Freeze-thaw and consolidation tests on Suncor mature fine tailings (MFT)

This paper presents the findings of a laboratory investigation of the effects of freeze-thaw, and sulfuric acid and quicklime amendment on Suncor mature fine tailings (MFT) post-thaw geotechnical behaviour and soil micro and macro-fabric. This paper gives the results of a consolidation test program on Suncor MFT using a large strain consolidation apparatus along with constant head flow tests to evaluate the void ratio versus effective stress and void ratio versus hydraulic conductivity data for three types of MFT specimens. The large scale and small scale fabric (macro-fabric and micro-fabric) of these specimens were also examined. The results indicated that freeze-thaw can effectively reduce the initial void ratio and the compressibility of untreated and amended MFT. Freeze-thaw can also significantly increase the hydraulic conductivity of MFT, which in combination with reduced compressibility enhances the MFT consolidation. These results were supported by changes observed in the macro and micro-fabric of the tested MFT specimens.     

“九五”选煤研究成果对中国选煤技术的影响

回顾了“九五”课题立项背景和立题指导思想，介绍了“九五”期间选煤科学研究在５个技术领域的国家“九五”攻关和部级课题分布，重点介绍了高硫难选煤脱硫、大型高效全重介简化工艺、干法与节水型选煤、细粒煤粉选、传统技术升级运用技术等领域的研究成果内容、特点及使用范围，并分析了这些研究成果对中国选煤技术的影响及其将对选煤业的推动作用。     

A simplified parameter extraction technique using batch settling data to estimate suspension material properties in dewatering applications

Batch settling tests are considered in order to obtain dewatering material properties of suspensions/sludges towards the low end of the range of solids fractions. Plausible functional forms are considered for fitting batch settling test (height vs. time) data. In particular, power law and exponential decay functions are shown to be reasonable fits to simulated synthetic batch settling data. These forms are subsequently employed to reconstruct functional relationships between a settling flux function and suspension solids fraction. The functional relationships so obtained are found to be faithful representations of the flux function used to generate the simulated settling data, with improved agreement being achieved by restricting the interval of solids fraction across which the reconstruction is performed. The results suggest that general features only (and not fine details) of batch settling curves are required to reconstruct settling flux functions. In the particular case where power law fits are employed to describe the settling height data, an analytic formula can be derived linking the settling flux function explicitly and directly to the power law fitting parameters. This simplifies immensely the technique for extracting parameters for the settling flux. When applied to real experimental data, errors arising from using the power law fits tend to be small compared to those inherent in the experimental measurements themselves.     

Advances and Challenges on Algae Harvesting and Drying

Biodiesel production from algae offers a promising prospect for practical applications among the still developing biofuel technologies. The fact that algae are capable of producing much more yield provides an edge over other types of biofuel. Though algal biofuel research is still developing and its practical application is yet to be ascertained, promising work on laboratory- and pilot-scale algae harvesting systems has been extensively reported. Because algae harvesting and drying are vital elements in biofuel production, recent advances on various algae harvesting, dewatering, and drying technologies are reviewed and discussed. Challenges and prospects of algae harvesting and drying are also outlined.     

低廉充填胶凝材料的开发与应用研究

开发了以炉渣、黄土、石灰为主要原料的低廉充填胶凝材料，试验了多孔直管滤网振动预脱水和分流沉降预脱水新技术，实现无水泥或少水泥胶结充填，大幅度降低胶充成本，经济效益和社会效益显著．     

沙特阿拉伯MA’ADEN取水口基坑降水

对沙特MA’ADEN取水口降水工程的设计、施工、运行、降水效果以及与预期的水文地质参数的比较及取值等方面进行了介绍、分析，希望对今后类似工程有所帮助。     

Effect of Operating Parameters on the Dewatering Performance of Press Filters: A Sensitivity Analysis

To optimize the press filters commonly used to dewater residual sludge, the impact of the operating parameters must be better understood. The objectives of this article are (1) to identify the impact of the operating parameters on press filter performances and (2) to classify the operating parameters regarding their impact on dewatering performances. Experiments were performed with conditioned activated sludge in a tangential filtration cell, and a sensitivity analysis of the process was performed. This study emphasizes that cake thickness and filtration pressure have the most significant impacts on dewatering efficiency. These results suggest a promising outlook for press-filter optimization.     

超临界CO_2萃取干燥技术及其在低阶煤干燥中的研究进展

综述了超临界CO2萃取干燥技术的原理及工艺流程,简要评述了国外超临界CO2萃取干燥低阶煤的研究进展,与传统干燥技术相比,超临界CO2萃取干燥技术具有快速、高效、干燥应力小等优点。     

Improved Sludge Dewaterability for Sequential Ozonation – Aerobic Treatment

Chemical treatment processes such as ozonation have mostly been considered as an efficient way for bio-solids minimization. The improvement of sludge dewatering was more a welcoming side-effect in these sequential processes. However, sometimes the loaded ozone dose to the sludge has a negative effect on dewaterability. This work address the most important issue found — the effect of ozone on sludge dewaterability in a single ozonation processes as well as in a sequential ozonation biological processes. It was found that the maximum sludge dewaterability was achieved with an ozone dose of 0.05 gO₃/gTSS. This value was found to be less than the required ozone dosage that leads to sludge disintegration. However, it was observed that the sequential ozone and aerobic treatment allows further strong improvement of dewatering efficiencies.     

Electrical field: A historical review of its application and contributions in wastewater sludge dewatering

Electric field-assisted dewatering, also called electro-dewatering, is a technology in which a conventional dewatering mechanism such a pressure dewatering is combined with electrokinetic effects to realize an improved liquid/solids separation, to increase the final dry solids content and to accelerate the dewatering process with low energy consumption compared to thermal drying. Electro-dewatering is not a new idea, but the practical industrial applications have been limited to niche areas in soil mechanics, civil engineering, and the ceramics industry. Recently, it has received great attention, specially, in the fields of fine-particle sludge, gelatinous sludge, sewage sludge, pharmaceutical industries, food waste and bull kelp, which could not be successfully dewatered with conventional mechanical methods. This review focuses on the scientific and practical aspects of the application of an electrical field in laboratory/industrial dewatering, and discusses this in relation to conventional dewatering techniques. A comprehensive bibliography of research in the electro-dewatering of wastewater sludges is included.As the fine-particle suspensions possess a surface charge, usually negative, they are surrounded by a layer with a higher density of positive charges, the electric double layer. When an electric field is applied, the usually negative charged particles move towards the electrode of the opposite charge. The water, commonly with cations, is driven towards the negative electrode. Electro-dewatering thus involves the well-known phenomena of electrophoresis, electro-osmosis, and electromigration. Following a detailed outline of the role of the electric double layer and electrokinetic phenomena, an analysis of the components of applied voltage and their significance is presented from an electrochemical viewpoint. The aim of this elementary analysis is to provide a fundamental understanding of the different process variables and configurations in order to identify potential improvements. Also discussed herein is the investigation of the electrical behaviour of a porous medium, with particular emphasis on porous medium conductivity determination.