disposal of solid waste

7/30/2019 Disposal of Solid Waste

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DISPOSAL OF SOLID

WASTE-LANDFILL-


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IMPORTANCE OF SITE

SELECTION

Most difficult task.

Minimize the future impact on public health.

Reduction of the cost of:1. Design and Construction

2. Operation

3. Maintenance

4. Recovery of potential leachate releases.


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CONSIDERATION FACTORS

1. Haul Distance

2. Location Restrictions

3. Available Land Area

4. Site Access

5. Soil Conditions And Topography

6. Climatologic Conditions

7. Surface Water Hydrology

8. Geologic And Hydro geologic Conditions

9. Local Environmental Condition

10. Ultimate Use For Completed Landfills


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1. HAUL DISTANCE

Minimize the haul distance

Environmental and political concern


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2. LOCATION RESTRICTION

Airport Safety

Floodplains

Wetlands

Fault Areas

Seismic Impact Zones

Unstable Areas


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3. AVAILABLE LAND AREA

Sufficient land area

Last for at least 5 years

Adequate buffer zone


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4. SITE ACCESS

Remote area

Developed own route


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5. SOIL CONDITIONS AND

TOPOGRAPHY Soil Cover

Type of operation

Type of Equipment

Preparation of the site


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6. CLIMATOLOGIC

CONDITIONS Local weather conditions

Excavation is impracticalcover must be stock-piled

Wind patterns ,strength have critical roles

To avoid flying debris ,adequate windbreaks must be

established


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7. SURFACE WATER

HYDROLOGY Natural drainage and runoff characteristics

Flooding problems, limit of 100 years flood

Divert runoff from lakes and streams

Measure storm runoff into landfill


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7. Geologic And Hydrogeologic

Conditions Important for establishing suitability

Hydrogeologic Siting requirements

Thickness of vadose zone

Low hydraulic conductivity

Outside floodplain area

Set back from population, lakes, streams and wetlands

Hydrogeologic data establish what can be done to site

Geological Survey maps and state or local geologic information

can be used as source data


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8. Local Environment

Conditions Recommended not to built near residential and industrial

developments

Presently, built in remote locations (to minimize impact of

filling operations)


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10. Ultimate Use for

Completed Landfills A capped ,decommissioned landfill can be used for other

purpose

Examined for recreation sites ,sport fields ,parking areas

During design ,layout and operation the end use should be

considered


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STAGES OF A LANDFILL

SITTING PROCESS Define project and its needs

Identify major environmental factors

Identify candidate sites

Collect and analyse environmental, economic, and

socioeconomic data

Evaluate candidates sites

Screen candidate sites to a small number

Collect and assess site-specific engineering and environmental

data

Recommend one or more sites for final selection

Determine final location


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FACTORS TO CONSIDER

ECONOMIC

SOSIOECONOMIC

ENVIRONMENTAL

/GEOTECHNICAL


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ECONOMIC

Access to highways and available highway capacity.

Compatibility with existing solid waste management systems.

Cost of police, fire, and road maintenance cost.

Distance to waste generation locations.

Economic effects on community.

Effect on property value

Land development

Highly productive agricultural areas

Flexibility


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SOCIOECONOMIC

Archaeological and historical sites

Cultural patterns

Dedicated land

Economic and community resources

Emergency response

Land use and zoning

Noise impact

Proximity to school and residents

Public safety and health

Sensitive receptors


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ENVIRONMENTAL/

GEOTECHNICAL Aesthetic impact

Agriculture preservation areas

Air quality, gas compositions, and particulate matter

Geology

Areas with high groundwater level

Climate and atmospheric conditions

Distance from water supply wells

Fault areas

Flood plain and wetlands

Forest, wilderness, and scenic areas


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LANDFILL TYPES

All landfill should be containment type.

Attenuate and disperse site are no longer

acceptable due to the environmental pollution

that it will cause.


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LANDFILLING METHODS

Excavated trench / cell

Area method

Canyon / depression method


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EXCAVATED TRENCH/CELL

Ideal for area with adequate depth of cover.

Water table is low

Trench is excavated in the ground

Liner put in place before waste are deposited

Excavated earth use back as cover at the end of each

operation.


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AREA METHOD

(GROUND LEVEL LANDFILL) Terrain not suitable for excavation.

High groundwater level.

Liner are place on original ground.

Cover material hauled from location nearby.

Compost can be use as alternative


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CANYON/DEPRESSION

METHOD Techniques vary with canyon geometry

Control of surface water drainage is critical


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CANYON LANDFILL


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RECLAIMED LAND

Landfill can also be constructed on reclaimed land from the

sea.

An embankment will separate the landfill from the sea..

Liners are constructed to prevent salt water intrusion as well

as to prevent leachate from polluting the sea.


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LINER

Primary purpose is to minimize leakage of landfill leachate and

gas into subsurface.

Allow collection of leachate for treatment and disposal.

Typical slope of base liner is 2% to 10%

Typical slope of side wall liner ranges from 20% to 40%.

Most commonly used materials for liner include one or all of

following:

Geomembrane (Hydraulic barrier)

Geosynthetic Clay Liner (GCL) (Hydraulic Barrier)

Compacted Clay (Hydraulic Barrier)

Geotextile (for cushion or separation)

Allow collection of leachate for treatment and disposal.


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CROSSSECTION

OF ALANDFILL


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LANDFILL UNDER

CONSTRUCTION


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GRAVEL


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Leachate

Leachate may be defined as a liquid that has percolated

through solid waste and has extracted dissolved or suspended

materials.

In most landfills leachate is composed of the liquid that has

entered the landfill from external sources, such as surfacedrainage, rainfall, groundwater and water from underground

springs and the liquid produced from the decomposition of

the waste if any.


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Composition in Leachate Composition


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Leachate Treatment

Leachate recycling

During early stages leachate contain high concentration of TDS,

BOD5, COD, nutrients and heavy metals

When leachate re-circulated the constituent are attenuated by

biological, chemical and physical activities reactions occurringwithin the landfill

Leachate evaporation

The most simple treatment is evaporation in lined leachate

storage facility


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Leachate Treatment

Leachate treatment

The treatment process selected will depend on the contaminants

to be removed

Selection of treatment facilities will depend primarily on

characteristics of contaminants which include TDS, COD, heavymetal and other non-specific toxic constituents

Treatment facilities:

Integrated leachate management system

Discharge to wastewater treatment plant


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LEACHATE COLLECTION


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LEACHATE COLLECTION

FACILITIES SLOPED TERRACES

to avoid the accumulation of leachate in the bottom of a landfill,

the bottom area is graded into a series of sloped terraces

perforated pipe placed in each leachate collection is used to

convey the collected leachate to a central location, from which itis removed for treatment

in very large landfills, the drainage channels will be connected to

a larger cross-collection system.


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Leachate collection facilities

PIPED BOTTOM

The bottom area is then divided into a series of rectangular strips

by clay barriers placed at appropriate distances

Leachate collection pipes are then placed lengthwise directly on

the geomembrane. A unique feature of the design shown is the method used to

remove the storm water from the unused portion of the

landfilled.

In the unused portion of the landfill , storm water is collected in

the lines that will ultimately be used for the collection ofleachate.


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Di h t t t


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Discharge to wastewater

treatment plant In locations where a landfill is located near a waste water

collection system or where a pressure sewer can be used to

connect the landfill leachate collection to a waste water

collection system.

The organic content of leachate required to be reduced beforedischarged to the sewer.


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Pump used to pump out leachate from landfill into collection

ponds.


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Leachate treatment pond

SELECTION OF GAS CONTROL


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SELECTION OF GAS CONTROL

FACILITIES To determine the size of the gas collection & processing

facilities needed, the quantity of landfill gas must first be

estimated.

The decision to use horizontal or vertical gas recovery wells

depends on the design & capacity of the landfill. The decision to flare or to recover energy from the landfill gas

is determined by the capacity of the landfill site & the

opportunity to sell power produced from the conversion of

landfill gas to energy.

MOVEMENT OF LANDFILL


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MOVEMENT OF LANDFILL

GASESMovement of Principal Landfill Gases

Most escape to atmosphere

Some will migrate laterally (case were recorded where gas

concentration of 40% at distance of 400 ft of unlined landfill)

Methane can accumulate in lateral disance if unvented. Can accumulate under building or enclosed space.

Carbon dioxide (heavier than air) tend to move downward.


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Control Of Landfill Gases

Passive control

Active control with perimeter facilities

Active control with vertical and horizontal extraction wells


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Passive control

Pressure relief vents / Flare in landfill cover

Perimeter interceptor trench

Perimeter barrier trench / slurry wall

Impermeable barriers within landfill

Sorption barriers within landfill for trace gas

Active Control With Perimeter


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Active Control With Perimeter

Facilities Perimeter gas extraction and odor control well

Perimeter gas extraction trenches

Perimeter air injection well (air curtain system)


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Management of Landfill Gases

Flaring

Common method of gas management

Also called thermal destruction

Methane will be burned together with other gas


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Gas purification and recovery

Separation of methane from carbon dioxide

Physical adsorption, chemical adsorption or membrane

separation method

Selection of Landfill Cover


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Selection of Landfill Cover

Configuration The use of geo-membrane liner as a barrier layer is favored by

most landfill designers to limit the entry of surface water & to

control the release of landfill gases

The specific cover configuration selected will depend on the

location of the landfill & the climatalogical conditions. To ensure the rapid removal of rainfall from the completed

landfill & to avoid the formation of puddles, the final cover

should have a slope of about 3% to 5%.


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Public Health and Safety

Health and safety of workers

The federal government through OSHA regulation & states

through OSHA-type programs have established requirements for

a comprehensive health & safety program for the workers at

landfill site.

Attention must be given to the type of protective clothing &

boots, air-filtering head gear & punctureproof gloves supplied to

the workers

Safety of the public

the use of a convenience transfer station at the landfill site, tominimize the public contact with the working operations of the

landfill is gaining in popularity

Landfill Closure and


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Landfill Closure and

Postclosure Care Development of long-term closure plan

Postclosure care

Development of Long Term


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Development of Long Term

Closure Plan Cover and landscape design

Control of landfill gases

Collection and treatment of leachate

Environmental monitoring system


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Post Closure Care

Routine inspection

Infrastructure maintainance

Environmental monitoring system


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disposal of solid waste

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