Application of Geotextile Bag Filters in Flow-Through Aquaculture Systems: Solid Waste Management and Water Quality Implication

Solids management plays an important role in the optimal aquacultural production and water quality improvement. The geotextile bag filters (GBFs) were used to dewater biosolids from flow-through aquacultural raceways in this study. Jar tests and geotextile cone tests were conducted to determine the polymer flocculant and its optimum dose for GBF application. In the meanwhile, the effect of GBFs on soluble nutrients (N&P) and BOD 5 was also evaluated. The solids content in the raw sludge generated from the flow-through aquacultural raceways in this study was highly variable ranging from 234 to 4290 mg/L (or 0.02 to 0.43% solids). GBFs was very effective in capturing the solids in the aquacultural sludge from flow-through raceways and the addition of Hyperfloc 626 polymer improved the solids removal by GBFs from 87.1±6.9% to 97.3±1.9%. Geotextile bags also effectively removed BOD 5 from the aquacultural sludge and enhanced removal (83.9±2.2%) was observed with polymer addition. On the other hand, the concentrations of soluble nutrient species (N and P) in the geotextile bag filtrate were higher than those in the raw sludge as a result of the decomposition of the particulate organic matter in the geotextile bags.