滾筒過濾技術在養殖上的應用

Abstract

本研究利用創新的自淨式(self-cleaning)過濾技術研發滾筒過濾機，用以快速且安全地濃縮豐年蝦無節幼蟲與輪蟲，並評估利用高水流交換率過濾高密度輪蟲生產系統的可行性。過濾器的滾筒有1/3沉於水中，而過濾水則由滾筒內部抽出。滾筒的旋轉會在濾網與周圍的水體間產生相對運動而使得濾網面自淨，豐年蝦無節幼蟲與輪蟲因此可以在高速下被濃縮到高密度而不會有太大的損傷。結果顯示滾筒過濾機可在9分鐘內將200公升的豐年蝦無節幼蟲由200/ml濃縮到13,500/ml，存活率超過99%。滾筒的比過濾率(specific filtration rate) 為楔形網的2倍以上而大約為浮游生物網的8倍。結合真空收穫裝置與滾筒過濾機而成的自動化系統可以在13分鐘內將350公升的輪蟲由密度大約250/ml濃縮到大約15,000/ml。平均存活率為95.4%。與文獻中的其他輪蟲收穫裝置相比，自動化系統的比過濾率10.88 m3/h/m2與收穫率97.3%均是最高。滾筒提供了快速且安全的過濾方式，可以用在收穫密度為2,000 rotifers/ml 而體積為1,000公升的養殖系統中，利用滾筒過濾機抽取天然藻水餵飼輪蟲每天可生產1.2億個輪蟲。自淨式的分離技術養殖上可以有很大的應用包括將水與豐年蝦、輪蟲、魚蝦的幼苗等加以分離。

A rotating drum filter, employing a novel self-cleaning filtration technique, has been developed to concentrate/filter brine shrimp nauplii and rotifers, and was performed to evaluate the feasibility for the high-density rotifer production system employing high water exchange rate. The rotating drum is partially submerged into the culture and the filtered water is pumped out from inside the drum. The rotation of the drum produces a relative motion between the filtering screen and the surrounding water making the filtering screen self-cleaning. Nauplii and rotifers thus could be concentrated at high speed to a high density with little damage. The rotating drum could process 200 liters of nauplii culture from an initial concentration of 200 nauplii/ml to a final concentration of 13,500 nauplii/ml in less than 9 minutes, with a survival rate of more than 99%. The specific filtration rate was more than twice that of the welded wedge screen and about eight times that of the plankton bag. Combined with the vacuum harvesting device, it could automatically concentrate 350-liter of the rotifer culture with a density of about 250 rotifers/ml to about 15,000 rotifers/ml in less than 13 minutes. The average survival rate was 95.4%. The specific filtration rate of 10.88 m3/h/m2 and the average rotifer collection rate of 97.3% were both highest compared with other devices reported in the literature. The rotating drum offers a fast and safe filtration operation. It may be used for a 1,000-liter of the rotifer culture system, with a harvested concentration of 2,000 rotifers/ml, to produce 1.2×109 rotifers/day by using the filter to pump the natural microalgae. The self-cleaning separation technology could have wide applications in aquaculture involving the separation of water from live organisms such as the live food Artemia sp. and rotifers as well as fish or crustacean larvae.