Browsing by Author "Amorim, Catarina"
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- Exploring the fate of chiral pharmaceuticals in an AGS system under saltwater intrusion phenomenaPublication . Miranda, Catarina; Amorim, Catarina; Piccirillo, Clara; Tiritan, Maria Elizabeth; Castro, PaulaAerobic granular sludge (AGS) is a robust technology, largely adopted in wastewater treatment plants (WWTPs) worldwide. However, there is a lack of knowledge regarding how this technology deals with saltwater intrusion and variable daily wastewater salinity loads. With the sea level rise, in coastline WWTPs, seawater infiltration into sewers is a growing problem. In addition, the increase in pharmaceutical production and consumption led to their accumulation in wastewater. Many of these are chiral pharmaceuticals (CPs) whose enantiomers can differ in their degradation ratio and toxicity in the environment. The fate of CPs in AGS systems is scarcely reported, especially if combined with variable salt concentration in wastewater. In this study, an AGS reactor was operated for 132 days for the treatment of urban saline wastewater sporadically containing a mixture of CPs namely: tramadol and venlafaxine and its metabolites o-desmethyltramadol and o-desmetylvenlafaxine, respectively, at concentrations near those found in the environment (8 μg/L). Both daily salinity fluctuations and the presence of CPs in wastewater did not affect the biological removal of COD, N, and P. However, the AGS system was not able to remove the CPs that ended up in the effluent. To address this challenge, a parallel experiment was performed using a bone char material derived from fish-food waste (tuna bones) to adsorb the pharmaceuticals tramadol and venlafaxine. The bone char exhibited removal efficiencies of around 40%, as such in combination with AGS systems it can help to decrease the release of CPs into the environment.
- Training an AGS reactor to treat high salinity wastewaterPublication . Paulo, Ana; Castro, Paula; Amorim, CatarinaAerobic granular sludge (AGS) is a promising technology for treating industrial wastewater, with higher biomass retention and tolerance to toxic substrates than conventional activated sludge systems. The presence of extracellular polymeric substances (EPS) in the AGS structure increases the bacterial protection and stability of the granules. Several industrial wastewaters contain high salt concentrations in their composition that often inhibit the bacteria responsible for nutrients removal. A strategy to prepare the system to high salinity is the gradual adaptation of the aerobic granules to increased salt concentrations. In this study, an AGS reactor was operated for 248 days and fed with synthetic wastewater containing ammonium, phosphate and acetate (40, 20 and 680 mg L-1, respectively) in its composition. Over operation, a stepwise addition of NaCl to the wastewater from 0 to 14 g L-1 was performed. Carbon and ammonium removal processes were stable throughout the operation, with an average removal efficiency of ca. 90 and 100 %, respectively. Nitrification and phosphate removal processes were only affected when NaCl concentration reached 8.5 g L-1, that lead to nitrite and phosphate accumulation in the outlet up to 0.7 mg NO2 - L-1 and 20 mg PO4 3- L-1. Both processes resumed while treating wastewater containing 10 g NaCl L-1 and remained stable thereafter. The microbial community presented a high diversity while treating wastewater containing up to 3 g NaCl L-1. Further increase up to 6 NaCl g L-1 caused a bacterial diversity reduction. From this point onwards, despite the salinity increase until 14 g NaCl L-1, the microbial community diversity was kept similar, indicating its adaptation to the wastewater composition. The stepwise addition of salt to the wastewater allowed the granular biomass to preserve stable carbon and nutrient removal processes. It also led to a selection of the microbial community, without causing detrimental effects on the biological removal performance. This strategy can be valuable to adapt biomass for treating high salinity wastewater as those produced in industrial settings.