The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to ent...The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to entrap the free hydroxyl radicals,cavitation contributed to 82.91%of the total sonication effect.The power consumed by temperature rising accounted for more than40%of ultrasound power input at the power density of 0.215 W/m L and the sonication time of 10 min.With the thermal insulation of polyfoam coating during sonication,a 18.37%of soluble chemical oxygen demand(SCOD)increment was observed.With the process of pre-heating the PS before sonication,64.15%of SCOD increment was achieved.Compared with the particle size of 13.77μm for the sonicated PS,the sludge mean particle size decreased to 12.83 and11.98μm by applying polyfoam coating and pre-heating the PS to enhance the cavitation and thermal effect.It suggested that if thermal energy consumption was relieved during the sonication process of PS,more energy could be used to disintegrate the sludge.展开更多
Saccharification of lignocellulosic wastes is the bottleneck of different bio-based chemical industries.Using enzymes for saccharification of lignocellulosic materials has several advantages over using chemicals.In th...Saccharification of lignocellulosic wastes is the bottleneck of different bio-based chemical industries.Using enzymes for saccharification of lignocellulosic materials has several advantages over using chemicals.In the current work,the application of the Maximyze■ enzyme system,which is industrially used in papermaking,was investigated in the saccharification of paper sludge and fiber dust wastes from the tissue paper industry.For optimizing the saccharification process,the effects of the consistency%,enzyme loading,and incubation time were studied and optimized using the Response Surface Methodology.The effect of these factors on the weight loss of paper sludge and total sugars in the hydrolyzate was studied.High-Performance Liquid Chromatography(HPLC)was used to measure the sugars composition of the hydrolyzate.Under the optimized conditions,~90% and~66% of the fiber dust and paper sludge could be hydrolyzed into sugars,respectively.The sugar composition was 80.23% glucose,10.99% xylose,and 8.65% arabinose based on the total sugars in the case of fiber dust.In comparison,80.63% glucose,8.43% xylose,and 10.75% arabinose were detected in the case of paper sludge.The results showed the applicability of the Maximyze Rcommercial enzymes used in the paper industry for efficient saccharification of paper sludge and fiber dust.The presence of non-cellulosic materials in the paper sludge(residual ink,paper additives,and ash)didn’t affect the activity of the enzymes.The study also showed the potential use of fiber dust as a valuable and clean source of sugars that can be used to prepare different bio-based chemicals.展开更多
Anaerobic digestion(AD)has long been used to treat different types of organic wastes especially in the developed world.However,organic wastes are still more often considered as a waste instead of a resource in the dev...Anaerobic digestion(AD)has long been used to treat different types of organic wastes especially in the developed world.However,organic wastes are still more often considered as a waste instead of a resource in the developing world,which contributes to environmental pollution arising from their disposal.This study has been conducted at Bugolobi Sewage Treatment Plant(BSTP),where two organic wastes,cow manure and brewery sludge were co-digested with primary sludge in different proportions.This study was done in lab-scale reactors at mesophilic temperature and sludge retention time of 20 d.The main objective was to evaluate the biodegradability of primary sludge generated at BSTP,Kampala,Uganda and enhance its ability of biogas production.When the brewery sludge was added to primary STP sludge at all proportions,the biogas production rate increased by a factor of 3.This was significantly(p<0.001)higher than observed gas yield(337±18)mL/(L·d))in the control treatment containing(only STP sludge).Co-digesting STP sludge with cow manure did not show different results compared to the control treatment.In conclusion,Bugolobi STP sludge is poorly anaerobically degradable with low biogas production but co-digestion with brewery sludge enhanced the biogas production rate,while co-digestion with cow manure was not beneficial.展开更多
The study investigates the potential of anaerobic co-digestion(AcoD)as a sustainable solution for managing putrescible organic waste generated by leather processing.Three experiments were conducted to assess the impac...The study investigates the potential of anaerobic co-digestion(AcoD)as a sustainable solution for managing putrescible organic waste generated by leather processing.Three experiments were conducted to assess the impact of various tannery wastes,pretreatment methods,and waste combinations on methane production.Experiment 1 demonstrated that co-digesting tannery wastewater primary sludge(TWPS)and fleshings significantly increased methane yield compared to digesting TWPS alone,though the addition of chromium-and vegetable-tanned leather wastes decreased yield.Experiment 2 explored TWPS pretreatment methods and found that ultrasonic pretreatment increased soluble chemical oxygen demand(SCOD)but did not significantly improve methane yield,suggesting that pretreatment may not be necessary.Experiment 3 revealed that increasing the proportion of fleshings to TWPS resulted in higher methane yield,ranging from 226.52 mL/gVS with 6%fleshings to 395.71 mL/gVS and 538.34 mL/gVS with 12%and 20%of fleshings,respectively.Additionally,this increase in fleshings also led to a reduction in digester volume.These findings highlight the importance of AcoD in addressing both environmental and eco-nomic challenges in the leather industry.展开更多
基金National Natural Science Foundation of China(No.51478099)Scientific Research Foundation for Returned Overseas Chinese Scholars of China(No.SEM-11W11329)
文摘The main pathways of primary sludge(PS)ultrasonic disintegration were analyzed at the sonication frequency of 20 kH z and the thermal effect on PS disintegration was investigated.By adding Na HCO3as a scavenger to entrap the free hydroxyl radicals,cavitation contributed to 82.91%of the total sonication effect.The power consumed by temperature rising accounted for more than40%of ultrasound power input at the power density of 0.215 W/m L and the sonication time of 10 min.With the thermal insulation of polyfoam coating during sonication,a 18.37%of soluble chemical oxygen demand(SCOD)increment was observed.With the process of pre-heating the PS before sonication,64.15%of SCOD increment was achieved.Compared with the particle size of 13.77μm for the sonicated PS,the sludge mean particle size decreased to 12.83 and11.98μm by applying polyfoam coating and pre-heating the PS to enhance the cavitation and thermal effect.It suggested that if thermal energy consumption was relieved during the sonication process of PS,more energy could be used to disintegrate the sludge.
基金funding of the current work by the Science,Technology,and Innovation Funding Authority(STDF),Egypt,project no.46104:“Recycling of sludge wastes from paper industry via green technologies”.
文摘Saccharification of lignocellulosic wastes is the bottleneck of different bio-based chemical industries.Using enzymes for saccharification of lignocellulosic materials has several advantages over using chemicals.In the current work,the application of the Maximyze■ enzyme system,which is industrially used in papermaking,was investigated in the saccharification of paper sludge and fiber dust wastes from the tissue paper industry.For optimizing the saccharification process,the effects of the consistency%,enzyme loading,and incubation time were studied and optimized using the Response Surface Methodology.The effect of these factors on the weight loss of paper sludge and total sugars in the hydrolyzate was studied.High-Performance Liquid Chromatography(HPLC)was used to measure the sugars composition of the hydrolyzate.Under the optimized conditions,~90% and~66% of the fiber dust and paper sludge could be hydrolyzed into sugars,respectively.The sugar composition was 80.23% glucose,10.99% xylose,and 8.65% arabinose based on the total sugars in the case of fiber dust.In comparison,80.63% glucose,8.43% xylose,and 10.75% arabinose were detected in the case of paper sludge.The results showed the applicability of the Maximyze Rcommercial enzymes used in the paper industry for efficient saccharification of paper sludge and fiber dust.The presence of non-cellulosic materials in the paper sludge(residual ink,paper additives,and ash)didn’t affect the activity of the enzymes.The study also showed the potential use of fiber dust as a valuable and clean source of sugars that can be used to prepare different bio-based chemicals.
基金The authors wish to acknowledge the financial support from VLIR,the Belgian scholarship body and National Water and Sewerage Corporation(NWSC)for further support in Uganda.We also wish to acknowledge Henry Mugabi(EABL),Cyrus Galyaki,Nabatesa Sylvia and Chaba Charles(NWSC)for the Lab and field work support.Willy Verstraete and Korneel Rabaey acknowledge support from the Ghent University Multidisciplinary Research Partnership(MRP)“Biotechnology for a Sustainable Economy”(01 MRA 510W).
文摘Anaerobic digestion(AD)has long been used to treat different types of organic wastes especially in the developed world.However,organic wastes are still more often considered as a waste instead of a resource in the developing world,which contributes to environmental pollution arising from their disposal.This study has been conducted at Bugolobi Sewage Treatment Plant(BSTP),where two organic wastes,cow manure and brewery sludge were co-digested with primary sludge in different proportions.This study was done in lab-scale reactors at mesophilic temperature and sludge retention time of 20 d.The main objective was to evaluate the biodegradability of primary sludge generated at BSTP,Kampala,Uganda and enhance its ability of biogas production.When the brewery sludge was added to primary STP sludge at all proportions,the biogas production rate increased by a factor of 3.This was significantly(p<0.001)higher than observed gas yield(337±18)mL/(L·d))in the control treatment containing(only STP sludge).Co-digesting STP sludge with cow manure did not show different results compared to the control treatment.In conclusion,Bugolobi STP sludge is poorly anaerobically degradable with low biogas production but co-digestion with brewery sludge enhanced the biogas production rate,while co-digestion with cow manure was not beneficial.
基金supported by Sanyo Leather Co.,Ltd.We also acknowledge the financial assistance provided by the Grant-in-Aid for JSPS Fellows under Grant Numbers 19F19106 and 22KF0257.
文摘The study investigates the potential of anaerobic co-digestion(AcoD)as a sustainable solution for managing putrescible organic waste generated by leather processing.Three experiments were conducted to assess the impact of various tannery wastes,pretreatment methods,and waste combinations on methane production.Experiment 1 demonstrated that co-digesting tannery wastewater primary sludge(TWPS)and fleshings significantly increased methane yield compared to digesting TWPS alone,though the addition of chromium-and vegetable-tanned leather wastes decreased yield.Experiment 2 explored TWPS pretreatment methods and found that ultrasonic pretreatment increased soluble chemical oxygen demand(SCOD)but did not significantly improve methane yield,suggesting that pretreatment may not be necessary.Experiment 3 revealed that increasing the proportion of fleshings to TWPS resulted in higher methane yield,ranging from 226.52 mL/gVS with 6%fleshings to 395.71 mL/gVS and 538.34 mL/gVS with 12%and 20%of fleshings,respectively.Additionally,this increase in fleshings also led to a reduction in digester volume.These findings highlight the importance of AcoD in addressing both environmental and eco-nomic challenges in the leather industry.
