THE FEEDBACK CONTROL SYSTEM OF THE ACTIVATED SLUDGE PROCESS FOR SWINE WASTEWATER TREATMENT

摘要

In the intensively extended three-stage swine wastewater treatment system by agriculture authority in Taiwan, the activated sludge process is the most difficult stage for pig farmers to operate. The main purpose of this study is to develop an automatic control system to help farmers operating this process and thus improving the effluent quality. In the developed control system, a single mixed liquor suspended solids (MLSS) sensor and a personal computer were used for data processing, while maintaining the MLSS of the aeration tank at a suitable level by sludge recycling was adopted as the control strategy. The results showed that, when system operating at influent BOD of 1,500-5,000 mg/L, a volumetric loading of 0.41 g BOD/L/d and an F/M ratio of 0.17 kg BOD/kg MLSS/d, 95% and 99% of BOD and SS removal efficiencies were achieved, respectively. Also, the tolerable shock loading for this system was 35% compared with the designated set point. Therefore, it could be concluded both the automation and improvement of the treatment efficiency were successfully achieved for this system.