Browsing by Author "Amorim, C. L."
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- Evaluation of two different granular sludge reactor configurations for the treatment of freshwater aquaculture streamsPublication . Santorio, S.; Couto, A. T.; Río, A. Val del; Amorim, C. L.; Arregui, L.; Castro, P. M. L.; Mosquera-Corral, A.Two aerobic distinct granular sludge reactors were operated to treat freshwater aquaculture streams at laboratory-scale: An Expanded Granular Sludge Bed(EGSB)reactor operated in continuous mode and an Aerobic Granular Sludge -Sequencing Batch Reactor(AGS-SBR) operated as a sequencing batch reactor. Both units were fed with low ammonium concentrations (2.5 mg N/L). Granular biomass accumulated in both reactors. With the imposed operational conditions, nitrogen removal was of 10 -20 % and 80 % for the EGSB and AGS-SBR, respectively.
- Extracellular polymeric substances recovered from aerobic granular sludge: a natural material for different applicationsPublication . Oliveira, A. S.; Pereira, S. I. A.; Amorim, C. L.; Loosdrecht, M. C. M. van; Castro, P. M. L.
- Impact of industrial wastewater on aerobic granules morphology and nitrification process in bioreactorsPublication . Paulo, Ana M. S.; Costa, Joana; Amorim, C. L.; Mesquita, Daniela P.; Ferreira, Eugénio C.; Castro, Paula M. L.Aerobic Granular Sludge (AGS) is an innovative wastewater treatment process used for carbon and nutrients removal from wastewater. Aerobic granules present a compact structure resistant to variable wastewater composition. Process disturbances might affect bacteria, especially those present in the granules outer layers, such as nitrifiers. In this study, fish canning wastewater with variable composition was treated for 107 days using an AGS sequential batch reactor. The operation was divided in 3 phases, according to different periods of organic loading rate (OLR): Phase I: 0.74 to 1.32 kg m-3 day-1; Phase II: 1.33 to 1.70 kg m-3 day-1; Phase III: 0.12 to 0.78 kg m-3 day-1. Carbon removal and nitrification performance were evaluated. Morphological and structural changes within granules were followed by quantitative image analysis (QIA). Principal component analysis (PCA) was performed using QIA data alone and relating QIA with reactor performance. Along the operation, carbon removal was stable, reaching less than 100 mg O2 L-1 at the outlet. Nitrification was inhibited during Phase II but recovered in Phase III. According to QIA data, biomass samples from Phase III clustered together, indicating higher granule stability. PCA analysis also revealed that a higher OLR might have led to a transitory loss of robustness during Phase II, recovered during Phase III. This study shows that OLR, nitrification process and biomass morphological and structural changes are possibly correlated during the treatment of industrial wastewater by AGS process.
- Microalgae-bacterial granular systems able to treat marine aquaculture water streamsPublication . Alves, M.; Oliveira, A. T.; Castro, P. M. L.; Amorim, C. L.This study aimed to evaluate the granulation of microalgae-bacterial biomass and its ability to treat marine aquaculture water streams. For this, a phototrophic consortium adapted to saline conditions was enriched from water collected from a marine aquaculture facility and then used to develop the microbial aggregates. Two lab-scale photo-reactors were used: one inoculated only with the enriched phototrophic consortium and the other with the consortium and activated sludge. Rapid granulation was achieved. High ammonium and organic carbon removals of about 100% and 80%, respectively, were quickly established and maintained in the long run. This study demonstrates the rapid granulation of phototrophic biomass and its robustness and feasibility for nutrient and carbon removal from extremely low loaded water streams.
- Pilot-scale continuous flow granular reactor for the treatment of extremely low-strength recirculating aquaculture system wastewaterPublication . Santorio, S.; Rio, A. Val del; Amorim, C. L.; Arregui, L.; Castro, P. M. L.; Mosquera-Corral, A.To avoid toxic ammonium and nitrite concentrations in aquaculture systems is crucial to maintain the fish production. When recirculating aquaculture systems (RAS) operate in freshwater farms during the dry seasons, the concentrations of these pollutants increase. The objective of the present study is the evaluation of a Continuous Flow Granular Reactor (CFGR) for the treatment of freshwater RAS stream at pilot-scale during two consecutive dry seasons. The CFGR was fed with a extremely low-strength recirculation stream of a trout farm (0.12–1.84 mg NH4+-N/L and 2.2–8.14 mg C/L). Two different configurations were evaluated. The first configuration consisted on a CFGR fed from the bottom, being the up-flow velocity the only shear force to mix the biomass. The second configuration incorporated a mechanical stirrer and a sieve to improve the biomass mixing and retention. The CFGR was operated at short hydraulic retention times (HRT) which ranged from 11 to 68 min. The configuration with a mechanical stirrer and sieve was optimal in terms of biomass retention and nitrogen removal performance. Despite the low nitrogen and organic matter concentrations, granulation was achieved in 55 days, with an average granule diameter up to 0.47 mm. Ammonium and nitrite removal percentages up to 81% and 100% were achieved, respectively. The ammonium and nitrite production rate in the trout farm were lower than the removal achieved by the CFGR, which makes the implementation of this system appropriated to maintain the concentration of these compounds below toxic levels for rainbow trout.