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- 저자 : Kaliappan S. (검색결과 15 건)
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Effect of Cation Binding Agents on Sludge Solubilization Potential of Bacteria
S. Gopi Kumar,J. Merrylin,S. Kaliappan,S. Adish Kumar,염익태,J. Rajesh Banu 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.2
The aim of the present study is to increase sludge solubilization potential of bacteria by the addition of cation binding agents. During the study, three strains of bacteria B1, B2 and B3 were isolated from waste activated sludge acclimatized to a thermophilic condition (55°C). Using these strains the mixed liquor suspended solids degradation was 67, 59, and 33% and the chemical oxygen demand solubilization enhancement was 71, 62, and 36%compared with the control. Cation binding agents such as citric acid, ethylenediaminetetraacetate and sodium tripolyphosphate were added to enhance the sludge solubilization further. Among these, citric acid along with B1 was more effective in solubilization with the mixed liquor suspended solids degradation of 110% and the chemical oxygen demand solubilization enhancement of 115%. 16s rRNA technique was used to identify the bacterial species B1 and it was found to be Bacillus licheniformis. It was also observed that mixed liquor suspended solids reduced rapidly when more soluble chemical oxygen demand was released, thereby increasing sludge solubilization.
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Raj, S.E.,Banu, J.R.,Kaliappan, S.,Yeom, I.T.,Adish Kumar, S. Elsevier Applied Science 2013 Bioresource Technology Vol.140 No.-
Introduction of sludge reduction practices in enhanced biological phosphate removal (EBPR) often leads to a decrease in phosphorous (P) removal efficiency. In this study, an attempt has been made to develop sustainable P removal in an anaerobic/anoxic/oxic (AAO) system integrated with sludge reduction by incorporating side-stream P recovery. Two AAO reactors, one acting as a control (CAAO) and the other as an experimental system (EAAO), were used in our experiment. The average P solubilisation efficiency and its recovery from thermally pre-treated sludge were found to be 28% and 99%, respectively. The P recovery process prevented the biomass in the EAAO system from reaching its threshold level and resulted in sustainable P removal throughout the study period. Thermochemical pre-treatment, at a rate of 1.5% Q in the EAAO reactor, was responsible for a 28% reduction in the amount of sludge produced. The yield observed (Y<SUB>obs</SUB>) values for the system with and without pre-treatment were found to be 0.28 and 0.22kg MLSS/kg COD, respectively. An initial 50days of reactor operation was utilised to stabilise the systems (Phase 1). The total nitrogen removal during Phase 2 (51-225days) was slightly higher than that in Phase 1 (76-80% and 68-75%, respectively). The MLSS/MLVSS ratios of both systems were identical and were between 78% and 83% for both the CAAO and EAAO. The effluent COD concentration was not significantly affected by the proposed method of treatment. From the results of the present study, it is concluded that the proposed mode of treatment was capable of both sustainable removal of P and control of excess sludge production.
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Kavitha, S.,Rajesh Banu, J.,Kumar, Gopalakrishnan,Kaliappan, S.,Yeom, Ick Tae Elsevier 2018 Bioresource technology Vol.254 No.-
<P><B>Abstract</B></P> <P>In this study, microwave irradiation has been employed to disintegrate the sludge biomass profitably by deagglomerating the sludge using a mechanical device, ultrasonicator. The outcomes of the study revealed that a specific energy input of 3.5 kJ/kg TS was found to be optimum for deagglomeration with limited cell lysis. A higher suspended solids (SS) reduction and biomass lysis efficiency of about 22.5% and 33.2% was achieved through ultrasonic assisted microwave disintegration (UMWD) when compared to microwave disintegration – MWD (15% and 20.9%). The results of biochemical methane potential (BMP) test were used to estimate biodegradability of samples. Among the samples subjected to BMP, UMWD showed better amenability towards anaerobic digestion with higher methane production potential of 0.3 L/g COD representing enhanced liquefaction potential of disaggregated sludge biomass. Economic analysis of the proposed method of sludge biomass pretreatment showed a net profit of 2.67 USD/Ton respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Floc deagglomeration happens significantly at 3.5 kJ/kg TS of ultrasonic energy. </LI> <LI> Biomass lysis efficiency of 33.2% was achieved in phase separated disintegration. </LI> <LI> Phase separation shows better amenability towards anaerobic biodegradation. </LI> <LI> Net profit of about 2.67 USD/Ton was achieved in phase separated disintegration. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Two-Stage Anaerobic Treatment of Dairy Wastewater Using HUASB with PUF and PVC Carrier
Banu, J. Rajesh,Kaliappan, S.,Yeom, Ick-Tae Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3
In the present study, an attempt has been made to treat dairy wastewater entirely via anaerobic treatment over a period of 215 days, using two-stage Hybrid Upflow Anaerobic Sludge Blanket (HUASB) reactors, which offer the advantages associated both with fixed film and upflow sludge blanket treatments. A HUASB with polyurethane foam cubes was used for stage I, and a HUASB utilizing PVC-cut rings was used for stage II. The output from stage I was used as the input for stage II. The two-stage reactor was operated at an organic loading rate that varied from 10.7 to 21.4kg $COD\;m^3/d$ for a period of 215 days, including the start-up period. The ideal organic loading rate for the two-stage reactor was 19.2kg $COD/m^3/d$. A further 21.4 kg $COD\;m^3/d$ increase in the organic loading rate resulted in the souring of the reactor function in stage I, which consequently reduced the overall reactor performance. Combined COD removal during the stable operation period (10.7 to 19.2kg $COD\;m^3/d$) occurred in a range between 97 and 99%. The methane content in the biogas varied from 65 to 70% in stage I, and from 63 to 66% in stage II. The two-stage anaerobic treatment using HUASB with PUF and PVC described in this work is expected to constitute a better alternative for the complete treatment of dairy wastewater than high-rate anaerobic, anaerobic/aerobic, and two-phase anaerobic treatment methods.
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Two-Stage Anaerobic Treatment of DairyWastewater Using HUASB with PUF andPVC Carrier
염익태,J. Rajesh Banu,S. Kaliappan 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3
In the present study, an attempt has been made to treat dairy wastewater entirely via anaerobic treatment over a period of 215 days, using two-stage Hybrid Upflow Anaerobic Sludge Blanket (HUASB) reactors, which offer the advantages associated both with fixed film and upflow sludge blanket treatments. A HUASB with polyurethane foam cubes was used for stage I, and a HUASB utilizing PVC-cut rings was used for stage II. The output from stage I was used as the input for stage II. The two-stage reactor was operated at an organic loading rate that varied from 10.7 to 21.4 kg COD m3/d for a period of 215 days, including the start-up period. The ideal organic loading rate for the two-stage reactor was 19.2 kg COD/m3/d. A further 21.4 kg COD m3/d increase in the organic loading rate resulted in the souring of the reactor function in stage I, which consequently reduced the overall reactor performance. Combined COD removal during the stable operation period (10.7 to 19.2 kg COD m3/d) occurred in a range between 97 and 99%. The methane content in the biogas varied from 65 to 70% in stage I, and from 63 to 66% in stage II. The two-stage anaerobic treatment using HUASB with PUF and PVC described in this work is expected to constitute a better alternative for the complete treatment of dairy wastewater than high-rate anaerobic, anaerobic/aerobic, and two-phase anaerobic treatment methods.
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Eswari, P.,Kavitha, S.,Kaliappan, S.,Yeom, I. T.,Banu, J. R. Springer Science + Business Media 2016 Environmental Science and Pollution Research Vol.23 No.13
<P>The aim of this study was to increase the sludge disintegration and reduce the cost of microwave (MW) pretreatment. Thermodynamic analysis of MW hydrolysis revealed the best fit with a first-order kinetic model at a specific energy of 18,600 kJ/kg total solids (TS). Combining H2O2 with MW resulted in a significant increment in solubilization from 30 to 50 % at 18,600 kJ/kg TS. The pH of H2O2-assisted MW-pretreated sludge (MW + H2O2) was in the alkaline range (pH 9-10), and it made the sludge unfavorable for subsequent anaerobic digestion and inhibits methane production. In order to nullify the alkaline effect caused by the MW + H2O2 combination, the addition of acid was considered for pH adjustment. H2O2-assisted MW-pretreated sludge in acidic conditions (MW + H2O2 + acid) showed a maximum methane production of 323 mL/g volatile solids (VS) than others during anaerobic biodegradability. A cost analysis of this study reveals that MW + H2O2 + acid was the most economical method with a net profit of 59.90 a,not sign/t of sludge.</P>
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Ushani, U.,Rajesh Banu, J.,Kavitha, S.,Kaliappan, S.,Yeom, Ick Tae Elsevier 2017 CHEMOSPHERE - Vol.175 No.-
<P><B>Abstract</B></P> <P>In this study, an attempt was made to disintegrate waste activated sludge (WAS) in a cost-effective way. During the first phase of this study, effective break down of extracellular polymeric substance (EPS) was performed by deflocculating WAS with 0.1 g/g SS of MgSO<SUB>4</SUB>. Deflocculation rate was 92% with discharge rate of extractable EPS at 185 mg/L. In the second phase, effective bacterial cell disintegration was obtained at 36 h post treatment. Maximum solubilization of deflocculated sludge was approximately 21%, which was higher than that of flocculated sludge (14.2%) or the control (4.5%). Biodegradability studies were assessed through kinetic analysis by non-linear regression modeling. Results revealed that the deflocculated sludge had higher methane generation (at about 235.8 mL/gVs) compared to flocculated sludge (at 146.1 mL/gVs) or the control (at 34.8 mL/gVs). Cost assessment of the present work revealed that the net yield for each ton of the deflocculated sludge was about 32.99 USD.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Optimum floc disruption was occurred at 0.1 g/g SS of MgSO<SUB>4</SUB>. </LI> <LI> COD Solubilization of about 21% is obtained in deflocculated sludge. </LI> <LI> A higher methane generation of 235.8 mL/gVs was achieved for deflocculated sludge. </LI> <LI> A net profit of 32.99 USD was obtained for deflocculated sludge. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Effect of Alum on Nitrification during Simultaneous Phosphorous Removal in Anoxic/Oxic Reactor
J. Rajesh Banu,Khac-Uan Do,S. Kaliappan,염익태 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.4
Phosphorus and nitrogen are the important eutrophication nutrients. They are removed in the anoxic/oxic reactor through simultaneous precipitation and biological nitrogen removal. The effect of alum a commonly used simultaneous precipitant on biological nitrification and denitrification are investigated in the present study. Simultaneous removal of phosphorus was carried out using the coagulant alum Al₂(SO₄)₃∙14H₂O at 2.2 mol ratio. Before the start of simultaneous precipitation the nitrification rate of the A/O reactor was found to be 0.05 g N-NH4+/g VSS/d. It starts to decrease with increase in coagulant dosage. The nitrification rate for alum dosage 97.13 mg/L was 0.38 g N- NH₄+/g VSS/d. There was no accumulation of nitrate in anoxic tank. The nitrogen removal efficiency of the reactor was affected and it fell from 88 to 78%. There was a slight decrease in effluent COD from 16~20 mg/L to 8~12 mg/L after the introduction of simultaneous precipitation into the reactor. The usage of alum as a simultaneous precipitant in the anoxic/oxic reactor was limited due to its inhibition on nitrification. Alum did not have any affect over denitrification process.
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