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ADSORPTION OF FECAL ADSORPTION OF FECAL COLIFORMS, COLIFORMS, ESCHERICHIA ESCHERICHIA
COLICOLI IN DIFFERENT SOILS IN IN DIFFERENT SOILS IN
SARAWAKSARAWAK
Ling Teck Yee, Goh Soon Hian and Ling Teck Yee, Goh Soon Hian and Kasing ApunKasing Apun
Faculty of Resource Science & Faculty of Resource Science & TechnologyTechnology
University Malaysia SarawakUniversity Malaysia Sarawak94300 Kota Samarahan94300 Kota Samarahan
INTRODUCTION INTRODUCTION
• animal waste is a potential source of animal waste is a potential source of bacteria pathogensbacteria pathogens
• microbial contamination occurs microbial contamination occurs through animal wastewater discharge through animal wastewater discharge & lagoon effluent& lagoon effluent
• adsorption of adsorption of E. coliE. coli in soil depends in soil depends on organism surface, soil particles & on organism surface, soil particles & medium medium
• microbial adsorption in soil increased microbial adsorption in soil increased with clay content & organic matterwith clay content & organic matter
INTRODUCTION INTRODUCTION
• microbial adsorption in soil increased microbial adsorption in soil increased with clay content with clay content (Ling et al., 2002; (Ling et al., 2002; Weaver et al., 1978) &Weaver et al., 1978) & organic matter organic matter (Marshall, 1971)(Marshall, 1971)
• Both solid waste and lagoon effluent Both solid waste and lagoon effluent application on land are viable options application on land are viable options for animal waste management for animal waste management
• soils that are not capable of soils that are not capable of adsorbing fecal bacteria can be adsorbing fecal bacteria can be avoided as waste disposal sitesavoided as waste disposal sites
OBJECTIVES OBJECTIVES
• to determine the adsorption kinetics to determine the adsorption kinetics of of E. coliE. coli in a soil‑water system in a soil‑water system
• to compare the adsorption of to compare the adsorption of E. coliE. coli in three different types of soilsin three different types of soils
MATERIALS & METHODSMATERIALS & METHODSSoils Collection & AnalysisSoils Collection & Analysis• 3 different soils collected around 3 different soils collected around
KuchingKuching• particle size analysis by Pipette method, particle size analysis by Pipette method,
Soil pH by pH meter, total organic Soil pH by pH meter, total organic matter by Loss-on-ignition method matter by Loss-on-ignition method
Bacteria Isolation & IdentificationBacteria Isolation & Identification• E. coliE. coli isolated from fresh farm isolated from fresh farm
wastewater wastewater • Gram test & API 20E diagnostic kitGram test & API 20E diagnostic kit
MATERIALS & METHODSMATERIALS & METHODSAdsorption KineticsAdsorption Kinetics• 6 ml of adjusted initial bacteria 6 ml of adjusted initial bacteria
concentration (10concentration (1066 cfu/ml) was added cfu/ml) was added to 6 g of soilto 6 g of soil
• sampling at 0, 5, 15, 30, 60 & 120 sampling at 0, 5, 15, 30, 60 & 120 minutesminutes
Batch AdsorptionBatch Adsorption• using different initial bacteria using different initial bacteria
concentrations from 10concentrations from 1022 to 10 to 101111 cfu/mlcfu/ml
Table 1. Physical & chemical characteristics of the 3 different soils
used in the study
Soil Clay
(%)
Fine Silt
(%)
Med. Silt
(%)
Coarse Silt
(%)
Sand
(%)
Organic Matter (%)
pH
Clay Loam
35.2 10.2 17.6 8.4 28.6 15.5 4.5
Silt Loam
18.6 8.3 47.7 13.0 12.4 13.3 5.7
Sandy Loam
6.8 3.6 19.1 11.5 59.0 7.3 3.8
RESULTS & DISCUSSIONRESULTS & DISCUSSION• sorption equilibrium of sorption equilibrium of E. coliE. coli
between water & soil achieved between water & soil achieved immediately in 2 stepsimmediately in 2 steps
• percent sorption increased with percent sorption increased with initial bacteria concentrations at initial bacteria concentrations at low bacteria concentrations low bacteria concentrations
• bacteria uptake over 99% at high bacteria uptake over 99% at high bacteria concentrationsbacteria concentrations
• soils with higher clay & organic soils with higher clay & organic matter has significantly higher matter has significantly higher adsorption capacityadsorption capacity
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
0 20 40 60 80 100 120
Time (Min)
Co
nc
en
tra
tio
n in
su
sp
en
sio
n
(cfu
/ml)
Clay Loam Silt Loam Sandy Loam
Figure 1. E. coli depletion from 3 soils for 120 mins, initial bacteria
concentrations of 4.50 x 106cfu/ml
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14Initial Concentration (log cfu/ml)
Perc
ent A
dsor
bed
(%)
Clay Loam Silt loam Sandy loam
Figure 2. Percent of E. coli adsorbed with different initial concentrations in
the 3 soils
RESULTS & DISCUSSIONRESULTS & DISCUSSION• significantly higher bacterial significantly higher bacterial
adsorption than Commerce clay loam adsorption than Commerce clay loam & San Angelo sandy clay loam & San Angelo sandy clay loam (Ling (Ling et al., 2002; Weaver et al., 1978) et al., 2002; Weaver et al., 1978)
• Daniels (1980),Daniels (1980), optimum adsorption optimum adsorption of bacterial to soil particles of bacterial to soil particles generally occurs in low pH generally occurs in low pH conditionsconditions
• Hattori (1970),Hattori (1970), bacteria-clay bacteria-clay complex is more stable in acidic complex is more stable in acidic conditionsconditions
CONCLUSION CONCLUSION
• sorption equilibrium of sorption equilibrium of E. coli E. coli was was immediateimmediate
• high high E. coliE. coli removal in soil systems removal in soil systems• effectiveness of bacteria removal is effectiveness of bacteria removal is
dependent on bacteria concentration dependent on bacteria concentration • soil with higher clay & organic matter soil with higher clay & organic matter
content has higher capacity for content has higher capacity for adsorbing adsorbing E. coliE. coli
ACKNOWLEDGEMENTACKNOWLEDGEMENT
The authors are grateful to The authors are grateful to University Malaysia Sarawak University Malaysia Sarawak for providing the research for providing the research
grant (No.249/01)grant (No.249/01)