Research On Push-Style Sludge Electrical Dehydration Technology By Fixed Plate Electrode

The deep dehydration is a key part of the sludge treatment and disposal process.Whether the moisture content of the sludge can be reduced economically and efficiently are not,plays a decisive role in realizing the targets of reducing,stabilizing,recycling and decontaminating.The technology of sludge electrical dehydration applies electroosmosis principle,which can quickly and efficiently complete the dehydration process.Compared with the heat-drying technology,it can greatly decrease the power consumption.Currently,most of the electrical dehydration equipment will introduce the electrode directly into the existing mechanical dewatering equipment,which will lead to poor stability in the electric field,inability in continuous work,low efficiency of dehydration.This topic proposed a push-style sludge electrical dehydration technology by fixed plate electrode,and develop the corresponding electrical dehydration equipment.The experimental verified that,the device had advantages such as good stability,high level of automation and continuous operation.Based on the static and dynamic experiments,this study improved and perfected the equipment,found the best operating conditions of the equipment,and also analyzed the water quality characteristics of the leachate and the economic indicators of the equipment.Through the static experimental research of the equipment,it is found that the effect of sludge dewatering is mainly affected by the voltage gradient and the dehydration time.Too high or too low voltage gradient would not achieve the optimum dehydration state.The reasonable voltage gradient is 30-50V/cm.For 30,40,50V/cm voltage gradient.Continuous power supply dehydration time should not exceed 9min,7min,5min,otherwise it will result in inefficient power consumption.When the voltage gradient is 40V/cm,the water content of sludge can be reduced to 56.9% within 7min,and the unit of water consumption per unit of power is 0.219kWh/kg.In order to optimize the power supply form and obtain better dehydration effect from the device,this paper studied the effect of intermittent power supply on the sludge dewatering effect.Through the experiment,it is found that the duty cycle of on-off has a greater impact on the dewatering effect of sludge.In order to ensure that the current and temperature were in better condition,the duty cycle should not be too large or too small.Under the intermittent power supply mode,the reduction of the single power-on time is beneficial to the removal of moisture.When the single power-on time is less than a certain value,the change of the single power-on time has little effect on the dehydration effect.Finally,the best form of intermittent power supply for each power cycle power was on for 20 s and off for 5s.Through the dynamic operation of the experimental equipment,it is found that the best operation parameters are as belows: the voltage gradient is 40V/cm,the total sludge dewatering time is 10 min,the power supply mode is on for 20 s and off for off 5s.In this case,the water content of the sludge can be reduced from 85% to 56.4% within 10 min,the electric energy consumed for removing 1 kg of water is 0.202 kWh,and the maximum temperature during equipment operation is 83.5°C.The total power consumption of handling one ton of wet sludge is 148.6kWh,the cost is about 124.3 yuan.The experimental equipment used a 200-mesh stainless steel mesh as the cathode filter.At this time,the pH value of sludge dewatered leachate was 12.12,the COD concentration was 2379mg/L,the TN concentration was 258.7mg/L and the C/N ratio was about 9:1.