azlan ahmad - Academia.edu (original) (raw)
Papers by azlan ahmad
Water Research, 2011
The physical characteristics, microbial activities and kinetic properties of the granular sludge ... more The physical characteristics, microbial activities and kinetic properties of the granular sludge biomass were investigated under the influence of different hydraulic retention times (HRT) along with the performance of the system in removal of color and COD of synthetic textile wastewater. The study was conducted in a column reactor operated according to a sequential batch reactor with a sequence of anaerobic and aerobic reaction phases. Six stages of different HRTs and different anaerobic and aerobic reaction time were evaluated. It was observed that the increase in HRT resulted in the reduction of organic loading rate (OLR). This has caused a decrease in biomass concentration (MLSS), reduction in mean size of the granules, lowered the settling ability of the granules and reduction of oxygen uptake rate (OUR), overall specific biomass growth rate (ìoverall), endogeneous decay rate (kd) and biomass yield (Yobs, Y). When the OLR was increased by adding carbon sources (glucose, sodium acetate and ethanol), there was a slight increase in the MLSS, the granules mean size, ìoverall, and biomass yield. Under high HRT, increasing the anaerobic to aerobic reaction time ratio caused an increase in the concentration of MLSS, mean size of granules and lowered the SVI value and biomass yield. The ìoverall and biomass yield increased with the reduction in anaerobic/aerobic time ratio. The HRT of 24 h with anaerobic and aerobic reaction time of 17.8 and 5.8 h respectively appear to be the best cycle operation of SBR. Under these conditions, not only the physical properties of the biogranules have improved, the highest removal of color (i.e. 94.1 ± 0.6%) and organics (i.e. 86.5 ± 0.5%) of the synthetic textile dyeing wastewater have been achieved.► Microbial granular sludge is used to treat synthetic textile wastewater in SBR. ► Effect of hydraulic retention time on the biomass treating textile wastewater. ► Physical properties of the microbial granular sludge were investigated. ► Microbial activities and biokinetic properties of the biomass were investigated. ► The percentage of removal efficiencies of color and COD were investigated.
Water research, 2010
Sequencing batch reactor Color removal a b s t r a c t Microbial granular sludge that is capable ... more Sequencing batch reactor Color removal a b s t r a c t Microbial granular sludge that is capable to treat textile wastewater in a single reactor under intermittent anaerobic and aerobic conditions was developed in this study. The granules were cultivated using mixed sewage and textile mill sludge in combination with anaerobic granules collected from an anaerobic sludge blanket reactor as seed. The granules were developed in a single sequential batch reactor (SBR) system under alternating anaerobic and aerobic condition fed with synthetic textile wastewater. The characteristics of the microbial granular sludge were monitored throughout the study period. During this period, the average size of the granules increased from 0.02 AE 0.01 mm to 2.3 AE 1.0 mm and the average settling velocity increased from 9.9 AE 0.7 m h À1 to 80 AE 8 m h À1 . This resulted in an increased biomass concentration (from 2.9 AE 0.8 g L À1 to 7.3 AE 0.9 g L À1 ) and mean cell residence time (from 1.4 days to 8.3 days). The strength of the granules, expressed as the integrity coefficient also improved. The sequential batch reactor system demonstrated good removal of COD and ammonia of 94% and 95%, respectively, at the end of the study.
This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the... more This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the performance and behaviour of the square sandwich panel under static loading was first examined. The sandwich panel was centrally loaded by using hemispherical and flat indenters on their respective support units. The panel materials used specifically for this project are mild steel skin and PVC foam namely R55 and polyurethane (PU) foam cores. The aim of this study is to obtain experimental evidence of the failure modes of square sandwich panels under concentrated load at the centre of panels, simply supported at the four edge corners for the square panel. After static tests, the whole curves for each panel were determined. The relation between the observed damage development, the property of degradation during the static test of the panels was investigated. In part II, the dynamic tests will be conducted in order to determine the performance, behaviour, effect of foam's type and the correlation between input energy from static and dynamic tests.
This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the... more This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the performance and behaviour of the square sandwich panel under static loading was first examined. The sandwich panel was centrally loaded by using hemispherical and flat indenters on their respective support units. The panel materials used specifically for this project are mild steel skin and PVC foam namely R55 and polyurethane (PU) foam cores. The aim of this study is to obtain experimental evidence of the failure modes of square sandwich panels under concentrated load at the centre of panels, simply supported at the four edge corners for the square panel. After static tests, the whole curves for each panel were determined. The relation between the observed damage development, the property of degradation during the static test of the panels was investigated. In part II, the dynamic tests will be conducted in order to determine the performance, behaviour, effect of foam's type and the correlation between input energy from static and dynamic tests.
Water Research, 2011
The physical characteristics, microbial activities and kinetic properties of the granular sludge ... more The physical characteristics, microbial activities and kinetic properties of the granular sludge biomass were investigated under the influence of different hydraulic retention times (HRT) along with the performance of the system in removal of color and COD of synthetic textile wastewater. The study was conducted in a column reactor operated according to a sequential batch reactor with a sequence of anaerobic and aerobic reaction phases. Six stages of different HRTs and different anaerobic and aerobic reaction time were evaluated. It was observed that the increase in HRT resulted in the reduction of organic loading rate (OLR). This has caused a decrease in biomass concentration (MLSS), reduction in mean size of the granules, lowered the settling ability of the granules and reduction of oxygen uptake rate (OUR), overall specific biomass growth rate (ìoverall), endogeneous decay rate (kd) and biomass yield (Yobs, Y). When the OLR was increased by adding carbon sources (glucose, sodium acetate and ethanol), there was a slight increase in the MLSS, the granules mean size, ìoverall, and biomass yield. Under high HRT, increasing the anaerobic to aerobic reaction time ratio caused an increase in the concentration of MLSS, mean size of granules and lowered the SVI value and biomass yield. The ìoverall and biomass yield increased with the reduction in anaerobic/aerobic time ratio. The HRT of 24 h with anaerobic and aerobic reaction time of 17.8 and 5.8 h respectively appear to be the best cycle operation of SBR. Under these conditions, not only the physical properties of the biogranules have improved, the highest removal of color (i.e. 94.1 ± 0.6%) and organics (i.e. 86.5 ± 0.5%) of the synthetic textile dyeing wastewater have been achieved.► Microbial granular sludge is used to treat synthetic textile wastewater in SBR. ► Effect of hydraulic retention time on the biomass treating textile wastewater. ► Physical properties of the microbial granular sludge were investigated. ► Microbial activities and biokinetic properties of the biomass were investigated. ► The percentage of removal efficiencies of color and COD were investigated.
Water research, 2010
Sequencing batch reactor Color removal a b s t r a c t Microbial granular sludge that is capable ... more Sequencing batch reactor Color removal a b s t r a c t Microbial granular sludge that is capable to treat textile wastewater in a single reactor under intermittent anaerobic and aerobic conditions was developed in this study. The granules were cultivated using mixed sewage and textile mill sludge in combination with anaerobic granules collected from an anaerobic sludge blanket reactor as seed. The granules were developed in a single sequential batch reactor (SBR) system under alternating anaerobic and aerobic condition fed with synthetic textile wastewater. The characteristics of the microbial granular sludge were monitored throughout the study period. During this period, the average size of the granules increased from 0.02 AE 0.01 mm to 2.3 AE 1.0 mm and the average settling velocity increased from 9.9 AE 0.7 m h À1 to 80 AE 8 m h À1 . This resulted in an increased biomass concentration (from 2.9 AE 0.8 g L À1 to 7.3 AE 0.9 g L À1 ) and mean cell residence time (from 1.4 days to 8.3 days). The strength of the granules, expressed as the integrity coefficient also improved. The sequential batch reactor system demonstrated good removal of COD and ammonia of 94% and 95%, respectively, at the end of the study.
This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the... more This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the performance and behaviour of the square sandwich panel under static loading was first examined. The sandwich panel was centrally loaded by using hemispherical and flat indenters on their respective support units. The panel materials used specifically for this project are mild steel skin and PVC foam namely R55 and polyurethane (PU) foam cores. The aim of this study is to obtain experimental evidence of the failure modes of square sandwich panels under concentrated load at the centre of panels, simply supported at the four edge corners for the square panel. After static tests, the whole curves for each panel were determined. The relation between the observed damage development, the property of degradation during the static test of the panels was investigated. In part II, the dynamic tests will be conducted in order to determine the performance, behaviour, effect of foam's type and the correlation between input energy from static and dynamic tests.
This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the... more This series of papers on behaviour of square sandwich panel consists of two parts. In part I, the performance and behaviour of the square sandwich panel under static loading was first examined. The sandwich panel was centrally loaded by using hemispherical and flat indenters on their respective support units. The panel materials used specifically for this project are mild steel skin and PVC foam namely R55 and polyurethane (PU) foam cores. The aim of this study is to obtain experimental evidence of the failure modes of square sandwich panels under concentrated load at the centre of panels, simply supported at the four edge corners for the square panel. After static tests, the whole curves for each panel were determined. The relation between the observed damage development, the property of degradation during the static test of the panels was investigated. In part II, the dynamic tests will be conducted in order to determine the performance, behaviour, effect of foam's type and the correlation between input energy from static and dynamic tests.