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Submitted to: Aquaculture Magazine
Publication Type: Trade Journal Publication Acceptance Date: 2/16/2004 Publication Date: 3/18/2004 Citation: Pfeiffer, T.J. System design - parallel or series flow. Aquaculture Magazine. 2004. pp.51-52. Interpretive Summary: The biofilter size in a recirculating aquaculture system is determined by the level of ammonia in the waste water. The level of ammonia in the water from a culture system is dependent upon many variables, however, variable that is not often considered is the arrangement of the tanks and the water flow through those tanks. Water flow that is equally distributed through each tank is defined as a parallel system. The ammonia generated in each tank and the ammonia concentration flowing out of any tank is the same for all the tanks in a parallel arrangement. When the flow of water is from one tank into another, one at a time, the tanks are considered to be in series arrangement. The levels of ammonia concentration in the water exiting tanks are lower when the tanks are in series rather than dividing the flow for tanks arranged in parallel. For experimental purposes, parallel tank arrangement is preferred so that increasing ammonia levels do not affect the treatment under study. However, for multiphase, flow-through systems (trout raceways or crab shedding systems) series tank arrangement is preferred as additional water usage is obtained before exiting the facility. Technical Abstract: In the water treatment processes for recirculating aquaculture systems, sizing the biofilter is determined by the level of ammonia in the waste water. The level of ammonia in the water from a culture system is dependent upon many variables. A variable not often considered is the arrangement of the tanks and the water flow through those tanks ' parallel or series flow. A parallel system is defined by having the incoming water equally distributed into each tank. Thus, the ammonia generation, PE, in each tank is the same and the level of ammonia concentration flowing out of any tank is the same for all the tanks in a parallel arrangement. The levels of ammonia in the water exiting tanks are lower when the tanks are in series rather than dividing the flow for tanks arranged in parallel. For experimental purposes, parallel tank arrangement is preferred so that increasing ammonia levels do not affect the treatment under study. However, for multiphase, flow-through systems (trout raceways or crab shedding systems) series tank arrangement is preferred as additional water usage is obtained before exiting the facility. |
