Railway washing wastewater, containing a large number of carbohydrates, fat, protein, cellulose, and other organic pollutants, will cause serious pollution, result in production of foul-smelling matter, impact on the survival of aquatic life and hinder the sustainable development of railway transport, if the wastewater is directly discharged into the nature water body. At present, the main treatment processes for railway washing wastewater are physical and chemical treatments which are inefficient, unstable and expensive and can not meet the requirements of water recycling, so a treatment process suitable for railway washing wastewater is badly in need of research and development. The constructed rapid infiltration (CRI), an ecological wastewater treatment technology, excels at treating wastewater especially toward CODcr,BOD5 and SS. But the efficiency of TP removal in CRI is inefficient. In order to improve efficiency of TP removal, sponge iron is added to the traditional CRIs. To determine the feasibility of railway washing wastewater disposal by CRI, the washing waste water of Chengdu Railway Administration was selected as test sample. Traditional CRIs and improved CRIs were applied to treat the washing waste water and degradation kinetics characteristics of TP were studied, the results show that: when average TP concentration of inflow is 6.24mg/L, in traditional CRIs and improved CRIs, average TP concentration of outflow are 4.17mg/L and 1.40mg/L respectively, average efficiency of phosphorus removal are 33.03% and 77.50% respectively; as the TP concentrations of inflow increase, TP concentrations of outflow increase accordingly but the removal rates of TP are stable. Because of addition of sponge iron, the removal rate of TP in improved CRIs is more 44% than traditional CRIs. The results of this experiment show that: Improved CRI is a clean, cheap and ecological technology which is suited for the railway washing wastewater treatment and can promote the sustainable development of traffic engineering, reduce the negative impact on the ecological environment and make railway traffic compatible with resources, environment and social economy.
This document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.The vessel collision risk in the bridge operation period has become an acute problem that bridge engineering have to be faced, therefore, probability analysis and risk assessment about vessel-bridge collision in the bridge operation period is important. Combine with Zhoushan mainland-islands link project, using the AASHTO guide method and correction formula to calculate the probability about vessel collision with the pier 3 and to assess the risk about vessel-bridge collision of Xihoumen bridge in the operation period. The whole vessel-bridge collision risk assessment grade of Xihoumen bridge is grade two in the operation period, which is a low risk level. The operation manager need to pay attention to risk management and take preventive and control measures.
From the traveler’s view, this paper uses random utility theory of the disaggregate model to construct travelers transportation choice model, employ software STATA to calibrate parameter for getting utility function for prediction, and then employ the critical condition which make rail transit and regular transit coordinated to calculate reasonable rail transit station spacing. Finally, example is given, the results show that rail transit station spacing based on passenger travel choice, make rail transit and regular transit to achieve harmonization and complementarities, and improve overall operating efficiency of urban transit system.
In order to study the effects of slate powder on mineral admixtures in suppressing ASR of slate aggregate, refer to the following methods: accelerated mortar bar test in “Standard for Constructional Quality Acceptance of Railway Concrete Engineering” TB10424-2010 and “Durability Design of Railway Concrete Structures” TB10005-2010, as well as an improved steam curing method. The text has studied the expansion of the specimens that are made from slate aggregate with different powder contents and specimens using slate powder as admixtures. The results show : When powder content in aggregate is less than 20%, it dose not have adverse effects; ASR of high-activity slate aggregate can be suppressed by using 30% fly ash and 5% silica fume as mineral admixtures; when the mineral admixtures are effective, a certain amount of powder mixed with admixtures can contribute to suppression; the main mechanism that slate powder can suppress ASR is that alkali in concrete can be consumed and physically diluted by slate powder.
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