Performance evaluation of UASB reactor systems with and without post-treatment

摘要

This article evaluates and compares the actual behavior of 18 UASB reactor systems operatingnwithout (10 plants) and with (8 plants) post treatment, considering their performance and theirnreliability in terms of compliance with specified discharge standards. The following types ofnpost-treatment processes were analyzed: aerated filter; anaerobic filter; trickling filter; dissolvednair flotation unit; facultative pond and maturation pond. The effluent quality and the removalnefficiencies were compared with typical values reported in the technical literature. Anmethodology developed by Niku et al. (1979) was used for the determination of the coefficientsnof reliability, in terms of the compliance of effluent BOD and TSS with discharge standards.nThe results showed that, in general, the inclusion of a post-treatment step, be it either aerobic,nanaerobic or physical-chemical, can provide a substantial improvement of the effluent qualitynfrom UASB reactors in terms of BOD and TSS. In terms of the systems reliability, the actualneffluent concentrations from UASB reactor followed by some post-treatment processes wouldnmeet more restrictive discharge standards than those considered in this study (60mg L21nfornboth constituents—values prevailing in most states in Brazil).