| 摘要: | 懸浮固體顆粒不僅為環保法規所規範的出流標準之一，更重要的是懸浮固體對環境中的危害影響甚鉅，故針對廢水處理而言，如何有效的對處理單元進行有效率的監測與控制乃為一大重要課題。分光光譜分析近幾年已發展相當成熟，不但具備快速且經濟的優點，更能夠對水樣一次進行多成分的分析；在懸浮固體顆粒的去除方面，目前多依靠沉澱處理單元進行重力沉澱的方式去除，故顆粒的沉澱特性及水力停留時間的設定將對沉澱處理單元的效率有決定性的影響。本研究透過分光光度計所測得之吸收光譜，針對懸浮固體所造成之影響進行分析，以可見光吸光面積比例原則建立一應用於實廠的自動監測與控制上的量測方法；其量測方法因受到儀器偵測範圍的影響故在30 mg/L～250 mg/L間具有較佳的量測結果。在水力停留時間的量測方面，進一步透過懸浮固體顆粒的量測方法與連續多次掃描程序相結合，來進行推估水力停留時間。在以1500秒左右的掃描時間中，若顆粒的沉澱效率達到一定的水準，則可透過1500秒的掃描數據推算出沉澱量不再變化的時間點，接著假定此時間點的沉澱量為定值，可得到往後時間懸浮固體顆粒的濃度，進一步以顆粒濃度低於30 mg/L的時間點為水力停留所需的時間；然而此方法因沉澱量為定值的假定，並非與現實狀況相同，故所得之水力停留時間將較真正所需時間短，但以自動監測與控制的角度思考，其所獲得的資訊已足以提供控制所需，進一步可提高沉澱處理單元之效率。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. |
