The Controlled Eutrophication Process for Concentration and Recovery of Nitrogen and Phosphorus from Agricultural Surface Waters

Abstract

We are proposing that a promising best management strategy for controlling eutrophication of public waters within agricultural watersheds will be through the use of high rate engineered ecosystems, in which, nutrient enriched public or private waters are passed through a “controlled eutrophication process” capable of converting excessive nutrient levels into recoverable algal biomass and high value aquatic products thereby reducing adverse downstream impacts. The basis of this technology, the Partitioned Aquaculture System (PAS) has been under development at Clemson University for the past 15 years (patented 2002). The Clemson PAS technique, was developed to control nutrient levels in captive water aquaculture production systems and has been demonstrated to be capable of yielding 3-5 times the fish production per land area using 1/8 the water volume of conventional aquaculture, in a system which is designed to recover N and P as high value fish flesh, biofertilizers and biofuels, thereby offsetting the system capital and operating costs. Recently, Clemson University investigators, in conjunction with industry scientists, initiated a project to modify the PAS process adapting it as a nutrient recovery and concentration technique to be used to clean eutrophying levels of N and P from drainage waters from irrigated agriculture in California’s Coachella valley. This modification of the PAS has been termed the Controlled Eutrophication Process (CEP). In this presentation we will present data from field studies at Clemson and California field sites and will outline the design requirements for a system capable of algal driven CEP water treatment technology to achieve a 90% reduction in nutrient discharges from surfaces waters at N and P concentrations typical of eastern and western U.S. agricultural watersheds.