Solid Waste Disposal In Landfill Area

 

 

 

 

 

 

 

Sevgi Tokgöz, Research Asistant,

Dokuz Eylül University,İzmir,Turkey

 

Davut Özdağlar, Assistant Professor Dr.,

Dokuz Eylül University, İzmir,Turkey

 

Ertuğrul Erdin, Professor,

Dokuz Eylül University, İzmir,Turkey

 

 

 

 

 

 

 

 

 

 

 

 

 

Present Situation

 

In Turkey together with many sanitary landfill areas, almost 4000 uncontrolled landfill regions are also present. In order to decrease the number of unsanitary areas and to change some of them to sanitary landfills, studies are continued. Also, at many uncontrolled landfill areas which were closed, studies are done for their final usage.

 

In big cities like İstanbul and İzmir, new projects are prepared for solid waste management strategy applications. These projects include, separate collection of solid wastes, recycling, energy recovery, sanitary landfilling and final landfill quality stages.

 

In Turkey, solid waste management is a rather new idea. Solid Waste Control Regulation, which was prepared depending on Environmental Law (1983), was enacted in 1991.

 

This regulation covers shortly “the main aspects for collecting, carrying, recovering, reusing, disposing of domestic solid wastes, plant wastes, industrial solid wastes having domestic waste properties, domestic wastewater treatment plant sludge, industrial wastewater treatment plant sludge that are not hazardous wastes.”

 

Selection of Solid Waste Landfill Site, Its Capacity

and Construction

 

In landfill site selection, Environmental Impact Assessment studies are done.

 

Depending on the Regulation; the landfill plants constructed to deposit domestic and industrial solid wastes having domestic properties and wastewater treatment plant sludge should not take place.

 

* in protection areas of surface and underground waters used for drinking, process and irrigation purposes,

* in places where flooding risk is high,

* in landslide, avalanche, erosion and earthquake regions.

 

Landfills should not constructed at sites which have less than 1000 m to settlement areas.

 

The maximum capacity of landfills are planned as 10 years for a population less than 100.000 people, and 500.000 m3 for populations more than 100.000 people. In planning, specific waste production is also taken into consideration. For Turkey this value is approximately 1 kg/capita/day.

 

During construction, precausions should be taken in order to prevent mixing of leachate waters with underground waters. For this reason the bottom of the landfill should be at least 1 m higher than the maximum level of underground water. In order to make the bottom impermeable, bottom should be covered with minimum 60 cm pressed clay layer. The permeability of this pressed layer should be minimum 1.10-8 m/s. In rocky sites with a depth of 10 m and with little cracks, this value can be taken as 1.10-7 m/s .

 

Over the bottom which was transformed into an impermeable form, drainage pipes are mounted to collect leachate waters at a certain point. The diameter of the drainage pipes should be minimum 100 mm and their minimum slope must be 1%. Around the drainage pipes 30 cm high sand-gravel filter should be placed.

 

Drainage pipes should not make any curves horizontally or vertically and they should continue till the outside of the landfill area. Leachate waters collected by these drainage pipes should be treated in order to meet discharge limits of Water Pollution Control Regulation .

 

Landfill gas is collected by horizontal and vertical collection lines and given to the atmosphere after being burned. Using landfill gas for energy production is still not applied in Turkey.

 

Properties of Solid Wastes for Landfills

 

With respect to the Regulation, before sending the solid wastes to a landfill their recovery should primarily taken into consideration. If recovery is not possible economically and technically, wastes are processed thermically and biologically in order to protect environmental health, to decrease solid waste volume and partially to obtain energy or compost.

 

But the wastes which are not appropriate for these processes or the by products produced as a result of these processes should be deposited. For this purpose; depending on Municipalities Law Number 1580, in sanitary landfills constructed to deposit domestic wastes the material given below should not be deposited .

 

 

 

* liquids and liquid wastes,

* wastewater treatment sludge (water content more than 65%),

* explosive materials,

* hospital and clinic wastes,

* animal carcasses,

* waste which may cause extensive dust, noise, pollution and odour during deposition,

* radioactive material and wastes,

* hazardous wastes.

 

Composition of Solid Wastes

 

Table 1: İstanbul and İzmir, Weight Percentages of Solid Wastes Compositions

Materials

İSTANBUL

İZMİR

Food wastes

42.2-61.4

45.4-51.0

Paper-cardboard

12.3-25.3

14.1-18.5

Plastic

2.8- 8.2

2.0- 3.7

Glass

0.2- 0.9

1.2- 2.5

Textile

0.0- 6.1

2.1- 6.2

Metal

5.4- 8.2

2.0- 4.7

Ash

5.2-23.2

-

Rock, ceramic

-

15.2-25.6

 

 

 

In Turkey the specific solid waste production is in between 0.5-1.5 kg/capita/day

 

 

İzmir Example in Solid Waste Deposition

 

The first studies, to solve solid waste problem of İzmir started in 1987 by a protocol between İzmir Metropolitan Municipality and Boğazici University.

 

The solid waste strategy decided in the project was recovery and recycle of materials, composting and sanitary landfill.

 

Recently, there were 6 uncontrolled landfill sites in İzmir. Closing these areas and determining their final usage were taken into the content of this project.

 

 

Table 2: The Amount of Solid Wastes in İzmir.

Solid Waste Type

 

Daily Amount

(tons/day)

Yearly Amount

(tons/year )

Domestic

2700

970.000

Industrial

470

170.000

Clinical

20

7.000

Total

3190

1.147.000

 

 

 

Today, 700-800 tons of the total domestic waste amount of 2700 tons/day in İzmir are deposited in a valley owned by government.

 

500 tons/day wastes are taken to Uzundere Composting Plant which began to function in 1988. This plant has a capacity to process 6% of İzmir wastes.

 

The income gained by the materials which are selected from the waste are around 1.5-2.0%, like glass, plastic, paper, and others and by compost do not completely meet the operational costs of the plant.

 

Only 20-25% of the waste coming to this plant is appropriate for composting. Studies are started for optimum operation of this plant. The waste composted at this plant are deposited at the same valley . The wastes other then the ones stated above are deposited at Harmandali sanitary landfill site began to function in 1992.

 

The permeability coefficient of the natural soil of this site is in between Kf=10-7 and 10-10 m/s range. As a result of this natural structure of the soil there was not any need to take any other prevention for impermeability.

 

30-40% of the 90 hectare landfill area is filled with the wastes of the city today. In this landfill area, domestic wastes, hospital wastes and treatment sludge are deposited in separate sites. The area other then these sites has a capacity to meet 10-15 years need of İzmir city.

 

Even though with respect to the Regulation, it is not allowed to deposit hospital wastes together with domestic wastes there are no alternative disposal methods applied in İzmir.

 

 

 

The wastes of 22 hospitals and many clinics, which are around 20 tons, are collected separately in nylon bags as a result of the Hospital Waste Control Regulation enacted in 1991, and they are deposited in separate sites in the plant. These wastes covered by 30 cm lime and then with soil.

In İzmir there are 135 medium and big industries that have totally 470 tons of solid wastes. From this waste 14 tons are domestic type and they are deposited together with other domestic wastes. The other industrial wastes are deposited in a separate area and every day these wastes are covered with soil.

 

Industrial treatment plant sludge are deposited at a separate area as a hazardous wastes. Asbestos wastes are burried in plastic bags and batteries are deposited in 20 liters of drums concrete and they are burried .

 

To collect landfill gas, PVC pipes with 150 mm diameter are placed at the bottom of the area.

 

From the measurements done at the landfill site, the leachate water quantity is determined to be 132 m3/day. Leachate waters are collected at the bottom of the valley and from this point they are pumped to the lagoon at the top of the area. Then, this water is sprayed over the wastes by a sprinkle system and evaporated .

 

Results and Evaluation

 

 

Together with other environmental problems solid waste problem has gained importance in Turkey.

 

Solution of this problem is only possible by, starting with a clean technology to the final deposition quality applying an integrated solid waste management.

 

Similar to the many countries, solid waste management concept is rather weak in Turkey.

 

But since deposition is the first method in solid wastes disposal, constructing sanitary landfill sites is very important. This will also form an important step in reaching integrated solid waste management.