dc.description.abstract | Suspended solids is not only one of the standard of environmental regulations regulating the flow of suspended solid particles, but also has tremendous hazard impacts on the environment. Therefore for wastewater treatment, how to monitor and control the processing unit effectively is one of the important tasks. In recent years, spectrophotometry spectroscopy has developed quite mature, not only fast and economic, but also able to conduct a multi-component analysis of water samples. For the removal of suspended solids, we used to rely on gravity precipitation to remove the precipitation processing unit, so the particle precipitation characteristics and the hydraulic retention time settings will play a decisive role on the efficiency of processing units. In this study, the absorption spectra measured by the spectrophotometer were analyzed for the effect of suspended solids; using the principle of proportionality of visible light absorption area to establish a measurement method which can be applied in the real factory process in automated monitoring and control. Due to the detect range of instruments, the measurement method has better measurement results in the range of 30 mg / L ~ 250 mg / L. In the measurement of the hydraulic retention time, this study through the combination of suspended solids measurement and repeatedly scan to estimate the hydraulic retention time. In the scan time about 1500 seconds, when the precipitation efficiency of the particles reach a certain level, you can calculate the time point that the precipitation amount does not change through 1500 seconds of scan data. And then assume that the precipitation amount for this time point is fixed, we can value the concentration of suspended solid particles in the subsequent time. Further, assume that when the time the particle concentration is lower than 30 mg / L is the time required for the hydraulic retention time. However, this method, due to the assumption of the precipitation amount being fixed, is not the same with the realities. So the resulting hydraulic retention time is shorter than the real required time. But in the of view of the automatic monitoring and control, there are sufficient information required to control the precipitation processing unit, and further to improve the efficiency of the precipitation processing unit.
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