Biodegradation of Lead from Accumulated Municipal Solid Waste …
107
2.8 Column Test
Column tests were done for 10 days using 30 cm high and 8 cm diameter columns.
Two columns were filled with 1.2 kg of ground solid waste. One column was kept as
control while the other was fed with bacterial consortium (Fig. 2). Two samples were
taken from the column on every alternate day for 10 days. Samples collected were
digested and analyzed the presently available amount of copper, lead, and nickel
after column test in comparison to control samples using Thermo Fischer Atomic
Absorption Spectroscopy, and the pH of the samples were recorded (Ayyasamy and
Lee 2009; Balint et al. 2013).
3 Results and Discussion
3.1 Isolation and Identification of Solid Waste Bacteria
Out of three samples of solid waste collected, 42 morphologically different bacterial
colonies were isolated before screening using Bergey’s manual of systematic bacteriology (David 1986). Based on the capability of heavy metal resistance, 4 isolates have
shown higher resistance to lead and were selected for further study in the column.
The selected isolates resistant to lead were identified as Escherichia spp, Klebsiella
spp., Pseudomonas spp. and Enterobacter spp.
3.2 Heavy Metal Analysis in Solid Waste Samples
Preliminary analysis of heavy metals concentrations in solid waste was done for all
the three samples before the identification of heavy metals resistant bacteria present
in the solid waste at the dump yard. Lead concentrations in solid waste samples
ranged between 12.8103–18.2907 mg/kg and were measured as 12.81 mg/kg in S1,
18.29 mg/kg in S2 and 16.08 mg/kg in S3. The highest concentration of lead was
observed at sample location S2, and S1 showed lower concentration compared to
other locations. The higher concentration with 18.29 mg/kg at S2 might be due
to migrated leachate from lead-containing household products, lead-based paints,
inclusion of chalcopyrite in batteries, and chemical for photograph processing waste
dumped along the other types of municipal solid waste in the dump yard.
107
2.8 Column Test
Column tests were done for 10 days using 30 cm high and 8 cm diameter columns.
Two columns were filled with 1.2 kg of ground solid waste. One column was kept as
control while the other was fed with bacterial consortium (Fig. 2). Two samples were
taken from the column on every alternate day for 10 days. Samples collected were
digested and analyzed the presently available amount of copper, lead, and nickel
after column test in comparison to control samples using Thermo Fischer Atomic
Absorption Spectroscopy, and the pH of the samples were recorded (Ayyasamy and
Lee 2009; Balint et al. 2013).
3 Results and Discussion
3.1 Isolation and Identification of Solid Waste Bacteria
Out of three samples of solid waste collected, 42 morphologically different bacterial
colonies were isolated before screening using Bergey’s manual of systematic bacteriology (David 1986). Based on the capability of heavy metal resistance, 4 isolates have
shown higher resistance to lead and were selected for further study in the column.
The selected isolates resistant to lead were identified as Escherichia spp, Klebsiella
spp., Pseudomonas spp. and Enterobacter spp.
3.2 Heavy Metal Analysis in Solid Waste Samples
Preliminary analysis of heavy metals concentrations in solid waste was done for all
the three samples before the identification of heavy metals resistant bacteria present
in the solid waste at the dump yard. Lead concentrations in solid waste samples
ranged between 12.8103–18.2907 mg/kg and were measured as 12.81 mg/kg in S1,
18.29 mg/kg in S2 and 16.08 mg/kg in S3. The highest concentration of lead was
observed at sample location S2, and S1 showed lower concentration compared to
other locations. The higher concentration with 18.29 mg/kg at S2 might be due
to migrated leachate from lead-containing household products, lead-based paints,
inclusion of chalcopyrite in batteries, and chemical for photograph processing waste
dumped along the other types of municipal solid waste in the dump yard.