Application of Direct Filtration Utilizing Floating Bead Filters and Flocculation Aids for Fine Suspended Solids and Phosphorus Removal

As aquaculture, particularly marine aquaculture continues to expand worldwide environmental regulations pertaining to waste discharge from fish farms are also becoming more stringent having an environmentally sound waste management, recovery and disposal plan are thus becoming increasingly more important, particularly in marine aquaculture. Two of the primary concerns for extending water reuse and recovery are the suspended solids and phosphorous in the effluent. The direct filtration process provides aquaculturist with a tool to allow both freshwater and marine recirculating aquaculture systems (RAS) (including zoos and aquaria) to recover and extend the use of water in their facilities resulting in a significant cost savings through the reduction of the volume of waste water being discharged and the cost of make-up water, especially on marine systems which rely on expensive artificial sea salt mixtures or transport of saltwater from offshore sites. The direct filtration process is a simplified strategy for implementing a coagulation/flocculation process. Coagulation and flocculation aids have long been used in the drinking water and wastewater treatment industries. Traditional water treatment utilizes the process of dosing chemical coagulation and flocculation aids for the removal of turbidity-causing fine solids in a progressive, 4-step process. To improve upon the traditional coagulation/flocculation approach to water treatment, the direct filtration process combines the individual unit processes with the particle capture benefits of a floating bead filter (FBF) to create an efficient, integrated, and streamlined package. The integration of electro-flocculation, a promising new technology which does not require the dosing of chemical coagulation and flocculation aids, may reduce the amount of residue from the coagulation/flocculation process and simplify the direct filtration process. Electro-flocculation is the application of electrical current to a pair of electrodes to improve and facilitate the flocculation of fine solids. While highly effective at the removal of fine suspended and colloidal particles, the direct filtration process may potentially be tuned to have the secondary benefit of effective phosphorus removal. As a result of the Phase I research, the application of the direct filtration process with a FBF was shown to be incredibly successful in the removal of turbidity-causing fine suspended solids. Likewise, the effect of orthophosphate sequestration and removal with an appropriate coagulant makes the direct filtration FBF even more desirable. Combining the removal of turbidity-causing fine suspended solids with the removal of orthophosphate in a space-saving, innovative package will serve as an excellent addition to the existing line of highly successful FBFs which AST has successfully marketed for over 17 years. The key to successful aquatic animal production systems is the availability of reliable and cost effective production technologies. AST has successfully commercialized a family of FBFs, or bioclarifiers, which can accomplish both solids capture and nitrification in a single unit economically and efficiently. AST believes that this "next generation" of FBF optimized for direct filtration will provide an efficient and cost effective solution which directly addresses the regulations imposed on the aquaculture, zoo and large aquarium industries.