利用低造價湧升柱改善水體水質之效率評估與應用研究

Abstract

由於水域普遍存在水溫以及溶氧分層，所以使用兼具上下水體交換與曝氣能力的湧升柱設備，以打破上下水體分層及增加水體溶氧。湧升柱裝置由市售硬質塑膠管材組裝而成，以打氣設備作為湧升柱裝置動力，此裝置利用氣體浮力揚升原理，將裝置內水體間歇式地湧升至水體表面，能夠使得上下水體交換，破壞水溫及溶氧分層，並提升水體溶氧量以改善水質環境。 根據裝置基本設計，初步地完成裝置的兩種規格，為了後續可建立多規格化設備的產品目標，明確提出對各項設備能力評估的實驗方法設計與計測結果。使用此兩種規格分別於實驗現場進行應用研究，觀察裝置於不同水體之增氧與打破水層效果，明確量化本裝置所能影響的水體範圍，以利日後針對不同水域，設計所需使用的增氧裝置數量與配置。 依湧升柱裝置標準化試驗結果，Ⅰ型裝置標準曝氣效率為0.56 (kgO2/kw/hr)，Ⅱ型裝置標準曝氣效率為0.72 (kgO2/kw/hr)，Ⅱ型裝置略優於Ⅰ型。本裝置應用於深水域之效果較淺水域顯著，增氧擴散範圍與水深成正相關，Ⅰ型裝置於1公尺淺水域之增氧範圍可達半徑8公尺，配置間隔可設計為16公尺，5公尺深水域則為15公尺，配置間隔可設計為30公尺。 低造價湧升柱裝置提供一個有效提高池底溶氧環境、加速改良池底有機物消化作用的途徑，如能提供長期連續曝氣，對水質改善應有正面效益。

Water areas have temperature and dissolved oxygen dividing layer. We use air-lift equipments with aerated ability to exchange upper and lower water to break the layer and increase the water’s dissolved oxygen. Air-lift equipments was assembled of PVC tubes. Regard air-lift pump as equipments’ motive force. Utilizing gas buoyancy that wells up the water in equipments and raises the water periodically to the surface, causing the water to exchange. Equipments increase dissolved oxygen in water to enhance the water quality. According to the design of the equipments, two kinds of specifications of the device are designed. The experiment methods and designs and results are clearly propositioned to standardize more product of equipment to set up. This research analyses two kinds of specifications for air-lift equipments and confirming its movement characteristic. Oxygen increasing efficiency and range were recorded as well for identifying applicable conditions and clarifying operation methods. We design the numbers of oxygenation device to be used in order to apply different water areas. The standard aeration efficiency (SAE) with air-lift equipments typeⅠis 0.56 kgO2/kw/hr, typeⅡis 0.72 kgO2/kw/hr. The latter is more efficient than type Ⅰ. The equipments showed outstanding effect in deep water since the oxygen diffused area expanded as the depth increased. The experiments showed that the oxygen diffused area can access to 8 meters in radius when the equipments was placed at 1 meter underwater,and 15 meters when it was placed at 5 meters . The results confirmed that air-lift equipments can aerate more effective of whole bottom water in ponds, and it should enhance the organic matter digestion. It benefits water quality improvement when we aerate the water for a long time in succession.