Instructor: Dr Mehdi Mokhtari For Master of Science Students April 2012 Lesson 7

Preparing a site for an sanitary operation

Terrain Upgrading One of the first steps in the development of a sanitary landfill involves the removal of all objects that may interfere with the operation and movement of vehicles and equipment like trees, shrubbery, and other interfering vegetation

Secondly, the site must be graded so as to eliminate interfering surface irregularities. The surface of the site should be contoured such that a controlled runoff is promoted and ponding is prevented. Appropriate measures should be employed for minimizing problems associated with erosion, the generation of dust, and sedimentation.

Roads With large sites, these access roads would be extended from the site’s entrance to the vicinity of the working area. The roads should be designed to support the anticipated volume of pedestrian and vehicular traffic.

Adequate drainage should be provided to prevent the roads from flooding during wet seasons Ideally, the roadway should consist of two lanes (minimum total width, 7 m) However, the width should be at least 3.5 m for a one-lane road and 6 m for a two-lane road.

Typical cross-section of access road

Because the location of the working face is constantly changing, roads for the delivery of wastes from the permanent road system to the working face usually are temporary in terms of nature and construction. Temporary roads may be constructed by compacting the native soil and by digging drainage ditches.

Traffic consisting of more than 50 trips/day probably would justify the use of calcium chloride as a dust inhibitor, or of binder materials such as soil cement or asphalt Traffic consisting of more than 100 to 150 trips/day would necessitate a base plus a binder

Measurement of Weight The importance of having an accurate knowledge of the gravimetric and volumetric amounts of wastes delivered to the disposal site Types of scales range from highly automated electronic scales to simple, portable beam versions.

UTILITIES Ideally, electrical, water, and sanitation services should be provided

STRUCTURES Office space ( recordkeeping and the required clerical activities) House employee facilities Sheltered area for equipment storage, maintenance, and repair A facility to serve as a scale house.

Buildings that will be used for less than 10 years should be of temporary construction and preferably be movable. The design and construction of all buildings should take into consideration landfill gas migration and differential settlement of the fill

Fencing Access to the landfill site should be controlled preferably by building a fence around the entire perimeter of the site or, at the very least, around the locations of easy access to equipment and wastes by unauthorised individuals A fence also serves to restrict access to the waste by animals, screens the landfill, and delineates property lines.

Fencing of about 1.5 m in height and with a minimum of 5 cm openings usually is adequate. Litter fences should be erected in the immediate vicinity of the working face to control blowing paper and other litter. A low (about 1 m) fence usually suffices at a trench operation; whereas, a 2 to 3 m height may be necessary at a windy, area- type operation.

Portable litter fence

Important Factors That Must Be Considered in the Design of Landfills Source: Handbook of Solid Waste Management (2002) George TchobanoglousFrank Kreith

Landfill Layout (Summary)

Landfill Operation Some of the more important operational procedures that must be considered for all methods of landfilling include:

Site Preparation and maintenance Environmental control Hours of operation Procedures during inclement climate

Site Preparation and maintenance 1-Clearing and grubbing 2- Installation of leachate control systems 3- Erection of structures 4- Installation of utilities 5- Constructions of roadways 6- Soil stockpiling

Installation of leachate control systems slope: 1 -5 %

Gas vent

General maintenance The site manager is the person responsible for the preparation of a detailed maintenance schedule. Specific dates should be scheduled for the performance of the following tasks:

Collection and disposal of litter Relocation of portable fences for the management of litter Maintenance of gates, fences, and structures; Maintenance of drainage system and final cover Preparation and upkeep of final site maps

As areas of the site are completed, a series of maps indicating the status of filling phases should be updated. The maps should identify: 1. Areas used for special wastes 2. The fill depth of the various areas 3. The type of waste disposed

Road maintenance Maintenance of access roads, If performed well, road maintenance often is an expensive operation. The roads must be inspected and repaired frequently (cleaning, filling holes,…)

Environmental control The most commonly used types of environmental controls include: Impermeable barriers (liners) Leachate collection and treatment systems Landfill gas management systems Cover systems

Vectors and pests Flies, mosquitoes, rodents are an occurrence at landfill sites. Vectors can be controlled by frequently placing an adequate quantity of compacted soil over the wastes

Mosquito control is best accomplished by preventing the accumulation of stagnant water anywhere on the site Occasionally, rats and mice may be delivered to the site with the solid waste. If Shelter occurs in areas adjacent to or in some neglected portion of the site, extermination by the local health department will be necessary.

Birds generally are attracted to a landfill in search of food. The bird problem is best met by rapidly and completely covering all wastes

Birds at the landfill site are not only a nuisance; they can cause serious problems if the landfill site is located near an airport Techniques to control birds at landfill sites include the use of noisemakers, recordings of the sounds made by birds of prey, and overhead Wires Because seagulls descend in a circular pattern when landing, it appears that the wires may interfere with the birds’ guidance

Operating hours The operating hours at a landfill typically are set by the collection schedules. Operating hours may be modified based upon the quantity of waste produced during a certain time.

Inclement climate Long periods of excessive rainfall, freezing temperatures, or extreme heat can disrupt routine operation of a landfill.

One of the more effective means of managing high rainfall is to construct and maintain drainage canals on the periphery of the site to divert water from the wastes.

Landfills in arid and semi-arid regions may be operated without liners and leachate collection systems. In fact, it has been suggested that the best sites for landfills are in arid regions

Important Factors That Must Be Considered in the Operation of landfills (Summary)

Solid Waste Filling Plan The specific method of filling will depend on the characteristics of the site, such as the amount of available cover material, the topography, and the local hydrology and geology To assess future development plans, it will be necessary to prepare a detailed plan for the layout of the individual solid waste cells example of such a plan

filling plan for single-lift landfill

filling plan for a multi lift landfill

Summary of U.S. Environmental Protection Agency Regulations for Municipal Solid Waste Landfills Source: 40 CFR Parts 257 and 258, 1991

Typical Equipment Requirements for Sanitary Landfills

Crawler tractor with dozer blade High track crawler tractor with trash blade crawler tractors are most commonly used

steel wheel compactor with trash blade

Dragline (for excavation of cell and trenches)

Thanks for Attention