好氧生物顆粒之穩定性

Stabilization of aerobic granules

陳昱佑(Yu-You Chen)

指導教授 ： 李篤中

國立臺灣大學/工學院/化學工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.03378

摘要

本論文主要探討三個主題：不同進料氮源比例對於好氧生物顆粒化之穩定性影響，以及探討將顆粒經過改質和乾燥保存後其生物顆粒活性與穩定性。
首先以原始活性污泥用丙酸鈉鹽與乙醇作為基質碳源，並以氨氮與硝酸氮作為不同氮源比例，於連續批式反應器中培養好氧顆粒。共三組反應器R1、R2及R3，其進料氨氮與硝酸氮比例為100/0、40/60及20/80，此三組反應器顆粒形成時間約2週，但R3系統之顆粒最後在提高OLR為6.87 kg COD m-3day-1時崩解，而R2系統之顆粒最後在提高OLR為14.24 kg COD m-3day-1時崩解，而R1系統之顆粒最後在提高OLR為21.85 kg COD m-3day-1尚未崩解。再將R1顆粒以連續式反應器操作，最高可承受OLR為39 kg COD m-3day-1且可長期操作至220天，並維持其顆粒之活性與穩定性。
利用外塗佈及內塗佈方式改質顆粒，以達強化顆粒的效果，結果顯示以內塗佈方式改質顆粒之強化效果較佳且較易操作。以不同改質溶劑進行改質時，以Mg3(PO4)2和CaSO4為改質溶劑的強化顆粒效果較佳。而經過MgCO3改質過後的顆粒，可保持顆粒結構在強鹼環境(pH = 12)下；而在強酸環境(pH = 3)下，相較於未改質的顆粒，有較高的生物活性。在長期連續式反應器長時間(220天)操作下，改質過後顆粒穩定性明顯優於未改質顆粒，而顆粒在長期連續式反應器長時間操作後(160天)，顆粒菌相會趨於一致，包含有Rhizobium 屬、Brevundimonas 屬、Nitratireductor 屬。
利用乾燥進行顆粒保存，保存22天與78天後的顆粒皆可重新馴化回復其生物活性，而不同乾燥方法中，以丙酮乾燥、放在黑暗中乾燥、改質完後乾燥完後回復活性效果最佳。而乾燥完且回復活性後的顆粒相較於未乾燥的顆粒，利用變性梯度電泳檢視其細菌相，Flavobacterium屬、Trigonala 屬、Arthrobacter
屬會出現在乾燥完且回復活性後的顆粒。

關鍵字

好氧生物顆粒 ； 穩定性 ； 連續批式反應器 ； 乾燥 ； 改質

並列摘要

There are three objectives in this study: to obtain stable aerobic granules in high organic loading rate (OLR) wastewater; to enhance its mechanical strength of aerobic granules and to find proper conservation approaches of the aerobic granules.

To obtain the stable aerobic granules, nitrogen source, ammonium (NH4-N) and nitrate (NO3-N), are prepared in three ratios (i.e. 100/0, 40/60, 20/80) while carbon source (propionic acid and ethanol) are fixed as feed. Following the three nitrogen ratios, aerobic granules are generated after two weeks in three sequence batch reactor (SBR), namely R1, R2 and R3. OLR in the three SBRs are gradually increased from 2.5 to 14 kg COD.m-3.day-1 in 25-days continuous operation. Broken of R3 granules are firstly observed at OLR= 6.87 kg COD.m-3.day-1, while R2 granules are then broken at OLR= 14.24 kg COD.m-3.day-1. R1 granules are not found any broken and still survive at the highest OLR (21.85 kg COD.m-3.day-1) till the end of the experiment. The result shows that nitrate (NH4-N) as the sole nitrogen source (R1) is the most stable among the three SBR experiments. Consequently, R1 granules are transfered to continuous stirred tank tractor (CSTR) and continuously running till a new-record (220 days) at the highest OLR forever (39 kg COD.m-3.day-1).

To increase mechanical strength of aerobic granules, two coating techniques, namely inside and outside coating, are developed. Inside coating are found easier fabricated and more stable than outside-coating granules. Among seven tested oversaturation solutions, Mg3(PO4)2 and CaSO4 achieved the highest mechanical strength. For granules coating by MgCO3, the strcture of granules are observed rigid in alkalne condition (pH=12) and its bioactivity in acid condition (pH=3) is better than the uncoated granules. Residual numbers of the MgCO3-coated granules in CSTR are found existing more than the uncoated ones during long-term CSTR operation (220 days). Diversity of microbial community in the aerobic granules is getting three uniform bacterial species (i.e. Rhizobium sp., Brevundimonas sp., Nitratireductor sp.) at 160-days continuous running.

Drying granules are carried out in order to reserve the aerobic granules. It is found the recovered granules still remian its bioactivity (i.e. COD degradation). Three drying approaches, i.e. drying by acetone, in dark and after coating, are found better than the other five drying approaches in terms of bioactivity recovery. Bioactivity of the recovered aerobic granules storaging after 22 days and 78 days are both the same as undried ones. Molecular biological techniques, i.e. DGGE, are applied to charaterize bacterial species of aerobic granules. Three species, Flavobacterium sp., Trigonala sp., and Arthrobacter sp., are found in the dried and recovered aerobic granules.

並列關鍵字

aerobic granules ； stabilization ； SBR ； dry ； coating

參考文獻

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