WASTE DISPOSAL No matter what processing is done, there will be some residue that needs to be disposed of safely Options for disposal Modern, engineered landfill Incineration.

WASTE DISPOSAL Sanitary Landfill Is defined as a land disposal site employing an engineered method of disposing of solid wastes in a manner that minimizes environmental hazards by spreading the solid wastes to the smallest practical volume, and applying and compacting cover material at the end of operation of each day. Systems- Sanitary Landfill i. Gas collection system ii. Leachate collection system iii. Monitoring well

Solid Waste - Sanitary Landfill

A landfill in México showing geomembrane in one of the slopes.

Cross-Section of Sanitary Landfill WASTE DISPOSAL Cross-Section of Sanitary Landfill

Sanitary Landfill-Site selection consideration WASTE DISPOSAL Sanitary Landfill-Site selection consideration 1. Public Opinion/opposition 2. Proximity of major roadways 3. Speed Limits 4. Load limits on roadways 5. Bridge capacities 6. Traffic patterns and congestion 7. Haul distance (time) 8. Hydrology

Sanitary Landfill-Site selection consideration WASTE DISPOSAL Sanitary Landfill-Site selection consideration 10. Availability of cover material 11. Climate (e.g. floods, mud slides, snow) 12. Buffer areas around the site (e.g. high trees on site perimeter) 13. to operate for at least 5 years 14. ultimate use of completed landfill

Sanitary Landfill-Methods of Operation WASTE DISPOSAL Sanitary Landfill-Methods of Operation Area Method Solid waste is deposited on the surface, compacted, then covered with a layer of compacted soil at the end of a working day. The cover material may come from on or off site.

WASTE DISPOSAL Area Method

Area method for constructing a sanitary landfill

Sanitary Landfill Cross Section - Area Method WASTE DISPOSAL Sanitary Landfill Cross Section - Area Method

Cell - volume of material place in the landfill during one day operating period. Daily cover - 6 to12 in of native soil/ alternative material applied into surface of the landfill at end of each one day - to control the blowing of wastes material. Lift - complete layer of cells over the native area of the landfill Bench - height of the landfill exceed 15 to 20 m. - to maintain the slope stability of the landfill Final lift - final cover layer Final cover layer - applied to entire landfill surface after all landfilling operations are complete. - usually multiple layers of soil/geomembrane material

Sanitary Landfill-Methods of Operation WASTE DISPOSAL Sanitary Landfill-Methods of Operation Trench Method: A trench is excavated and the solid waste is placed in it and compacted; and the soil that was taken from the trench is then laid on the waste and compacted. This method is used on level or gently sloping land where the water table is low. The advantage of this method is that the soil taken from the trench can readily be used as daily cover and final cover.

WASTE DISPOSAL Trench Method

Trench method for constructing a sanitary landfill

Environmental Considerations of Sanitary Landfill WASTE DISPOSAL Environmental Considerations of Sanitary Landfill 1.A well designed and operated landfill will minimize vectors (carrier of disease), water and air pollution. 2.Burning is not permitted in a landfill. Keeping the waste covered will prevent the production of flies, control of rodents and fires.

WASTE DISPOSAL Landfill Leachate: Liquid that passes through the landfill and that has extracted dissolved and suspended matter from it is called leachate. Liquid enters the landfill from external sources such as rainfall, surface drainage, groundwater, and the liquid in and produced from the decomposition of the waste.

Leachate Collection System WASTE DISPOSAL Leachate Collection System Impermeable liner Granular material Collection piping Leachate storage tank Leachate is trucked to a wastewater treatment facility

WASTE DISPOSAL Estimating Landfill Requirements Sizing of landfill requires estimates of: - The rate at which wastes are discarded. The density of wastes when they are compacted in the fill. The density of wastes will be depends on how well it is spread and compacted . For MSW, the density in a landfill will usually between 480 to 600 kg/m3.

WASTE DISPOSAL vMSW= Vcell = Alift =

EX1 Estimate the landfill area needed to handle one year’s MSW for a town of 100,000 people. Assume per capita national average discard of 1.35 kg per day, no combustion. A landfill density of 600 kg/m3., and one 3 meter lift per year. Assume 20 percent of the cell volume is soil used for cover.

EX2 The United States sends about 1.29x1011 kilograms of a municipal solid wastes to a landfills what landfill area be required for one year’s worth of MSW if the landfill density is 480 kg/m3, cell depth is 3 m with one lift per year. And 80 percent of the cell is MSW?

EX3 Suppose a city of 50,000 people generates 40x106 kilogram of MSW per year. At current recovery and recycling rates, 22 percent of that is recovered is or recycled and the rest goes to a landfill. Suppose also that the landfill density is 600 kg/m3, cell depth is 3 m, and 80 percent of the cell is MSW. a) What is the lift area would be required per year? b) If the current landfill site covers 20 hectares, including 4 hectares needed for access roads and other facilities, and two more lifts are envisioned, how long would it take to complete this landfill?

EX4 If the city in EX 3 increases its recovery and recycling rate to 40 percent, how many years would it take to complete the landfill?