市鎮污水處理廠厭氧消化系統操作參數最佳化之研究

Optimization of Operating Parameters of Anaerobic Sludge Digestion in Domestic Wastewater Treatment Plant

李淑娟(Lee,Shu-Chuan)

指導教授 ： 張添晉

國立臺北科技大學/工程學院/環境工程與管理研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00344

摘要

經以批次分析方式，利用Biowin模擬出最佳VSS去除率操作參數及最佳甲烷產氣量操作參數後，得到以下結論：若由現況調整，則VSS去除率最佳化參數僅需將二沉/初沉污泥比例由4.8調整至7.0、進流污泥含水率由95.8%調整至97%，VSS去除率即可由65.27%上升至65.489%，而甲烷產氣量也將由12,271.16CMD增加至14,637.36CMD；而甲烷產氣量最佳化則需調整二沉/初沉污泥進流流量、進流污泥含水、槽內pH及槽內溫度，故相較之下，VSS去除率最佳化參數為最容易調整之參數。
若再將模擬出之參數加入經濟效益考量，由於甲烷產氣最佳化之最佳槽溫為36℃，為使槽溫上升由35.15℃上升至36℃，需燃燒甲烷以產生熱能加溫厭氧消化槽，且由於加溫所需之甲烷量非常大，故甲烷產氣量最佳化之經濟效益相對較低。
而綜觀國內其他廠，厭氧消化仍有些許問題待克服，除營運初期污泥含量不足，導致難以養菌外，還有外加熱源成本的問題，及厭氧消化系統本身待克服的問題，以上因素均會影響到厭氧消化槽的運作成效。故厭氧消化槽是需長期觀察並伺機調整操作參數的一敏感反應槽，而是否可順利的運作，如何尋求各廠適合的操作參數，實為一重要課題。

關鍵字

厭氧消化 ； Biowin ； 經濟效益 ； 甲烷產氣

並列摘要

The anaerobic digestion uses acid-producing facultative bacteria and anaerobic methane-forming bacteria to transform volatile solid (VSS) in sludge into methane and carbon dioxide. The key to sludge stabilization is the speed at which methane-forming bacteria transform VSS into methane. Therefore the primary task for the operator is keeping the tank in optimized condition for methane-forming bacteria. Optimized condition for methane forming bacteria involves pH, ORP, alkalinity, volatile acids, temperature, hydraulic retention time, and gas composition.
In order to find the best operating parameter for the domestic sludge anaerobic digestion unit, this research presents Dihua Sewage Treatment Plant (hereafter Dihua Factory), a treatment plant that is currently in operation and treats nearly 500,000 ton domestic sewage every day, as a case study. Further, this research analyzes Dihua Factory’s historic data and simulates the actual factory condition by Biowin software in order to find the best operation settings that can maximize cost-effectiveness and achieve sludge stability. Tank temperature, pH, water content of inflow sludge, amount of sludge in secondary/primary settlement tanks, and the number of tanks are the parameters that operators can make adjustments to find the best operation settings.
After by the raid of analysis mode, Biowin simulates the best operation parameter of VSS elimination rate and draw the following conclusion: if adjusted from current settings, Dihua Factory can optimize VSS elimination rate by only raising the primary/secondary sludge ratio from 4.8 to 7.0 and the sludge moisture content from 95.8% to 97%. Doing so will increase VSS elimination rate from 65.27% to 65.489% and methane production from 12,271.16CMD to 14,637.36CMD. To optimize methane production, on the other hand, requires adjustments on secondary/primary sludge ratio, inflow sludge moisture content, tank pH and temperature. Comparatively, optimization of VSS elimination rate by adjusting parameters can be easier achieved.
When cost-effectiveness is taken into account, optimization of methane gas production is not the best solution since heating up anaerobic digestion tank from 35.15 to 36℃, the temperature for maximized methane production, requires a lot of energy from burning a large amount of methane.
Other domestic treatment plants have common problems in association with anaerobic digestion tanks that are yet to resolve. The operation of the treatment plant in the initial stage often produce small amount of sludge not enough to breed bacteria and bear high heating costs. Such problems will affect the operation of anaerobic digestion tank. As long term observation is required to carefully adjust operation settings for sensitive anaerobic tanks in operation, finding the best operation parameters would be the most important topic.

並列關鍵字

Anaerobic Digestion ； Biowin ； Economic Effective ； methane-forming

參考文獻

[18] 朱敬平、李篤中，污泥處置(IV)：策略與永續利用，2002

[20] 丁健弘、李篤中，活性污泥之厭氧消化產氣，2003

[3] 中興工程顧問股份有限公司，迪化污水處理廠操作手冊，台北：台北市政府衛工處，2008。

[5] Water Environment Federation，Design of Municipal Wastewater Treatment Plants(Fourth edition)Volume 3，美國：ASCE，1998。

[11] Glen T.Daigger & John A.Buttz，Upgrading Wastewater Treatment Plants，美國：Technomic Publishing Company,Inc.，1992