Articles

This paper depicts the research conducted at lab scale on aerobic granular sludge sequential biological reactors for wastewater treatment in order to assess the influence of operational parameters on the treatment performances and microbial diversity of the granules. The proposed objectives were reached by testing in similar reactor conditions different organic nitrogen and phosphorus loading rates. The study focused both on treatment performances as organic, nitrogen and phosphorus removal based on chemical analysis of main quality parameters and on diversity of microbial population in granules based on real-time polymerase chain reaction by targeting mainly the specific species or functional genes with high influence on process performance in terms of nitrification, denitrification and phosphorus removal.

Increasing the efficiency and capacity of existing wastewater treatment plants can be carried out by using intensive biological processes. One of the currently studied biological solutions consists in using aerobic granular sludge in order to achieve both organics and nutrients removal simultaneously in one tank and with high efficiency. Aerobic granular sludge is currently used at full scale in sequential batch reactors, research for identifying the optimal solutions for continuous flow systems being carried out worldwide. The paper summarizes the results obtained for two continuous flow configurations with aerobic granular sludge, in terms of organics and nutrients removal for synthetic wastewater in laboratory conditions. Both experimental setups led to wastewater treatment efficiencies, with values ranging between 80 and 99% for COD, 85 and 99% for BOD5, 52 and 98% for NH4 and 5 to 87% for TP.