MEETING THE CHALLENGE LANDFILL IN SAMOA

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1 MEETING THE CHALLENGE LANDFILL IN SAMOA Ellen Blake Bruce Chapman Programme manager Pacific Futures, SPREP Abstract Landfills are usually a community asset that are unpleasant to visit and not much of a tourist attraction. The Tafaigata landfill in Samoa provides a contrast, in that it is operating well with no evidence of odour or litter. The landfill, which caters for the whole of Upolu island, has been upgraded using the Fukuoka method (semi-aerobic landfill method) developed by Japanese researchers. The Fukuoka method involves careful monitoring and placement of rubbish in a landfill designed to maintain the bioreactor at optimum functioning. This paper describes the particular conditions the landfill operates under and some advantages of the Fukuoka method in terms of cost effectiveness and environmental benefits (including reduced emissions of greenhouse gases). The Tafaigata landfill is supported with development assistance and offers an encouraging model to other small and not so small islands on how to run an effective and appropriate waste disposal facility. Introduction Final waste disposal has been an increasing issue in the last 60 years as the range and nature of goods available has increased along with population and per capita waste produced. These factors, coupled with the limited areas available for waste disposal and the NIMBY phenomenon, mean that there are some real challenges common to both developed and less developed nations. Most countries opt for some type of bioreactor landfill as part of their waste disposal strategy, as is the case in Japan where this particular semi-aerobic landfill method was developed. The method has proven so successful that most sites in Japan now use it, and it was also found to be a good cost-effective model for less developed nations to follow. The reason it has been so successful is that it is a simple, relatively easy system to operate, it has advantages over anaerobic systems, it is cost effective, and is able to use local materials in its construction. In short a system that can be used successfully anywhere in the world. This paper outlines the Fukuoka semi-aerobic landfill method and its application in Samoa. 1

Fukuoka semi aerobic landfill method This semi-aerobic landfill method was developed in Fukuoka city by the local university and city council in the 1970s as a response to familiar problems of open

2 Fukuoka semi aerobic landfill method This semi-aerobic landfill method was developed in Fukuoka city by the local university and city council in the 1970s as a response to familiar problems of open dumping and lack of disposal space. Several pilot projects were run to determine the nature of the processes within landfills and the most effective system of landfill. The most common type of landfill is anaerobic. As waste is deposited in layers and leachate accumulates at the bottom of the pile, biochemical processes rapidly use all the oxygen available creating anaerobic conditions, releasing in particular methane and the distinctive smells of volatile organic compounds. The Fukuoka team discovered that they could maintain aerobic processes if they introduced air back into the waste layers (initially by pumping it in) promoting aerobic microbial degradation with heat generation of around 50-70C. They found they could maintain these processes if they allowed the leachate to flow away quickly through an inclined perforated pipe, and the convection current, created by the warm waste pile, to passively draw air back through the same leachate pipes and disperse air through the waste pile. Diagram 1: Comparison of conventional and semi-aerobic landfill systems Conventional Semi-aerobic There are many advantages to using the semi-aerobic landfill method over an anaerobic system, including: rapid draining of leachate achieved by gravity (not pumps) leads to increased circulation of air and promotion of aerobic microbial decomposition rapid decomposition of organic component of wastes (most occurs in first 3 years) leads to early stabilisation of landfill and ability to use for other purposes less pressure on landfill lining from leachate therefore less chance of seepage gases designed to escape therefore less chance of build-up of dangerous gas pockets 2

3 use of crushed rock around leachate pipes adds to strength of pipe, easy ingress of leachate and egress of air through pipes relatively easy to maintain and operate no smell therefore increased community acceptance the quality of leachate improves significantly and rapidly, helping to reduce costs for secondary treatment. the technology is cost-effective and simple to construct and operate. There is flexibility in selection of materials and pipes so that local materials can be used the overall effectiveness depends on the continuous monitoring of various performance parameters. The monitoring aids understanding of what it takes to achieve a given environmental standard in final waste management, thereby laying a sound foundation for future upgrading and improvement. One of the key advantages of the semi-aerobic method is the significant reduction in greenhouse gas emissions. Diagram 2: Comparison of methane and carbon dioxide emissions from anaerobic and semi-aerobic conditions 3

4 The emission of greenhouse gases from semi-aerobic landfills is calculated as 54% smaller than for anaerobic types (Tashiro, 2005, JICA/SPREP). This semi aerobic landfill method has been promoted as part of Japanese aid packages to other countries through the Japan International Cooperation Agency (JICA) and the UN-HABITAT programme, including to Malaysia, Iran, Guangzhou and Weifang cities in China. Samoa Samoa has a population of 180,000 most of whom live on Upolu, one of the two large islands. It has until recently been classed by the UN as a least developed country and was therefore able to receive the highest levels of development aid. Japan has provided aid for many different infrastructure projects, the landfill being one. The landfill development was set up as part of a tripartite project between JICA, the government of Samoa and the Secretariat of the Pacific Regional Environment Programme (SPREP). The project overall aims to improve waste management practices in Pacific island countries through training/capacity building, producing regional and national waste plans, and demonstrating the use of the Fukuoka method as a cost-effective disposal option. JICA support is provided through deployment of a landfill expert on site in Samoa over a six year period to oversee the redevelopment and train local staff. The Tafaigata landfill serves the whole island of Upolu. A rubbish collection system operates with twice weekly household gate collection around the Apia area and once weekly around the rest of the island. This is let to contractors. There is also one landfill serving the other main island of Savaii which is being redeveloped along similar lines as Tafaigata. Tafaigata landfill development The Tafaigata landfill had been an open dump site for many years before this project began with all the concomitant problems. It was decided for the obvious reasons to redevelop the existing site in preference to finding a new site. The landfill receives on average 4-5 truck loads of rubbish a day. It is not open to the public. The redevelopment took place in two phases from 2002 to The first phase was the redevelopment of the existing dump into a proper sanitary site with waste cell spaces, leachate and storm water collection. The later phase was the development of a leachate treatment system. 4

Photo 1: Tafaigata landfill - the existing site 2002 Phase 1 Site redevelopment The basic engineering saw the access road upgraded to allow all weather access which also stopped roadside dumping.

5 Photo 1: Tafaigata landfill - the existing site 2002 Phase 1 Site redevelopment The basic engineering saw the access road upgraded to allow all weather access which also stopped roadside dumping. The old rubbish, covered in dirt, was used to build the bund walls to contain the new waste and the floor was rolled and compacted to minimise any leachate leaking into the ground. The Fukuoka method uses over-size leachate pipes to allow oxygen into the waste pile through passive ventilation. This requires that the waste pile be higher than the outlet for the leachate into the collection pond. The decomposing organic wastes give off warm carbon dioxide which passively draws the cooler oxygen-rich air through the pipes into the base of the waste. Following the construction of the bund walls, further work involved a gatehouse, office, and establishment of recycling areas. 5

6 Diagram 3: Fukuoka semi-aerobic landfill leachate flow (Tashiro, 2005, JICA/SPREP) Blue pipes air-leachate pipe outlet always open Yellow pipes gas venting pipe Photo 2: Tafaigata landfill phase 1 development 6

Phase 2 Leachate treatment system The leachate treatment system consists of a collection pond with piping to recirculate leachate through the trickle filter beds and then back to the pond where it is

7 Phase 2 Leachate treatment system The leachate treatment system consists of a collection pond with piping to recirculate leachate through the trickle filter beds and then back to the pond where it is aerated. The leachate is monitored at this stage and when it has reached certain parameters it is able to be discharged through the discharge line via gravel beds, coral filters and into a wetland system using local plant varieties. The final water reservoir is intended to house fish as a final check on discharge quality but these have not so far been successful. Diagram 4: Leachate treatment system This treatment system is able to be relatively simple as the leachate from a semiaerobic landfill is more dilute and weaker in COD and BOD. The leachate collection pond was connected to a re-circulating trickling filter and then through a series of biological treatment stages and acidity neutralisation. The final result is discharged to an absorption zone where most is transpired by plants or evaporated. Staff training At the same time as the landfill was being redeveloped twelve local staff members were trained to run the landfill operation. Through a series of workshops, some conducted in Japan, staff learned every aspect of landfill management. This included proper compaction of the waste using a bulldozer (shared with the road making department) and monitoring of leachate. 7

8 Landfill cost The cost of redeveloping the landfill was just over US$400,000 including the peripheral works such as the access road and gatehouse complex, but not land acquisition, capital equipment such as the bulldozer nor Japanese expert supervisors. Lack of synthetic liners to the landfill also contributed to the comparative cheap cost. Technology transfer The redevelopment of the Tafaigata landfill transformed an open dump into a wellmanaged landfill using simple cost-effective technology. The landfill quickly became recognised as a model for developing countries in the Pacific. The Samoan government recognised the benefits of the design and undertook to build a Fukuoka method landfill on the island of Savaii at its own cost (i.e. without financial support from JICA or other aid agencies). Current situation Despite this success story the importance of strong institutional support, management structure and human resources can not be understated. Our last site visit in June 2008, revealed an inoperative leachate treatment system (it is designed to run continuously), no bulldozer available for compaction, poorly placed and rapidly filling sixth waste cell, scavengers, and dogs. A bare month after our visit a large fire swept through the last unconsolidated cell of waste The decline in operating conditions appears due to changes in staff (one trained person who had taken up the task of running the landfill with skill and enthusiasm left the position), and lack of sufficient resources dedicated to operating the landfill. Future Should the landfill operation be able to be rectified (which is technically possible according to a 2008 JICA report, E Blake, pers com) this landfill can be successfully operated for years with the ability to extend on top of the existing cells. Conclusion The Tafaigata landfill example shows that the Fukuoka method can be used to rapidly redevelop existing sites in difficult circumstances. Yet despite a well planned development package there are still extraneous factors that can disrupt its smooth operation. 8

9 The Fukuoka semi-aerobic landfill method is an effective system for landfilling waste which could be applied in New Zealand as well as in other countries. It is a well researched method that reduces negative environmental effects, removes some of the objections of community (smell and leachate discharge quality) and yet doesn t seem to cost too much. References Institute for Global Environmental Strategies,?2000, Fukuoka city Mark Ricketts, 2006, Samoa s Tafaigata landfill rehabilitation project in action SPREP Prof Matsufuji Yasushi, Fukuoka university Semiaerobic landfill system (Fukuoka method) attracts the attention of the world Tashiro Takeo, 2005, What is Fukuoka method a case of Tafaigata landfill SPREP Tashiro Takeo, 2004, Solid waste management and global warming SPREP Tashiro.pdf Special thanks to Frank Griffin, SPREP and Shiro Amano, JICA 9

COST ANALYSIS OF THE FUKUOKA METHOD LANDFILL SYSTEM IN NORTH KOLAKA REGENCY, SOUTHEAST SULAWESI, INDONESIA

COST ANALYSIS OF THE FUKUOKA METHOD LANDFILL SYSTEM IN NORTH KOLAKA REGENCY, SOUTHEAST SULAWESI, INDONESIA Irwan Ridwan Rahim 1, Abdulrahman Jamaluddin 1, 1 Hasanuddin University, Faculty of Engineering,