The effect of with and without anoxic period for removal synthetic wastewater contaminated cadmium (Cd2+) by sequencing bath reactor system (SBR)

Abstract

The objective of this research is to evaluate the performance of a lab-scale sequencing batch reactor system (SBR) with and without anoxic period to treat synthetic wastewater contaminated cadmium (Cd2+). The SBR operation cycle 12 hours (h), the reaction phase 9 h, Hydraulic Retention Time (HRT) 5 days, and the mix liquor suspended solids (MLSS) 2,000 mg/L. The reactor-I controlled oxic period only, while the reactor-II and reactor-III controlled reaction phase had an anoxic period of 5 h and 7 h, respectively. The result of this study showed when increased anoxic period of the SBR system the cadmium and the total nitrogen removal efficiency increasing due to the system operated anoxic and oxic conventional occurred denitrification and nitrification process, theses process released nitrogen compounds. The SBR system increased the anoxic period the cadmium removal efficiency increasing. The oxygen limited of the system that respiratory of aerobic bacteria related to the removal efficiency of BOD5 and COD decreased when increasing anoxic period. Yet, the COD and BOD5 efficiency of all systems is more than 90%. The performance of the SBR with an anoxic period showed suitable growth for denitrification and nitrification bacteria. That is an alternative for treated heavy metals contaminated wastewater.