Treatment of Saline Domestic Wastewater Using RBCs

The treatment of high salinity wastewaters from small island communities by use of rotating biological contactors was evaluated. Domestic wastewaters containing up to full strength seawater were utilized. The effects of salinity, loading rate and disk media composition on organic removal rate were examined. It was shown that RBCs can treat high salinity wastewaters to the same degree as non-saline wastewaters. The resulting effluent organic content was adequate for discharge into either marine or freshwater receiving waters. Mean COD removals of 61% and 64% were achieved using hydraulic loading rates of 0.04 and 0.08 m³/m²⋅d (1.0 and 2.0 gpd/sq ft), respectively. At higher loading rates, up to 0.33 m³/m²⋅d (8.0 gpd/sq ft), organic removal efficiency was reduced. No difference in treatment efficiency was observed using either plastic or Masonite® as the disk media.