酸碱调质对污水厂剩余污泥电渗深度脱水的影响

EFFECT OF ACID-BASE CONDITIONING ON ADVANCED ELECTRO-DEWATERING OF MUNICIPAL EXCESS ACTIVATED SLUDGE IN WASTEWATER TREATMENT PLANTS

以城市污水处理厂机械脱水后的剩余污泥为对象,研究了不同pH条件下酸碱调质对污泥电渗脱水的影响。试验结果表明:电渗脱水过程的前30 min污泥含水率下降迅速,之后逐渐变缓。Matlab拟合结果表明:含水率随时间的变化曲线与高斯函数(二维)高度吻合(R^2>0. 99)。pH<5时,升高pH有助于改善电渗脱水效果、减少耗电量和阳极腐蚀量; pH>5时,pH越大电渗脱水效果越差。说明微酸性环境有助于污泥的电渗脱水;当pH为5时,脱水所得泥饼的含水率为32. 5%,耗电量和腐蚀量分别为201. 7 k W·h/t和20. 1 kg/t,为试验最低值。

In this study,the excess activated sludge after mechanical dewatering in wastewater treatment plants was used to investigate the effect of acid-base conditioning on its advanced electro-dewatering( EDW) under different pH. The results showed that the sludge moisture content( SMC) decreased rapidly in the first 30 min,and then it gradually slowed down.Fitting results via Matlab indicated that the change of SMC over time was consistent with Gaussian function( two-dimensional)( R^2> 0. 99). When the conditioning pH of sludge was less than 5,increasing pH was helpful to improve the sludge ’s dewatering ability,reduce power consumption and anode corrosion. However,when the conditioning pH exceeded 5,EDW was worse in a higher pH value. Besides,the results indicated that the slightly acidic environment was conducive to the EDW of sludge: when pH was 5,the SMC of dehydrated mud cake was 32. 5%,and the consumption of electricity and corrosion amount were 201. 7 k W·h/t and 20. 1 kg/t after sludge dewatered,respectively,which were the lowest values.