| Abstrakt: |
A combined chemical coagulation/flocculation‐Fluidized Bed Biofilm Reactor (FBBR) process was evaluated for the treatment of an equalized slaughterhouse wastewater. Results obtained from jar and tank tests indicated that alum, with supplemental use of ferric chloride and an anionic polymer, yielded the following removal performance: Five‐Day Biochemical Oxygen Demand (BOD5), 24–53&percent;; grease, 66–80&percent;; and Suspended Solids (SS), 62–73&percent;. Furthermore, the performance of chemical coagulation/flocculation process at constant chemical dosages improved with increasing feed BOD5, grease, and SS concentrations. The steady‐state performance of the oxic FBBR in treating the chemically pre‐treated slaughterhouse wastewater was evaluated under the following conditions: Food‐to‐Microorganism (F/M) ratio, 1.45–9.25 kg/kg‐day; empty bed hydraulic retention time, 8.8–30.8 minutes; and feed BOD5 concentration, 305–602 mg/L. The observed BOD5, grease and NH3‐N removals were 71–93&percent;, 29–84&percent;, and 20–73&percent;, respectively. More than 70&percent; of feed BOD5, grease, and NH3‐N could be removed up to an F/M ratio of 2.0 kg/kg‐day. The FBBR would become anaerobic when the F/M ratio applied exceeded 4.0 kg/kg‐day and its performance deteriorated sharply. A relatively high and constant biomass holdup (i.e., 10,000 mg TVS/L) could be maintained in the oxic FBBR over the range of F/M ratios applied. This was achieved through regular bioparticle wasting designed for expanded bed height control. Secondary treatment performance was achieved in this investigation at an F/M ratio of 2.0 kg/kg‐day without secondary clarification. |
