Development of biological livestock wastewater treatment system combined with physical pretreatment and chemical posttreatment

Abstract

Lab-scale livestock wastewater treatment process was operated. Treatment process was composed of anaerobic reactor, aerobic reactor, anoxic reactor, settler, and microorganisms activation reactor. We divided this system into Systems 1-5 according to various conditions. In Systems 4 and 5, ammonia stripping was performed as pretreatment. And flocculation was performed Lis posttreatment. Average influent concentrations of COD. BOD, TKN, and TP were 21,894, 11,533, 2255, and 415 mg/L, respectively, and COD/N and BOD/N ratios in influent were 9.9 and 5.3, respectively. When ammonia stripping was performed as pretreatment, effluent BOD concentration was 44.4 mg/L and removal efficiency was 99.62%. TN removal efficiencies in Systems 4 and 5 were 84.1 and 95.2%, respectively, and effluent TN concentrations were 305.9 and 78.4 mg/L, respectively, which was because of with/without pH control. In operation period of Systems 4 and 5, average SNR and SDNR were 18.6 and 17.4 g N/kg MLSS/d, respectively, which was rate as much as endogenous denitrification rate because of long SRT due to low F/M ratio. In Systems 3, 4 and 5, optimal doses of flocculation agent were 350, 100, and 100 mgFe/L. This difference was caused by alkalinities of Systems 3, 4, and 5, which were 750, 284, and 162 mg/L as CaCO3.