Experimental study on treatment of municipal sludge by electro-osmotic method

The field test proves that it is feasible to reinforce the beach land in Bohai Bay by electro-osmotic method (Cheng et al., 2001).In the contrast test of electrode arrangement in electro-osmotic method, 3 kinds of electrodes are arranged with rectangle, plum blossom shape and parallel dislocation. Comparing the experimental results, it is found that the parallel arrangement electrode is reasonable(Tao et al., 2013).In the theoretical and experimental study of reducing the energy consumption of electro-osmotic energy, it is found that the gradual increase of voltage can delay the occurrence of cracks in the process of electro-osmosis and the extent of the crack development. This method effectively reduces the energy loss at the crack during the electro-osmotic process(Pan et al., 2014).In the experimental study of the effect of electro-osmotic reinforcement of soft soil, the effectiveness of electrode inversion has been proved. The concrete calculation method of the parameters of the drainage volume and the electrical permeability coefficient is given through the experimental data. According to the existing engineering examples, the range of empirical values is given for the parameters that can not be determined(Zhuo Chen., 2015).In the experimental study on Influence Factors of electro-osmotic coefficient of soft clay and improvement method, the electro-osmosis heap loading combined air pressure splitting test is carried out aiming at the problem of the poor effect of the electro-osmosis method on the deep soil. The experimental results show that the shear strength of the combined pressure splitting test of electro-osmotic loading is higher than that of the deep soil under the electro-osmotic loading test. This discovery has certain reference significance for some projects which have high requirements for the reinforcement effect of deep soil soil (Hu et al., 2015).An experimental study of the effect of electrode spacing on electro-osmosis under the equal potential gradient using an indoor 1:5 model. The effects of two electrode spacing of 2m x 1m and 1m x 0.5m on the electro-osmotic properties of soft clay under the equal potential gradient were also studied. The results show that keeping the electric potential gradient unchanged and reducing the electrode spacing by half can speed up the electro-osmotic drainage, reduce the soil moisture content, reduce the energy consumption and electrode interface resistance, but also cause the change of pH value and the amount of anode corrosion. It is also found that the smaller the electrode spacing, the lower the potential loss on the electrode and the soil interface, but the loss potential increases the proportion of the supply voltage (Li et al., 2015).

There are few experiments in many literatures on the treatment of heavy metals in municipal sludge by electro-osmotic method. At present, if the basic physical indicators of sludge are improved and the content of heavy metals can be effectively reduced, the basic situation of urban land stress can be alleviated. In this paper, the basic physical properties of the treatment of sludge by electro-osmotic method and the content of heavy metals in sludge are described in this paper.