REVIEW AND POSSIBILITIES OF WATER HYACINTH (Eich/wrniacrassipes) UTILIZATION FOR BIOCAS PRODUCTION BY RURAL

COMMUNITIES IN KAINJI LAKE BASIN

A.A. EYO.

iVational Institute for Freshwater FisherIes Research ('NIFFR),PMB, 6006, New Bussa, Nigeria

ABSTRACT

The paper gives some background information on the production of biogas usingagricul(ural Waste. Studies on biogas production with water hyacinth conducted inNIFFR using the floating type biogas digester complete with gas holder and anexperimental metal digester with a measuring cylinder as gas collector are highlighted. Aproposal for the construction of a dome — type biogas digester at Rofla and Zamare closeto the boom are presented. This will ease utilization of water hyacinth harvested from theboom for biogas production The gas will provide an energy source for the localcommunity and the slurry will be a ready source of fertilizer for the farmland,

INTRODUCTION

Nigeria is a country blessed with abundantenergy resources. These are the primary energysources such as crude oil, natural gas and coaland renewable energy most of which areunderutilized such as hydro, wind, solar,biomass and fuel wood.

Most of the energy needs of Nigerians forhousehold and industrial use are petroleum-based namely petrol, diesel, kerosene andnatural gas. While kerosene and gas are usedextensively by most households in urban areas,the rural dwellers, which form 70-80% of thepopulation, depend almost exclusively on fuelwood for household use. This high dependenceon fuel wood for doinestic and commercialpurposes is a matter of public concern as it is themajor cause of deibrestation in many pail:s ofthe country. Since the rate of regeneration ofwood is not commensurate with the high rate of

consumption, there is an increasingly high rateof desert encroachment, soil erosion and loss ofsoil fertility in places with high rate ofdeforestation. Thus complete reliance on fuelwood to meet the domestic energy needs ofrural cominun ities enhances environmentaldegradation - a situation which is very difficuh:to reverse.

One of the ways of saving the environmentfrom further deterioration and also supplementthe energy needs of rural dwellers on KainjiLake Basin is by the production of biogas. Thetechnology of biogas production is not new. Thedevelopment and construction of biogas digesterstarted in the I 920s and has spread to severaldeveloping countries such as India, Taiwan etc.In these countries biogas technology hassupplemented a large proportion of energyrequirements of the rural majority. Theavailability of raw materials coupled with theever-increasing prices of fossil fuel has madethis technology attractive.

52

In India for example biogas generating plantsusing cow manure have been iii operation for.years. In Taiwan more than 7,500, methane-generating devices utilizing pig Ii1anur havebeen in construction. The technology of biogasproduction is therefore advantageous in that itcan be used to provide energy for householdsand rural. communities without tampering withfuel wood.

REVIEW OF BIOGAS PRODUCTION

Biogas is a mixture of colourless,flammable gases produced by anaerobicfermentation of organic waste materials.Biogas is a mixture of methane, carbon dioxide,small amounts of carbon monoxide, hydrogen,nitrogen, oxygen, hydrogen-su Iph ide andhydrocarbon gas. The actual percentage of eachgas varies with raw materials, ratio of inputmaterials,' temperature and fermentation stages.Typically the composition of biogas is asfollows (Fernando and Dangaggo 1986).

Methane

Carbon monoxide

Carbon dioxide

Oxygen

Nitrogen

Hydrogen sulphide

Hydrogen

54 -70%

0.1%

2745%

0.1%

0.5-3 %

Trace

1-10%.

Methane is the n'iajo.r combustible component ofbiogas. Others usually in small quantity arecarbon dioxide, hydrogen and hydrogensulphide.

Biogases are obtained by fermentation oforganic materials such as animal, human,agricultural and industrial wastes. Theseinclude animal faeces, municipal sludge andgarbage, abattoir waste, paper waste andwaterweeds. The rate of conversion of theorganic waste to the end products atappropriate temperature depends oii the

53

complexity of the waste. In the treatment ofcomplex wastes such as sewage and slaughterhouse waste, generally slower loading ratesshould betised due to mitch slower conversionrate of the biodegradable suspendedcompounds than of the soluble compoundssuch as young plant materials. It is thusexpected that the complexity of the waste is asignificant factor that affects the rate ofanaerobic digestion of any type of wasted.(Maishariu et.al., 1993).

The quantity, quality and composition ofbiogas produced vary from one animal waste tothe other. So, also biogas produced fromagricultural waste varies from that of animals.For this reason, investigation of the quantity,quality and composition of biogas producedfrom agricultural wastes is imperative. Biogashas been produced from the aquatic weed Pistiastratoites (Maishanu, 1992). It should also bepossible to produce from water hyacinth.Accordingly, a report of the quantity and qualityof biogas produced from water hyacinth(Eichhornia crassipes) has been shown here.

Chemistry of biogas production.

Anaerobic digestion of organic matteroccurs in three phases; the first phase in whichfacultative in icro-organ isms convert complexorganic compounds (polymers) examplesstarch, cellulose via enzymatic hydrolysis intoless complex soluble organic compounds(monomers) examples glucose, fructose.

In the second phase, a group of bacteriacollectively known as "acid formers" convertsthese soluble monomers into acids and in thethird phase, the soluble organic acidsconstituting mainly acetic acids serve assubstrate for methanogenic bacteria which arestrictly anaerobic in nature.

M.ethanogenic bacteria can generatemethane through two different routes; eitherby fermenting acetic acid to methane (Cl4)and carbondioxide (GO2) or by reducingcarbondioxide methane via hydrogen gas orformate generated by other bacterial species asshown in the reactions below:

n (C6 H10 0) + nH2O Hydrolysis n C6 111206)

n(C6 06) nCH4 ±3n CO7

CO2 + 4H2 Reduction H4 + 21120

CO2 + H20 Hydrolysis I2 CO3

n (C6 H12 06) + 311 1-130 hydrolysis 3CH4 + 3nH2C03

H2C0 + 4H2 Reduction H4 + 3 H20.

Factors affecting biogas production.

In order to enhance the performance ofbiogas generation process, and to prevent theprocess failure, certain operating parameterssuch as temperature, p11, nutrient addition,mixing ratio and retertion period, all need tobe. controlled. Micro-organisms are highlysensitive to pH changes. Buffering is

necessary for pH control and therefore anessential step in the overall operation (Garbaand Sambo 1992).

Temperature is an important physico-chemical factor in the degradation of organicwastes and as such the anaerobic process isdependent on temperature

Temperature has significant effect onbiogas production more especially when freshplant material is involved. Two temperatureranges have been reported to affect tile overallprocess of biogas production. These are; tilemesoph ii ic temperatures and thermoph ii ictemperatures. Tile mesophilic temperaturerange of 30-40°C has been reported toeffectively aid in degradation of organicwastes that are not lignified. Increased biogasproduction was reported in tile digestion offresh water weed known as Pistia stratiotes(water lettuce) at mesophilic temperature of30 °C.). Tile mesophilic temperature range ispreferred when fresh plant material is involved(Maishanu et.al, 1993) Also, it is easier tomaintain the digester at this temperature.

Methane-producing bacteria are, verysensitive to sudden thermal changes andtherefore any drastic change in temperatureshould be carefully avoided so that no abruptdecrease in gas production occurs. Thedigestion process must thus be designed tooperate at constant temperature conditions.Temperatures above 65°C cause gasproduction to stop (Garba and Sambo, 1992).

Anaerobic digestion process can beoperated over p11 range of 6.0 — 7.0. Asorganic acids are produced during thebreakdown of cellulose, when the pH dropsbelow 7.0, there is a significant inhibition ofrnethanogellic bacteria and tile acid conditionsof a pH of 4.0 are toxic to these bacteria. Atp1-I of 4.0, tile production of gas will be verylow and later stops (Garba and Sambo 1992).

Several steps such as introduction ofbacteria having ceilulolytic capacity,preheatng the media material, milling themedia material, chemical treatments withNaOH etc, aid drying have been shown toimprove biogas yield (Itodo et. al., 1992)

Small digester.

This ranges from 4m3 to 20m3. The size ofthe plant depends on the number of peopie llthe house hold. On the average an individualrequire about 0.3% of biogas for cooking,heating and lighting in a day.

54

Medium digester

This has capacity ranging between 50mband 500 rn. These are community-based biogasdigesters. Biogas is supplied to the users viapipelines from one or more coupled digester.

Large-scale digester

This is usually for industrial production ofagro-based residues and other waste productsthat are organic in nature. This requires buildingdigester of 5000m3 capacity or more.

Use of water-hyacinth for biogas production

The menace of water hyacinth in Kainjilake reservoir with its unfavourable effect onnavigation and aquatic life has raised publicinterest on its eradication without adverse effecton the aquatic flora and fauna as well as humanlife within and outside the lake basin. Amongthe three control methods i.e. biological,chemical and physical, the last is considered thesafest method since it involves manual ormechanical harvesting of the weed. Theharvested water hyacinth could find alternativeuse in the production of biogas at thecommunity level. This added benefit willencourage community participation in theharvesting of the weed because of the gainsderivable from biogas production.

Other raw materials

Iii the absence of water hyacinth, cowmanure, which is also rampant in the area will,be an alternative raw material so that the plantwill be kept running even after the waterhyacinth has been eradicated.

Importance of biogas téthnology

Biogas technology has succeeded in

generating a stable energy source that can beused for direct combination in cooking orlighting or indirectly tO, fuel combustionengines for delivery of electrical power.

Production of stabilized residue (biogasslurry) that can be used as a fertilizer; an

55

energy efficient means of manufacturing anitrogen containing fertilizer.

o A process ha'ing the potential for wastesterilization which can iiThibit pathogenicaction and thus reduce public healthhazards from faecal pathogens as well asinhibit 'athogens (usually found in highconcentration in manure) like Ehizotomiasolainia of rice and Helminthosporriurnsatluin of wheat.

o The various products of a biogas plantsuch as methane, carbon dioxide andhydrogen can be used in the production ofmany industrial chemicals; methane isused in the production of methanol anindustrial alcohol used in the making ofmethylated spirit. The chlorination ofmethane through photocatalysis yieldchloroform and carbon tetrachioride.Carbon tetrachloride is used in drycleaning and in fire extinguishers.

° Carbon dioxide is used in the manufactureof ammoniurn sulphate from powderedanhydrite as described in the chemicalreattion:

CaSO4 + 2NH4OH + CO2 (g) =CaCO3 (s) ± (NH4)2 SO4 ± H20.

it can also be used in the production of urea asshown in the reaction

C02(g) + 2NH3 (g) C02(g) + 2NH3(g). Urea can be utilized as fertilizer and inthe manufacture of plastics. Other uses ofcarbon dioxide include the manufacture oforganic chemicals, such as coolants in nuclearreactors, for the aeration of soft drinks, forstoring fruits while blocks of solid carbondioxide are used as refrigerant (Aliyu et.ai.,1996)

MATERIALS AND METHODS

Laboratory preparation

The procedure has beer reported by Eyoand Madu (2000).

Fresh water hyacinth (SOOg) were cut intoone inch sizes and placed in a two litre metalcontainer with water at the ratio of 1:3 (w/v).The metal container served as the digester. Ahole was bored oxi top of the digester and arubber hose was inserted into the hole via arubber cork and glued using araidite adhesive.The mixture was fed into the digester throughthe inlet on the digester. The inlet of thedigester was then sealed to ensure that it wasairtight. A one-litre measuring cylinder wasused as a gas holder or gas collector. Retortstand and clamp were used to hold themeasuring cylinder in a vertical positionwithout slanting.

The unattached end of the rubber troughwas placed in water iii a trough and the one-litre measuring cylinder filled with water, wasinverted into the trough such that the outlet ofthe rubber hose (delivery tiThe) was directedupwards within the measuring cylinder. Fig.shows the experimental set up of the process.The downward displacement of the water inthe measuring cylinder was used as a measureof the volume of biogas produced.

(ii) Experimental trial with floating typebiogas digester.

Preparation of sample

Water hyacinth freshly harvested fromJebba lake by staff of Aquatic Weed Projectwas used for the experiment which cotnni-eneed on Monday 1' July 1997.

Samples were initially subjected togrinding iii a hammer mill arid pounding in amortar, respectively. When these two methodscould not produce hornogetious particlesneeded for the experiment it was decided tochop the weed into small pieces (1-2 in

average length). The pieces were transferredinto two large plastic bowls containing equalvolume of water (W/V) and left overnightbefore pouring into the digester.

Loading the digester.

Since slurry could not he produced fromthe weed, it was not practicable to insert thematerial through the inlet pipe of the digesterwithout blocking the pipe. The solution was topass the material via the drain channel afterremoving the stopper. The digester wastilted to the offside position to facilitateloadiig the digester with sample.

The drain stopper was closed tightly afterloading the digester. With the digester nearlyfilled up, an anaerobic environment wascreated which is a prerequisite for the activityof methanogenic bacteria. The digester wasthereafter returned to its normal verticalposition. The outlet pipe remained

closed throughout thepermanentlyexperiment.

RESULTS AND DISCUSSION

Table 1 shows the volume of biogasproduced during the experimental period. Thequantity of biogas increased from 50 cm3 inthe first week to 82 cm3 in the 2 week. In the3 week the volume of biogas was 122 cm3increasing to 150cm in the fourth week andreaching a peak at 170 cm3 in the 5th weekafter which the level of production declined.Tlie volume of biogas collected on the ninthweek was 80cm3. Total biogas producedduring the experimental period was 970 cm3.

Temperature in the laboratory ranged from24°C with a mean temperate of 27°C over the63 days experimental period. This low meantinperature could affect the level of biogasproduction since temperature profoundlyinfluence the action of methanogenic bacteriaand the rate of hydrolysis (Aliyu t al 1996;Garba and Sambo 1992; Garba et cii, 1996:Fernando and Dangoggo 1986; Maishanu ciai 1993). Increased biogas production ofwater lettuce (Pistia stratoites) was reported atmesophilic temperature or3O°C (Maishanu cicii, 1993).

56

57

50CM >1KEY

OWES TER

2 SLURRY OUTLETSLURRY INLETSTIRRER

5 045 HOWERGAS OUTLET

7 IJEAM7

T

IIIIt'ill

I

'I'I

II__JL

IIs.'- I

— —Il—

I,II

zU

55014

Fig4. PORTA8LE BLDGAS FLAUT WITH SEPARAtE GAS HOLDER (IDOUTRES CApACITY)

I.

The mixing ratio of 1:3 (w/v) of waterhyacinth and water could also affect the rate ofbiogas production. Aliyu et al, (1996) reported

an increase in biogas production when theratio of pigeon droppings with water wasincreased from 1:3 to 1:4. (w/v).

Table 1: Yield of Biogas from Water i-Iyacinth nuder Laboratory Conditions

Day Volume ofBiogas Cm3

0-7 50

8-14 8215-21 122

22-28 15029-35 170

36-42 150

43-49 7050-56 90

._____ 57-63 80

Total 63 970

Biogas prod action with the floating typebiogas digester.

The apparatus was left with the two valves(digester and gas holder) open in the firstweek, to allow escape of the gas produced atthe initial fermentation process, which containvery low methane. This gas would dilute themethane gas when it is subsequently producedand thereby affects combustion. The contentwas stirred daily to accelerate the rate offermentation.

With the two valves closed a rernarkai,rise in the water level was discernible at theinlet pipe the next day. As the day progressed,the water level increased in volume and filledup the inlet pipe and started dropping. Thisoverflow stopped when the digester gas valvewas open. On the first day of the 3d week, thetwo gas valves were again closed. When bothvalves were opened the next day gas started toooze out from the gas pipe. When the gas wasigiited it burst into a luminous blue flame.This fascinating sight was over in less than 1 0

minutes.

The digestei was again closed and thesame p: cedure was repeated the next day andthe emted gas was allowed to burn away. Thepeak of gas production appeared to have beenreached one month after loading the digester.The gas produced as from that day has been onthe decrease. As a result of the increased waterlevel in the digester it was decided to repeatthe experiment with dry water hyacinth.

PROCEDURE FOR THE SECOND TRIALSAMPLE PREPARATION

1 kg of dried water hyacinth was measuredand placed in the digester after which 5kg offresh cow dung dissolved in 50 liter of waterwas poured into the digester through the inlet.

The apparatus was left for fermentation totake place with the digester valve open duringthe first 4 days. Thereafter the digester valvewas closed and connected to the gas holder. Thegas produced was ignited daily to determine thei-ate of proth.iction. This is shown in Table 2.

This second experiment started on Tuesday 26thAugust. 1997.

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Table 2 Quantity Of Biogas Flow From The Digester(As Measured By The Duration Of Burning)

DATE QUANTITY OF GAS26/8/97 3 Minutes burning27/8/97 228/8/97 2

29/8/91 230/8/91 1

31/8/91 Nil1/9/97 Nil2/9/97 Nil3/9/97 1 minute 10 sec.4/9/97 42 seconds5/9/97 2 minute6/9/97 2.407/9/97 4 minutes8/9/97 3

9/9/97 2U

10/9/97 3

11/9/97 3

12/9/97 6

13/9/97 3

14/9/97 5

15/9/97 5

16/9/97 5

18/9/97 5

19/9/97 5

20/9/97 5

2l/9/97 422/9/97 5

23/9/97 4

25/9/97 4

26/9/97 3

27/9/91 3

28/9/91 3

29/9/91 3

30/9/97 3

31/9/97 2

1/10/97 2

2/10/97 6

3/10/97 3

4/10/97 3

5/10/97 4

6/10i)7 4

7/10/97 3

8/10/97 3

9/10/97 3

10/10/97 3.11/10/97 3

12/10/97 4

13/10/97 3

14/10/97 4

15/10/97 3

59

A proposal for the provision of biogasplants at Rofia and Zarnare along the Lake

Kainji Basin.

The use of the barrier (boom) to trap the waterhyacinth mats as they flow into the LakeKainji has provided water hyacinth which areeasily harvestable and therefore available forbiogas production. Below are costing for theconstruction of a portable floating gas holderwhich is for demonstration only (Table 3 and

3Figi) and 4m fixed —Dorne digester which isrecommended for Rofia and Zamare (Table 4and Fig. 2)

Costing

Tables 3 and 4 show costing for theconstruction of the Portable floating gasholder biogas Plant (for demonstration only)and construction of 4m3 fixed-Dome digesterrespectively. The prices are cx New Bussa andare due to change with time.

Table 3:Materiais and Labour for the Construction of a Portable Floating Gas BolderBiogas Plant (For Demonstratioii Only)

Materials Quality Unit Cost Total Cost

A

1. 18 guage Galvanised steel sheet 3 sheets 2,000 6,000.002. V2 steel G.1. pipe 1 length 500 500.003. 1" G.L Pipe 1 " 750 750.004. "flatbar I " 150 150.005 " gate valve I " 600 600.006. ¾" nipple and socket I set 800 800.007. Gas control valve (1/2") 2 Nos 850 1,700.008. 3" G.I.plug 3 " 100 300.009. 2" G.I. Socket 3 " 100 300.00JO. 10mm dia steel rod I length 300 300.00ii. Eazec cooker gas stove I No. 5,000 5,000.0012. '/2" elbow 2 No 50 100.0013. 34 elbow 2 " 50 100.00B.

C.

LabourSheet metal cutting and welding expenses.5% Contingency

16600.005,000,001,080.00

D. Consultaney 20,000.00E. Total. N42,680M0

60

61

5$IJb over6us woivt

tflge sit'

flG.2S4V)Vlxed-lIonIc lype blugas plant

1t1G.()Wurklng priticlple ol fixed-dome lype Jdugas plant

Table 4: Materials and labour for the construction of4m3 fixed-dome digester.

S/No. Materials

1. 46x22x12cmCement blocks

2. 25x12x6cm

Burnt bricks

3. Cement (50kg)

4. Sand 3.5m3 tipper

5. Gravel 4m3 tipper

6. PVC or Asbestos pipe(for inlet and outlet)full length % 20cm

7. Steel rod (8mmdiameter 9mm length)

8. 3/4" G.I.Pipe-full length.

9. '/2' G.I. pipe full length

10. Gas control valve

11. Rubber hose for gas piping

12. 6" Paint brush

13. 411 II

14. Wire gauze for

sieving sand

15. 2" x 12" x 12" woodenplank.

16. 3" nails

17. Hacksaw blade

18. 6" G.f. Socket and plug

Quality Unit Cost

150 35

Total Cost.

5,250.00

20 600 12,000.00

2 1,200 2,400.00

1 2,000 2,000.00

2 3,000 6,000.00

2 700 1,400.00

1 600 600.00

1 500 500.00

2 1,850 3,700.00

- 1,400 1,400.00

2 200 400.00

2 150 300.00

3 200 600.00

4 400 1,600.00

1kg 50 50.00

2 100 200.00

1 700 700.00

62

Table 4 (contd;)

S/No. Materials Quality Unit Cost Total Cost.

19. 3/4" Socket 3 35 105.00

20. Biogas burner (2 waytype) 1 5000 5,000.00

A. Sub-Total for materials 49,375.00Labour

21. Site clearing and 4 labourers 300 perpits excavation working for day per

30 days from person 36,000.008am — 5pm i.e.

300x3 x4

22. Plant body construction 2 Masons for 500 per7 days mason per

day i.e.500 x2x7 7,000.00

23 " 2 labourersx 7 200x2x7 2,800.00

B Sub Total 45,800.00

C Total for labour A & B 78,305.00

5% contingency 3,915.25

D. Grand total fOr materials,labour and variation 82,220.25

E. Subsistence for Number of Rate Amount.Supervisors days

S/No. Category of staff days

1. 2 Senior staff 14 days from 2,500the date per day 70,000.00work commence x2x7

2. 1 Junior staff U 1,500per day 42,000.00x2x7

112,000.00F, Transportation (2 trips) 40,000.000. Honorarium or Coiisultancy charges 50,000.00

Grand total D + E + F + G N244,220.25

63

CONCLUSION

Biogas can be produced from waterhyacinth. The rate of production wi I depend onmany factors ino'uding the size of the digesterand the degree of dryness of the material. Theuse of the fixed dome type is recommended.The water hyacinth should be dried before useand seeding with cow manure wifl increase

production.

Biogas can be used in the househQld,community farm or industry for:

(i) Heating, cooking and lighting using dome-stic biogas stoves and lamps.

(ii) Electricity generation in rural areas usinginternal combustion engines, which can beused for irrigation, lifting and pumpingportable water, threshing, feed processingetc.

(iii) Agricultural production such as drying ofcrops, hatching eggs, grain storage,production of biornanure which can 'oc usedas fertilizers in farms and ponds etc.

(iv) Smoking or drying of fish by fish

processors using the KainjiGas kiln.

REFERENCES

Abubakar, A and A.A. Zuru. (1996). Potential for the

development of Algal-Bioconversion Biogas forAtiIization in the Rural areas of Northern Nigeria.Nigerian Journal of Renewable Energy, 4,24-2.5

Aliyu, M., S.M. Dangoggo and A.T. Atiku. (1996).

Effect of seedin\g on biogas production using pigeondroppings. Nigerian Journal of Renewable Energi,4, 19,

Aliyu, A., S.M. Dangoggo and A.T. Atiku, (1996).J3iogas production from Pigeon droppings. NigerianJournal of Renewable Energy, 4, 48 — 49.

1tyo Aix. arul N. MatS i2M) A P'e ary tthidy oBiogas Production from Water Hyacinth (EichorniaCrassipes). Proceedings of the 12 AnnualConference of the Biotechnology Society of Nigeria.Edited by: Eyo A.i\., P.O. Aluko, S.A. Garba, U.D.Au, S.L. Lamai and SO. Olufeagba. pp. 37 —39.

Fernando,C.E.C. and S.M. Dangoggo. (1986).Investigation of sonic parameters which affect theperformance of Biogas plants. Nigerian Journal ofSolar Energy, 5, 142-144

Gavb B.. 2QOO Challenges in Energy Biotechnologywith special Reference to J3iogas Technology.Proceedings of the 12th Annual Conference of theBiotechnology Society of Nigeria. Edited by: EyoA.A., P.O. Aluko, S.A. Garba, U.D. Au, S.L.Larnaiand S.O. Olufeagba. pp. 20—36,

Garba, B., A.A. Zuru and A.S. Sambo. (1996). Effectof slurry concentration on biogas production fromcattle dung. Nigerian Journal of Renewable Energy,4, 38-40,

Garba, B. and A.S. Snibo. (1992). Effect of someparameters on biogaS production rate. Nigerianicurnal of Renewable Energy, 3, 36, 41-42,

Itodo, LN., E.B. Lucas and FJ. Kuch (1992). Theeffects of media material an ls quantity on biogasyield. Nigerian Journal of ,l èv.ctble Energy, 3: 45.

Maishanu, S,M. (1992). '3iogs Oeneraion from freshaquatic weed - Pisia Tiiqt. M.Sc. Bayero

University, Kano. Nigeria pp. 166pp.

Maishaflu, S.M., A.S. Sanibo and M.Z. Abdullabi(1993). Temperature efbets on B1os productionfrom fresh water we4, Nigerian Journal ofRenewable Energy, 12,14146.

9yagade,J.O, and D.A. Alabi, (1996) A review ofBiomass resource as an alternative energy source inNigerIa. Nigerian Journal of Renewable Energy, 4,80.

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