Water chemistry characterization and component performance of a recirculating aquaculture system producing hybrid striped bass
<p>Eight identical and independent pilot scale recirculating aquaculture production systems were populated with fingerling hybrid striped bass <i>(Morone chrysops</i> female x <i>Morone saxatilis male</i>). Three population densities were established with two replicates...
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| Format: | Others |
| Language: | en |
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Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/45132 http://scholar.lib.vt.edu/theses/available/etd-10102009-020254/ |
| Summary: | <p>Eight identical and independent pilot scale recirculating aquaculture production
systems were populated with fingerling hybrid striped bass <i>(Morone chrysops</i> female x
<i>Morone saxatilis male</i>). Three population densities were established with two replicates
at 132 fishlm3 and three replicates each at 66 and 33 fishlm3.</p>
<p> Water chemistry and water
quality characteristics were monitored throughout the 228 day growth trial for all eight
systems. A system component performance analysis was done for both the multi-tube
solids clarifier and rotating biological contactor (RBC).</p><p>Water chemistry and water quality analysis included dissolved oxygen (DO),
alkalinity, ions, carbonaceous biochemical oxygen demand (CBODS), chemical oxygen
demand (COD), dissolved organic carbon (DOC), total suspended solids (TSS), volatile
suspended solids (VSS), total ammonia nitrogen (TAN) , nitrite and nitrate. The major
ions present were chloride, nitrate, sulfate, phosphate, sodium, calcium, magnesium and
potassium. Trace levels of TAN, nitrite, iron and copper were also observed. Sodium,
calcium and chloride levels were controlled based on a preplaned water exchange and
chemical management method. TAN, nitrite and nitrate levels increased over time with
increasing feed rates but never reached levels toxic to the fish population. CBODS,COD,
DOC, TSS and VSS increased over time increasing as a function of increasing feed rates.
No correlation was observed between fish mortality or fish growth rates for the range of
organic and solids parameters observed during this study. On average 67% of the TSS
present was between 1.5 and 30 microns in size. Diurnal cycles were observed for DO,
TAN and alkalinity. The magnitude of these cycles were population dependent.</p><p>
Multi-tube clarifiers removed an average 56% of all suspended solids in a single
pass with 81 % removal efficiency for particles above 70 microns in size. Analysis of the
system effluent generated by the clarifier indicates a high degree of similarity between
the aquaculture effluent and standard municipal waste on a nutrient basis but with much
higher levels of nitrogen and phosphate species.</p><p>
RBC nitrification performance was fitted to an empirical equation. A nearly
constant TAN removal rate was observed over the range of mass loading experienced in
this growth trial. This implies that within a reasonable range higher flow rates resulting
in higher mass loading will yield higher TAN removal rates for a given RBC.</p> === Master of Science |
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