No abstract

a b s t r a c tA lab-scale UASB reactor was operated for the treatment of p-acetamidobenzene sulfonyl chloride (p-ASC)-containing wastewater with and without ethanol for 210 days. The influence of the organic loading rate on the performance of reactor by step-decreasing HRT reduction/step-increasing the concentration of p-ASC was evaluated. Almost complete degradation of 50 mg/l p-ASC and COD removal efficiency (79.5%) was noticed with a COD removal of 79.5% at HRT of 0.5 day or longer and an applied p-ASC loading rate below 120 mg/l/day. No inhibition to the performance of this reactor was observed even at a p-ASC concentration up to 1000 mg/l. Of interest that despite the absence of sulfate in the feed, a certain quantity of sulfate and sulfide was simultaneously generated in the effluent. The trial result in the absence of ethanol demonstrated that p-ASC could be used as the sole source of carbon and energy. Clone libraries for the archaeal and bacterial communities were constructed for a biomass sample taken on day 190. The majority of bacterial clones were represented by Proteobacteria, followed by Thermotogae, Bacteroidetes and Firmicutes. Bacterial groups within the phyla Clostridia might be responsible for the desulfonation of p-ASC.