Biodewaterability and Liquid State Bioconversion of Activated Sludge Under Non-Sterilized Conditions
The study was conducted to evaluate the microbial treatment of domestic wastewater treatment plant (DWTP) or activated sludge by Liquid State Bioconversion (LSB) process under non-sterilized conditions. The selected two filamentous fungi, Penicillium corylophilum and Aspergillus niger isolated fr...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2006
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/6094/1/FK_2006_4.pdf |
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| Summary: | The study was conducted to evaluate the microbial treatment of domestic
wastewater treatment plant (DWTP) or activated sludge by Liquid State
Bioconversion (LSB) process under non-sterilized conditions. The selected two
filamentous fungi, Penicillium corylophilum and Aspergillus niger isolated from
Activated sludge were used to evaluate the treatment performance in LSB process
under non-sterilized conditions through adaptation. It was observed that
Penicillium corylophilum (WWZP1003) was the better strain compared to the
Aspergillus niger (SCahmA103) for the bioconversion of activated sludge through
adaptation. The visual observation in plate culture showed that about 95%-98% of
cultured microbes (Penicillium corylophilum and Aspergillus niger) dominated in
treated sludge after two days of treatment. In this study, it was also found that the
Penicillium corylophil~rrn was capable of removing 94.40 % of chemical oxygen
demand (COD) and 98.95% of turbidity of filtrate with minimum dose of inoculum of 10% V/V in activated sludge with total suspended solids (TSS) of 1% w/w. The
pH level was lower at 3.4-3.5 (acidic condition) in the fungal treatment with
maximum reduction of COD, turbidity and specific resistance to filtration (SRF)
were observed. The results for SRF showed that the fungi led a great role to
enhance the dewaterability and filterability. Ln particular, the strain Penicillium
corylophilum had more capability (than Aspergillus niger) of reducing 93.20 % of
SRF compared to the uninoculated sample. Effective results were observed by
using fungal inoculum after 2 days of treatment. A statistical optimization of
process factors was carried out to evaluate the linear and interaction effects on
effective bioconversion of activated sludge using Penicillium. Three parameters
namely temperature, agitation and pH with three levels were used to evaluate the
process factors in term of biodegradability and biodewaterability/biofilterabiIity of
activated sludge of 1% (w/w) TSS with 10% of inoculum dose of Penicillium
corylophilum. A 3-level full factorial design (3" and response surface methodology
(RSM) were used for the optimization of process factors through the
biodegradability (removal of COD) and biodewaterability (SRF) of treatment
sludge by a statistical software Minitab. The experimental data were designed by
developing a second order polynomial regression model considering linear,
quadratic and interaction effect. The optimum temperature, agitation and pH were
observed to be 33S°C, 105 rpm and 5.5 respectively by the regression analysis on
using experimental data under RSM. The maximum removal 98.5 % of COD, 99.0
% of turbidity and 95.0 % of SRF reduction were observed at that optimum process
conditions in the activated sludge treatment by LSB under non-sterilized
conditions. The maximum dry biosolids of 17.4 gkg production was observed with
optimum process conditions by the fungal treatment (Penicillium corylophilum).The results in this study clearly indicate the effective bioconversion of activated
sludge under non-sterilized conditions which may provide better waste
management and disposd concerned. |
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