Pumping Performance of a Slow‐Rotating Paddlewheel for Split‐Pond Aquaculture Systems

Abstract

Commercial catfish farmers are intensifying production by retrofitting ponds with variations of the partitioned aquaculture system. The split‐pond system is the most common variation used commercially. The split‐pond consists of a small fish‐holding basin connected to a waste treatment lagoon by two conduits. Water is circulated between the two basins to remove fish waste and provide oxygenated water to the fish‐holding basin. Although much research has been devoted to algal and fish production dynamics in variations of the partitioned aquaculture system, little information is available on basic engineering considerations for devices to circulate water in these systems. This study evaluated performance characteristics for a slow‐rotating paddlewheel pump that looked at the relationships among power input, rotational speed (circular tip velocity), water velocity, and water flow rate. Rotational speeds of 1.0, 2.0, 3.0, and 4.0 rpm were evaluated in open channels and in channels with fish barriers. Measured power input was greater than the calculated power input for all four rotational speeds and ranged from 0.11 to 1.80 hp. Water flow rate ranged from 4,548–19,330 gal/min and water discharge per unit power input decreased dramatically as rotational speed increased. Installation of fish barriers decreased channel open area and the resulting frictional losses reduced water flow rates. Results from this study provide initial pump performance data for designing split‐pond aquaculture systems.