Graduation Year

2012

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Maya Trotz

Co-Major Professor

Sarina Ergas

Abstract

Land based aquaculture systems are growing in popularity, and there is a drive to improve the efficiency of their energy and water systems for both economic and environmental benefit. Recirculating Aquaculture Systems (RAS) generally refer to systems that recycle their wastewater streams to be more or less a zero discharge facility. A more sustainable approach is emerging in the form of Integrated Aquaculture Systems (IAS) where maximum utility is realized from the various components so that fresh water use is reduced, water quality is improved, energy use is reduced, and new markets are created or fulfilled. Under a grant from the National Oceanic and Atmospheric Administration (NOAA), an interdisciplinary group from MOTE Aquaculture Research Park, Mote Marine Lab, the University of South Florida, and Aquatic Plants of Florida have been working on a pilot IAS in Sarasota, FL starting 10/1/2010 which couples high- value pompano fish production with the production of native FL marine plant species (Spartina alternaflora (smooth cordgrass), Juncus roemareanus (needlegrass rush), and Rhizophora mangle (red mangrove) for wetlands restoration. This research contributes to the understanding of water quality as a function of space and time in the MOTE IAS system and compared the performance of the plant bed configurations (with and without a sand filter) with a more common geotube membrane used in RAS, for treating effluent sludge from marine fish tank systems.

For the same influent concentration from the solids waste tank, the overall average percentage of Total Suspended Solids (TSS) removed was 84%, 84%, and 80% from the south plant bed (SB), north plant bed (NB), and geotube (GT) and the overall average Volatile Suspended Solids (VSS) removed was 85%, 90%, and 87% from the SB, NB, and GT respectively. The plant beds performed as well as the geotube in terms of TSS and VSS removal.

Dissolved oxygen concentrations ranged from 0.28 mg/L in the geotube effluent (GTe) to 10.72 mg/L in the moving bed bioreactor influent (MBBRi). Overall averages (n = 5 per sample) of DO between May 2011 and January 2012 varied from 1.97±1.92 mg/L in the solids tank effluent (STe) to 8.20±1.60 mg/L in the MBBRi. pH values ranged from 6.35 STe to 7.74 in the GTe. Overall averages of pH between May 2011 and January 2012 varied from 6.89±0.5 mg/L in the STe to 7.45±0.21 in the MBBRe. Temperature values ranged from 17.3 oC in the GTe in December to 28.8 oC in the SFe during the month of September.

The average unfiltered Chemical Oxygen Demand (UCOD) ranged from 105±37 mg/L in the NBe to 231±99 mg/L in the STe. Compared to the STe the percentage of COD removed from the SBe, NBe, GTe, and SFe was 47%, 55%, 53%, and 23% respectively. Average filtered COD (FCOD) ranged from 91±46 mg/L in the NBe to 132±66 mg/L in the STe. Compared to the STe the percentage of FCOD removed from the SBe, NBe, GTe, and SFe was 22%, 31%, 25%, and 2% respectively.The average unfiltered total nitrogen (UTN) concentration ranged from 24±17 mg/L in the SBe to 52±25 mg/L in the MBBRi. The overall average

percentage removed was 54%, 46%, 47%, 15% from the SBe, NBe, GTe, and SFe respectively based on the STe concentration. The average filtered total nitrogen (FTN) concentration ranged from 20±13 mg/L in the SBe to 68±37 mg/L in the MBBRi and for the given effluent streams, FTN was either comparable to UTN or higher with the higher values seen prior to and after the moving bed bioreactor (MBBR). The majority of total nitrogen is dissolved. Average filtered N03--N concentrations ranged from 0.73±0.79 mg/L in the NBe to 29± mg/L in the MBBRe. The overall average percentage removed was 96%, 76%, -2%, 95% from the SBe, NBe, GTe, and SFe based on the STe concentration. Average filtered NH3-N concentrations ranged from 0.2±0.2 mg/L in the MBBRi to 3.9±3.1 in the SFe. The overall average percentage removed was 51%, 80%, 71%, -5% from the SBe, NBe, GTe, and SFe based on the STe concentration

The average unfiltered total phosphorous (UTP) concentration ranged from 30±11 mg/L in the SBe to 37±12 mg/L in the GTe. The average filtered total phosphorous (FTP) concentration ranged from 23±17 mg/L in the MBBRi to 36±29 mg/L in the NBe and for the given effluent streams, FTP was always less than UTP with the NBe being an exception. The average filtered total reactive phosphorus (FOP) concentration ranged from 18±18 mg/L in the MBBRe to 26±15 mg/L in the SBe and for the given effluent streams.

Samples taken over an 18 hour period on 2/1/12 showed high variability in terms of concentrations in the solids tank effluent which was not seen in the rest of the system.

Metals and trace elements were of similar concentration in all effluents from 5/17/11 to 9/7/11. Accumulation of metals of elements was not observed,but a removal mechanism was not identified. The SBe had the lowest concentrations of Mn, Ni, Se, Fe, and B, however a longer monitoring period is recommended.

The IAS is successfully growing pompano in land based low salinity tanks, the fish wastewater is producing wetlands restoration plants and zero discharges of water or solid waste (dead fish an exception) have occurred from the system which began operation in October 2010.

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