Search results for "Wastewater"
showing 10 items of 718 documents
Variance-based sensitivity analysis for wastewater treatment plant modelling
2014
Global sensitivity analysis (GSA) is a valuable tool to support the use of mathematical models that characterise technical or natural systems. In the field of wastewater modelling, most of the recent applications of GSA use either regression-based methods, which require close to linear relationships between the model outputs and model factors, or screening methods, which only yield qualitative results. However, due to the characteristics of membrane bioreactors (MBR) (non-linear kinetics, complexity, etc.) there is an interest to adequately quantify the effects of non-linearity and interactions. This can be achieved with variance-based sensitivity analysis methods. In this paper, the Extend…
Global sensitivity analysis in ASM applications: comparison of the SRC and Extended-FAST method for a UCT-MBR model
2011
In this study global sensitivity analysis is performed to identify influential as well as non-influential parameters in a model of a University Cape Town Membrane Bioreactor (UCT-MBR). In particular, the Standardised Regression Coefficients (SRC) and Extended-FAST sensitivity analysis methods are applied. The sensitivity of model variables towards parameter variation is analysed for CODTOT, SNH4, SNO3, SPO, and MLSS along five reactor compartments. Both methods indicate that the parameters identified as being influential differ from section to section due to the different processes involved. Moreover, the relevant influence of the membrane filtration parameters is detected in the first plan…
A moving bed membrane bioreactor pilot plant for carbon and nutrient removal
2016
The paper reports the main results of an experimental gathering campaign carried out on a moving bed membrane bioreactor pilot plant conceived for carbon and nutrients removal according to a University of Cape Town scheme. Organic carbon, nitrogen and phosphorus removal, biokinetic/stoichiometric constants, membrane fouling tendency and sludge dewaterability have been assessed during experiments. The achieved results showed that pilot plant was able to guarantee very high carbon removal, with average efficiency of 98%. In terms of nitrification, the system showed an excellent performance, with efficiencies higher than 98% for most of the experiments. This result might be related to the pres…
Integrated production of biopolymers with industrial wastewater treatment: Effects of OLR on process yields, biopolymers characteristics and mixed mi…
2022
The production of polyhydroxyalkanoates (PHA) using industrial wastewaters as feedstocks is a current and challenging topic. This study investigated the production of biopolymers by a mixed microbial culture under different OLRs equal to 1 kgCOD m-3d-1 (Period 1), 2 kgCOD m-3d-1 (Period 2) and 3 kgCOD m-3d-1 (Period 3). The maximum PHA content was achieved in Period 2 (0.38 gPHA gTSS-1), whereas lower values were obtained in Period 1 (0.13 gPHA gTSS-1) and Period 3 (0.26 gPHA gTSS-1). Overall, the maximum PHA productivity resulted equal to 0.08 gPHA L-1h-1 (P2), 0.05 gPHA L-1h-1 (P1) and 0.04 gPHA L-1h-1 (P3), respectively. The molecular weight of the PHA increased from Period 1 (250 kDa) t…
Characterization of wastewater and biomass activity in a membrane bioreactor using respirometric techniques
2010
Over the last two decades, Membrane Bioreactors (MBRs) emerged even more for wastewater treatment, ensuring high removal efficiencies as well as very small footprint required. Indeed, in this kind of process, a modification in biomass activity and viability can exist compared to that of a conventional activated sludge (CAS) process. In this context, respirometric analysis represents a reliable tool in order to evaluate the actual biomass kinetic parameters, to insert in mathematical models in the design phase, as well as to monitor the biomass viability, especially when these processes are operated with high sludge retention time (SRT) values. The paper presents some results of respirometri…
Wastewater treatment sludge composting
2023
In recent years, the amount of sewage sludge generated by wastewater treatment plants (WWTPs) has increased due to worldwide population growth and to efficiency of biological treatment processes [1,2]. Sludge is an important source of secondary pollution to aquatic environments and a potential risk to human health; moreover, it represents one of the most important cost items in the functioning of water treatment plants [3–5]. About 60% of the operating costs of secondary wastewater treatment plants in Europe can be associated with the treatment and disposal of products [6]. For this reason, proper sludge management becomes increasingly important, at both national and international level, an…
A mathematical model for a sequential batch membrane bioreactor pilot plant
2016
A mathematical model to quantify the nitrogen removal for a membrane bioreactor (MBR) has been presented in this study. The model has been applied to a pilot plant having a pre-denitrification MBR scheme. The pilot plant was cyclically filled with real saline wastewater according to the fill-draw-batch operation. The model was calibrated by adopting a specific protocol based on extensive field dataset. The Standardized Regression Coefficient (SRC) method was adopted to select the most influential model factors to be calibrated. Results related to the SRC method have shown that model factors of the efficiency of backwashing and the biological factors affecting the soluble microbial products …
Frontiers in Wastewater Treatment and Modelling FICWTM 2017
2017
Today, multidisciplinary is a key to solving issues in the water field. The works in several International Water Association (IWA) Specialist Groups have demonstrated the importance of both innovative technologies and mathematical modelling, and that the exchange of scientific and technical information among researchers and practitioners involved in these fields is crucial for effectively advancing knowledge. Mathematical modelling has the advantage of allowing scenario analysis before designing the real plant in order to ensure an optimized system. To foster the multidisciplinary collaboration among different water specialists, the dialogue is a must in order to better share specific knowl…
Dewatering of excess sludge produced by CAS and MBR aerobic treatment plants. effects of biochemical stability and EPS composition
2016
This paper investigates the behavior of different sludges from several treatment plants at full and pilot scale configured as Conventional Activated Sludge (CAS) and Membrane Bio Reactor (MBR) plants treating different kinds of wastewaters. The sludges collected were subjected to complete analytical and technological characterization in order to correlate the rheological properties that affect the dewatering behavior to the sludge chemical physical properties. In detail the EPS from the samples collected is extracted and characterized in terms of carbohydrates, proteins, uronic acids and humic acids content. Moreover, once characterized, the sludges were subjected to AD in order to assess t…
The GSA-GLUE approach for uncertainty assessment of an integrated MBR model
2012
In the recent literature, the uncertainty of wastewater treatment plant (WWTP) modelling has had relevant interest both for designers and operators. Indeed, the frequent data lacking and the need to improve process knowledge, in case of innovative technologies, make the use of mathematical models more uncertain. Therefore, the need to make model uncertainty more explicit is warmly recommended. However, only few applications of uncertainty analysis in the wastewater field have been carried out. In this work, the combination of the global sensitivity analysis (GSA) and the Generalized Likelihood Uncertainty Estimation (GLUE) is applied for the uncertainty assessment of a WWTP model, in order …