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Water conservation and reuse has become a major issue in aquaculture in recent years. Concern over increased demand in aquifers, cost of operating wells, environmental impact of aquaculture effluent, and the desire to increase production efficiency continues to drive advances in technology and management practices. Several of the management strategies developed to address these issues include enhancing water circulation in ponds and developing intensive, recirculating tank systems. The combination of these two technologies is referred to as pond recirculating systems.
Pond culture is the most widely used production technology in world aquaculture. The lower stocking and feeding rates, permit of water and lower investment and production costs have contributed to the present expanse of pond production worldwide (Wheaton, 1977).
Masser et al. (1992) stated that recirculating system is biologically complex and mechanically sophisticated. It requires constant monitoring to ensure that they are functioning properly.
Major objective of water circulation is to destratify, or mix, the deeper, cooler, oxygen-deficient waters with the shallow, warmer waters rich in dissolved oxygen, reducing the risk of low dissolved oxygen due to turnovers and again water disinfection is important. In this experiment filtered water was passed through UV light to destroy any microbes causing disease that may be in the water.
One way of achieving high production intensities is through the use of recirculating aquaculture tanks systems (concrete or fibre glass). This system requires aeration and complete feeds to support the high stocking densities (Boyd, 1982). In aquatic production aeration is vital to the vigorous health and vitality of fish. Intensively cultured fish becomes stressed without enough oxygen if not aerated, Boyd (1982). Paddle wheels and surface aerators do not address these problems or correct them. Complete aeration of pond through pond bottom is achieved with recirculating systems and toxic gas removal enables oxygen-breathing micro organisms and insects to feed on the organic sediment and organic water (Boyd and Watten, 1989). Recirculating system maximizes water re-use by employing comprehensive water treatment system. Water treatment processes typically are solid removal, infiltration, gas balancing, oxygenation, and disinfection. By addressing each of the key water concern through treatment rather than flushing as is used in flow-through and the partial reuse systems, ultimate control over culture conditions and water quality is provided. Deborah and...