Real-Time And Online Measurement Method Of Zeta Potential And Monitoring System

Coagulation is a commonly used method for wastewater treatment, and the essence is to remove charged colloidal particles and suspended solids, the key technology is precisely controlling the amount of flocculant.The effect of coagulant is to change the electrical properties of solid-liquid interface,while zeta potential is the potential of slip surface which is in the colloidal structure of the electric double layer.The greater of the zeta potential, the stability of colloid is much butter.Because flocculants can compress the electrical double layer, zeta potential decreases then elimination the stability of colloid and coagulation. The samller of the zeta potential, the better of effect of flocculation.Therefore, not only can zeta potential characterize flocculation effect, also can accurately guide flocculant dosage.Against the measuring equipments of zeta potential are almost offline, different batches of wastewater and zeta potential, the optimum flocculant dosage is different. To accurately obtain the optimum dosage of flocculant,this paper presents a method of measuring the zeta potential online which can real-time measure the zeta potential of wastewater.Using the phenomenon of interface electrokinetic, measure the flow potential value within the capillary channel structure, and according to Helmholtz-Smoluchowski equation, indirectly get the zeta potential of wastewater.The experiment data shows that within the allowable error,the zeta potential could real-time guide flocculant dosing. While exploring the conditions of water quality and the effects of operating conditions on the measurement results, it’s propel to get the stirring speed, PH value and pressure conditions,which minimizes the measurement error. In addition, using neural network model can establish the curve of flocculant quantity and zeta potential, the curve can accurately predict the optimal dosage of flocculantFinally, combination the above methods, it is well designed the monitoring system based on PLC and WinCC. The system runs well in the laboratory, which provides great reference significance on flocculants dosage in wastewater treatments.