| 摘要: | 本研究將人工溼地技術應用到魚塭循環水養殖中，利用溼地的自然淨水能力作為養殖廢水的淨化及管理單元，以維護魚塭養殖池水水質及降低養殖場排廢水的污染。本文主要探討了人工溼地對養殖水中主要汙染物的處理效能，及人工溼地的淨化能力對維持魚溫水質的影響。人工溼地是利用既有的漁塭整地後改造完成（105m2），由一個表面流動式（FWS，free water surface flow system）溼地與另一個表面下流動（SSF，subsurface flow system）溼地所組成，此人工溼地並與一個魚塭（1125m2）以管線及抽水機建構成循環水養殖系統；另外，設置一個無循環水處理的魚塭（1138m2）作為傳統魚溫養殖水質比較的控制組；兩處魚塭均飼養白蝦(Litopenaeus vannamei)。本研究進行了三個試程的養殖及水質淨化試驗，第一試程自93年7中旬至9月中旬，第二試程自94年1月初至94年5月底，第三試程自95年5月初至95年7月底。由水質監測結果得知，魚塭循環水經人工溼地處理後出流水均維持相當良好的水質，由進流水—出流水水質評估，三個試程其水力負荷分別為4.41、4.51及2.92 m/day，停留時間為4.57、4.77及7.37hr。在三個試程中，人工溼地對循環水養殖池廢水的各污染物水質濃度的去除效率在SS的污染物去除效率分別為78、54及59%，對濁度的削減效率分別為52、58及65%，對葉綠素a的去除效率分別為68、54及65%，在BOD5上分別為40、46及27%，及COD的去除效率分別為32、26及65％。再比較三個試程中控制組養殖池與循環水養殖池的水質分析結果，第一試程中SS水質濃度分別為22±14與21±14 mg/L，濁度分別為19.0±7.8和15.0±5.1NTU，葉綠素a分別為53.5±56.7和34.9±31.1μg/L，BOD5分別為6.1±2.1與5.6±1.6mg/L，及COD分別為53.5±25.8和42.8±13.5；第二試程中SS水質濃度分別為62±45與23±12 mg/L，濁度分別為29.8±10.2和16.5±6.1NTU，葉綠素a分別為56.1±53.2和18.9±11.2μg/L，BOD5分別為10.5±2.6與6.2±3.0mg/L，及COD分別為99.9±23.9和76.6±24.1；第三試程中SS水質濃度分別為60±16與37±10mg/L，濁度分別為34.6±13.5和18.3±12.4NTU，葉綠素a分別為76.0±49.6和37.6±24.1μg/L，BOD5分別為10.1±2.6與6.6±2.2mg/L，及COD分別為76.0±49.6和37.6±24.1 mg/L；可見循環水養殖池的水質顯著的(p<0.05)優於控制組養殖池的水質。在第三試程中白蝦生長情況在飼養100天時，在中控制組養殖池白蝦與循環水養殖池之白蝦在體長上分別為9.8及10.5cm，體重上分別為6.96及7.38g，可見在飼養上循環水養殖池成效優於控制組養殖池，期釵b未來採收上有更佳的收穫量。人工溼地建置成本上約每平方公尺需花費1540元，故本研究結果除顯示人工溼地可作為傳統魚塭養殖在水質控制及管理外，對於飼養物生長及產量也有所助益，為一種低成本之生態工法。
This study is to integrate constructed wetland, or treatment wetland, technology into the recirculating aquaculture, in which constructed wetland is used as a facility for aquaculture water treatment so as to control the water quality in fishpond and reduce pollutant level in the fishpond discharge. The constructed wetland (105m2) was built using part of an existing fishpond, and included a free water surface flow unit followed by a subsurface flow unit. A fishpond (1125m2) was connected with the treatment wetland to constitute a recirculating aquaculture system. Another fishpond (1138m2) without connection of treatment wetland was used as a control fishpond, in which traditional static aquaculture was carried out. This study investigated the performance of the constructed wetland in removing the major pollutants from the recirculating aquaculture water, and examined the effect of wetland treatment on water quality of the fishpond in the recirculating aquaculture system. Two aquaculture trials stocked with larvas of Pacific white shrimp was conducted. One trial was carried out from the middle July to the late September, 2004; Two trial was started from the first January, 2005 to the late May, 2005; Three trial was started from the first may, 2006 to the late July, 2006. Results of water monitoring of influent-effluent showed that constructed wetland effectively reduced TSS (54~78%), turbidity (52~65%), chlorophyll a (54~68%), BOD5 (27~46%) and COD （26~65%） from the recirculating aquaculture water. Water quality of recirculating fishpond were maintained at 21±14, 23±12 and 37±10 mg/L for TSS, 15.5±5.1, 16.5±6.1 and 18.3±12.4 NTU for turbidity, 34.9±31.1, 18.9±11.2 and 37.6±24.1μg/L for chlorophyll a , 5.6±1.6, 6.2±3.0 and 6.6±2.2 mg/L for BOD5, and 42.8±13.5, 76.6±24.1 and 37.6±24.1 for COD in trials 1 , 2 and 3, respectively. These levels of pollutants were significantly lower (p<0.05) than those in the control fishpond. Constructed wetland was demonstrated to be an efficient and low-cost ecological approach to management water quality and control pollution discharge in a fish farm. |
