Applying Nephelometric turbidimeter monitoring system (NTMS) in the coagulation efficiency of water treatment plants

• Main Authors: Jen-Neng Chang, 張仁能
• Other Authors: Wen Po Cheng
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/92935382265470408916

碩士 === 國立聯合大學 === 環境與安全衛生工程學系碩士班 === 98 === In Taiwan, due to the suaphote is be exploited excessively, which often damage the natural environment. Thus, the rain will scour terram when the rainy season coming, which will cause turbidity of the raw water be heightened. The foregoing condition make the water treatment plant have to face the condition which the quality of the raw water is unsettled for long-term period. Therefore, how to reflect the change of the condition of the quality of the raw water in short term and find the best controlling condition to purifying water, which has been the important challenge for the water purification system. In this research, combined the common Nephelometric turbidimeter with a data acquisition unit to set up Nephelometric turbidimeter monitoring system (NTMS), and use the Nephelometric turbidimeter to measure the changing condition of the turbidity value in every second. The results show that the wave climate of turbidity value in every second is in accordance with Poisson-distribution. According to the material feature of the Poisson-distribution, the standard deviation(SD) will has different degrees of change by the variation of floc particles characteristics(e.g. particle diameter (r), scattering coefficient (Q), scattering cross-section of particle (C, C=Qπr2), particle number (N) ,etc.) during the process of coagulation. Accordingly, in order to proof the correlation in SD of turbidity and particle characteristics, using the particle of different material(different scattering coefficient, Q), different particle size (particle diameter, r) to dispose the suspensions of different turbidity (particle number, N). There will being a continuous measurement when the condition of the uniform suspension solution, and the rate of change of turbidity value which be measured is designated as Standard Deviation(SD). According to the result, the change of Standard Deviation of turbidity which be influenced by particle characteristics conform to the theory of " turbidity fluctuation technique". In addition, through the skill which use “Turbidity amplitude of floc size measurement technology” can help to understand the variation of particle diameter, and digital image analysis is performed to elucidate the characteristics of the coagulation floc, to proceed the continuous-flow pilot plant, which the flow is 500 mL/min, to study the difference of particle size in the different conditions of coagulation( pH, coagulation dosage, velocity gradient, G…etc). From the result of experiment, indeed, it finds that the turbidity SD and the floc size have perfect relevance and applicability to each other. And also, in the range of the higher turbidity, it can use the continuous online Nephelometric turbidimeter monitoring system (NTMS) to get the best of additive content in the short term. Finally, in this research, also put the nephelometer probe of NTMS to the flocculation of actual Water Purification Station(Taiwan, Meandear Water Purification Station) in directly to measure the turbidity continuously. The result also shows that in the different dose of the coagulant, the floc size which is formed by turbidity SD and flocculation is in well direct proportion. It means the turbidity SD which gets from NTMS are indeed to be an important reference of deciding the coagulation operating conditions.