brunson
Effect of Solids Removal on Production of Pacific White Shrimp Litopenaeus vannamei in a Minimal Exchange, Biofloc‐Based System neworleans2011
Jeff Brunson*, Jason Haveman, Edward DuRant, Daryl Weldon, and John Leffler South Carolina Department of Natural Resources James A. Waddell Mariculture Center Bluffton, South Carolina
Solids in Biofloc Systems y Potential benefits y Reduced water use y Greater biosecurity y Reduced capitalization cost y Flexibility in site selection y Solids removal reduced: y TSS and VSS y Cyanobacteria y Bacteria density y Rate of nitrate accumulation y Increased primary production y Shrimp growth?
Experimental System y Fifteen (15) plastic tanks fitted with vinyl pool liners. y Tank Volume = 6.2 m3 at an average depth of 70 cm. y Air supplied by a regenerative blower . y Conical bottom settling chambers. y Airlift driven, 5.1‐6.2 L/min y 15 L of sludge removed weekly
Experimental Design y Five treatments, in triplicate: y
TRT A “Control”‐ Continuously unsettled y Airstone in settling chamber
y
TRT B Settled 10 hours/week
y
TRT C Settled 50 hours/week
y
TRT D Settled 150 hours/week
y
TRT E Settled 168 hours/week, with 250 μ mesh bag on return pipe.
Stocking y y y y
All tanks “seeded” with established biofloc‐ rich water Stocking Date – June 8, 2010 Initial Weight‐ 1.89 g 1000 shrimp/tank 145 shrimp/m³
Early Problems y y y y y y y
Mortality June 15‐22 (beginning one week after stocking) Dead shrimp removed twice per day. Losses from 0‐188 shrimp Daily measurements uniform No correlation with NH3‐N or solids level. No treatment effect detected Shrimp redistributed
Daily Water Quality y Temperature 23.9‐32.8 ⁰ C y Cold snap around July 4th y pH 7.1‐8.9 y Dissolved oxygen ≥ 4.3 mg/L y Salinity 20.3‐25.8 ppt
Total Chlorophyll Predicted by Settleable Solids 1200
Tot. Chl. (ug/L)
1000
P
Jeff Brunson*, Jason Haveman, Edward DuRant, Daryl Weldon, and John Leffler South Carolina Department of Natural Resources James A. Waddell Mariculture Center Bluffton, South Carolina
Solids in Biofloc Systems y Potential benefits y Reduced water use y Greater biosecurity y Reduced capitalization cost y Flexibility in site selection y Solids removal reduced: y TSS and VSS y Cyanobacteria y Bacteria density y Rate of nitrate accumulation y Increased primary production y Shrimp growth?
Experimental System y Fifteen (15) plastic tanks fitted with vinyl pool liners. y Tank Volume = 6.2 m3 at an average depth of 70 cm. y Air supplied by a regenerative blower . y Conical bottom settling chambers. y Airlift driven, 5.1‐6.2 L/min y 15 L of sludge removed weekly
Experimental Design y Five treatments, in triplicate: y
TRT A “Control”‐ Continuously unsettled y Airstone in settling chamber
y
TRT B Settled 10 hours/week
y
TRT C Settled 50 hours/week
y
TRT D Settled 150 hours/week
y
TRT E Settled 168 hours/week, with 250 μ mesh bag on return pipe.
Stocking y y y y
All tanks “seeded” with established biofloc‐ rich water Stocking Date – June 8, 2010 Initial Weight‐ 1.89 g 1000 shrimp/tank 145 shrimp/m³
Early Problems y y y y y y y
Mortality June 15‐22 (beginning one week after stocking) Dead shrimp removed twice per day. Losses from 0‐188 shrimp Daily measurements uniform No correlation with NH3‐N or solids level. No treatment effect detected Shrimp redistributed
Daily Water Quality y Temperature 23.9‐32.8 ⁰ C y Cold snap around July 4th y pH 7.1‐8.9 y Dissolved oxygen ≥ 4.3 mg/L y Salinity 20.3‐25.8 ppt
Total Chlorophyll Predicted by Settleable Solids 1200
Tot. Chl. (ug/L)
1000
P
