Control of a swine manure treatment process using a specific feature of oxidation reduction potential

A real-time control strategy for waste treatment, using a specific feature of oxidation-reduction potential (ORP) feature, was developed; the usefulness of this technology was evaluated through two separate operations. A newly designed, two-stage, bench-scale wastewater treatment process for swine wastewater was successfully operated with this real-time control technology. The nitrogen break point (NBP) on the ORP-time profile was designated as a real-lime control point. By designating the NBP as such, sufficient organic carbon matter for denitrification could be left in the mixed liquor and completely removed during denitrification. Since the treatment stages were not controlled by a timer, but by the ORP real-time control point, the process could provide consistently high reduction of combined organic carbon (C), nitrogen (N) and phosphorus (P) concentrations, despite the large fluctuation of animal wastewater characteristics. The average system performance, relative to influent strength, was in excess of 96% for the C, N and P. Real-time control techniques worked effectively without the addition of an external carbon source in the treatment of swine manure: effective N and P removal was achieved, using internally available organic matter. (C) 1999 Elsevier Science Ltd. All rights reserved.