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Determination of the Optimum Hydraulic Retention Time in Two-Stage Anaerobic Fluidized Bed Bioreactor for Landfill Leachate Treatment Prasetyo, Eli; Sudibyo, Hanifrahmawan; Budhijanto, Wiratni
Journal of Engineering and Technological Sciences Vol 49, No 3 (2017)
Publisher : ITB Journal Publisher, LPPM ITB

Leachate in Indonesian landfill sites poses a high risk to the surrounding environment should there be leakage in the accumulating ponds. Anaerobic digestion is an attractive option to clean up leachate, mostly due to the affordability of its operational cost. To enhance the efficiency of leachate digestion, anaerobic microbes were immobilized on the surface of natural zeolite powder. The powder was fluidized in a mesophilic anaerobic fluidized bed reactor (AFBR) for more stable biofilm formation. The AFBR scheme was split into two stages, with the first stage dominated by the acidogenic process and the second stage dominated by the methanogenic process. The dominating microbes in each stage were provoked by pH control to maintain the first stage acidic at pH 5-5.5 and the second stage neutral at pH 7-7.5. The first stage was run at five different hydraulic retention times (HRTs), while the second stage was run at three different HRTs to determine the optimum HRT for each stage. For acidogenic AFBR with HRTs of 5 days and 2.5 days, the VFA concentration profile increased for a longer period compared to the other HRTs. The COD removal efficiency at steady state was almost identical for all HRTs. For methanogenic AFBR, all three HRTs showed an identical rate of biogas formation at steady state.

Comparison of Formulation Methods to Produce Nano-Chitosan as Inhibitor Agent for Bacterial Growth Nugraheni, Prihati Sih; Soeriyadi, Alexander H.; Ustadi, Ustadi; Sediawan, Wahyudi Budi; Budhijanto, Wiratni
Journal of Engineering and Technological Sciences Vol 51, No 3 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Chitosan is known as an antibacterial agent. The effective surface area ratio of chitosan can be increased by modification into nanoparticles. Nano-chitosan can be prepared with several simple methods, i.e. precipitation, ionic gelation, or the polyelectrolyte complex method. This study compared these three methods in terms of the targeted product characteristics, i.e. stability of the average nanoparticle size as well as the colloidal dispersion, and the antibacterial characteristics. All three methods resulted in nanoparticle formation, but in the precipitation method significant zeta potential reduction was observed due to the presence of negative ions from the alkali that neutralized the chitosan amine group. The ionic gelation method yielded higher zeta potential and higher inhibition of bacterial growth than those yielded by the polyelectrolyte complex method. Ionic gelation and the polyelectrolyte complex method resulted in much better colloidal dispersion stability than the precipitation method, where a significant particle size increase was observed after one week of storage. This result indicates that both ionic gelation and the polyelectrolyte complex method can be used for forming nano-chitosan for the purpose of food preservation. However, for fishery products it is advisable to use the polyelectrolyte complex method because the TPP usually used in ionic gelation is not allowed to be applied to fish.

EVALUATION OF THE EFFECT OF OPERATING PARAMETERS ON THE PERFORMANCE OF ORIFICE/POROUS PIPE TYPE MICRO-BUBBLE GENERATOR Pambudiarto, Benny Arif; Mindaryani, Aswati; Deendarlianto, D.; Budhijanto, Wiratni
Journal of Engineering and Technological Sciences Vol 52, No 2 (2020)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2020.52.2.5

The micro-bubble generator (MBG) is a novel aeration technology utilizing the concept of fluid flow through an orifice, where air is sucked into the internal chamber of the MBG by the pressure difference created by the orifice and immediately pushed by the high-velocity flow of the fluid. This mechanism creates micro-size bubbles with a high dissolution rate. This study focused on studying the effect on the oxygen dissolution rate of the two most important operating parameters, i.e. the volumetric flow rate of the liquid (QL) and the volumetric flow rate of the air (QG). Various combinations of values for QL and QG were systematically compared by means of the oxygen mass transfer coefficient (kLa). The experiment was carried out in a transparent container of 2.8 m x 0.6 m x 0.4 m filled with tap water that was aerated using an orifice/porous-pipe type MBG. The dissolved oxygen (DO) values were measured at distances of 60 cm, 120 cm, and 180 cm from the MBG outlet. The experiment was designed with five different values for QL and QG respectively. The results showed that the value of kLa, which is proportional to the oxygen dissolution rate, increased asymptotically with increasing QL value, while the QG values did not significantly affect the kLa value.

Determination of the Optimum Hydraulic Retention Time in Two-Stage Anaerobic Fluidized Bed Bioreactor for Landfill Leachate Treatment Eli Prasetyo; Hanifrahmawan Sudibyo; Wiratni Budhijanto
Journal of Engineering and Technological Sciences Vol. 49 No. 3 (2017)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2017.49.3.7

Leachate in Indonesian landfill sites poses a high risk to the surrounding environment should there be leakage in the accumulating ponds. Anaerobic digestion is an attractive option to clean up leachate, mostly due to the affordability of its operational cost. To enhance the efficiency of leachate digestion, anaerobic microbes were immobilized on the surface of natural zeolite powder. The powder was fluidized in a mesophilic anaerobic fluidized bed reactor (AFBR) for more stable biofilm formation. The AFBR scheme was split into two stages, with the first stage dominated by the acidogenic process and the second stage dominated by the methanogenic process. The dominating microbes in each stage were provoked by pH control to maintain the first stage acidic at pH 5-5.5 and the second stage neutral at pH 7-7.5. The first stage was run at five different hydraulic retention times (HRTs), while the second stage was run at three different HRTs to determine the optimum HRT for each stage. For acidogenic AFBR with HRTs of 5 days and 2.5 days, the VFA concentration profile increased for a longer period compared to the other HRTs. The COD removal efficiency at steady state was almost identical for all HRTs. For methanogenic AFBR, all three HRTs showed an identical rate of biogas formation at steady state.

Comparison of Formulation Methods to Produce Nano-Chitosan as Inhibitor Agent for Bacterial Growth Prihati Sih Nugraheni; Alexander H. Soeriyadi; Ustadi Ustadi; Wahyudi Budi Sediawan; Wiratni Budhijanto
Journal of Engineering and Technological Sciences Vol. 51 No. 3 (2019)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2019.51.3.9

Chitosan is known as an antibacterial agent. The effective surface area ratio of chitosan can be increased by modification into nanoparticles. Nano-chitosan can be prepared with several simple methods, i.e. precipitation, ionic gelation, or the polyelectrolyte complex method. This study compared these three methods in terms of the targeted product characteristics, i.e. stability of the average nanoparticle size as well as the colloidal dispersion, and the antibacterial characteristics. All three methods resulted in nanoparticle formation, but in the precipitation method significant zeta potential reduction was observed due to the presence of negative ions from the alkali that neutralized the chitosan amine group. The ionic gelation method yielded higher zeta potential and higher inhibition of bacterial growth than those yielded by the polyelectrolyte complex method. Ionic gelation and the polyelectrolyte complex method resulted in much better colloidal dispersion stability than the precipitation method, where a significant particle size increase was observed after one week of storage. This result indicates that both ionic gelation and the polyelectrolyte complex method can be used for forming nano-chitosan for the purpose of food preservation. However, for fishery products it is advisable to use the polyelectrolyte complex method because the TPP usually used in ionic gelation is not allowed to be applied to fish.

Evaluation of the Effect of Operating Parameters on the Performance of Orifice/Porous Pipe Type Micro-bubble Generator Benny Arif Pambudiarto; Aswati Mindaryani; D. Deendarlianto; Wiratni Budhijanto
Journal of Engineering and Technological Sciences Vol. 52 No. 2 (2020)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2020.52.2.5

The micro-bubble generator (MBG) is a novel aeration technology utilizing the concept of fluid flow through an orifice, where air is sucked into the internal chamber of the MBG by the pressure difference created by the orifice and immediately pushed by the high-velocity flow of the fluid. This mechanism creates micro-size bubbles with a high dissolution rate. This study focused on studying the effect on the oxygen dissolution rate of the two most important operating parameters, i.e. the volumetric flow rate of the liquid (QL) and the volumetric flow rate of the air (QG). Various combinations of values for QL and QG were systematically compared by means of the oxygen mass transfer coefficient (kLa). The experiment was carried out in a transparent container of 2.8 m x 0.6 m x 0.4 m filled with tap water that was aerated using an orifice/porous-pipe type MBG. The dissolved oxygen (DO) values were measured at distances of 60 cm, 120 cm, and 180 cm from the MBG outlet. The experiment was designed with five different values for QL and QG respectively. The results showed that the value of kLa, which is proportional to the oxygen dissolution rate, increased asymptotically with increasing QL value, while the QG values did not significantly affect the kLa value.

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