SELECTING BEST AVAILABLE TECHNOLOGIES FOR DAIRY FARM PHOSPHORUS RUNOFF MANAGEMENT

Lake Okeechobee, in south central Florida, has experienced increasing eutrophication over the last 30 years due to high phosphorus (P) loads from non-point sources in the contributing basins. Agricultural land uses, particularly dairies, have been identified as the primary sources of P. These basins have a high concentration of large (average herd > 1000) dairy farms. Improvements in farm management practices aimed at reducing P in runoff from the farms began in earnest in the late 1970s and are still ongoing. Previous efforts have been partially successful in reducing total phosphorus (TP) concentrations in dairy farm runoff to the 1200 ppb. However, recent reevaluation of the external loading reductions necessary to restore and maintain water quality in Lake Okeechobee has resulted in a reduction of the target runoff TP concentration to 40 ppb. Four firms, led by Soil and Water Engineering Technology, Inc. and including CH2M HILL. Mock Roos & Associates, and ENTEL Environmental Companies, have teamed to develop, implement and monitor cost-effective technologies for Okeechobee Basin dairy farms to meet the target runoff concentration. The South Florida Water Management District (SFWMD – the agency responsible for managing water quality in the basin) funds the three-year project which began in November 2000.The project team will be working closely with a technical advisory committee made up of agency staff, university experts, and individuals from the dairy industry that will advise and provide oversight for the project. The dairymen selected for the project will also serve on the committee. The involvement of all interested parties ensures that a workable solution acceptable to the various interests in the basin is applied.The objectives of this first project year include identifying the technology (or technologies) to be used, selecting and contracting with the farms where the project will be implemented, developing comprehensive nutrient management plans for the selected farms, and providing the recommendations to the SFWMD. The second and third years will see the implementation and monitoring efforts if the results of the first year indicate that the proposed efforts have sufficient potential for success.The presentation will focus on the current results of the process being used to identify the best available technologies for the project. A decision model including project goals and objectives, selection criteria, and ranking method was developed as the primary tool for the selection process. A literature search to evaluate the current state of the art in phosphorus management technologies was then completed. The search provided a list of possible technologies, their removal efficiencies, and their place in the farm waste management process. The three participating farms have also been selected for the project. Dairies were ranked and selected based on the interest of the dairymen themselves, including a willingness to invest in the effort, the investments already made in P management practices, their access to management expertise, and the diversity of farming practices and management issues presented. The process of matching technologies to individual dairies will also be discussed.