Treatment of malting wastewater using suspended-growth and attached-growthsequencing batch reactors

Malting wastewater was treated using both suspended-growth and attached-gro wth sequencing batch reactors (SBR). Both types of reactor were capable of treating the malting wastewater successfully with the attached-growth SBRs achieving higher treatment efficiencies. At a hydraulic retention time (HRT ) of 2.66 days, the attached-growth reactors achieved removal efficiency fo r BOD, COD and NH3-N of 99.2, 95.3, and 86.8%, respectively. The highest tr eatment efficiency for the suspended-growth reactors was achieved at a HRT of 3.33 days at 91.0, 93.2, and 84.6%, respectively, for BOD, GOD, and NH3- N. The attached-growth SBRs had the advantage of being able to function wel l at shorter HRTs than the suspended-growth SBRs. The attached-growth SBRs were able to withstand shock loading of low pH with a relatively small redu ction in treatment efficiency and a speedy recovery from the shock.