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ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #254730
Title: Treatment of Aquaculture Wastewater Using Floating Vegetated Mats

Author
item Hubbard, Robert
item Anderson, William - Bill
item BURTLE, GARY - University Of Georgia
item NEWTON, G. - University Of Georgia
item RUTER, JOHN - University Of Georgia
item Wilson, Jeffrey - Jeff

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 8/11/2010
Publication Date: 9/11/2010
Citation: Hubbard, R.K., Anderson, W.F., Burtle, G., Newton, G.L., Ruter, J., Wilson, J.P. 2010. Treatment of Aquaculture Wastewater Using Floating Vegetated Mats. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE).

Interpretive Summary: Methods are needed to protect and improve water quality. Technologies for wastewater commonly include using constructed wetlands or land application. A new concept is to use floating vegetated mats to cover part of the surface water body. The mats grow on floating platforms. Roots of the plants reach into the water and take up nutrients. Biomass can be harvested from the mats or in the case of grasses or horticultural plants, the plants can be transplanted. Harvested biomass can be used to make compost for use as a soil amendment, or potentially for use in making biofuel. Both past and ongoing research has shown that floating vegetated mats can be used to grow biomass and remove nutrients from wastewater. Completed experiments on both moderately and severely contaminated swine lagoon wastewater have shown that species can be found to grow in such waters. Ongoing research is evaluating the floating mat concept for aquaculture wastewater. The objective of the study is to determine amount of biomass produced and nutrients removed with the harvested biomass, and quality of the treated wastewater. Wastewater from fish-production ponds is pumped into sets of aquaculture tanks. There are three tanks in series in each treatment set, and three replicate sets per vegetative species. Each tank contains a floating platform (1 m 2) for growth of vegetation. Results to date indicate that iris has potential for treating aquaculture wastewater.

Technical Abstract: Methods are needed for treating aquaculture wastewater. The goal is to improve wastewater quality sufficiently for it to be recycled to production ponds. One potential method for improving aquaculture wastewater is to use floating vegetation in treatment tanks. Alternatively, potential exists for growing the floating vegetation directly on the production ponds. A study with floating vegetated mats for improving aquaculture wastewater quality is being conducted at the University of Georgia’s Aquaculture Unit in Tifton, GA. The objective of the study is to determine amount of biomass produced and nutrients removed with the harvested biomass, and quality of the treated wastewater. Wastewater from fish-production ponds is pumped into sets of 1285 L aquaculture tanks. There are three tanks in series in each treatment set, and three replicate sets per vegetative species. Each tank contains a floating platform (1 m 2) for growth of vegetation. During a prototype test of wetland, horticultural, and agronomic plants, it was determined that cattail, iris, or soft rush were suitable for growing in aquaculture wastewater. The treatments for the study are three tank sets of cattail, iris, soft rush, or a control (no plants). The water in the sets of tanks is circulated every three weeks such that tank 1 always receives water directly from the fish pond, tank 2 receives water from tank 1, tank 3 receives the water from tank 2, and tank 3 is drained into a nearby storage pond. Water samples are collected from each tank prior to transfer to the next tank or storage pond to determine water quality. Plant biomass is harvested as needed. Measurements are made of total biomass per tank and nutrient content (N, P, and K) of the plant tissue. Water quality measurements include N, P, K, BOD, chlorophyll, O2, turbidity, and pH. This paper presents current results of the three-year study which started in May 2009.