ADDIS ABABA SCIENCE & TECHNOLOGY UNIVERSITY

1. Hayleab tesfaye cde 0092/052. Lakew mengistu cde 0105/053. Dereje kuma cde 4. Kemal a/kadir cde5. Dereje seman cde6. Ayichew cde7. alemayehu

Effect of Landfill on the enviroment

ENGINEERING FOUNDATION ASSIGNMENT ON :-

Prepared By:

Class – A

Since there is a rapid increase in the average trash produced by a human being per day, it results in a huge amount of additive increase in trash at a international level.

Where Does our Trash Go?

31% Recycled69% Land filled

After recycling!

32%

14%12%

6%

9%

9%

6%

12%PaperYard WastePlasticsWoodMetalsFood WasteGlassOther

Total 151.9 million tons of trash per year

What is a trash?Trash is a rubbish people throw away

because they can no longer use it.Trash can be household, commercial or

industrial.There can be variations in the trash

produced depending on the consumption.

These huge sums of trash cannot be kept in open.

They increase toxicity of the environment and there will be no fresh air to breathe.

It promotes increase of parasites and give birth to many diseases.

So to dispose of these wastes various waste disposal techniques are used.

Of all the techniques, efficient ones are

Landfill Sites

What is a landfill site?A landfill site is a licensed facility where waste is

deposited for permanent disposal. It is a structured place

Whereas, a dumping site is a site same as a landfill but it is not properly structured.

Probably it is a hole or a pit where waste is over thrown.

A Landfill Cell

Tractors Compact Waste to Create Layers in a Landfill Cell

The goal of a landfill is to cover it, isolate it, and keep it from contaminating our air and

groundwater.

Problems the Landfill sites poseGroundwater ContaminationProduction of Landfill Gas Landfill firesOffensive odoursLitterPests (Vermin, seagulls, flies)Increased traffic for duration of infillingLong term settlement after completion

Groundwater ContaminationGroundwater contamination can occur if

Leachate leaks into the soils and rock surrounding a landfill site, eventually making its way to the water table.

Leachate is formed when water percolates through solid waste.

It can be highly toxic.

Landfill Gas

Landfill gas is produced during the natural breakdown of biodegradable waste.

The composition of landfill gas changes over time.

The gas from a typical landfill site consists mostly of methane and carbon dioxide.

Landfill fires

As waste decomposes it generates heat and underground fires may start.

These are difficult to extinguish, may last for long periods, and may spread throughout the landfill.

How are landfills made

Landfill DesignModern landfills are designed to minimise these

problems:◦ Location◦ Landfill Liner◦ Compaction of waste◦ Daily Cover ◦ Landfill Cap◦ Leachate Management System◦ Landfill Gas management System

Location In order to obtain a permit a landfill operator must first carry out a

detailed investigation and prove to the satisfaction of the planning authority and the EA that the site: ◦ is located in a geologically stable area◦ is not located on a major aquifer;◦ Is not located in a vulnerable area;◦ is designed to reduce the risk of damage to the environment and

human health;◦ will be monitored regularly for the duration of operations and

aftercare period.

Liners Landfill Liners are constructed on the base and sides of a landfill

site to prevent Leachate from leaking into the surrounding soils. Landfill Liners may be constructed from:

◦ Compacted Clay◦ Bentonite Enhanced Sand◦ Geomembrane◦ Geotextile Protector◦ Dense Asphaltic Concrete (DAC)◦ Combination of the above

How is Landfill operated

Waste is placed in layers approximately 3 m thick and compacted.

At the end of each working day approximately 0.3 m of clay or sand material is placed on top of the waste to:◦ minimise the infiltration of rainwater◦isolate the waste from birds and vermin◦reduce odours

Landfill operations

Landfill operations

To prevent wastage and the formation of layers of weakness within the waste mass the daily cover is scraped off and re-used each day.

Leachate that collects at the base of the waste mass is collected and re-circulated into the waste. This:◦increases the rate of decomposition of the waste and

therefore, rate of settlement;◦decreases disposal costs.

LANDFILL CAP• Landfill caps placed above the waste

after completion of infilling prevent the infiltration of rainwater, minimising the production of Leachate.

• Landfill Caps are usually constructed from:– Recomputed clay– Geomembrane

Leachate management systems

Leachate management systems are installed to:◦prevent the accumulation of leachate in the base of

the landfill ◦collect, re-circulate and dispose of leachate during

operations and after closureThey comprise of:

◦ leachate drainage blanket at base of landfill◦pipes along base and sidewalls of landfill◦wells to monitor and extract the leachate

Landfill gas management systemLandfill gas management systems are installed

to prevent the build up of gases within the landfill and to prevent migration of landfill gas through the underlying strata.

There are 2 ways landfill gas can be managed:◦passive◦active

Passive management systems comprise of wells with perforated tops to allow the gas to vent into the atmosphere

Active management systems involve the active extraction of the gas.

The extracted gas can be used to generate electricity.

Electricity generating

system

MonitoringMonitoring is carried out before, during, and after the

placement of waste.Numerous monitoring wells are constructed around a

landfill site (both upstream and downstream) to check for contamination.

Chemical testing is carried out regularly on: ◦Groundwater ◦Leachate◦Landfill Gas

Conclusion

Hence we conclude that landfill sites are not very pleasant and common to visit, but they help use to

reduce the negative effects caused by wastes

generated by humans.

Thanking you