Swine wastewater treatment using attached-growth and suspended-growth two stage sequencing batch reactors with real-time control

Two two-stage sequencing batch reactors (TSSBR), one attached-growth and one suspended-growth, were operated under three levels of wastewater concentration (approximate to 4,000, 2,000 and 500 TOC mg/L), respectively, to compare the pH and ORP (oxidation-reduction potential) patterns and system performance. In both TSSBR systems, the pH and ORP profiles varied with organic loading yet exhibited consistent patterns with distinctive features suitable for real-time control. For all runs at the three levels of influent, both systems achieved similar levels of treatment for BOD5, TOC and TSS of over 97.5, 93.4, and 97.3 %, respectively. The attached-growth system out performed the suspended growth system in achieving the same levels of treatment at much shorter aeration cycle times. The treatment efficiency for NO3--N and PO4-3 was greatly affected by the carbon content in the wastewater, and the best treatment was achieved during the TOC approximate to 4,000 mg/L runs with final effluent at 4.0 and 21.3 mg/L, respectively.