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201.
Wastewater characteristics and sludge generation potential of point source categories are reviewed critically. Novel industry-specific sludge dewatering/drying solutions necessary to establish a sustainable model are examined through a detailed literature survey. Knowledge of sludge properties is one of the most critical issues needed to design dewatering/drying equipment. This study focuses on industrial wastewater/sludge characterization. In addition, a comprehensive review of current drying models and technologies is also presented. A summary of the results derived from a novel thin-film-based photonic sludge dewatering/drying study is outlined as an alternative approach for industrial sludge control. Sludge was dried in a tubular quartz reactor (TQR), the inner surface of which was coated with a TiO2 thin film. The TQR was irradiated with UV A, UV B, and UV C lamps. The consumed and generated energy fluxes through endergonic and exergonic reactions driven by photolysis and photocatalysis were investigated. In addition, the variations in sludge dewatering/drying characteristics were also examined and compared with conventional methods to evaluate the energy requirements. 相似文献
202.
Jie Li Lyes Bennamoun Laurent Fraikin Thierry Salmon Dominique Toye Raphael Schreinemachers 《Drying Technology》2014,32(14):1706-1717
Convective drying of wastewater sludges and sawdust/sludge mixtures was studied. The first part of this work was an experimental study performed in a cross-flow convective dryer using 500 g of wet material extruded through a disk with circular dies of 12 mm. The results showed that the sawdust addition has a positive impact on the drying process from a mass ratio of 2/8, on a dry basis, with observed drying rates higher than the original sludge. The second part of this work consisted of developing a drying model in order to identify the internal diffusion coefficient and convective mass transfer coefficient from the experimental data. A comparison was made between fitted drying curves, well represented by the Newton's model, and the analytical solutions of the diffusion equation applied to a finite cylinder. Variations of dimensional characteristics, such as the volume and exchange surface of the sample bed, were obtained by X-ray tomography. This technique allowed us to confirm that shrinkage, which is an important phenomenon occurring during sludge and sawdust/sludge mixture drying, must be taken into account. The results showed that both the internal diffusion coefficient and convective mass transfer coefficient were affected by mixing and sawdust addition. The internal diffusion coefficient changed from 7.77 × 10?9 m2/s for the original sludge to 7.01 × 10?9 m2/s for the mixed sludge and then increased to 8.35 × 10?9 m2/s for the mixture of a mass ratio of 4/6. The convective mass transfer coefficient changed from 9.70 × 10?8 m/s for the original sludge to 8.67 × 10?8 m/s for the mixed sludge and then increased to 12.09 × 10?8 m/s for the mixture of a mass ratio of 4/6. These results confirmed that sawdust addition was beneficial to the sludge drying process as the mass transfer efficiency between the air and material increased. Reinforcing the texture of sludge by adding sawdust can increase the drying rate and decrease the drying time, and then the heat energy supply will be reduced significantly. The study also showed that neglecting shrinkage phenomenon resulted in an overestimation for the internal diffusion coefficient for the convective drying of sludges and sawdust/sludge mixtures. 相似文献
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以SBR反应器运行过程产生的剩余污泥为研究对象,采用MAP法对经超声处理后的污泥中的氮、磷元素进行回收研究。考察不同超声时间(10、20、30 min)、超声频率(40、80 kHz)和pH(7.0、8.0、9.0)条件下,剩余污泥上清液中氮、磷的回收效果,以期探求最佳回收条件。结果表明污泥在超声频率为80 kHz,时间为10 min后所释放的氮、磷量最大。在最佳的磷镁比为1.8-2.0条件下用磷酸铵镁沉淀法(MAP)进行回收,当pH值为7.0,反应时间为15 min时获得最佳磷回收效果,磷回收率可达62.3%。 相似文献
206.
厌氧氨氧化反应器的启动时间过长是制约厌氧氨氧化在工程实践中发展和应用的一个关键性因素,因此实现厌氧氨氧化反应器的快速启动对于该项技术的推广意义十分重大。分析比较了选取不同类型的反应器和接种不同类型的污泥对于厌氧氨氧化反应器启动时间及脱氮效果的影响,并对今后的研究方向提出了建议。 相似文献
207.
为了提高污泥水解酸化产酸率,采用SBR工艺处理污水厂污泥,研究了不同水力停留时间时间隔排泥天数(决定生物固体停留时间)对污泥水解酸化过程的影响。结果表明,在HRT 6.6d和HRT 3d时,污泥产酸率随着排泥间隔天数的增加而增加。排泥间隔天数2d时达最大,分别为135.62mg/g、125.61mg/g;排泥间隔天数3d时,污泥产酸率稍有下降。HRT 4.4d,污泥产酸率随着排泥间隔天数的增加而增加。排泥间隔天数3d时,污泥产酸率达57.88mg/g。所以,最优工况为HRT6.6d、排泥间隔天数2d的运行方式。 相似文献
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209.
Koen Grijspeerdt Herwig Bogaert Willy Verstraete 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1996,67(4):404-412
A model clarifier was designed using conventional methods for the surface calculation and an alternative pathway for the determination of the height and constructed accordingly. In addition, a new approach was used to evaluate the necessary scraper speed in comparison to full-scale clarifiers. Scaling effects were taken into account. The model clarifier was first tested by tracer experiments. Conductivity measurements were used for the clarification zone, whereas the thickening zone was tested using pyrene as an organic tracer compound. Finally, the behaviour of the model clarifier was compared with a full-scale settler. The results indicated that operation of the model clarifier was representative of full-scale behaviour, except for severe overloads. Hence, the small-scale clarifier qualified as a model for small-scale studies and could be installed on large-scale plants to monitor more transparently plant performance and sludge behaviour 相似文献
210.
洪门水电站溢洪道基础排水廊道排水孔析出物分析 总被引:1,自引:0,他引:1
本文简要分析了排水廊道析出物及与之相关的基本资料,对析出物的成因进行了探讨。分析认为,廊道析出物成因复杂,可能来自上游粘土铺盖、左侧副坝粘土和基础岩体节理裂隙的充填物,或是三者的混合物,并认为必须对工程缺陷进行及时处理。 相似文献