1

Report

Biogas Plant Construction Training

Amatuku Alofa Tuvalu Renewable Energy Training Center

April to May 2007

by:

Sikeli B Raisuqe Ministry of Agriculture

Fiji Islands

2

Acknowledgement

It is a great pleasure to be given the opportunity to work with South Pacific Applied Geo science Commission (SOPAC) on the construction of Bio Digester plant on the Island of Tuvalu as part of the Alofa Tuvalu’s renewable energy demonstration and training center project. . I would like to thank Mr. Anare Matakiviti of SOPAC, the members of Alofa Tuvalu consultation team of Gilliane LeGalic, Mr.Chris Horner and Dr Sarah Hemstock. The assistance from Alpha Pacific in Tuvalu Mr. Eti Esela and Capt. John Hensford coordinators for the project, as well as the TMTI staffs and trainees, is very much appreciated for their support in moving all materials from Suva to the site. The trainee or construction team of Mr. Gabriel Aiemea from Ministry of Energy Solomon, Mr. Ipati, Manato and Utala from TMTI. The staffs and students of Tuvalu Maritime school with chief officer Mr. Leota and Mr.Puga for their assistance, hospitality and consideration in hosting the project.

3

Table of Content

EXECUTIVE SUMMARY ......................................................................................4

1.0 INTRODUCTION........................................................................................5

2.0 BACKGROUND.........................................................................................6

3.0 WHAT IS BIOGAS?...................................................................................7

3.1 Construction terms for bio plant or biodigester (refer to annex 1)......7

4.0 AMATUKU BIO-DIGESTER ......................................................................8

5.0 PROJECT STRUCTURAL ACTIVITIES ....................................................8

6.0 TRAINEE .................................................................................................15

7.0 WORKSHOPS .........................................................................................15

8.0 LESSONS LEARN...................................................................................16

9.0 CONCLUSION. ........................................................................................16

4

Executive Summary Tuvalu is at the crossroad of 2 issues, each with major strategic implications: climate change and worldwide oil crises. Not to mention the impact of trash on soil and waters. The nation’s economy is almost totally dependant on oil and only approx. 18% comes from local biomass. On the other hand, the 9 islands don’t have efficient septic systems and raise 12000 pigs which having an impacted on soil and water pollution. The Alofa Tuvalu’s Small is Beautiful program’s objective is to help Tuvalu become more oil independent. The first implementation of the plan is a life size RET’s demonstration and training center to give Tuvaluans the keys to sustainable RET’s and waste management development taking into consideration the specificities of the country. Its first focus is biomass energies using pig manure and human waste for biogas The April/May mission’s goal was to construct and train on the first digester ever built on a coral island, an 8m3 digester running from the manure of 40-50 pigs. As of June 2007 four (4) people have been fully trained in the construction of biogas digesters. Four (4) workshops on construction, operation & maintenance have been held with a total number of 198 attendees, of which around 60% were women and 10% were selected TMTI students. A first trip in August 2006 gave the opportunity to see the site and discuss the issues with civil engineer and architects. Although many professionals were pessimistic about the chances to dig into a coral soil without heavy equipment, the Tuvaluan team managed to dig to the rock, at around 1.3m. However, this was not enough to host an 8m3 digester. For the digester to work .we have to dig through coral rock using electrical drill for the first week to lower the level of the piggery. It took us five (5) weeks to complete the actual structural activity of the bio digester from digging, lying of the first brick and the closing of the bio plant. On the first day of work the trench dug was not as discussed previously. If we were to start the work from day one then three quarter (3/4) of the digester will be on top of the ground and the piggery floor would be 1.6 meters above ground. For the digester to work .we have to dig through coral rock using electrical drill for the first week to lower the level of the piggery. After five days of digging we managed to reach a reasonable depth but still short of the 2 meters required. We have to dig through coral rocks to reduce the height of the floor of the piggery as well as to put at least 70% of the digester under ground. The bio digester works on gravitational forces so we have to work in such a way that we do not use any electrical equipment either for collecting water or pumping waste in to the bio digester. It has been proven in other places that the use of such equipment will not last (as the case of a project on Funafuti) Time was running against us through out the operation phase because of the extra digging, the king tide, the unpredictable weather pattern, the usual worker missing work and the occasional missing of the daily transport contributed to the five weeks taken to complete the work.

5

Manato and Gabriel digging the foundation for the digester

ki d illi

The contribution of all stake holders made the operation run smoothly from redelivering of materials to planning of workshops, transportation of workers and the construction team was very much appreciated for the completion of the project. . We started with four trainees, one from the Solomon Islands and three (3) from Tuvalu who completed the work of bio digester construction, but the contribution of Amatukus Maritime students and staffs assisted the project.

1.0 Introduction. SOPAC has been assisting all its member countries in the development of their energy policy framework through the Government of Denmark funded project called the “Pacific Islands Energy Policy and Strategic Action Planning” or PIEPSAP in short. From the PIEPSAP experience, it is clear that Pacific Island Countries (PICs) are more and more aware that their heavy reliance on imported fossil fuels has been a great burden on their economies. Their dependence is exacerbated by the escalating fuel price which most countries are struggling to sustain with their small economies. The above situation has given pressure to PICs collectively, through regional collaboration and individually, through national development plans to re-look at their energy sector plans and develop appropriate strategies to address this predicament. And many have put in plans to develop locally available energy resources to meet their energy needs. Many PICs are looking at developing their bio-energy resources. Bio-energy resources derived from plants and animals are in abundance in many PICs. While there has been an increasing interest in this area in PICs, the lack of expertise in the countries has been the major barrier to the widespread use of biogas. Under its progarmme PIEPSAP is coordinating a Regional Biogas Construction Training Programme to build the capacity in PICs on biogas construction. It is envisaged that this programme will help promote the wide spread use of biogas in the Pacific region. Fiji is one of the countries that have an established biogas programme. Under this programme the Fiji Government through the Ministry of Agriculture, Sugar and Land

6

Resettlement with the assistance of the Fiji Department of Energy has installed a number of biogas plants in the country in collaboration with piggery and dairy farmers. The Ministry as part of its biogas programme offers training to local carpenters and farmers in the construction and installation of biogas plant.

2.0 Background Today global warming is a reality that could not be treated in isolation and a threat to low-lying nation all over the region. Tuvalu, one of the earth’s tiniest nations, is a South Pacific archipelago of nine atolls with a total land-mass of 26 square kilometers. Tuvalu according to some climate change scientists is also the earth's first sovereign nation faced with becoming totally uninhabitable due to global-warming related flooding within the next fifty (50) years. Its 10,000 citizens are thus threatened with becoming the planet’s first entire nation of environmental refugees. Face with these impending catastrophe one must act now without waiting until this first nation is wiped off the map. This can be achieved by a combination of reduction of greenhouse gas emissions and raising awareness of other sustainable development solutions and initiatives (using some of the tools of the Small Island Beautiful project, participating in campaigns for the application of international directives and by changing individual habits through education). Study of appropriate on-site solutions for local environmental problems. Plan for worst case scenario: identifying a new homeland where the nation of Tuvalu can be resettled, and establishment of an official status for environmental/climatic refugees. . To reverse current trends and avert disaster in Tuvalu and the rest of the world, immediate action must be taken both locally and globally by governments and average citizens alike. Following the announcement of the seasonal King tides in Tuvalu, the media spoke of the all-too-real risk of inundation. Once the immediate threat was over, the media turned its attentions elsewhere…as if no larger or longer-term problem exists for the country. Today, flooding happens each month of the year at high tides not only at Spring tides. Tuvalu has a School for Seafarers known as Tuvalu Maritime Training Institute (TMTI) which started in the 1980s with forty (40) students at present. The maritime school provides a solid project base while its discipline is stricter than in the rest of Tuvalu, it is that very discipline that will lead this first project “model” to be a success, be accomplished more rapidly and be sustainable after project workers have left. with

7

3.0 What is Biogas? It is believed that biogas was used by the early Babylonians for heating water and the ancient Chinese literature on biogas goes back 2000-3000 years ago. By 1850 the concept of biogas was starting to become better understood and in sewage processing plant was built to create biogas, and this energy was used to illuminate streetlights. Methane was first recognized as having practical and commercial value in England in the 1890s where a special designed septic tank was used to generate gas for the purpose of lighting. The technology as highlighted above has been known in China for a longtime and they have develop various design and size to suite consumers may it be animal waste, human waste, domestic sewage, garbage and organic liquid waste from factories. Biogas, a gas that is derived from the decomposition of waste in a digester offers great potential in meeting the households energy needs, especially for cooking. It is simply the decomposition of Agricultural waste such as Cow dung, Pig manure, Night soil, Bird droppings and Industrial waste to form a gas called –BIOGAS (Methane – CH4). The Biogas can be used for coking, lighting, refrigeration, vehicle running, .generator operation and Food preservative. Processed waste can be used for fertilizer liquid or dry for vegetable farms. It is very high in (NPK) and can be used as fish feed. Methane gas produced by the process has significant energy value as fuel for domestic use. The digested residue is almost odorless homogenous slurry with fertilizing nutrient conserved. Even rats and flies are not attracted to the digestive residue with liquid sludge can be reused for irrigation.

Methane gas produced by the process has significant value as fuel. The dried slurry can be bagged and sold as organic fertilizer for horticulturalist.

3.1 Construction terms for bio plant or biodigester (refer to annex 1) • Radius stick is used to ensure a uniform radius of brick around hemispherical

structure. • Weak Ring-done at the bottom of the main chamber. • Out let pipe through which the digester discharge slurry from the main chamber

is transferred to the expansion chamber.. • Strong Ring-foundation of upper chamber spherical shell use of chicken wire

and 1/4 inch rod to strengthen the digester • Inlet pipe where waste are charged into the main digester chamber from the

mixing chamber. • Neck the portion above the ground. • Lid the inner lid with the outer lid

8

• The gas pipe • Expansion chamber or slurry storage before discharging out to be used as

fertilizer. • Backfill used are sand. • Plastering of inside chamber mix – (2 sand, 1 cement, ¼ lime) use for

putting bricks together with water proffer. • Concrete mix – 4 gravel, 2 sand, 1 cement

4.0 Amatuku Bio-digester The island of Amatuku which is part of the Funafuti lagoon is the site of the bio digester plant project. Two sites were selected for the project. One for human waste and the other for pig waste. After the site was visited last year it was discussed that an 8 cubic meter bio digester to be built because of the number of pigs in the area, about forty (40) in total. The pigs belong to the staff and they will have to look after the feeding and cleaning of the piggery and the digester operation to be discussed by staffs. The biogas digester at Amatuku is an 8 m3 Camartec fixed dome plant. The plan (drawing) of this biogas digester is provided as Annex I. One of the benefits of the bio digester is that it will control the pig discharge which at the moment is drained directly into the sea thus causing a threat to the eco system in years to come as can already be seen in some areas in Funafuti. With this project all the waste from the piggery will be channel in the bio plant. The gas produced by the plant will be used by the staff of the school for cooking. The effluent or discharge from the digester, which is a very good fertilizer, will be used for watering the school garden. All the materials for piggery and digester were procured from Fiji with a cost of F$27,400.00 and transportation cost F$20,900. Materials purchased locally in Tuvalu were valued at AUD $3,500.00.

5.0 Project structural activities . The work lasted for five weeks from re-digging of the trench to the completion of the construction of the bio plant. We checked the digging done previously to ascertain the depth and width of the trench on measurement the trench was too shallow for the construction of the digester. If we were to go ahead with the construction the bottom of the piggery will be about 1.6m above the ground. So we decided to dig a bit more through coral rocks with the use of crowbars, pick axe and later a small electrical drill.

9

a b

Fig 1 (a b) Digging of the trench through coral rock We were to excavate a diameter of 3m x 2 meter deep but after digging and hitting coral rocks we could only manage a depth of 1.8 m and we could not go any deeper because of a lower water table mark.( Fig 2 a, b).

a b Fig 2 a ,b Center of Bio digester plant

During the King Tide occurrence sea water seeped from the bottom of the digester and it was sealed with concrete. Under normal condition the bottom of the digester is not usually sealed. (Fig 3 a, b).

a b

Fig 3 a,b Sea water sipping from under the plant and also sealing done. After reaching a depth of 1.8m the bottom was level, a center was marked and fixed with a rod. A radial stick was cut with a radius of 1.7m. From the centre, we fixed the first layer of bricks using the radial stick. ( Fig .4 a ,4b).

10

a b

Fig 4 the radial stick used to lay the first brick. We continue laying bricks around the circumference of the digester until we reach the 5th layer to insert the outlet pipe. Then the outlet pipe (Fig 5) was laid from the main chamber to the Expansion chamber at an angle of 60° it was packed with concrete on the side to make it stand upright.

Fig 5 outlet pipe put in place

The laying of bricks around the main chamber continued (Fig 6)

a b Fig 6 a,b Laying of bricks continue

until we reach a height of 1.24m with the inlet pipe (Fig7) placed at 45˚ from the center of the dome.

11

a b

Fig 7a,b Tthe inlet pipe and mixing chamber Then a strong ring (Fig 8) was made around the circumference using bricks wrap in chicken wire with 1/4'’ rod around the circumference of the digester with a mixture of concrete pour around to strengthen the ring.(Fig9).

a b

Fig 8 a, b Strong ring with chicken netting.

a b

Fig 9a,b strong ring cover with concrete The inlet pipe was placed about 1.24m from the bottom of the digester which separate the waste digestion area from the gas holding area. After the strong ring we continued laying the bricks using the same radial stick. From here the bricks structure would be curving in side so the need of support to hold the brick in place until it dried off. (Fig10).

12

a Expansion chamber b Main chamber

Fig 10a and 10b - timber support to hold bricks until dry We continue laying bricks around the circumference of the digester until we reach a diameter of 64cm at the top (Fig 11).

a. outlet pipe from main chamber b Puga checks progress

Fig 11 (a,b0 brick laying on both chamber continue Then we start forming the neck (Fig 12 a b ) of the digester with the use of a stick of different diameter from 60cm then 44cm. It was smoothen by the use of the lid of the neck

. a b

Fig 12 forming the neck of the digester

The entire main chamber was plastered using 7 layers of plaster which included throwing of plaster, brushing and plastering using cemestick as last layer. The outside was also plastered using cemestick (Fig 13 a, b).

13

a b

Fig 13 (a.b ) Plastering inside of chamber The expansion chamber (Fig. 14a b) was also constructed using a 1.00m radial stick but after reaching 35cm the radial stick was reduced by 5cm after every brick layer, until the chamber was completed.

a b

Fig 14(a b )Expansion chamber work in progress The outlet pipe was cut just above the bottom of the expansion chamber where slurry will overflow into the chamber. (Fig. 15).

Fig 15 Cutting of outlet pipe for over flow of waste from Main chamber The expansion chamber outlet was fitted with 2 over flowing structure for collecting water to be used for the garden (Fig 16).

14

Fig. 16 Waste collection chamber

After plastering the outside of both chamber the sand was use to back fill the structure for roots not to damage the plant and also reducing the impact in times of earthquake. (Fig 17a,b).

Fig. 17 TMTI students filling sand around the plant. The inner lid was also measured and cut using flat iron as a mould to shape the conical shape of the neck of the digester. It was then filled with cement and two handle using 1/4inch rod for handle (Fig 18a ,b, c.).

Fig 18 Cutting of flat iron and filling the inside lid with concrete On the neck the gas pipe was fixed to carry gas out of the gas chamber to the house for cooking via a Polythine pipe to the gas stove.(Fig 19)

15

Gilliane addressing the workshop participants

Workshop participants at site in Amatuku

Fig 19 The gas pipe on the side of the Neck

6.0 Trainee The project started with four (4) trainees for the first two (2) weeks then it dropped to three (3) when one of the local counterparts was sick .Then Gabriel departs on the third week so we were left with only two trainees. During the fourth week all the local trainees were present so we worked overtime to finish the project. The trainee’s eagerness to learn the skill of biogas plant construction moved them to do extra hours to complete the project. The construction team of Mr. Utala, Manato and Ipati were left with instruction to fill the sand and plastering of neck which was carried out satisfactorily as reported by Dr Sarah.

7.0 Workshops We conducted four workshops. The first was done in Funafuti and the other three on Amatuku at the project site. The first workshop was held on the main land, Funafuti, at the government conference room. The conference was opened by the Home affairs Minister Mr. Uili Televa and Mr. Panapase Nelesoni the Secretary to Parliament (Fig 20a,b,c). The conference was well attended and the Minister for Natural Resources, Mr.

Tavau Teii and former ministers also attended the workshop with 80 participants from various women’s group on the Island and individuals. Participants were briefed on the operation of the Alofa Tuvalu project by Miss Gilliane and I made a presentation on the

biogas operation. The three other workshops were carried out on site at Amatuku and participants were briefed on the progress of construction and the mechanics of the bio digester. They were also told the pros and cons of the digester and how to maintain and operate the digester. An important message was made clear to the participants that seawater and detergents are

16

Governor General visiting the project site

not to be used in the bio digester. All the workshops were well attended by the community and staff of TMTI. The Governor General of Tuvalu, his wife and the Ambassador of the Republic of China Taiwan paid a visit to the project site one afternoon. They showed a lot of interest in the project and expressed their wish that the project could be replicated in other parts of Tuvalu.

8.0 Lessons learn In undertaking this training, I have listed below a number of observations that I feel should be taken into consideration when a future training such as this is planned.

• The site must be visited first before any work is carried out on the bio digester project. The site visit last year (2006) was beneficial as it helped in identifying the location for the biogas digester. The workmen in Amatuku were able to dig the trench well before the construction began;

• The daily commuting from Funafuti to Amatuku usually takes one hour and on a few occasions due of communication problems we were left behind and a special boat had to be sent to pick us up;

• If we were housed on site the above scenario would have been avoided; • All materials should be made ready before construction begins. This would have

enabled a shorter time period (about 4weeks) to complete the construction; • Those with carpentry skills will be suitable as trainees; • In Tuvalu extra hands were needed because of the nature of soil (rocky) for

digging and re-filling; and • Despite all the mishaps that occurred during the construction we managed to

finish the project in good time.

9.0 Conclusion. The danger that hangs over Tuvalu is now a constant one which awaits all the earth’s low-lying lands (and others) if we do not act now it may be too late within the next generation to save the ecosystem. The coral Island of Tuvalu which is about one metre above sea level is an opportunity to test my knowledge and experience in working with other communities. It is the first project done outside Fiji and I once again thank SOPAC for their support and looking forward to working with SOPAC in the next biogas plant project.

17

Annex I

Plan of a Camartec 8 m3 Fixed Dome Biogas Plant

18

Annex II

Material List for the Camartec 8cubic meter Biogas Digester

Material No 1. Bricks 200x100cm 1800 2. Cement 35bags 3. Sand 100bgsload 4. Gravel 60 load 5. Waste/PBC 6” 2 length 6. Ion rod ¼” 10 length 7. Galvanize Pipe 1” C grade 1 length 8. Cemestick(water proffer ) 3x4liters 9. Lime (calcium carbonate) 200kg 10. Polythune Pipe 1 roll /1” 11. Stop cock 2 12. T Joint 1” galv 3 13. Union !” 6 14. Cast Ion Gas burner 1 15. Glue plastic -500g 1 16. Tape 2 17. Reducer 1” ½ galv ’ 2 18. Union nipple 1” 2 :” ½´ -1” 2 19. Stopper 1” 3 20. Chicken netting 15mt Fitting Extra $50.00 Estimated cost $3,500.00