超声破解联合湿法检测活性污泥中COD_(Cr)的研究

Determination of COD_(Cr) in activated sludge by ultrasonic cracking assisted wet method

准确测定活性污泥中化学需氧量(Chemical Oxygen Demand,COD_(Cr))含量,是实现污泥资源化利用的重要条件。文章提出一种超声破解联合湿法测定活性污泥中COD_(Cr)含量的检测方法。基于单因素实验结果,以COD_(Cr)浓度作为响应值,采用响应曲面法考察了污泥混合液的稀释倍数、超声功率和超声时间3个因素间单独及交互作用,并对影响因素进行了评估。结果表明,取样量为10 mL,稀释倍数为225倍,超声时间为18 min,超声功率为720 W时,样品平行测定的相对标准偏差小于等于2.00%,加标回收率为96.51%~105.32%,测定结果的准确度、精密度较高。光学显微镜照片和激光粒度仪分析表明,超声破解能够有效破碎微生物细胞的絮体结构,显著降低污泥颗粒粒径,减少污泥取样过程中的误差。对不同f的污泥样品,COD_(Cr)测定值与理论值相关性拟合曲线的拟合值R^(2)≥0.996 1。研究结果证明超声破解联合湿法测定活性污泥中COD_(Cr)具有良好的可靠性和经济性。

Accurate determination of the COD_(Cr) content in activated sludge is essential for resource utilisation.This study proposes an ultrasonic cracking assisted wet method to detect COD_(Cr) content in activated sludge.Based on the single-factor experiment and using the COD_(Cr) content as the response value,the response surface method is employed to investigate the individual and interactive effects of three factors:the dilution factor of the sludge mixture,ultrasonic action time,and ultrasonic power,and an evaluation for the influencing factors is conducted.The results show that when the sample volume is 10 mL,the dilution ratio is 225-fold,the ultrasonic action time is 18 minutes and the ultrasonic power is 720 W,the relative standard deviation(RSD) of the samples determination in parallel is less than or equal to 2.00%,and the spiked recovery rate is between 96.51% and 105.32%.The accuracy and precision of the determination results are high.The results of optical microscope and laser particle size analyzer show that ultrasonic can effectively break the floc structure of biological sludge,significantly reduce the size of sludge particles,and reduce the error in the process of sludge sampling.For the sludge samples with different f,the simulated value R^(2) ≥0.996 1 in the correlation fitting curves between the COD_(Cr) determination value and the theoretical value.It is proven that the ultrasonic cracking assisted wet method for the determination of COD_(Cr) content in activated sludge is a method with good reliability,economy and ease of operation.