Utilization of Bamboo in Fixing Biomass From Wastewater

Progress Report By Hunja Murage

Supervisors: 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 speciesWastewater has little impact on water use efficiency

Materials & Methods

3 bamboo species, Bambusa vulgaris, Dendrocalamus giganteus, and BambusaX 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 70.9

TOC = 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 (

um

/m2/

(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

Sto

mata

l C

on

du

cta

n

(mil

imo

les/m

2/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 4E (um/ms2/s)

A(um

/ms2

/

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

200.0400.0

600.0800.0

1000.0

1200.01400.0

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

Nu

mb

e

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

SPAD

Preliminary ConclusionsConfirm 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.