Electroosmotic Dewatering And Model Construction Of Urban River Sediment

In recent years,the dredging project has produced a large number of river sediments.These sediments have high water content and low permeability,the reduction of sediment treatment is a key step in the application of the project.Traditional gravity-based dewatering is often difficult to achieve.Electro-dewatering（EDW）is considered to be an effective method for treating high moisture content sediment and has also been widely studied and concerned.However,higher energy consumption has always restricted the engineering application of electroosmotic dehydration.The effects of Na₂SO₄ dosage on EDW under different electrode materials（iron,copper,stainless steel and graphite）were studied.Electroosmotic effect,electrode consumption and electrode surface corrosion reveal the effect of different electrode materials on EDW.Based on the lack of knowledge of electro-dewatering in different electric field forms,the different electric field forms on electro-dewatering are compared,and the effects of different electric field forms on electroosmotic dewatering of river sediments are discussed.In view of the current lack of engineering model and calculation of river sediment electro-osmosis dehydration,the relationship between plate spacing,electric field strength and solid content,energy consumption and dehydration efficiency was studied,and the construction of electroosmotic dehydration model for river sediment was constructed.The main work of this paper is as follows.The effect of Na₂SO₄ dosage on the electroosmotic dewatering of river sediments under different electrode materials.The effects of different anode materials（copper,iron,graphite,stainless steel）on EDW under different Na₂SO₄ dosages（0,10,25,50,100）g kg_DS^-1 were compared.The result shows that stainless steel and iron have better electroosmotic dewatering performance than copper and graphite.The non-conductive oxide produced on the copper surface inhibits electroosmotic dehydration,making copper the worst performance among the four electrodes.Na2SO4 can strengthen the EDW of sediment and improve the dewatering efficiency.The best effect was obtained when the electrolyte dosage was 10 g kg_DS^-1.However,excessive electrolyte dosage will change the Zeta potential of the sediment to lower the isoelectric point,thereby inhibiting EDW and increasing the energy consumption.Compared the effectiveness of different electric field forms.The influence of the sediment thickness and the applied voltage were examined.Vertical electro-dewatering（V-EDW）was found to significantly improve dewatering and reduce process time,while horizontal fields has the potential to save energy but results in sediment containing greater moisture.The horizontal uniformity（H-EDW）and the non-uniform（HN-EDW）are not significantly different.As the applied voltage was increased from 10V to 30 V,the final dry solids content and energy consumption increased for both modes.Increased sludge thickness from 3 cm to 7 cm was found to have a negative influence on the final dry solid content of the sludge for V-EDW,but is not a prominent influence with H-EDW.In the low voltage mode,H-EDW can appropriately reduce the energy consumption while maintaining high solid content.Construction of horizontal electric field electroosmosis dehydration model:The results show that both sediment cake thickness and electric field strength affect sediment dewatering performance.An electric field strength>10 V cm^-11 enhance the final solids content and dewatering efficiency,but also increases energy consumption.An electric field<10 V cm^-1 reduces energy consumption while maintaining a high solids content.When the electric field strength>10 V cm^-1,the final solid content growth rate is slow,but the energy consumption increases significantly.Therefore,the actual application of EDW should be carried out under low electric field strength.