REHABILITATION OF SAIDA DUMPSITE

Traditionally a landfi ll’s construction involves large quantities of natural materials such as clay (waterproofi ng), gravel (drainage) and sand (fi lter and separation). These materials are scarce in the environment and are diffi cult, expensive and slow to place, especially on slopes. In the rehabilitation of Saida’s dumpsite (Lebanon), discussed in this case study, the fi nal design was based on the placement of a drainage geosynthetic for leachate collection and a geomembrane for waterproofi ng.

For over two decades geosynthetics manufactured by Intermas Nets have been used in landfi lls (new landfi lls and cappings) with great success around the world due to their many advantages over natural elements:

Geosynthetic’s reduced thicknesses allow a greater volume of operation of the Landfi ll.

They can be installed in steep slopes.

Due to their low weight they signifi cantly reduce surcharge on waste.

Waterproofi ng and fl ow capacities are homogeneous as they are industrial products.

Comfortable, quick and easy to install and they require no heavy equipment.

They are a better solution for the environment, constituted by safe, non-polluting and recyclable materials.

TABLE 1. REHABILITATION OF SAIDA DUMPSITE DATASHEET

JOB: REHABILITATION OF SAIDA DUMPSITE

COUNTRY: LEBANON

CLIENT: AL-JIHAD FOR COMMERCE & CONTRACTING

PRODUCTS: INTERDRAIN GMG 512

MANUFACTURER: INTERMAS NETS, SA AND JUTA A.S.

CONSTRUCTOR: AL-JIHAD FOR COMMERCE & CONTRACTING

INSTALLER: GLOBAL INTERNATIONAL ENVIRONMENTAL COMPANY

REHABILITATION OF SAIDA DUMPSITE

SCOPESaida dumpsite is located in the southern part of the city of Saida, at the sea front, only 200 meters from nearby residences and commercial units. The city urban areas are closely surrounding the landfill site at a distance of several hundred meters.Managed by the Municipality of Saida, the dumpsite used to receive, until its closure for rehabilitation in 2013, about 300 tons of solid waste per day from 15 municipalities (approximately 250,000 people). The waste mountain covers an area of 60,000m! and it used to be an enduring eyesore and health threat to local residents and tourists. The environmental repercussions were severe; occupational hazards related to incoming health care waste, recurring waste slides into the Mediterranean Sea, and stench which invited countless complaints from local fishermen and residents, in addition to official complaints from the neighbouring island of Cyprus. The Dumpsite had no basal lining barrier and no leachate collection system.

SOLUTIONThis rehabilitation project, promoted by the United Nations Development Programme, aims to solve an environmentally unacceptable situation and to use the land again for the benefit of the Saida municipality. The procedure of the rehabilitation is “Landfill Mining” which includes a treatment of excavated waste at site to produce secondary construction material complying with local and EU standards.The landfill’s design includes the use of drainage geocomposites for:

Leachate collection in the new cell of the landfill (base and slopes).

Rainwater drainage in the capping of the landfill (base and slopes).

As well, the design includes geomembrane for waterproofing in the new cell and the capping.

TABLE 2. MATERIALS, THICKNESSES AND FUNCTIONS OF THE DIFFERENT CAPPING LAYERS IN THE REHABILITATION OF SAIDA DUMPSITE

Waste 32 m - -

Soil 20 cm - Regularization and protection

Drainage Geocomposite 1 cm INTERDRAIN GMG 512

HDPE Geocomposite 1 cm Junifol PEHD

Natural Clay - - Waterproofing. Natural clay layer

MATERIAL THICKNESS PRODUCT FUNCTION

Filter+Drainage (leachate)+ Waterproofing. Protection.

Collects leachate

Waterproofing. Prevents leachate to infiltrate in the

ecosystem

REHABILITATION OF SAIDA DUMPSITE

WaterproofingThe landfill’s waterproofing was carried by placing a high density polyethylene geomembrane manufactured by Juta as. Junifol PEHD is a 1.5 mm geosynthetic geomembrane commonly used in waste storage and disposal sites. This geomembrane is smooth in the flat areas and texturized in the slopes to increase stability.Junifol’s main characteristics are:

Guarantees full waterproofing of the new cell.

Rolls available in widths up to 8 m.

Stabilized against UV radiation.

Withstands the effects of chemicals, acid, alkaline and salt solutions and are not affected by mildew and micro-organisms.

USED PRODUCTS

Leachate collection and rainwater drainageINTERDRAIN GMG 512, a product manufactured by Intermas Nets, was placed as a leachate collection layer (base and slopes of the landfill) and rainwater drainage layer (capping of the landfill). It is constituted by a high density polyethylene (HDPE) geonet and 2 polypropylene (PP) geotextiles heat-bonded to the net. The geonet is formed by two over-crossed strands at 60º, whose geometry creates channels with high flow capacities even under high pressures and at very low gradients (placed almost horizontally).

The geonet’s main function is drainage while the geotextile acts as waterproofing protection, filter element and fine particle anti-pollutant. The main reasons why INTERDRAIN GMG 512 was selected are:

High flow capacity.

High tensile and crush resistance which allow usual construction loads (vehicle traffic, compacting process, tensions due to land disposal, etc) without any damage in the product.

Excellent creep and fatigue behavior that guarantees a long-term drainage solution.

Durability. PP and HDPE are chemically inert, imperishable and not sensitive to saline water or microorganisms.

TABLE 3. INTERDRAIN GMG 512 MAIN CHARACTERISTICS

Mass per unit area g/cm2 890 ISO 9864

Thickness at 2 kPa/200 kPa mm 5,8/5,2 ISO 9863-1

Peak tensile strenght MD/CD kN/m 20/17 ISO 10319

Elongation at break, MC/CD % 40/50 ISO 10319

Flow capacity (MD, i=1, H/H) - - -

s=20 kPa l/sec·m 1,16 ISO 12958

s=50 kPa l/sec·m 1,03 ISO 12958

s=200 kPa l/sec·m 0,74 ISO 12958

s=400 kPa l/sec·m 0,48 ISO 12958

Geotextile opening size mm 170 ISO 12956

PROPERTY UNIT INTERDRAIN GMG 512 STANDARD

REHABILITATION OF SAIDA DUMPSITE

INSTALLATION PROCESSThe steps followed in the installation process were:

Installation of Junifol PEHD geomembrane. In general, seams must be oriented parallel to the line of the maximum slope. The membrane must be overlapped prior to seaming to affect a good weld and allow for proper testing with a minimum overlap of 7.5 cm.

Placement of INTERDRAIN GMG 512 for leachate drainage. In case of adverse climate conditions (wind) it is convenient to join the geotextiles with a hot-air gun to prevent lifting. Minimum geotextile overlap is 10 cm.

Extension and compaction of a soil layer for regularization and protection of the geosynthetic package. This soil layer covered INTERDRAIN immediately after its installation, avoiding possible problems with adverse climate conditions (wind).

Waste disposal in the rehabilitated cell.

TABLE 4. JUNIFOL HDPE 1.5 MAIN CHARACTERISTICS

Density g/cm3 0.94 EN ISO 1183

Thickness mm 1.5 EN 1849-2

Surface - -

Permeability to liquids m3/(m2·d) EN 14150

Tensile strenght (MD/CD) N/mm2 30/30

Elongation % 800/800

Puncture resistance kN 4.5 EN ISO 12236

Tear strength N/mm 140 ISO 34-1

PROPERTY UNIT JUNIFOL PEHD STANDARD

Smooth (base)Texturized (slopes)

EN ISO 527-1,3Specimen Type 5

U= 1.75·10-6

D= 1.66·10-6

REHABILITATION OF SAIDA DUMPSITE

CONCLUSIONSDrainage geocomposites manufactured by Intermas Nets and geomembranes manufactured by Juta guarantee all the important characteristics in landfi ll rehabilitation:

Complete waterproofi ng.

Rainwater drainage.

Leachate drainage.

Long-term performance of the landfi ll.

The use of geosynthetic products in this project certifi es:

The use of INTERDRAIN drainage geocomposite and Junifol PEHD waterproofi ng is suitable for their application in new cells of landfi lls.

Geosynthetic installation is fast, easy and economic.

INTERDRAIN’s fl ow capacities and Junifol PEHD’s waterproofi ng capacities are reliable,homogeneous (industrial products) and can substitute gravel and clay layers respectively (products with heterogeneous characteristics).

Geosynthetics usage in landfills is a better environmental option because PP and HDPE are non-polluting products and 100% recyclable. On the other hand, large quantities of natural materials are needed, which are scarce elements in nature and whose extraction creates a great environmental impact.