Experimental And Theoretical Study On Electroosmotic Dewatering Of Mud

Mud mainly includes river dredging mud and industrial waste mud at present,and its annual output is still with a giant number,discharge directly not only pollutes the environment,but also wastes water resources,does not meet the requirements of green environmental protection,but how to use it reasonably and effectively has been a technical problem.Most of the waste mud have the characteristics of low permeability and high compressibility.For this kind of mud,in order to facilitate transportation,reducing its volume,mud-water separation,has become the key point of research.Electroosmosis method has the characteristics of high efficiency and environmental protection in the process of treating mud with high compressibility and low permeability.But in the combination of electroosmosis theory and practice,there are many uncertain factors,among which the electroosmosis coefficient has a great influence on the implementation process of electroosmosis method.Therefore,a new laboratory experiment was designed to study the influence of the pore ratio,the electric potential gradient and flocculant dosage on the coefficient of electroosmosis.One-dimensional electroosmosis dewatering experiment was carried out in laboratory then,a one-dimensional electroosmotic dewatering theoretical model was established by introducing the idea of piecewise linearization,and the main influencing factors of mud electroosmotic dewatering process were studied by parameter analysis.The main conclusions are as follows:(1)The influence of pore ratio,electric potential gradient and flocculant dosage on the electroosmosis coefficient was studied by using a self-developed electroosmosis coefficient measuring device.The experimental results show that the electroosmosis coefficient increases linearly with the increase of pore ratio or electric potential gradient,but the electric potential gradient has less effect.The addition of anionic polyacrylamide(APAM)had little effect on the electroosmosis coefficient.(2)One dimensional electroosmosis dewatering model test of mud was carried out with a self-developed test device.The experimental results show that the loading voltage has a significant effect on the final dewatering and dewatering rate.With the increase of the loading voltage at both ends of the mud,the final water dewatering increases,and the time for dewatering to reach the stable state also decreases gradually.However,with the increase of loading voltage,the energy consumption coefficient in electroosmosis process increases correspondingly.Therefore,the relationship between dewatering effect and energy consumption should be considered comprehensively in practical engineering,and then select appropriate loading voltage.(3)A one-dimensional electroosmotic dewatering model of mud was established by introducing the idea of piecewise linearization.The applicability of the model was verified by comparing with laboratory test results.The parameter analysis shows that the increase of loading voltage,overburden load and compression index can increase the final dewatering amount of electroosmosis and decrease the final average pore ratio.However,with the increase of voltage and overburden,the increase of final dewatering decreases.In addition,the increase of compression index has little influence on the initial stage of electroosmotic dewatering process,but the influence on water dewatering gradually appears in the later stage.