ADSORPTION OF FECAL COLIFORMS, ESCHERICHIA COLI IN DIFFERENT SOILS IN SARAWAK Ling Teck Yee, Goh Soon Hian and Kasing Apun Faculty of Resource Science & Technology University Malaysia Sarawak Kota Samarahan

INTRODUCTION animal waste is a potential source of bacteria pathogensanimal waste is a potential source of bacteria pathogens microbial contamination occurs through animal wastewater discharge & lagoon effluentmicrobial contamination occurs through animal wastewater discharge & lagoon effluent adsorption of E. coli in soil depends on organism surface, soil particles & mediumadsorption of E. coli in soil depends on organism surface, soil particles & medium microbial adsorption in soil increased with clay content & organic mattermicrobial adsorption in soil increased with clay content & organic matter

INTRODUCTION microbial adsorption in soil increased with clay content (Ling et al., 2002; Weaver et al., 1978) & organic matter (Marshall, 1971)microbial adsorption in soil increased with clay content (Ling et al., 2002; Weaver et al., 1978) & organic matter (Marshall, 1971) Both solid waste and lagoon effluent application on land are viable options for animal waste managementBoth solid waste and lagoon effluent application on land are viable options for animal waste management soils that are not capable of adsorbing fecal bacteria can be avoided as waste disposal sitessoils that are not capable of adsorbing fecal bacteria can be avoided as waste disposal sites

OBJECTIVES to determine the adsorption kinetics of E. coli in a soil ‑ water systemto determine the adsorption kinetics of E. coli in a soil ‑ water system to compare the adsorption of E. coli in three different types of soilsto compare the adsorption of E. coli in three different types of soils

MATERIALS & METHODS Soils Collection & Analysis 3 different soils collected around Kuching3 different soils collected around Kuching particle size analysis by Pipette method, Soil pH by pH meter, total organic matter by Loss-on-ignition methodparticle size analysis by Pipette method, Soil pH by pH meter, total organic matter by Loss-on-ignition method Bacteria Isolation & Identification E. coli isolated from fresh farm wastewaterE. coli isolated from fresh farm wastewater Gram test & API 20E diagnostic kitGram test & API 20E diagnostic kit

MATERIALS & METHODS Adsorption Kinetics 6 ml of adjusted initial bacteria concentration (10 6 cfu/ml) was added to 6 g of soil6 ml of adjusted initial bacteria concentration (10 6 cfu/ml) was added to 6 g of soil sampling at 0, 5, 15, 30, 60 & 120 minutessampling at 0, 5, 15, 30, 60 & 120 minutes Batch Adsorption using different initial bacteria concentrations from 10 2 to cfu/mlusing different initial bacteria concentrations from 10 2 to cfu/ml

Table 1. Physical & chemical characteristics of the 3 different soils used in the study SoilClay (%) Fine Silt (%) Med. Silt (%) Coarse Silt (%) Sand (%) Organic Matter (%) pH Clay Loam Silt Loam Sandy Loam

RESULTS & DISCUSSION sorption equilibrium of E. coli between water & soil achieved immediately in 2 stepssorption equilibrium of E. coli between water & soil achieved immediately in 2 steps percent sorption increased with initial bacteria concentrations at low bacteria concentrationspercent sorption increased with initial bacteria concentrations at low bacteria concentrations bacteria uptake over 99% at high bacteria concentrationsbacteria uptake over 99% at high bacteria concentrations soils with higher clay & organic matter has significantly higher adsorption capacitysoils with higher clay & organic matter has significantly higher adsorption capacity

Figure 1. E. coli depletion from 3 soils for 120 mins, initial bacteria concentrations of 4.50 x 10 6 cfu/ml

Figure 2. Percent of E. coli adsorbed with different initial concentrations in the 3 soils

RESULTS & DISCUSSION significantly higher bacterial adsorption than Commerce clay loam & San Angelo sandy clay loam (Ling et al., 2002; Weaver et al., 1978)significantly higher bacterial adsorption than Commerce clay loam & San Angelo sandy clay loam (Ling et al., 2002; Weaver et al., 1978) Daniels (1980), optimum adsorption of bacterial to soil particles generally occurs in low pH conditionsDaniels (1980), optimum adsorption of bacterial to soil particles generally occurs in low pH conditions Hattori (1970), bacteria-clay complex is more stable in acidic conditionsHattori (1970), bacteria-clay complex is more stable in acidic conditions

CONCLUSION sorption equilibrium of E. coli was immediatesorption equilibrium of E. coli was immediate high E. coli removal in soil systemshigh E. coli removal in soil systems effectiveness of bacteria removal is dependent on bacteria concentrationeffectiveness of bacteria removal is dependent on bacteria concentration soil with higher clay & organic matter content has higher capacity for adsorbing E. colisoil with higher clay & organic matter content has higher capacity for adsorbing E. coli

ACKNOWLEDGEMENT The authors are grateful to University Malaysia Sarawak for providing the research grant (No.249/01) The authors are grateful to University Malaysia Sarawak for providing the research grant (No.249/01)