- 期刊
以奈米乳化液與奈米氧化鐵作為河川底泥汙染整治助劑之研究：由實驗室到模場試驗
Soybean Oil Nanoemulsion and Magnetite Nanoparticle as Remediation Enhancers for River Sediment: From Lab to Field
摘要
台灣西半部主要河川之底泥均已經受到不同程度之污染，持久性有機污染物將逐漸累積於河川底泥當中，進而依循食物鏈進入動植物體內，造成生態系及人體健康之危害。本研究以國內嚴重污染之二仁溪底泥為研究標的，二仁溪流域早期隨著工業發展而遭受燃燒廢五金、酸洗、電鍍業之廢水排放，導致污染物進入河川並沉積於底泥中，導致二仁溪底泥污染物包含戴奧辛、多氯聯苯、多環芳香烴與重金屬等，於歷史測值中多氯聯苯與多環芳香烴皆已超過現行底泥品質指標之分類管理及用途限制辦法管制標準。本研究運用大豆油奈米乳化液(soybean oil nanoemulsion, SONE)先於實驗室中進行多氯聯苯之Aroclor1242批次式生物降解實驗，獲得初步結果後，繼續進行二仁溪現地底泥污染整治模場試驗。由於現地底泥中也存在相當大量之多環芳香烴與重金屬之污染，故進行現地模場試驗時也必須將其納入考量。實驗室中Aroclor 1242生物降解實驗結果顯示：於研究結果可發現二仁溪底泥中好氧菌與厭氧菌皆適合於靜置狀態下代謝多氯聯苯，厭氧環境下添加少量SONE（小於1%）即能增加產氫量及多氯聯苯的降解，若再添加少量奈米氧化鐵(magnetite nanoparticle, MNP)可提升降解效果。好氧情況下則不適合添加SONE，而添加MNP似乎並不影響菌群對多氯聯苯的分解。模場試驗則以四種不同條件進行試驗，即自然回復、生物刺激、吸附回收及整合式復育進行去除底泥中之萘、Aroclor 1242與重金屬，於現地模場試驗設施完成後執行五個月試驗之初步成果顯示積極式工程復育之效果（最佳者重金屬移除22.6%，萘移除100%，Aroclor 1242移除91.4%）普遍優於自然回復（重金屬移除7.2%，萘移除99%，Aroclor 1242移除61.4%），單獨添加MNP或SONE不如同時添加之效果，其結果顯示相對最佳處理條件為添加1.0%之SONE與1,000 mg L^(-1)之MNP並進行回收操作之組別，可較自然回復之組別縮短61%之整治時間。本研究之實驗室與模場試驗結果顯示添加SONE與MNP之工程干預方式對底泥污染整治優於自然回復方式且整治時程可有效縮短。
並列摘要
River sediments in the western coast of Taiwan have been contaminated by persistent organic pollutants which have been accumulated there. These pollutants may enter plants and animals through food chains and threaten the ecosystems and human health. This study aimed at the heavily polluted Er-Ren River to study the effects of different strategies on sediment remediation. Er-Ren River was polluted by open burning of scrape metals, acid treatment of metals, and wastewater discharged by electroplating factories. Now, high levels of dioxins, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals are found in the sediment. Historical monitoring data showed that PCBs and PAHs are above the regulated standard in Taiwan. This study is to apply in-house synthesized soybean oil nanoemulsion (SONE) as a biodegradation enhancer for Aroclor 1242. Based on the successful experience in the lab, SONE is subsequently applied to a pilot study for in-situ bioremediation of Aroclor 1242, naphthalene, and heavy metals. The lab test results on Aroclor 1242 indicated that both aerobic and anaerobic bacteria in the sediment can degrade PCBs under undisturbed (no shaking) conditions. Under anaerobic conditions, addition of 1.0% of SONE can increase the production of hydrogen and enhance biodegradation of PCBs. Addition of magnetite nanoparticle (MNP) at lower level may benefit the biodegradation of PCBs. However, under aerobic conditions, SONE will not enhance the biodegradation of PCBs and addition of MNP seemed to have no effects on PCBs biodegradation. Pilot study were implemented for four different remediation strategies, natural recovery, biostimulation, adsorption, and integrated remediation, for removal of Aroclor 1242, naphthalene and heavy metals. The best one reached 22.6% removal of heavy metals, 100% removal of naphthalene, and 91.4% removal of Aroclor 1242. Further, the one amended with 1.0% of SONE and 1,000 mg L^(-1) of MNP exhibited the highest removal rate and may shorten remedial time up to 61%. The studied results strongly supported that engineering intervention with addition SONE and MNP is better than natural recovery and it can shorten the remedial time frame remarkably.