Utilization of Bamboo in Fixing Biomass From Wastewater

Progress Report By

Hunja MurageSupervisors: Prof. C. Ong, Dr.K. Ngamau,

Dr. C. Muthuri

Introduction 1

■ Water pollution is a major problem in Kenya.

■ Effluent from industries and human settlements is the main source of the problem.

■ Rural urban migration has given pollution an urban focus.

■ Effluent finds its way into the water supply: both surface and ground water.

Introduction 2

■ The forest cover in Kenya is under siege, because of increased need for settlement, farmland and forest products.

■ Bamboo can, while providing a substitute for wood, because of its water pumping properties, be useful in fixing biomass from wastewater.

■ Wastewater from urban areas is not suited to growing food crops due to pollutants.

Objectives

• To test bamboo species for their utility in wastewater treatment.

• To test the tolerance of these bamboo species to high nutrient conditions.

Hypotheses

■ Different bamboo species respond to wastewater by taking up nutrients and increase leaf area.

■ Water use efficiency will remain relatively similar between species

■ Wastewater has little impact on water use efficiency

Materials & Methods

■ 3 bamboo species, Bambusa vulgaris, Dendrocalamus giganteus, and Bambusa X were used in this study.

■ They were grown in 100 litre pots at the JKUAT experimental farm, in a randomized complete block design.

■ Wastewater from the University treatment ponds was used to irrigate the plants

Materials & Methods

■ Growth parameters such as plant height, leaf number, number of branches, collar diameter were taken at monthly intervals.

■ Infra Red Gas Analyzer was used to measure assimilation, evaporation and stomatal conductance twice a week.

■ Measures of chlorophyll content were also taken using SPAD, and soil moisture levels monitored with a moisture metre.

Bamboo Wastewater Trial in Juja

Constitution of Juja wastewater

■The levels of K and Na are very high.

■This would have an effect in the opening and closing of stomata.

Cu (mg/kg)Ni (mg/kg) Cd (mg/kg)Pb (mg/kg) Zn (mg/kg) K (mg/kg) Na (mg/kg)0.6 0.7 0.2 1.0 7.6 542.6 962.1

TOC (mg/l)TC (mg/l) IC (mg/l) P (µg/l)

5.8 37.9 32.1 70.9TOC = Total Organic Carbon TC = Total Carbon IC = Inorganic Carbon

■ The diurnal assimilation trend for the 3 bamboo species is the same.

■ The plants receiving wastewater (red) have higher levels of assimilation than clean water (black).

Diurnal A for 3 Bamboo species

0

2

4

6

8

10

12

0 2 4 6 8Hours

A (u

m/m

2/s)

(from 8am)

Diurnal Stomatal Conductance for 3 Bamboo Species

0

50

100

150

200

250

300

0 1 2 3 4 5 6 7 8

Hours

Stom

atal

Con

duct

ance

(m

ilim

oles

/m2/

s)

■ The diurnal stomatal conductance trend for the 3 bamboo species is the same.

■ This supports the data on diurnal assimilation.

(from 8am)

■ D. giganteus has a higher Instantaneous WUE.■ Plants receiving wastewater appear to have a

higher WUE in comparison to clean water plants.

Water Use Efficiency

0

2

4

6

8

10

12

14

0 1 2 3 4

E (um/ms2/s)

A(u

m/m

s2/s

)

giant

Stem & Branch Biomass

■ Plants receiving waste water (-w) had the biggest culm and branch weight.

■ Bambusa vulgaris (middle) did not show sensitivity to wastewater.

0.0

200.0

400.0

600.0

800.0

1000.0

1200.0

1400.0

1600.0

GC GW VC VW XC XW

Stem & branches weight (kg)

B. vulgaris

Giant

B. x

Leaf Biomass

■ Total leaf weight showed a clear difference between plants receiving wastewater and clean water.

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

GC GW VC VW XC XW

Leaves (gm)

Giant

B. vulgaris

B.x

Biomass

■ XW and VW had the highest number of new branches.

■ GW had a decrease in number of branches in the same period.

Number of Branches

0

50

100

150

200

250

300

0 1 2 3 4Months

Numb

er

B.x

B.v.

giant

■ B. vulgaris and B.x had more than double the leaf area of the other treatments.

■ These treatments therefore have assimilation and evaporation rates that are three times of the other three.

Average Total Leaf Area Per Plant

0

5000

10000

15000

20000

25000

30000

0 0.5 1 1.5 2 2.5 3 3.5Months

Squ

are

cm.

■ Wastewater plants (orange) had higher chlorophyll values

Chlorophyll Values (SPAD)

0

5

10

15

20

25

30

35

40

45

0 1 2 3 4 5Months

SPA

D

Preliminary Conclusions

■ Confirm hypothesis 1 that main responses to wastewater is increase in leaf area and chlorophyll.

■ Although giant bamboo appears to have a higher WUE it is also the slowest growing.

■ Water use efficiency was relatively similar although wastewater WUE appeared to be higher (significance?).

Further Studies

■ Different sources of wastewater particularly from industrial sites to be investigated.

■ A wider range of concentration of wastewater to be tested.

■ Analysis of nutrient uptake to be carried out.