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
This work deals with the effect of combined microwave-ultrasonic pretreatment on the anaerobic biodegradability of primary, excess activated and mixed sludge. The characteristics, biodegradability and anaerobic digest...This work deals with the effect of combined microwave-ultrasonic pretreatment on the anaerobic biodegradability of primary, excess activated and mixed sludge. The characteristics, biodegradability and anaerobic digester performance for untreated primary, excess activated and mixed sludge were compared to combined microwave-ultrasonic pretreated primary, excess activated and mixed sludge. All sludge samples were subjected to Microwave treatment at 2450 MHz, 800 W and 3 min followed by ultrasonic treatment at a density of 0.4 W/mL, amplitude of 90%, Intensity of 150 W, pulse of 55/5 for 6min. Methane production in pretreated primary sludge was significantly greater (11.9 ml/g TCOD) than the methane yield of the untreated primary sludge (7.9 ml/g TCOD). Cumulative methane production of pretreated Excess Activated Sludge (EAS) was higher (66.5 ml/g TCOD) than the methane yield from pretreated mixed sludge (44.1 ml/g TCOD). Furthermore, digested EAS showed significantly higher dewaterability (201 s) than digested primary sludge (305 s) or mixed sludge (522 s). The average Methane: Carbondioxide ratio from EAS (1.85) was higher than that for mixed untreated sludge (1.24). VS reduction was also higher for EAS than the other two sludge types. However, pretreatment of EAS resulted in significant reduction in dewaterability due to higher percentage of fine floc particles in the pretreated EAS.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
以月桂醇聚醚硫酸酯钠(AES)、月桂醇聚醚硫酸酯铵(AESA)为例:通过污泥耗氧速率的变化了解表面活性剂对活性污泥的抑制情况;用磁力搅拌表面曝气法代替震荡培养法测试了城镇污水处理厂的活性污泥对表面活性剂的生物降解能力;用污泥负荷表...以月桂醇聚醚硫酸酯钠(AES)、月桂醇聚醚硫酸酯铵(AESA)为例:通过污泥耗氧速率的变化了解表面活性剂对活性污泥的抑制情况;用磁力搅拌表面曝气法代替震荡培养法测试了城镇污水处理厂的活性污泥对表面活性剂的生物降解能力;用污泥负荷表征表面活性剂的初级生物降解速率,便于计算用活性污泥法处理表面活性剂至其起泡性能消失所需的时间。实验结果表明,AES、AESA浓度≥200 mg·L^(-1)时对活性污泥中部分微生物有抑制作用。当AES、AESA浓度≤100 mg·L^(-1)时,用城镇污水处理厂的活性污泥好氧处理的初级生物降解速率分别为0.06 kg AES.(kg MLSS·d)^(-1)、0.06 kg AESA.(kg MLSS·d)^(-1);用活性污泥法好氧处理20小时后的CODCr去除率分别为75.7%、79.9%;AESA的可生物降解性优于AES。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.
文摘This work deals with the effect of combined microwave-ultrasonic pretreatment on the anaerobic biodegradability of primary, excess activated and mixed sludge. The characteristics, biodegradability and anaerobic digester performance for untreated primary, excess activated and mixed sludge were compared to combined microwave-ultrasonic pretreated primary, excess activated and mixed sludge. All sludge samples were subjected to Microwave treatment at 2450 MHz, 800 W and 3 min followed by ultrasonic treatment at a density of 0.4 W/mL, amplitude of 90%, Intensity of 150 W, pulse of 55/5 for 6min. Methane production in pretreated primary sludge was significantly greater (11.9 ml/g TCOD) than the methane yield of the untreated primary sludge (7.9 ml/g TCOD). Cumulative methane production of pretreated Excess Activated Sludge (EAS) was higher (66.5 ml/g TCOD) than the methane yield from pretreated mixed sludge (44.1 ml/g TCOD). Furthermore, digested EAS showed significantly higher dewaterability (201 s) than digested primary sludge (305 s) or mixed sludge (522 s). The average Methane: Carbondioxide ratio from EAS (1.85) was higher than that for mixed untreated sludge (1.24). VS reduction was also higher for EAS than the other two sludge types. However, pretreatment of EAS resulted in significant reduction in dewaterability due to higher percentage of fine floc particles in the pretreated EAS.
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.
文摘以月桂醇聚醚硫酸酯钠(AES)、月桂醇聚醚硫酸酯铵(AESA)为例:通过污泥耗氧速率的变化了解表面活性剂对活性污泥的抑制情况;用磁力搅拌表面曝气法代替震荡培养法测试了城镇污水处理厂的活性污泥对表面活性剂的生物降解能力;用污泥负荷表征表面活性剂的初级生物降解速率,便于计算用活性污泥法处理表面活性剂至其起泡性能消失所需的时间。实验结果表明,AES、AESA浓度≥200 mg·L^(-1)时对活性污泥中部分微生物有抑制作用。当AES、AESA浓度≤100 mg·L^(-1)时,用城镇污水处理厂的活性污泥好氧处理的初级生物降解速率分别为0.06 kg AES.(kg MLSS·d)^(-1)、0.06 kg AESA.(kg MLSS·d)^(-1);用活性污泥法好氧处理20小时后的CODCr去除率分别为75.7%、79.9%;AESA的可生物降解性优于AES。
