優養化水體水質處理技術及應用之研究

優養化水體的處理技術，可分為物理處理法、化學處理法及生物處理法。目前改善湖庫水體優養化的方法，較常使用物理性方法中的曝氣法；生物濾床法通常用於處理高污染水質，在濾床內填充濾材介質，使微生物附著於濾材上並與廢水中有機質接觸，以淨化水質，處理效率高，適合小面積的水質處理；生物控制水質管理法，係利用水域中生態系食物鏈方式進行水質淨化的方式，是近10年來國外極為重視及使用的生物處理法。本研究主要目的有兩部分，一是生物濾床系統及曝氣設備的研發及應用、一是建立國內生物控制水質管理法的操作參數及實地應用。研究重點偏重在研發設備的水質處理效率及生物控制水質管理法現地實驗的應用結果之探討。研究結果包括: 1.研發｢低動力生物濾床系統｣並應用於景觀池及養殖池。景觀池實驗操作共計400日，實驗期間氨氮平均去除率為58%；養殖池實驗操作116日，實驗前期(15天~57天) 設備去除總氨氮的效率最高可達63%。而自第75天開始，設備出水總氨氮均高於入水總氨氮，推測可能原因是養殖過程中定期持續地投放營養劑，設備有機物堆積太多，硝化菌生物膜老化，因而抑制硝化作用，以致設備在實驗後期無法正常發揮作用。 2.研發曝氣設備｢耘水機｣，同時在台大醉月湖及湖泊水庫探討此曝氣設備的增氧效率評估及景觀湖泊的水質改善分析。實驗結果顯示｢耘水機｣曝氣設備的攪動水體擴散半徑約20公尺，攪動水體擴散面積約1,256 m2，攪動水體體積約3,140 m3。 3.生物控制水質管理法(Biomanipulation)是以人為方式改變魚類相的組成，再利用魚類的食性關係，控制浮游生物相的群聚結構，以達到水質淨化。本研究於台大醉月湖放養黑鰱進行生物控制水質管理，實驗中計算其生長過程，以6年為期，即6年後應再補充新的魚苗，原有黑鰱則可進行捕撈替換，結果顯示如此可穩定水質、維持黑鰱攝食藻類的穩定性，成功地提高黑鰱在醉月湖的合理利用效益。

關鍵字

優養化水體；生物濾床系統；曝氣設備；生物控制水質管理法；黑鰱

並列摘要

The treatment of eutrophication water bodies can be divided into physical, chemical and biological treatment method. At present, aeration of the physical method is frequently adopted to improve the eutrophication of lakes and reservoirs. The biological filter is usually used to treat highly polluted water, with the media filled in the filter, the microorganisms will be attached on the media and thus to purify the water. It has a high treatment efficiency and is suitable for small-scale water bodies. The biomanipulation is a most prevailing biological method in this decade by using the ecological food chain in the water body to purify the water. The objective of this study has two parts: one is to developa facilicity - recirculating aquaculture system (RAS) with biofilters and aeration equipment, and its application; the other is to establish the operational parameters and field application of domestic biomanipulation. To achieve the above objective, the research focuses on investigating the treatment efficiency of the facility developed and the application results of the field experiment of the Biomanipulation. The results of this study include: 1. Development of the "recirculating aquaculture system (RAS) with biofilters" and its application on landscape pond and culture pond. The landscape pond was operated for a total of 400 days, and the average removal rate of ammonia nitrogen was 58% during the experiment. The operation of the culture pond was 116 days. At the early stage of the experiment (15 ~ 57 days), the removal efficiency of the total ammonia nitrogen could reach up to 63%. While starting from the 75th day, the total ammonia nitrogen of the effluent was higher than the influent. It was presumed too much organic matters accumulated in the equipment due to the periodically supply of the nutritional broth. It thus resulted the aging of the nitrifier biofilm and inhibited the nitrification, so that the system could not normally function at the later stage of the experiment. 2. Development of the aeration equipment "pond aeration system" and evaluation of its oxygenation efficiency by conducting experiment at the Drunken Moon Lake of National Taiwan University, and its efficacy in improvement of the water quality of the landscape lake reservoir. The experimental results showed that the aeration equipment of the "pond aeration system" had a diffusion radius of about 20 meters, a diffusion area of about 1,256 m2, and a volume of about 3,140 m3 of agitated water. 3. Biomanipulation is a water quality management practice which the natural aquatic organisms is controlled by changing the composition of the fish phase artificially, and then uses the feeding relationship of the fish to control the cluster structure of the plankton phase so as to achieve the water purification. In this study, the silver carp was stocked in the Drunken Moon Lake of National Taiwan University by using biomanipulation method to biologically control the water quality. During experiment, the growth process of the silver carp was monitored and calculated for a period of 6 years, i.e., new fry would be added after 6 years, and the original silver carp were replaced by fishing. Experimental results showed the water quality and the feed algae of the silver carp was able to stably maintained, could enhance the rational utilization of the silver carp in Drunken Moon Lake successfully.