Nutrient, Linear Alkyl Benzene Sulfonate, and Caffeine Removal from Synthetic Wastewater with an Algal–bacterial Culture and an Activated Sludge Culture in Batch Mode

Abstract

An algal-bacterial culture and an activated sludge culture were cultivated for simulating wastewater treatment in an algal pond and an aerated pond, respectively. Linear alkyl benzene sulfonates (LAS) and caffeine were selected as model pollutants. In 7-day batch treatment of synthetic wastewater (dissolved organic carbon (DOC) 106 mg/L, dissolved nitrogen (DN) 57 mg/L, dissolved phosphorous (DP) 6.7 mg/L, LAS 16 mg/L, caffeine 0.03 mg/L), the degradation kinetics for LAS and sulfophenyl carboxylic acids as the intermediates, and caffeine suggested that the bacterial species and population in the activated sludge culture and the algal-bacterial culture were quite different from each other. Finally, the algal-bacterial culture showed balanced removals for the pollutants (DOC 82%, DN 32%, DP 72%, LAS 100%, caffeine 50%). The activated sludge culture showed rapid degradation of LAS and caffeine but it only insufficiently removed nutrients (DOC 73%, DN-20%, DP 23%, LAS 100%, caffeine 63%). These results suggest that the algal pond is a promising technology for simple and low-cost wastewater treatment in warm countries.