LOWLOW--COSTCOST PLASTIC BIOGAS PLASTIC BIOGAS DIGESTER DIGESTER ININ INTEGRATED INTEGRATED

FARMING FARMING SYSTEMS IN VIETNAMSYSTEMS IN VIETNAM

Vo Lam, Vo Lam, TakeshiTakeshi Watanabe,Watanabe,

Tran Tran Thi Phan Thi Phan & Ly & Ly ThiThi Lien Lien Khai Khai

Funded by Funded by J IRCASJIRCAS

Why have we worked with lowWhy have we worked with low--cost plastic biogas digesters?cost plastic biogas digesters?

•• Livestock production in Mekong delta of Livestock production in Mekong delta of Vietnam is mainly in smallholdersVietnam is mainly in smallholders

•• Plastic biogas digesters can: Plastic biogas digesters can:

–– Control Control pollutionpollution

–– Produce biogas Produce biogas dailydaily

–– Produce a big amount of effluent Produce a big amount of effluent dailydaily

•• Plastic biogas digester technique Plastic biogas digester technique

-- simplesimple

-- easy to easy to adoptadopt

-- supporting for the agricultural supporting for the agricultural production systems production systems (interaction & (interaction & solely play role) solely play role)

•• But:But:

The number of PBD in the area is very The number of PBD in the area is very limitedlimited

may have some constraints to limit the development of the technique

OBJECTIVESOBJECTIVES-- Clarifying the bottleneck of PBD Clarifying the bottleneck of PBD

-- Improving the efficiency of this techniqueImproving the efficiency of this technique

-- Producing biogas from manuresProducing biogas from manures

-- UtilizationUtilization of effluent of effluent tthehe ability of introducing PBD into the ability of introducing PBD into the smallsmall --scalescale IFSIFS

Introduction

• Low cost plastic biodigesters can play role as a sub-component in integrated farming systmes

• More than 30,000 units installed during the past ten years (Khang, 2003)

The number of plastic film biodigesters in year

152

458

9861025 1135

12691624

2149

3335

29212896

3246

3654

0

500

1000

1500

2000

2500

3000

3500

4000

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Number of biodigester s

MethodologyMethodology•• Carried out the researches at the universityCarried out the researches at the university

•• Interviewed the farmersInterviewed the farmers

•• Selected the participant farmers Selected the participant farmers

•• Carried out the technical demonstrationsCarried out the technical demonstrations

•• Monitored gas composition, nitrogen and Monitored gas composition, nitrogen and phosphate concentrations, bacteria in phosphate concentrations, bacteria in effluenteffluent

•• Carried out the Carried out the experimentsexperiments on using effluenton using effluent

•• Organized Workshop with the farmers and transfer Organized Workshop with the farmers and transfer

practical technique practical technique

Results and discussionResults and discussion

Researches at the university•• The suitable ratio of The suitable ratio of

length and diameterlength and diameter

•• Total nitrogen, Total nitrogen, ammonia nitrogen, pH ammonia nitrogen, pH of the effluent from of the effluent from biodigesters with biodigesters with different length : different length : diameter ratiosdiameter ratios

Effluent for cassava forage production

• Cassava can be produced as forage for ruminant

• Cassava plant also produces a lush crop of leaves

• The CP content in cassava foliage ranges from 19-23% of DM

• Cassava forage are regarded as a good protein source for animal feed

• The effects of effluent (slurry)from biodigester on foliage and tuber yields and nutritive value of cassava foliage hadbeen investigated

Fresh and dried weight proportions of cassava foliage applied w ith or w ithout slurry (Khang, 2003)

_____________________________________________________________

Slurry__________________

Proportion (%) Without With SEM p _____________________________________________________________

Fresh proportion Leaf 60.45 61.85 0.44 0.05Petiole 20.46 20.72 0.19 0.53Stem 19.09 17.43 0.52 0.05Dry proportion Leaf 60.14 65.53 0.53 0.001Petiole 20.13 18.39 0.14 0.001Stem 19.75 16.08 0.49 0.001_____________________________________________________________

Introducing PBD Introducing PBD intointo VAC VAC farming sytem modelsfarming sytem models

•• Conversion organic matters Conversion organic matters

•• Increasing productivitiesIncreasing productivities

•• Generating incomeGenerating income

•• Contributing the sustainable Contributing the sustainable development of the farming systemsdevelopment of the farming systems

•• Improving farm and farmer living Improving farm and farmer living conditionsconditions

Integrated FS modelIntegrated FS model Incomes of householdsIncomes of households(Small(Small--scale farms)scale farms)

Goat, local cattleGoat, local cattleRabbit,Rabbit,……

Pig, localPig, localChicken, Chicken,

MuscovyMuscovy ducks,ducks,……

ManuresManures

RiceRiceSugar caneSugar caneCash cropsCash crops

AquacultureAquaculture

Market Market (Market demands)(Market demands)

Income Income

InputsInputsYoung animals,Young animals,

Eggs, meat,..Eggs, meat,..BB****PP

Effluent Effluent

Natural resourcesNatural resources(fishes, forest, (fishes, forest, vegetation,vegetation,……))

Biogas Biogas digesterdigester

Treaments of pig manure in the villagesTreaments of pig manure in the villages

56%

2% 2%

40% fish pond

biogas

com posting

canal

Installation and monitoring Installation and monitoring •• Interviewed with farmersInterviewed with farmers

•• Selected participant farmers:Selected participant farmers:

–– favorable to apply the technique;favorable to apply the technique;

–– dominantly engaged pigs;dominantly engaged pigs;

–– having ability to diffuse the technique;having ability to diffuse the technique;

–– enthusiastically cooperated with the project;enthusiastically cooperated with the project;

–– …………

•• FarmersFarmers ’’ excursions (PBD users)excursions (PBD users)

Introducing PBDIntroducing PBD……(con’d)

•• Demonstration: cost, Demonstration: cost, practices on using and practices on using and management management

•• Workshop with farmers Workshop with farmers

•• TrainingTraining

•• Transfer technology of Transfer technology of lowlow--cost plastic biogas cost plastic biogas digesterdigester

•• Follow up (farmersFollow up (farmers ’’practices and further practices and further supports) supports)

Introducing PBDIntroducing PBD……((concon ’’dd))

•• 44 PBDs were installed44 PBDs were installed into VAC modelsinto VAC models

•• FarmerFarmer ’’s visits (108 farmers)s visits (108 farmers)

•• Training on practical Training on practical technique (49 technique (49 farmers, 11 extention members)farmers, 11 extention members)

•• 14,000,000 VND credit for famers14,000,000 VND credit for famers

•• Costs about 6Costs about 6--700,000 VND (40700,000 VND (40--50USD)50USD)

Development of plastic biogasDevelopment of plastic biogas

33332929111122Hoa an Hoa an

22221818----Dong Dong ThanhThanh

24241414121288T. P. T. P. ThanhThanh

2003200320022002200120012000 2000 Village Village

Matr ix ranking of the constraints and incomeMatr ix ranking of the constraints and income

*********Biogas

************Pigs

**************Fish rear ing

***********Rice

*************Fruit/crops

Income Income Technology Technology Capital Capital Labour Labour Cr iter ia

Chemical and biological Chemical and biological analysisanalysis

•• Gas composition:Gas composition:–– 65:35 (methane and dioxide)65:35 (methane and dioxide)–– 5050--70% methane70% methane–– 3030--40% dioxide40% dioxide–– 55--10% hydrogen10% hydrogen–– 11--2% nitrogen2% nitrogen––Water vapor 0.3%Water vapor 0.3%––Hydrogen sulfate (trace)Hydrogen sulfate (trace)

Ammonium and phosphate (mg/l)Ammonium and phosphate (mg/l)

542542538538484484462462157157NHNH44--NN4 4

52527777656566666868POPO44--PP

204204236236204204206206153153POPO44--PP217217316316323323275275314314NHNH44--NN3387876262474789893333POPO44--PP168168848475751141143232NHNH44--NN2 2 129129158158106106129129116116POPO44--PP357357430430424424409409428428NHNH44--NN1 1 5544332211Time Time Site Site

AffluentAffluent:668 x:668 x++101022 effluent: effluent: 9292 x x ++ 101022

Affluent:Affluent: 11 x11 x++101022 effluent:effluent: 0 0

E.coliSalmonella spp.

Farm 4

AffluentAffluent: 700 x: 700 x++101022 effluent: effluent: 4242 x x ++ 101022

Affluent:Affluent: 1.7 x1.7 x++101022 effluent:effluent: 1717

E.coliSalmonella spp.

Farm 3

AffluentAffluent: 8,200x: 8,200x++101022 effluent:effluent:1818 x x ++ 101022

AffluentAffluent:: 8.3x8.3x++101022 effluent:effluent: 0 0

E.coliSalmonella spp.

Farm 2

AffluentAffluent:740 x:740 x++101022 effluent: effluent: 10 x10 x ++ 101022

Affluent:Affluent: 1.7 x1.7 x++101022 effluent:effluent: 0 0

E.coli Salmonella spp.

Farm 1

Average number/ml Average number/ml Bacteria Bacteria Site Site

Using the effluent as an Using the effluent as an organic fertilizerorganic fertilizer

P=0.056, * different significant at 95%P=0.056, * different significant at 95%0.45 *0.45 *2.02 2.02 EFEF--660.33 *0.33 *2.3 2.3 EFEF--3 3 0.32 *0.32 *2.182.18CF CF 0.26 ns 0.26 ns 1.34 1.34 Control Control

SE +SE +Mean yield Mean yield (kg) (kg)

Treatment Treatment

Conclusion Conclusion •• Plastic biogas digester was accepted Plastic biogas digester was accepted

by farmersby farmers

•• Effluent can be use as organic Effluent can be use as organic fertilizer sourcefertilizer source

•• Plastic biogas digester can support Plastic biogas digester can support for the systemsfor the systems

•• But there are constraintsBut there are constraints

The constraintsThe constraints for the dissemination of this for the dissemination of this technology to smalltechnology to small--scale scale farmsfarms

•• farmerfarmer ’’s perception s perception •• instability of swine productioninstability of swine production•• easy broken of fermentation easy broken of fermentation tube tube •• flooding water effectflooding water effect•• lack of promotion activities of local government lack of promotion activities of local government

or other or other organisationsorganisations•• some technical problemssome technical problems•• labourlabour for using for using effluenteffluent

Biogas digesters around the Biogas digesters around the southeast Asia countriessoutheast Asia countries

•• Thailand Thailand

•• LaosLaos

•• CambodiaCambodia

•• Malaysia, and ChinaMalaysia, and China

•• Workshop on renewable energy and Workshop on renewable energy and biogas technology in March of 2002, Ho biogas technology in March of 2002, Ho Chi Chi Minh Minh city, city, VietnamVietnam

Some pictures of our story !Some pictures of our story !

Setting:Setting:

Farmer can install PBD by themselves

Water spinach using effluent

Cassava is as a perennial crop by untilization of effluent