以六標準差方法延長廢水回收系統中生物薄膜反應器之薄膜使用壽命

Abstract

隨著時代演變，廢水回收不斷地導入新的技術及處理設備，表示企業對環境保護要求已非只符合廢水回收門檻，而是追求企業責任與綠色的零污染工業。在既存之廢水回收設備上，也被要求持續提升回收率，以光電廠低濃度有機廢水處理之生物薄膜處理設備為例，在運轉成本以及水質考量，以最佳化的運轉參數設定條件下，提高其效率。 本研究以六標準差之D-M-A-I-C (Define-Measure-Analyze- Improve-Control) 改善步驟手法，以特性要因圖、柏拉圖、效果圖及SPC等品質管制圖表，並套用Minitab軟體工具，逐一探討分析生物薄膜反應器(membrane bioreactor,MBR)運轉最佳化，降低運轉成本。 研究結果顯示，在產水量不變的條件下，影響MBR系統使用壽命共有7個因子，利用品質分析圖表及回歸分析，可將其收斂至3個主要因子，分別為原水TOC濃度、生物處理系統MLSS濃度及MBR循環水量，此3因子影響MBR使用壽命貢獻度達88.6%。透過實驗設計法(DOE)，得知原水TOC濃度及生物系統MLSS偏低操作，而MBR循環水量偏高操作，可降低運轉膜壓，延長MBR使用壽命。實際運用於MBR處理設備之案例研究結果顯示，其最佳化組合為調勻槽TOC濃度於82.97 mg/L、生物系統MLSS濃度於6,339 mg/L、MBR系統循環水量為88,583 CMD，得到最佳MBR運轉膜壓，膜負壓從0.269 bar降至0.184 bar，減少31.6%，降低運轉風險，每年可減少運轉成本達286萬元，指標符合且達到預期成果。

The facility and new technology for wastewater reclamation treatment are introduced lately, that process are not only to meet the regulatory mandate but they are also a mission to pursue the long term goal for zero waste operation in companies. In the existing wastewater reclamation treatment facility, they are also required to improve for the water recycling efficiency. By the TFT-LCD membrane bioreactor(MBR) procedure is used in the low concentration organic wastewater treatment; the system parameters were modified and optimized for a better outcome considering the water quality level as well as the costs reduction. Used D-M-A-I-C (Define-Measure-Analyze-Improve-Control) method by Six Sigma, it was approach to improve the operation procedure in this research; and used cause-effect diagram figure、plato chart figure、effect figure、SPC and other qulity control charts were used as well as the Minitab software as tools for efficiency in the MBR facility and to reduce costs. In this research results, it was found that 7 variables to influencing in the MBR system for service life management. Among them, 3 variables were identified after the further investigation using the quality analysis and the regressive analysis. They are influent TOC concentration、bio-system MLSS concentration and MBR system criculation volume, They are contributing of as high as 88.6% of the MBR service life. And through the Design of Experiment (DOE), the influent TOC and bio-ststem MLSS parameters were too low, and the MBR system criculation volume was too high; the membrane pressure was modified to be lower to improve the MBR service life. In conclusion, the parameter is now configured as follow : 82.97 mg/L influent TOC, 6.339 mg/L bio-system MLSS and 88,583 CMD circulation volume MBR system; As the outcome, the MBR running negative pressure was improved from 0.269 bar to 0.184 bar which is 31.6% decrease, the operation risk was improved, and reduce TWD 2,860,000 costs every year, and the project goal was fulfilled.