Search results for "Nutrient removal"
showing 10 items of 22 documents
Bacterial Community Structure of an IFAS-MBRs Wastewater Treatment Plant
2017
TIn this work, the bacterial community putatively involved in BNR events of a UCT-MBMBR pilot plant was elucidated by both culture-dependent and metagenomics DNA analyses. The presence of bacterial isolates belonging to Bacillus (in the anoxic compartment) and to Acinetobacter, Stenotrophomonas, Rhodococcus, Escherichia and Aeromonas (in the aerobic compartment) is in agreement with the nitrification/denitrification processes observed in the plant. Moreover, the study of bacterial community structure by NGS revealed a microbial diversity suggesting a biochemical complexity which can be further explored and exploited to improve UCT-MBMBR plant performance.
Mathematical modelling of greenhouse gas emissions from membrane bioreactors: A comprehensive comparison of two mathematical models.
2018
Abstract This paper compares two mathematical models (Model I and Model II) to predict greenhouse gases emission from a University Cape Town (UCT) – membrane bioreactor (MBR) plant. Model I considers N 2 O production only during denitrification. Model II takes into account the ammonia-oxidizing bacteria (AOB) formation pathways for N 2 O. Both models were calibrated adopting real data. Model comparison was performed in terms of (i) sensitivity analysis (ii) best fit and (iii) model prediction uncertainty. On average 6% of factors of Model I and 9% of Model II resulted to be important. In terms of best fit, Model II had a better capability of reproducing the measured data. The average effici…
Moving bed membrane bioreactors for carbon and nutrient removal: The effect of C/N variation
2017
In this paper, an experimental campaign was carried out on a University of Cape Town Integrated Fixed Film Activated Sludge Membrane Bioreactor (UCT-IFAS-MBR) pilot plant. The aim of the study was to evaluate the effect of the influent C/N ratio on the system performance in terms of organic carbon, nitrogen and phosphorus removal, biomass viability (through respirometry), activated sludge features and membrane filtration properties. The experiments were organized into three phases, characterized by a variation of the C/N ratio (namely, Phase I: C/N= 5, Phase II: C/N =10; Phase III: C/N = 2). The results highlighted that the system performance was significantly affected by C/N ratio. The rem…
The role of EPS in fouling and foaming phenomena occurring in an UCT-MBR pilot plant
2012
The aim of this study is to detect a possible relationship between EPS and fouling and EPS and foaming in a University Cape Town (UCT) membrane bioreactor (MBR) pilot plant. The UCT-MBR pilot plant was fed with 40 L/h of real wastewater and monitored for 165 days. Specifically physical/chemical features of influent, permeate and mixed liquor in different sections were analyzed. The fouling phenomenon was studied monitoring the hydraulic resistances of the membrane. The extracellular polymeric substances (EPSs) concentration inside the aerobic tank were also measured. The foaming phenomenon was monitored by performing the Foam Power and Scum Index testes. Results have shown a high correlatio…
The role of EPS in fouling and foaming phenomena for a membrane bioreactor
2013
In contraposition to conventional activated sludge processes, the foaming phenomenon in membrane bioreactor (MBR) is still in its infancy. On the other hand, although several studies have been carried out for better understanding the fouling phenomenon in MBR there are still some gaps in the up-to-date knowledge. The extracellular polymeric substances (EPSs) may have a primary role in fouling and foaming phenomena which in turn can be crucial for MBRs. The aim of this study is to detect a possible relationship that EPSs may have with fouling and foaming in an MBR for wastewater treatment. Foaming phenomenon is monitored by performing specific foam-tests: Foam Power, Scum Index, Foam Rating …
Biological nutrient removal in a UCT-MBR pilot
2010
In the last years, there has been an increasing awareness about the environment pollution protection. As a consequence, the Environmental Regulation has increased the emission limits imposing, for instance, lower concentrations at the wastewater treatment plant (WWTP) outlets. As a consequence of this fact, several WWTPs are not able to respect the emission limits and need to be upgraded. In view of such needs new technology are emerging and new WWTP solution schemes are being realized. With respects to the nutrient removal enhancing, a possible solution can be the UCT-MBR which couples the University of Cape Town scheme with a Membrane Bioreactor. In the light of such considerations, the s…
Comparison of Two Mathematical Models for Greenhouse Gas Emission from Membrane Bioreactors
2017
In this study two mathematical models (Model I and Model II), able to predict the nitrous oxide (N2O) and carbon dioxide (CO2) emission from an University Cape Town (UCT) – membrane bioreactor (MBR) plant, have been compared. Model I considers the N2O production only during the denitrification. Model II takes into account the two ammonia-oxidizing bacteria (AOB) formation pathways for N2O. Both models were calibrated adopting real data. Results highlight that Model II had a better capability of reproducing the measured data especially in terms of N2O model outputs. Indeed, the average efficiency related to the N2O model outputs was equal to 0.3 and 0.38 for Model I and Model II respectively.
Aerobic granular sludge treating anaerobically pretreated brewery wastewater at different loading rates.
2020
Abstract In this study, three different aerobic granular sludge (AGS) reactors fed with anaerobically pre-treated brewery wastewater were studied. The AGS reactors were operated under different conditions including organic loading rates (OLR) between 0.8 and 4.1 kg COD m−3 d−1, C:N:P ratios (100:10:1 and 100:6:1) and food to microorganism ratios (F/M) between 0.8 ± 0.6 and 1.2 ± 0.5 and 0.9 ± 0.3 kg-TCOD kg-VSS−1d−1. Stable granulation was achieved within two weeks and the size of the granules increased according to the OLR applied. The results indicated that low C:N:P and F/M ratios were favorable to achieve stable aerobic granules in the long term. The carbon removal rate was load-indepen…
Application of the General Model "Biological Nutrient Removal Model No.1" to upgrade two full-scale WWTPs
2012
In this paper, two practical case studies for upgrading two wastewater treatment plants (WWTPs) using the general model BNRM1 (Biological Nutrient Removal Model No. 1) are presented. In the first case study, the Tarragona WWTP was upgraded by reducing the phosphorus load to the anaerobic digester in order to minimize the precipitation problems. Phosphorus load reduction was accomplished by mixing the primary sludge and the secondary sludge and by elutriating the mixed sludge. In the second case study, the Alcantarilla WWTP, the nutrient removal was enhanced by maintaining a relatively low dissolved oxygen concentration in Stage A to maintain the acidogenic bacteria activity. The VFA produce…
Selecting the most suitable microalgae species to treat the effluent from an anaerobic membrane bioreactor.
2018
[EN] Conventional treatments for nutrient removal in wastewater are shifting to Anaerobic Membrane Bioreactors, which produce a high-quality effluent with minimum sludge production. The effluent resulting contains high nitrogen and phosphorus load that can be eliminated by microalgae culture. The aim of this study is to evaluate the ammonium and phosphorus removal rate of different microalgae species in the effluent of an anaerobic treatment. For that, 4 different microalgae species have been tested (Chlamydomonas reinhardtii, Scenedesmus obliquus, Chlorella vulgaris and Monoraphidium braunii) in batch monoculture and mixed conditions. Results indicate that all species are able to eliminate…