Field Demonstration of the Performance of an Electrocoagulation System to Reduce Phosphorus and Other Substances from Dairy Lagoon Effluent.

摘要

Two upper North Bosque River segments were designated as impaired in 1998 due to point source and nonpoint source (NPS) pollution of phosphorus (P) to these segments in the watershed. As a result, two Total Maximum Daily Loads (TMDLs) were applied which called for the reduction of annual loading and annual average soluble reactive P (SRP) concentrations by an average of 50%. This demonstration was conducted to evaluate the efficacy of a prospective new technology, an Electrocoagulation (EC) system, to potentially aid the dairy farmers in meeting the goals set by the TMDLs. This EC system used chemical pre-treatment to coagulate and separate solids in slurry pumped from the dairy lagoon, the liquid then flowed over charged iron electrodes giving off ions that cause coagulation and precipitation of P and other metals. The configuration of the system and its components varied from event to event. To accommodate these changes, the points at which samples were taken varied as well. At all sampling events, samples were taken from the lagoon effluent, the lagoon effluent after the addition of the chemical pre-treatments, the effluent from the EC system and the residual solids. Samples were also taken where the mixture exited the centrifuge after it was added to aid in removing solids. These samples were sent to the lab where they were analyzed for solids, nutrients, metals, pH, and conductivity.