Management of CAFO Discharges Utilizing Controlled Eutrophication Process (CEP) Ponds for Liquid Waste Storage and Conversion to Bioproducts and Slow-Release Biofertilizers

Kent SeaTech Corporation and Dr. David Brune of the Agricultural and Biological Engineering Department at Clemson University will conduct joint research on the application of high-rate algal pond water treatment technology to reduce the negative environmental impacts of nutrient wastes produced by concentrated animal feeding operations (CAFOs). The Pacific Southwest leads the Nation in the production of milk, eggs, and other foods that are produced in intensive farming facilities, which results in a large concentration of waste nutrients in a limited area. The 2,400 dairies in California alone produce 30 million tons or more of manure annually. Currently, most solid and liquid waste nutrients from CAFO operations in the Pacific Southwest are delivered to field crops, where the nutrients are assimilated into plant material. Although this overall concept is ecologically sound, as farming operations become more intensified and the amount of cropland available for distribution of the nutrients is reduced, more instances of over-application of nutrients and negative impacts to surface water, groundwater, and the atmosphere will occur. In some California counties, the amount of manure from CAFO facilities is greater than the assimilative capacity of the total pastureland and cropland present in the county, and more than 60 percent of groundwater wells are contaminated with nitrate. A cost-effective solution to this complex problem is required. Previous studies by Kent SeaTech and Clemson have shown that the controlled eutrophication process (CEP) is capable of removing nitrogen and phosphorus nutrients from contaminated surface water flows. The CEP process uses carefully managed, dense cultures of unicellular algae to rapidly convert waste nutrients to algal biomass through photosynthesis. CEP may provide an environmentally sound technology for treating waste nutrients that are difficult to remove from CAFO waste using traditional methods. Two existing 0.7-acre CEP treatment systems and a series of smaller evaluation systems will be used to determine the optimal conditions for converting solid and liquid CAFO waste from a cooperating CAFO facility into algal biomass. In the ultimate implementation of this concept, a high-rate algal pond using CEP technology would be installed adjacent to the existing CAFO wastewater collection lagoon and would be operated to reduce phosphorus and nitrogen in the discharge, utilize a portion of the solid and liquid waste nutrients to produce valuable byproducts, and thereby reduce the overall nutrient loading that ultimately passes into the environment through field crop application.