sewer system by theforce of gravity, solid wastes are

usually collected and transported tothe treatment or recycling facility bymeans of containers and vehicles.

The importance of solid wastecollection

Collection, transfer and transport are the

most costly activities in solid waste

management process.

The waste collection system

- Containers

- Collection vehicles

- transfer stations

- Long distance collection vehicles

Waste Collection

• The functional element of collection,includes not only the gathering of solidwastes and recyclable materials, but alsothe transport of these materials, aftercollection, to the location where thecollection vehicle is emptied.

• This location may be a materialsprocessing facility, a transfer station, or alandfill disposal site.

Solid waste collection challenges

• Collection of solid waste in an urban area is difficultand complex because the generation of wastestakes place in every house, every apartmentbuilding and commercial and individual facility aswell as in the streets, parks, and even vacantareas.

• Therefore in any waste collection operation it is

important to look into; types of waste collection

services/systems, type of equipment to be used

and associated labor requirements and collection

routes.

Types of Collection Systems

- Hauled container systems

- Stationary container systems

Hauled container systems

• They are operated such that eachcontainer is picked up at its location atthe source and transported to thetreatment facility or disposal site whereit is emptied. The empty container isthen returned to its original location.

Hauled container system

Hauled collection system in a city in the USA

Stationary container systems

• Stationary container systems are used in areaswhere the amount of waste generated at eachpickup location is much less than the transportcapacity of the collection vehicle and thetransport of each container separately thereforeis economically infeasible.

• A stationary container system is operated suchthat the contents of each container along thecollection route are transferred to the collectionvehicle. When the vehicle is full at the end of thecollection route the contents are transported tothe treatment or disposal facility.

Stationary container systems in Malaysia(Sharifah Yaakob, EU-Asia SWM conference, 2008)

Transfer stations• In cases where the distance from

the collection area to the disposalor treatment facility is long directtransport by the collectionvehicles usually is economicallyinfeasible due to the relativelysmall quantities of wastestransported with each vehicle.

• The use of a transfer station andlarger capacity vehicles for longdistance transport between thetransfer station and the disposalfacility can improve collectioneconomy significantly.

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Optimization of collection routes

• Optimization of collection routes is mostimportant in the cases where most of the time isspent driving such as in connection with hauledcontainer systems.

• For collection of residential wastes usingstationary containers a significant amount of thetime is spent loading and unloading.

• The most valuable tool in optimizing suchcollection service is still the knowledge of localconditions such as one-way streets and roadconstruction by the collection teams.

Waste collection route in city of Oviedohttp://alafayawoodshoa.com/print.php?sid=37

Important factors in route layout

Determination of the best route layout is normallydone by a trial-and-error approach where severalcombinations are proposed based on:

- Information on waste quantity

- Infrastructure

- Collection frequency

- Available equipment

- Crew size

- Road conditions

- Topography

Solid WasteCollectionSystem in IpohCity: a Review

Example: Estimate the collection routes for the

following:

• Hilly areas

• Stationary container systems collection

• Collection points located in traffic

congested areas

• Sources where extremely large quantities

of waste

• In hilly areas the routes should start at the top of thegrade and proceed downhill as the vehicle becomesloaded.

• For stationary container systems collection routesshould be laid out so the last container to beemptied on the route is closest to the treatment ordisposal facility.

• Collection points located in traffic-congested areasshould be preferably be serviced as early in the dayas possible or at least outside rush hour to avoiddelays due to traffic congestion.

• Sources where extremely large quantities of wasteare generated should be serviced during the firstpart of the day to avoid excessive buildup of wastesat these sources during the day.

Example 2: Predict the break-even time for a stationary-container system and a separate transfer and transport systemfor transporting wastes collected from a metropolitan area to alandfill disposal site. Assume the following cost and systemdata are applicable:

Transportation costs:- Stationary-container system using an 18-m3 compactor = RM20/h

- Tractor-trailer transport unit with a capacity of 120 m3 = RM25/h

Other costs:- Transfer station operating cost = RM0.40/m3

- Extra cost for unloading facilities for tractor-trailer transport unit =RM0.05/m3

Other data:Density of waste in compactor = 325 kg/m3

Density of waste in transport unit = 150 kg/m3