Collection of Solid Waste Chapter 8

Collection of Solid Waste Chapter 8

Presentation Outline • Introduction • Waste Collection • Types of Collection Systems, Equipment and Personnel Requirements • Analysis of Collection System

Introduction • Collection of un-separated and separated in an urban area is difficult and complex because the generation of residential and commercial industrial solid waste takes place in every home, every facility and even vacant area • As the patterns of waste generation become more diffuse and the total quantity of waste increase, the logistics of collection become more complex and now they become more critical because of the high cost of fuel and labor. • Of the total amount of money spent for collection, transportation and disposal in 1992, approximately 50 – 70 percent was spent on the collection phase. • This fact is important because a small percentage improvement in the collection operation can effect a significant saving in the overall cost.

Waste Collection • The term COLLECTION includes • The gathering or picking up of solid wastes from various sources • Hauling of these wastes to the location where the contents of the collection vehicles are emptied • Unloading of the collection vehicle • Collection of un-separated waste from Low-Rise Detached Dwellings • the most common types of collection services are curb, alley, setout – setback and setout. • Comparison of residential MSW collection services is summarized in Table 8-1.

Comparison of Residential MSW Collection Services

Waste Collection • Manual methods used for the collection of residential wastes include • Direct lifting and carrying of loaded containers to the collection vehicle for emptying • the rolling of loaded containers on their rims to the collection vehicle for emptying • the use of small lifts for rolling loaded containers to the collection vehicle • Where mechanically loaded collection vehicles are used, the container used for the onsite storage of waste must be brought to the curb. Typically, 90 gal containers are used in conjunction with mechanized collection vehicles • Collection of un-separated waste from Low-and medium rise apartments • Curbside collection service is very common • The maintenance staff is responsible for transporting the containers to the street for curbside collection by manual or mechanical means • Where large containers are used, the containers are emptied mechanically using collection vehicles equipped with unloading mechanisms.

Waste Collection • Collection of solid waste from high-rise apartments • Typically, large containers are used to collect wastes from large apartment buildings. • Depending on the size and type of containers used, the contents of the containers may be emptied mechanically, or the loaded containers may be hauled to an off-site location (e.g., MRF) where the contents are unloaded • Collection of solid waste from Commercial-Industrial facilities • Both manual and mechanical means are used. • To avoid traffic congestion during the day, wastes are collected in the late evening and early morning hours. • Wastes are put into disposable containers that are placed at the curb for collection. • the crew of collection waste consists of driver and two or three collectors who load the wastes from the curbside into the collection vehicle.

Waste Collection • Collection of wastes separated at the source • waste materials that have been separated at the source must be collected or gathered together before they can be recycled. • The principal methods now used for the collection of these materials include curbside collection using conventional and specially designed collection vehicles and delivery by homeowners to drop-off and buy-back centers. • Collection of wastes separated at the source/Residential curbside collection • The participation in curbside programs is typically much higher than for drop-off programs because the residents do not have to transport the recyclable any further than the curb • curbside programs vary greatly from community to community. • Some programs require residents to separate several different materials (e.g., newspaper, plastic, glass and metal), which are then stored in their own containers and collected separately. • Other programs use only one container or two containers, one for paper and the other for heavy recyclable

Waste Collection • The principal types of collection vehicles used for the collection of separated waste are • Standard collection vehicle • Specialized collection vehicle

Waste Collection

Waste Collection • Collection of wastes separated at the source/Commercial Facilities • Source-separated materials are usually collected by private haulers • The wastes to be recycled are stored in separate containers • in some cities, cardboard is bundled and left at curbside where it is collected separately • In large commercial facilities, baling equipment may be used for the paper and cardboard, and can crushers are used for aluminum cans.

Types of Collection Systems, Equipment and Personnel Requirements • The collection systems have been classified according to their mode of operation into two categories • hauled container systems • stationary container systems • Hauled Container Systems (HCS) • HCS is suited for the removal of wastes from sources where the rate of generation is high because relatively large containers are used ( reduces the handling time, unsightly accumulations and unsanitary conditions associated with the use of numerous smaller containers) • HCS is flexible : containers of many different sizes and shapes are available for the collection of all types of waste

Types of Collection Systems, Equipment and Personnel Requirements • Hauled Container Systems (HCS) • 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 are provided. • While hauled container systems have the advantage of requiring only one truck and driver to accomplish the collection cycle. Each container picked up requires a round trip to the 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.

Types of Collection Systems, Equipment and Personnel Requirements • Hauled Container Systems (HCS) • there are three main types of HCS • Hoist truck • Tilt/frame container • Trash/ trailer

Types of Collection Systems, Equipment and Personnel Requirements

Types of Collection Systems, Equipment and Personnel Requirements • Personnel Requirements for HCS • In most cases, a single collector driver is used. For safety reasons both a driver and helper are used. • The helper usually is responsible for attaching and detaching any chains or cables used in loading and unloading containers on and off the collection vehicle. • A driver and helper should always be used where hazardous waste are to be handled

Types of Collection Systems, Equipment and Personnel Requirements • Stationary Container Systems • There are two main types • systems in which mechanically loaded collection vehicles are used • System in which manually loaded collection vehicles are used • Personnel Requirements for Stationary Containers Systems • Labor requirements for mechanically loaded stationary container systems are essentially the same as the for HCS. Occasionally, a driver and tow helpers are used. • For manually loaded collection vehicles, typically, two persons, a collector and a driver are used for curb and alley service. And a multi person crew is used for backyard carry service.

Analysis of Collection System • To establish vehicle and labor requirements for the various collection systems and method, the unit time required to perform each task must be determined. • By separating the collection activities into unit operation is possible • to develop design data and relationships that can be used universally • to evaluate both the variables associated with collection activates and the variables related to, or controlled by, the particular location.

Analysis of Collection System

Analysis of Collection System • Definition of Terms • the operation tasks for the hauled and stationary container systems are shown schematically in figures 8-14 and 8-15 . • The activities involved in the collection of the solids wastes can be resolved into four unit operation: • Pick up • Haul • At site • Off route • Pick up • For hauled container system operated in the conventional mode , pick up refers to the time spent driving to the next container after an empty container has been deposited, the time spent picking up the loaded container and the time required to re-deposit the container after its contents have been emptied

Analysis of Collection System • Pick up • For hauled container system operated in the exchange mode, pick up includes the time required to pick up a loaded container and to re-deposit the container at the next location after its contents have been emptied. • For Stationary container systems, pick up refers to the time spent loading the collection vehicle, beginning with stopping the vehicle before loading the contents of the first containers and ending when the contents of the last container to be emptied have been loaded.

Analysis of Collection System • Haul • For hauled container systems, haul represents the time required to reach the location where the contents of the container will be emptied, starting when a container whose contents are to be emptied has been loaded on the truck and continuing through the time after leaving the uploading location until the truck arrives at the location where the empty container is to be re deposited. • For stationary container systems, haul refers to the time required to reach the location where the content of the collection vehicle will be emptied, stating when the last container on the route has been emptied or the collection vehicle is filled and continuing through the time after leaving the uploading location until the truck arrives at the location of the first container to be emptied on the next collection route

Analysis of Collection System • At site • The unit operation at site refers to the time spent at the location where the contents of the container or collection vehicle are unloaded and includes the time spent waiting to unload as well as the time spent unloading the waste from the container or collection vehicle • Off-Route • The unit operation off route includes all time spent on activities that are nonproductive from the point of view of the overall collection operation. Many of the activities associated with off routes • The time spent on off route activities may be subdivided into two categories necessary and unnecessary. • Necessary off route time includes • time spent checking in and out in the morning and at the end of the day • Time lost due to unavoidable congestion • Time spent on equipment repairs and maintenance

Analysis of Collection System • Off-Route • Unnecessary off route time • Time spent for lunch in excess of the state lunch period • Time spent on taking unauthorized coffee breaks • Talking to the friends and the like

Analysis of Collection System Hauled Container System Thcs = Phcs + S + h Thcs: time per trip for hauled container systems, h/trip Phcs: pick up time per trip for hauled container system, h/trip S : at site time per trip, h/trip H : haual time per trip, h/trip The time per trip can be expressed as follows Thcs = Phcs + S + a + bx The pick up time per trip for the hauled container system is equal to Phcs = pc + uc + dbc Phcs: pick up time per trip, h/trip Pc : time required to pick up loaded container, h/trip Uc : time required to unload empty container, h/trip Dbc : time required to drive between container locations, h/trip

Analysis of Collection System Hauled Container System The number of trips that can be made per vehicle per day with a hauled container systems, taking into account the off route factor w, can be determined by using

Analysis of Collection System

Analysis of Collection System Thank You

Collection of Solid Waste Chapter 8