DESIGN, DEVELOPMENT, AND PERFORMANCE EVALUATION OF PLASTIC- BASED RADIAL- FLOW SETTLING UNIT FOR NFT AQUAPONICS

One cylindrical settler of capacity 200 L (& Oslash; 0.6x0.7 m) with a center-bottom inlet has been designed developed in High-Density Poly Ethylene (HDPE) under the All-India Co-ordinated Research Project on Plastic Engineering in Agriculture Structures & Environment Management (AICRP on PEASEM) center at ICAR-CIFA, Bhubaneswar fitting to the developed Nutrient Film Technique (NFT) aquaponics system. The water flow into the settling unit comes a single-drain fish culture tank with the outlet at the bottom-center with a downward slope of 1:22. The experiment carried out for the evaluation of the efficiency of Total Suspended Solid (TSS) removal in the developed radial-flow settling unit. The performance is assessed in terms of capturing the suspended solids from the water of aquaculture operation varying specific gravity (1 <= SG>2) <= SG>2) as well as the skimming of the floating organic surfactants before entering into biofilter. During the 90 days of study, a total of 60 water samples were collected from the outlet of the fish culture tank the overflow of the settler, which were filtered through the standard 11 mu m pore paper filter for further processing in laboratory. The average TSS concentration removed was calculated to be 128.55 mg/L on dry weight basis and a efficiency of 80.06 +/- 9.36% was observed in the experiment with a surface loading rate of 0.00103 m3/min-m2 3 /min-m 2 of the radial flow settler. The right-angle submerged overflow of the settler helped in complete surfactant removal.