Tafaigata Landfill Rehabilitation Project

1. Overview

The Tafaigata landfill has been transformed using the Fukuoka method (Semi-Aerobic Landfill Structure) funded by JICA (Japan International Corporation Agency)

The 1st phase is complete and includes the setting up of leachate collection pipes, leachate collection pond, and boundaries (see Pic. 1, 2).

The 2nd phase includes the setting up of Leachate Treatment Facilities (see Fig.1)
Pic.1 April 2005

Pic.2 Leachate collection and gas venting pipe
Fig.1 Draft of Leachate Treatment Facilities
2. What is the Fukuoka Method ?

Fig.2 Anaerobic Landfill structure (Conventional type) Tafaigata landfill before 2003




Condition
Fig.3 Semi-Aerobic Landfill structure (Fukuoka Method)
Tafaigata landfill from 2003 onwards
Leachate adjustment pond
      l
Treatment Facility
Rubbish dumped on the ground or in a hole stagnates with leachate in an anaerobic condition.

Characteristics
1. Emits an offensive odor and dirty leachate.
2. Aggravates Global Warming through the generation of Methane gas (CH4 )
3. CH4 Gas has a 21 times stronger effect than Carbon Dioxide (CO2)
4. Long term decomposition is required under anaerobic conditions before land can be reused.



Function

Leachate collection and gas venting pipes are set up, which provide fresh air automatically into the rubbish layer using convection effect of heat generated by fermentation in the rubbish.

Characteristics
1. Less smell and cleaner leachate than conventional landfill
2. Generation of Methane gas (CH4) is low and thus effective for prevention of Global Warming
3. Fast stabilization and easy maintenance
4. Cost effective using local materials such as bamboo, waste tyres, waste drums for pipes ( see Pic.2,3)

Local materials can be used for leachate collection pipes such as bamboo, waste tyres, etc

Pic .3 using bamboo / China

Pic .4 using waste tyres / Mexico

Pic .5 Nakata landfill / Japan
Fukuoka Method is the standard method of landfill in Japan
3. Leachate Treatment System>
@ Circulation
Outline of Treatment System

Tafaigata Leachate Treatment Facility will mainly be set up employing natural cleansing methods/effects such as Gravel-bed Channels, Compact Wet Land, Biotope, etc.. This Eco-friendly system also requires less energy for operation and minimum maintenance.
@ Circulation Treatment
Circulation treatment (Ci) is a leachate treatment system combining Trickling filters (TF) with the leachate collection pipe. TF is an aerobic treatment system that utilizes microorganisms attached to a medium to remove organic matter from wastewater. Leachate from the Leachate Collection Pond is sprinkled to a TF surrounding a Gas ventilation pipe ,and runs back to the Leachate Collection Pond again. By repeating this process, organic matter is gradually removed.
Fig.5 Circulation Treatment
Fig. 6 Top view of Trickling Filter
Fig. 7 Cross Section of Trickling Filter
A Aeration
Aeration provides oxygen for microorganisms to decompose organic matter in water.
B Gravel-bed Channel
The Gravel-bed Channel is one of the natural cleansing methods, using aquatic organisms attached to the surface of gravel. When water flows between gravel, aquatic organisms decompose and absorb the pollutants.

Pic.8 Aerator
C Filtration
Local materials such as coral sand and coconut husk activated carbon will be used as filters to remove heavy metals and organic compounds in the leachate.
D Compact Wet Land
Compact wet land is another natural cleansing method as well using aquatic vegetation such as reed, which removes Phosphorous and Nitrogen, so called eutrophication substances.

Pic.9 Compact Wet Land
E Biotope Natural vegetation shall be used as one of the treatments.
A Biotope also conserves the natural Ecosystem.

Pic.10 Image of biotope 1

Pic.11 Image of biotope 2
Takeo Tashiro Program Officer for Solid Waste & Landfill Management, SPREP E-mail Takeo@sprep.org