Nasir Ismail | University Putra Malaysia (original) (raw)

Papers by Nasir Ismail

Process Biochemistry, 2005

This work reviews the potential of anaerobic digestion for material recovery and energy productio... more This work reviews the potential of anaerobic digestion for material recovery and energy production from fruit and vegetable wastes (FVW). These wastes contain 8-18% total solids (TS), with a total volatile solids (VS) content of 86-92%. The organic fraction includes about 75% easy biodegradable matter (sugars and hemicellulose), 9% cellulose and 5% lignin. Anaerobic digestion of FVW was studied under different operating conditions using different types of bioreactors. It permits the conversion of 70-95% of organic matter to methane, with a volumetric organic loading rate (OLR) o f 1-6.8 g versatile solids (VS)/l day. A major limitation of anaerobic digestion of FVW is a rapid acidification of these wastes decreasing the pH in the reactor, and a larger volatile fatty acids production (VFA), which stress and inhibit the activity of methanogenic bacteria. Continuous two-phase systems appear as more highly efficient technologies for anaerobic digestion of FVW. Their greatest advantage lies in the buffering of the organic loading rate taking place in the first stage, allowing a more constant feeding rate of the methanogenic second stage. Using a two-stage system involving a thermophilic liquefaction reactor and a mesophilic anaerobic filter, over 95% volatile solids were converted to methane at a volumetric loading rate of 5.65 g VS/l d. The average methane production yield was about 420 l/kg added VS.

Skin colour detection is frequently been used for searching people, face detection, pornographic ... more Skin colour detection is frequently been used for searching people, face detection, pornographic filtering and hand tracking. The presence of skin or non-skin in digital image can be determined by manipulating pixels' colour and/or pixels' texture. The main problem in skin colour detection is to represent the skin colour distribution model that is invariant or least sensitive to changes in illumination condition. Another problem comes from the fact that many objects in the real world may possess almost similar skin-tone colour such as wood, leather, skin-coloured clothing, hair and sand. Moreover, skin colour is different between races and can be different from a person to another, even with people of the same ethnicity. Finally, skin colour will appear a little different when different types of camera are used to capture the object or scene. The objective in this study is to develop a skin colour classifier based on pixel-based using RGB ratio model. The RGB ratio model is a newly proposed method that belongs under the category of an explicitly defined skin region model. This skin classifier was tested with SIdb dataset and two benchmark datasets; UChile and TDSD datasets to measure classifier performance. The performance of skin classifier was measured based on true positive (TF) and false positive (FP) indicator. This newly proposed model was compared with Kovac, Saleh and Swift models. The experimental results showed that the RGB ratio model outperformed all the other models in term of detection rate. The RGB ratio model is able to reduce FP detection that caused by reddish objects colour as well as be able to detect darkened skin and skin covered by shadow.

... KILANG KELAPA SAWIT MENGGUNAKAN KULTUR CAMPURAN DI DALAM REAKTOR JUJUKAN BERKELOMPOK (SBR)) M... more ... KILANG KELAPA SAWIT MENGGUNAKAN KULTUR CAMPURAN DI DALAM REAKTOR JUJUKAN BERKELOMPOK (SBR)) MUZAFFAR ZAINAL ABIDEEN MOHD. FADHIL BIN MD. DIN ZAINI UJANG SALMIATI ... Lampiran 20 MUZAFFAR ZAINAL ABIDEEN Page 3. ABSTRACT ...

The effectiveness of cow dung for biogas production was investigated, using a laboratory scale 10... more The effectiveness of cow dung for biogas production was investigated, using a laboratory scale 10L bioreactor working in batch and semi-continuous mode at 53 o C. Anaerobic digestion seemed feasible with an organic loading of up to 1.7 kg volatile solids (VS)/L d and an HRT of 10 days during the semi-continuous operation. The averaged cumulative biogas yield and methane content observed was 0.15 L/kg VS added and 47%, respectively. The TS, VS and COD removals amounted to 49%, 47% and 48.5%, respectively. The results of the VS/TS ratio showed very small variation, which denote adequate mixing performance. However there was some evidence of ammonia inhibition probably due to the uncontrolled pH employed. The data obtained establish that cow dung is an effective feedstock for biogas production achieving high cumulative biogas yield with stable performance. The future work will be carried out to study the effect of varying organic loading rate on anaerobic digestion of cow dung in a semi-continuous mode.

The feasibility of an anaerobic digestion of cattle manure for biogas production is studied in th... more The feasibility of an anaerobic digestion of cattle manure for biogas production is studied in this paper. A batch thermophilic oscillatory flow anaerobic bioreactor (OFBR) operated in thermophilic (55 o C) condition was used. Within the experimental conditions set in this study, the effect of mixing intensity on volatile solids removal was found out to be significant. Results demonstrated that increasing the level of mixing decreased the digester performance. Low intensity mixing at oscillatory Reynolds number (Re o) of 100 achieved an increase of 37% in biogas yields compared to high mixing intensity, Re o of 500. It was observed that the mixing intensity effect interacts with the methane composition in the biogas. The benefit of decreasing mixing intensity emerges to significantly increase the methane composition in the biogas. These experiments established that high intensity mixing was not essential for good performance of oscillatory flow anaerobic bioreactor. In addition, the effect of mixing intensity might be reduced through the use of a slightly lower total solid concentration, hence, lowering the operational cost of the process. Although the study was lab scale a pilot-scale system where mixing retention times are longer would be useful.

Renewable energy projects in many developing countries need financial and legal back up from gove... more Renewable energy projects in many developing countries need financial and legal back up from governments and other supportive bodies. There is a viable alternative to finite energy via usage of biomass waste a renewable energy source. The electrical energy production analysis on biomass waste presented in this paper is based on the experimental analysis carried out using the laboratory and pilot scale bioreactors. Electrical energy generated with oscillatory flow bioreactor (OFBR) was 10.12 kWh or up to 91% higher than the 10 L lab scale bioreactor (0.9 kWh), demonstrating that the novel OFBR has a great potential for renewable electricity. Also, the pilot scale plant achieves a value of 12.3 kWh, which the difference is not quite significant with that of OFBR. These results illustrate that the generation of the renewable electricity is feasible especially with the OFBR thereby achieving high methane potential during the treatment of manure and food waste. Nevertheless, energy recoveries should be enhanced to improve the entire operational performance.

A novel oscillatory flow bioreactor (OFBR) was designed and constructed to investigate the start-... more A novel oscillatory flow bioreactor (OFBR) was designed and constructed to investigate the start-up and performance of the reactor for the treatment of cattle manure for biogas production. The start-up of the OFBR could be accomplished in less than 65 days through the stepwise increase of the organic loading rate (OLR) and sustaining a constant hydraulic retention time (HRT). Results showed that at OLR between 2.8 to 5.2 g VS/L/day, the biogas production of the OFBR varies between 3 L/day to 26 L/day, respectively with overall average methane content of about 67%. The pH and the volatile fatty acids (VFA) concentration remained stable. Overall, the process efficiencies appeared to increase considerably with increase in the OLR and providing a stabilised anaerobic treatment. Hence, the use of OFBR seemed to have a positive effect on the process stability both at both lower and higher OLR as indicated by the improved performance.

Biogas produced from lignocellulosic biomass, e.g. animal manure, has the potential to be a promi... more Biogas produced from lignocellulosic biomass, e.g. animal manure, has the potential to be a promising renewable energy source. Special emphasis has been placed on animal manure pretreatment in an anaerobic digestion as a means of enhancing biogas yield. Here, we review the existing pretreatment methods of anaerobic digestion with regard to their effects on the conversion of animal manure to biogas. Various methods and their challenges are highlighted. The effects of pretreatment are complex and usually depend on the animal waste characteristics and the method of choice. In general, pretreatment enhances the anaerobic digestion of the lignocellulosic content of the animal manure, by increasing the methane yield in similar operating conditions as those without the pretreatment.

A literature review has been undertaken to investigate the potential of anaerobic digestion for m... more A literature review has been undertaken to investigate the potential of anaerobic digestion for material recovery and energy production from cattle manure. These wastes constitute 8-20% total solid, with a volatile solid content of 70-85%. The biodegradable fractions include about 11% hemicellulose, 26-53% cellulose, and 11% lignin. Anaerobic digestion of cattle manure was studied under various operating conditions using different types of bioreactors and it allows the conversion of 50-75% of organic matter to methane with an organic loading rate of 1-6 g VS/L day. Continuous two-stage configuration involving a first-stage thermophilic reactor and mesophilic second reactor emerges to be superior and the most effective technologies for anaerobic digestion of cattle manure. It was demonstrated that 41% of volatile solids were converted to methane at an organic loading rate of 5.82 g VS/L day. The methane yield was found to be 620 L/kg VS added.

This study evaluated the performance of anaerobic treatment of cattle manure (CM) with palm oil m... more This study evaluated the performance of anaerobic treatment of cattle manure (CM) with palm oil mill effluent (POME) inoculum in terms of biogas production and volatile solid (VS) reduction. The objective of the study was to determine the effect of substrate to (POME) ratio used as inoculum on digester performance. The study was conducted in a 10-L lab-scale bioreactor operated at thermophilic (53 o C) temperature. The result from the study showed that anaerobic digestion of cattle manure with POME inoculum can be done successfully in batch and semi-continuous mode. Biogas production was observed to commence immediately and the POME inoculum shown a strong influence on the initial biogas production rate. Average biogas yield was estimated to be about 0.346 and 0.299 m 3 kg -1 VS added for the CM(5) : POME(1.5) and CM(5) : POME(1) respectively. However, nearly similar chemical oxygen demand (COD) removal of 33% and 30% with volatile solids (VS) removal of 58.6% and 52% for the CM(5):P0ME(1.5) and CM :POME(1), respectively was achieved. These results are hopeful for the treatment of cattle wastes and POME mass available in Malaysia.

Anaerobic digestion of cattle manure was investigated to estimate the volume and the quality of b... more Anaerobic digestion of cattle manure was investigated to estimate the volume and the quality of biogas produced for both batch and semi-continuous system. The process was performed in a lab scale bioreactor at 55 o C; the semi-continuous experiment was conducted at an organic loading rate (OLR) of 1.7 kg VS m -3 day -1 equivalent to hydraulic retention time (HRT) of 20 days. The volatile solid-based biogas and methane yield were observed to be averagely 0.346 m3 kg -1 VS added and 0.19 m 3 kg -1 VS added respectively. The average methane content was 55% from the cattle manure during the anaerobic digestion process. Overall, the result of this study indicates that the quality of biogas obtained from the cattle wastes can be used for heat and power production.

Biogas production from cattle manure (CM) is of growing importance as it offers considerable envi... more Biogas production from cattle manure (CM) is of growing importance as it offers considerable environmental benefits. The supplementation of palm oil mill effluent (POME) in anaerobic digestion of CM can be beneficial as it provide a source of energy, while simultaneously resolving ecological and water pollution. Biogas production was investigated in a 10 L bioreactor operated in batch and semi-continuous mode at 53 o C. An enhanced biogas yield of 0.346 m 3 kg -1 VS added was observed from the CM with POME digestion, while the biogas production is not higher when CM was digested alone. Also, the VS and COD reduction for CM with POME digestion were 69 and 65% higher than raw CM digestion. The results showed that valid contribution has been done by the use of POME.

Anaerobic digestion treatments have often been used for biological stabilization of solid wastes.... more Anaerobic digestion treatments have often been used for biological stabilization of solid wastes. These treatment processes generate biogas which can be used as a renewable energy sources. Recently, anaerobic digestion of solid wastes has attracted more interest because of current environmental problems, most especially those concerned with global warming. Thus, laboratory-scale research on this area has increased significantly. In this review paper, the summary of the most recent research activities covering production of biogas from solid wastes according to its origin via various anaerobic technologies was presented.

This article reviews the potential of anaerobic digestion (AD) for biogas production from livesto... more This article reviews the potential of anaerobic digestion (AD) for biogas production from livestock manure wastes and compares the operating and performance data for various anaerobic process configurations. It examines different kinds of manure waste treatment techniques and the influence of several parameters on biogas and methane yield. The comparison indicates that a variety of different operational conditions, various reactor configurations such as batch reactors, continuously stirred tank reactor (CSTR), plug flow reactor (PFR), up-flow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), temperature phased anaerobic digestion (TPAD), and continuous one-and two-stage systems, present a suitable technology for the AD of livestock manure waste. Main performance indicators are biogas and methane yield, degradation of volatile solids (VS), higher loading, and process stability with a short retention time.

Process Biochemistry, 2005

This work reviews the potential of anaerobic digestion for material recovery and energy productio... more This work reviews the potential of anaerobic digestion for material recovery and energy production from fruit and vegetable wastes (FVW). These wastes contain 8-18% total solids (TS), with a total volatile solids (VS) content of 86-92%. The organic fraction includes about 75% easy biodegradable matter (sugars and hemicellulose), 9% cellulose and 5% lignin. Anaerobic digestion of FVW was studied under different operating conditions using different types of bioreactors. It permits the conversion of 70-95% of organic matter to methane, with a volumetric organic loading rate (OLR) o f 1-6.8 g versatile solids (VS)/l day. A major limitation of anaerobic digestion of FVW is a rapid acidification of these wastes decreasing the pH in the reactor, and a larger volatile fatty acids production (VFA), which stress and inhibit the activity of methanogenic bacteria. Continuous two-phase systems appear as more highly efficient technologies for anaerobic digestion of FVW. Their greatest advantage lies in the buffering of the organic loading rate taking place in the first stage, allowing a more constant feeding rate of the methanogenic second stage. Using a two-stage system involving a thermophilic liquefaction reactor and a mesophilic anaerobic filter, over 95% volatile solids were converted to methane at a volumetric loading rate of 5.65 g VS/l d. The average methane production yield was about 420 l/kg added VS.

Skin colour detection is frequently been used for searching people, face detection, pornographic ... more Skin colour detection is frequently been used for searching people, face detection, pornographic filtering and hand tracking. The presence of skin or non-skin in digital image can be determined by manipulating pixels' colour and/or pixels' texture. The main problem in skin colour detection is to represent the skin colour distribution model that is invariant or least sensitive to changes in illumination condition. Another problem comes from the fact that many objects in the real world may possess almost similar skin-tone colour such as wood, leather, skin-coloured clothing, hair and sand. Moreover, skin colour is different between races and can be different from a person to another, even with people of the same ethnicity. Finally, skin colour will appear a little different when different types of camera are used to capture the object or scene. The objective in this study is to develop a skin colour classifier based on pixel-based using RGB ratio model. The RGB ratio model is a newly proposed method that belongs under the category of an explicitly defined skin region model. This skin classifier was tested with SIdb dataset and two benchmark datasets; UChile and TDSD datasets to measure classifier performance. The performance of skin classifier was measured based on true positive (TF) and false positive (FP) indicator. This newly proposed model was compared with Kovac, Saleh and Swift models. The experimental results showed that the RGB ratio model outperformed all the other models in term of detection rate. The RGB ratio model is able to reduce FP detection that caused by reddish objects colour as well as be able to detect darkened skin and skin covered by shadow.

... KILANG KELAPA SAWIT MENGGUNAKAN KULTUR CAMPURAN DI DALAM REAKTOR JUJUKAN BERKELOMPOK (SBR)) M... more ... KILANG KELAPA SAWIT MENGGUNAKAN KULTUR CAMPURAN DI DALAM REAKTOR JUJUKAN BERKELOMPOK (SBR)) MUZAFFAR ZAINAL ABIDEEN MOHD. FADHIL BIN MD. DIN ZAINI UJANG SALMIATI ... Lampiran 20 MUZAFFAR ZAINAL ABIDEEN Page 3. ABSTRACT ...

The effectiveness of cow dung for biogas production was investigated, using a laboratory scale 10... more The effectiveness of cow dung for biogas production was investigated, using a laboratory scale 10L bioreactor working in batch and semi-continuous mode at 53 o C. Anaerobic digestion seemed feasible with an organic loading of up to 1.7 kg volatile solids (VS)/L d and an HRT of 10 days during the semi-continuous operation. The averaged cumulative biogas yield and methane content observed was 0.15 L/kg VS added and 47%, respectively. The TS, VS and COD removals amounted to 49%, 47% and 48.5%, respectively. The results of the VS/TS ratio showed very small variation, which denote adequate mixing performance. However there was some evidence of ammonia inhibition probably due to the uncontrolled pH employed. The data obtained establish that cow dung is an effective feedstock for biogas production achieving high cumulative biogas yield with stable performance. The future work will be carried out to study the effect of varying organic loading rate on anaerobic digestion of cow dung in a semi-continuous mode.

The feasibility of an anaerobic digestion of cattle manure for biogas production is studied in th... more The feasibility of an anaerobic digestion of cattle manure for biogas production is studied in this paper. A batch thermophilic oscillatory flow anaerobic bioreactor (OFBR) operated in thermophilic (55 o C) condition was used. Within the experimental conditions set in this study, the effect of mixing intensity on volatile solids removal was found out to be significant. Results demonstrated that increasing the level of mixing decreased the digester performance. Low intensity mixing at oscillatory Reynolds number (Re o) of 100 achieved an increase of 37% in biogas yields compared to high mixing intensity, Re o of 500. It was observed that the mixing intensity effect interacts with the methane composition in the biogas. The benefit of decreasing mixing intensity emerges to significantly increase the methane composition in the biogas. These experiments established that high intensity mixing was not essential for good performance of oscillatory flow anaerobic bioreactor. In addition, the effect of mixing intensity might be reduced through the use of a slightly lower total solid concentration, hence, lowering the operational cost of the process. Although the study was lab scale a pilot-scale system where mixing retention times are longer would be useful.

Renewable energy projects in many developing countries need financial and legal back up from gove... more Renewable energy projects in many developing countries need financial and legal back up from governments and other supportive bodies. There is a viable alternative to finite energy via usage of biomass waste a renewable energy source. The electrical energy production analysis on biomass waste presented in this paper is based on the experimental analysis carried out using the laboratory and pilot scale bioreactors. Electrical energy generated with oscillatory flow bioreactor (OFBR) was 10.12 kWh or up to 91% higher than the 10 L lab scale bioreactor (0.9 kWh), demonstrating that the novel OFBR has a great potential for renewable electricity. Also, the pilot scale plant achieves a value of 12.3 kWh, which the difference is not quite significant with that of OFBR. These results illustrate that the generation of the renewable electricity is feasible especially with the OFBR thereby achieving high methane potential during the treatment of manure and food waste. Nevertheless, energy recoveries should be enhanced to improve the entire operational performance.

A novel oscillatory flow bioreactor (OFBR) was designed and constructed to investigate the start-... more A novel oscillatory flow bioreactor (OFBR) was designed and constructed to investigate the start-up and performance of the reactor for the treatment of cattle manure for biogas production. The start-up of the OFBR could be accomplished in less than 65 days through the stepwise increase of the organic loading rate (OLR) and sustaining a constant hydraulic retention time (HRT). Results showed that at OLR between 2.8 to 5.2 g VS/L/day, the biogas production of the OFBR varies between 3 L/day to 26 L/day, respectively with overall average methane content of about 67%. The pH and the volatile fatty acids (VFA) concentration remained stable. Overall, the process efficiencies appeared to increase considerably with increase in the OLR and providing a stabilised anaerobic treatment. Hence, the use of OFBR seemed to have a positive effect on the process stability both at both lower and higher OLR as indicated by the improved performance.

Biogas produced from lignocellulosic biomass, e.g. animal manure, has the potential to be a promi... more Biogas produced from lignocellulosic biomass, e.g. animal manure, has the potential to be a promising renewable energy source. Special emphasis has been placed on animal manure pretreatment in an anaerobic digestion as a means of enhancing biogas yield. Here, we review the existing pretreatment methods of anaerobic digestion with regard to their effects on the conversion of animal manure to biogas. Various methods and their challenges are highlighted. The effects of pretreatment are complex and usually depend on the animal waste characteristics and the method of choice. In general, pretreatment enhances the anaerobic digestion of the lignocellulosic content of the animal manure, by increasing the methane yield in similar operating conditions as those without the pretreatment.

A literature review has been undertaken to investigate the potential of anaerobic digestion for m... more A literature review has been undertaken to investigate the potential of anaerobic digestion for material recovery and energy production from cattle manure. These wastes constitute 8-20% total solid, with a volatile solid content of 70-85%. The biodegradable fractions include about 11% hemicellulose, 26-53% cellulose, and 11% lignin. Anaerobic digestion of cattle manure was studied under various operating conditions using different types of bioreactors and it allows the conversion of 50-75% of organic matter to methane with an organic loading rate of 1-6 g VS/L day. Continuous two-stage configuration involving a first-stage thermophilic reactor and mesophilic second reactor emerges to be superior and the most effective technologies for anaerobic digestion of cattle manure. It was demonstrated that 41% of volatile solids were converted to methane at an organic loading rate of 5.82 g VS/L day. The methane yield was found to be 620 L/kg VS added.

This study evaluated the performance of anaerobic treatment of cattle manure (CM) with palm oil m... more This study evaluated the performance of anaerobic treatment of cattle manure (CM) with palm oil mill effluent (POME) inoculum in terms of biogas production and volatile solid (VS) reduction. The objective of the study was to determine the effect of substrate to (POME) ratio used as inoculum on digester performance. The study was conducted in a 10-L lab-scale bioreactor operated at thermophilic (53 o C) temperature. The result from the study showed that anaerobic digestion of cattle manure with POME inoculum can be done successfully in batch and semi-continuous mode. Biogas production was observed to commence immediately and the POME inoculum shown a strong influence on the initial biogas production rate. Average biogas yield was estimated to be about 0.346 and 0.299 m 3 kg -1 VS added for the CM(5) : POME(1.5) and CM(5) : POME(1) respectively. However, nearly similar chemical oxygen demand (COD) removal of 33% and 30% with volatile solids (VS) removal of 58.6% and 52% for the CM(5):P0ME(1.5) and CM :POME(1), respectively was achieved. These results are hopeful for the treatment of cattle wastes and POME mass available in Malaysia.

Anaerobic digestion of cattle manure was investigated to estimate the volume and the quality of b... more Anaerobic digestion of cattle manure was investigated to estimate the volume and the quality of biogas produced for both batch and semi-continuous system. The process was performed in a lab scale bioreactor at 55 o C; the semi-continuous experiment was conducted at an organic loading rate (OLR) of 1.7 kg VS m -3 day -1 equivalent to hydraulic retention time (HRT) of 20 days. The volatile solid-based biogas and methane yield were observed to be averagely 0.346 m3 kg -1 VS added and 0.19 m 3 kg -1 VS added respectively. The average methane content was 55% from the cattle manure during the anaerobic digestion process. Overall, the result of this study indicates that the quality of biogas obtained from the cattle wastes can be used for heat and power production.

Biogas production from cattle manure (CM) is of growing importance as it offers considerable envi... more Biogas production from cattle manure (CM) is of growing importance as it offers considerable environmental benefits. The supplementation of palm oil mill effluent (POME) in anaerobic digestion of CM can be beneficial as it provide a source of energy, while simultaneously resolving ecological and water pollution. Biogas production was investigated in a 10 L bioreactor operated in batch and semi-continuous mode at 53 o C. An enhanced biogas yield of 0.346 m 3 kg -1 VS added was observed from the CM with POME digestion, while the biogas production is not higher when CM was digested alone. Also, the VS and COD reduction for CM with POME digestion were 69 and 65% higher than raw CM digestion. The results showed that valid contribution has been done by the use of POME.

Anaerobic digestion treatments have often been used for biological stabilization of solid wastes.... more Anaerobic digestion treatments have often been used for biological stabilization of solid wastes. These treatment processes generate biogas which can be used as a renewable energy sources. Recently, anaerobic digestion of solid wastes has attracted more interest because of current environmental problems, most especially those concerned with global warming. Thus, laboratory-scale research on this area has increased significantly. In this review paper, the summary of the most recent research activities covering production of biogas from solid wastes according to its origin via various anaerobic technologies was presented.

This article reviews the potential of anaerobic digestion (AD) for biogas production from livesto... more This article reviews the potential of anaerobic digestion (AD) for biogas production from livestock manure wastes and compares the operating and performance data for various anaerobic process configurations. It examines different kinds of manure waste treatment techniques and the influence of several parameters on biogas and methane yield. The comparison indicates that a variety of different operational conditions, various reactor configurations such as batch reactors, continuously stirred tank reactor (CSTR), plug flow reactor (PFR), up-flow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), temperature phased anaerobic digestion (TPAD), and continuous one-and two-stage systems, present a suitable technology for the AD of livestock manure waste. Main performance indicators are biogas and methane yield, degradation of volatile solids (VS), higher loading, and process stability with a short retention time.