Performance of a successive hydrolysis, denitrification and nitrification system for simultaneous removal of COD and nitrogen from terramycin production wastewater

A bench-scale continuous flow system, consisting successively of an anaerobic hydrolysis column (column A), an anoxic column (column D) and two aerobic columns (columns B and F), was constructed to remove nitrogen and carbon simultaneously from terramycin crystallization mother solution (TCMS). Columns A and D were sludge-bed reactors, and columns B and F were biofilm reactors packed with polyethylene balls and soft fibers hung on plastic rings, respectively. Approximately 82% of the chemical oxygen demand (COD) and 81% total nitrogen were removed by the system when tap water diluted TCMS was continuously fed (dilution ratio, 1:4). Sulfide which was produced during anaerobic hydrolysis was used as part of electron donors for denitrification in column D. Comparison results show that porous polyethylene balls had a better COD and NH4+-N removal performance than the fiber type biocarrier.