高氮廢水生物處理程序廢棄活性污泥生物水解產酸之研究

Abstract

ABS 為一種高品質之化學合成塑膠原料，此原料係由acrylonitrile、butadiene 以及 styrene 三種化學物質進行聚合反應而產生，且原料的用途於目前台灣的需求遍及電子產品、汽車業及其周邊相關產品的製造。由於此類產品的需求快速成長，使得此類製程廢水的產生快速地增加，進而使得處理廠所產生的污泥迅速累積，因此，衍生出污泥處理與處置的問題，為了能有效解處理污泥及避免二次污染的產生，利用厭氧水解酸化程序為一種可行的處理程序，此一處理程序的特點在於有機物進行水解酸化反應後，會釋出大量的揮發酸於上澄液中，對於碳源需求之相關生物處理程序如脫硝反應等，可同時進行碳的資源化回收與減低外加碳源的成本需求，為一種同時具有處理與回收的處理程序，因此，急待積極的開發此項技術而運用於實廠上，本研究即利用厭氧水解酸化程序對 ABS 工業廢棄活性污泥進行研究，探討因子包括 HRT (5 天與 10 天)、pH 值 (5.0, 5.5, 6.0 與 6.5) 溫度 (室溫與 35oC) 與有機負荷 (0.71-1.96 Kg VS/m3d) 等四項，主要的目的即為求得反應之最佳反應條件，使反應能於最短的時間達到處理回收的目標。 污泥的獲得係採自台南某家 ABS 製造廠中之硝化脫硝處理設備。為使反應不受原廠操作情況干擾，廢棄活性污泥於進行水解酸化反應前均于以調整 TS 為 1、2 或 2.5% (10,400、20,257或 24,640 mg/l)，反應槽之操作體積為 3 升，並設計為完全攪拌型式下完成此序列的反應。實驗結果顯示，反應過程中有五種短鏈的揮發酸產生，且當 HRT 與溫度提高時均有助於有機碳的溶出與揮發酸的形成，此外，當 pH 介於 5.5-5.0 之間會抑制氣體的產生，但有助於揮發酸的累積；若以改變 TS 濃度增加有機負荷率將有利於 DOC 的溶出與 VFAs 的產生，因此，若將反應控制於最佳條件 (HRT 10天、 pH 5.0、反應溫度 35oC 以及有機負荷率為 1.52 Kg VS/m3d) 時，DOC 的溶出與 VFAs 的形成可分別達到 510 mg C/l 與 1,516 mg COD/l，由以上結果可證明水解酸化程序，確實能由污泥減量的過程中回收揮發酸以達到處理與資源回收的目的。

The chemical mixture, including acrylonitrile, butadiene and styrene (named as ABS), is widely used in the manufacturing industries of car and electronic products in Taiwan. A large amount of the waste activated sludge (WAS) containing the ABS is generated from the industrial wastewater treatment plants. To effectively dispose the WAS, it is understood that the anaerobic hydrolysis is a suitable process. For the purpose of getting the maximum formation of the volatile fatty acids (VFAs), four reaction parameters such as the hydraulic retention time (HRT of 5 and 10 days), pH value (5.0, 5.5, 6.0 and 6.5), organic loading rate (0.71-1.96 Kg VS/m3d) and temperature (ambient temperature and 35oC) are studied in this research. The objective of this research is to find out the optimal condition for the treatment of WAS using an anaerobic hydrolysis process. The WAS sample was collected from a nitrification/denitrification tank in the industrial wastewater treatment plant located in southern Taiwan. In this research, the total solids (TS) concentration of the WAS was pre-adjusted to 1、2 and 2.5% (10,400、20,257 and 24,640 mg/l) and then was used as a feeding substrate in the anaerobic hydrolysis system. The working volume of the reactors was 3 liter, which was designed as a completely mixed reactor. Experimental result indicates that there are five types of short-chain VFAs are produced when the WAS is anaerobic hydrolyzed. A longer HRT and a higher reaction temperature give better productions of dissolved organic carbon (DOC) and VFAs. When the pH value was conducted between 5.0 and 5.5, there is no biogas and was observed in the anaerobic reactors. Experiment al result also indicated that the concentration of DOC and VFAs in supernatant increases with increasing TS conc. or organic loading. When the reaction was performed in the optimal condition (HRT 10 days, pH 5.0, reaction temperature 35oC and organic loading rate 1.52 Kg VS/m3d), the concentration of DOC and VFAs containing in supernatant were 510 mg C/l and 1516 mg COD/l, respectively. In conclusion, the anaerobic hydrolysis process was proven in this study that it was enough to generated VFAs and DOC to achieve the purpose of resource recovery.