Activated sludge modelling: development and potential use of a practical applications database

A critical comparison of systematic calibration protocols for activated sludge models: A SWOT analysis

Influence of selecting secondary settling tank sub-models on the calibration of WWTP models – A global sensitivity analysis using BSM2

Membrane bioreactors (MBRs) are attracting global interest but the mathematical modeling of the biological performance of MBRs remains very limited. This study focuses on the modeling of a side-stream MBR system using the Activated Sludge Model No. 1 (ASM1), and compares the results with the modeling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated (i.e. Y(H) = 0.72 gCOD/gCOD, Y(A) = 0.25 gCOD/gN, b(H) = 0.25 d(-1), b(A) = 0.080 d(-1) and f(p) = 0.06), and generally agreed with the parameters in traditional activated sludge processes, with the exception that a higher autotrophic biomass decay rate was observed in the MBR. Influent wastewater characterization was proven to be a critical step in model calibration, and special care should be taken in characterizing the inert particulate COD (X(I)) concentration in the MBR influent. It appeared that the chemical-biological method was superior to the physical-chemical method. A sensitivity analysis for steady-state operation and DO dynamics suggested that the biological performance of the MBR system (the sludge concentration, effluent quality and the DO dynamics) are very sensitive to the parameters (i.e. Y(H), Y(A), b(H), b(A) micro(maxH) and micro(maxA), and influent wastewater components (X(I), S(s), X(s) and S(NH)).

Mathematical modelling of activated sludge systems is used widely for plant design, optimisation, training, controller design and research. The quality of simulation studies varies depending on the project objectives, finances and expertise available. Consideration has to be given to the model accuracy and the amount of time required carrying out a simulation study to produce the desired accuracy. Inconsistent approaches and insufficient documentation make quality assessment and comparison of simulation results difficult or almost impossible. A general framework for the application of activated sludge models is needed in order to overcome these obstacles.The genesis of the Good Modelling Practice (GMP) Task Group lies in a workshop held at the 4th IWA World Water Congress in Marrakech, Morocco where members of research groups active in wastewater treatment modelling came together to develop plans to synthesize the best practices of modellers from all over the world. The most cited protocols were included in the work, amongst others from: HSG (Hochschulgruppe), STOWA, BIOMATH and WERF.The goal of the group is to set up an internationally accepted framework to deal with the ASM type models in practice. This framework shall make modelling more straightforward and systematic to use especially for practitioners and consultants. Additionally, it shall help to define quality levels for simulation results, a procedure to assess this quality and to assist in the proper use of the models.The framework will describe a methodology for goal-oriented application of activated sludge models demonstrated by means of a concise guideline about the procedure of a simulation study and some illustrative case studies. The case studies shall give examples for the required data quality and quantity and the effort for calibration/validation with respect to a defined goal. The final report will include an extended appendix with additional information and details of methodologies.Additional features in Guidelines for Using Activated Sludge Models include a chapter on modelling industrial wastewater, an overview on the history, current practice and future of activated sludge modelling and several explanatory case studies. It can be used as an introductory book to learn about Good Modelling Practice (GMP) in activated sludge modelling and will be of special interest for process engineers who have no prior knowledge of modelling or for lecturers who need a textbook for their students. The STR can also be used as a modelling reference book and includes an extended appendix with additional information and details of methodologies.This title belongs to Scientific and Technical Report Series.ISBN: 9781780401164 (eBook)ISBN: 9781843391746 (Print)

The autotrophic maximum specific growth rate constant, muA,max, is the critical parameter for design and performance of nitrifying activated sludge systems. In literature reviews (i.e., Henze et al., 1987; Metcalf and Eddy, 1991), a wide range of muA,max values have been reported (0.25 to 3.0 days(-1)); however, recent data from several wastewater treatment plants across North America revealed that the estimated muA,max values remained in the narrow range 0.85 to 1.05 days(-1). In this study, long-term operation of a laboratory-scale sequencing batch reactor system was investigated for estimating this coefficient according to the low food-to-microorganism ratio bioassay and simulation methods, as recommended in the Water Environment Research Foundation (Alexandria, Virginia) report (Melcer et al., 2003). The estimated muA,max values using steady-state model calculations for four operating periods ranged from 0.83 to 0.99 day(-1). The International Water Association (London, United Kingdom) Activated Sludge Model No. 1 (ASM1) dynamic model simulations revealed that a single value of muA,max (1.2 days(-1)) could be used, despite variations in the measured specific nitrification rates. However, the average muA,max was gradually decreasing during the activated sludge chlorination tests, until it reached the value of 0.48 day(-1) at the dose of 5 mg chlorine/(g mixed liquor suspended solids x d). Significant discrepancies between the predicted XA/YA ratios were observed. In some cases, the ASM1 predictions were approximately two times higher than the steady-state model predictions. This implies that estimating this ratio from a complex activated sludge model and using it in simple steady-state model calculations should be accepted with great caution and requires further investigation.

Clozapine is a second-generation antipsychotic typically used for refractory schizophrenia or otherwise psychotic pathology. There are no FDA or manufacturer guidelines for use of clozapine in pediatric population. We investigated the current state of research concerning the use of clozapine in pediatric patients. We describe consistent calls for more research into the long-term and short-term effects of clozapine use in a young patient population. Despite the strongly supported efficacy, questions concerning clear indications for use and risk-benefit analysis persist. We acknowledge that a more comprehensive meta-analysis would greatly benefit the field. However, this is the first article of its kind for clozapine in recent history, and therefore, serves as a focus and reference point for future, more in-depth analyses. We conducted a search of PubMed, ClinicalKey, PsycINFO, and MEDLINE databases. Keywords used included, in varying combinations: clozapine, off-label, indications, children and adolescent, pediatric, behavioral, suicidality, psychosis, early and very-early onset schizophrenia, side-effect profile, and long-term use. Further criteria and selection are described in Methods below. We describe the documented efficacy of clozapine for the management of refractory psychotic and nonpsychotic symptoms in the pediatric population. The authors highlight the risk of unmanaged early-onset schizophrenia, aggressive or suicidal behavior, and severe nonpsychotic pathology. Unfortunately, these studies are generally small. There is little consistency in when clozapine is prescribed, how long it is administered, and how long patients are followed. Despite the lack of FDA and manufacturer guidelines, clozapine continues to be used for the benefit of young patients. Indications for prescription of clozapine should be revisited, given the data presented in this manuscript of a low risk-benefit ratio for properly chosen patients. Larger studies should be conducted to provide more statistical power and determine clear guidelines for use, risk of side effects, and long-term adverse events that may arise.

Towards a consensus-based biokinetic model for green microalgae – The ASM-A

An innovative and integrated scheme that encompasses two well-established waste treatment technologies, the aerobic biological degradation of organic matter bioprocess via membranes and anaerobic digestion, was demonstrated as a zero-waste approach that may effectively treat wastewater and biowaste in an integrated and symbiotic manner. Aiming to create a tool for the design, monitoring, and control of the scheme, prediction models were developed, validated, and implemented for the process simulation of the integrated scheme. The minimization of selected objective functions led to the estimation of the models’ parameters. The activated sludge model no. 1 (ASM1) was adopted for the simulation of the aerobic membrane bioreactor. The kinetic parameters were calibrated using volatile suspended solids and total nitrogen as the objective functions permitting the model to simulate the bioprocess satisfactorily (Nash–Sutcliffe efficiency > 0.86) and to calculate the concentration of the active biomass. The predominance of heterotrophic bacteria (4300 to 9770 mg COD/L) over autotrophic biomass (508 to 1422 mg COD/L) was showcased. For the anaerobic process unit, a simplified anaerobic digestion model 1 ADM1-R4 was used, and the first-order hydrolysis constants (kch 0.41 d−1, kpr 0.25 d−1, kli 0.09 d−1) and microbial decay rate (kdec 0.02 d−1) were evaluated, enabling an accurate prediction of biogas production rates. A full-scale implementation of the integrated scheme was conducted for a decentralized waste treatment plant in a small community. Preliminary design calculations were performed in order to estimate the values related to certain process and technical parameters. The performance of this full-scale plant was simulated by the developed model, presenting clear benefits for practical applications in waste treatment plants.

In June the National Institute for Health and Clinical Excellence (NICE) published welcome but bewildering guidelines for short term circulatory support with left ventricular assist devices (LVADs) as a bridge...

This chapter and Chapter 5 include a reprise of the discussion in the earlier chapters pertinent to these sections, and together with Chapter 5 present guidelines for use in practical applications. Besides understanding the basic tenets of the discipline of single event phenomena (SEP), it is felt important for the reader that they be transformed into useful expressions so as to obtain practical answers to important questions. Examples include the following: a how to compute SEU error rates for various radiation particle environments to satisfy electronic designer needs b how to accomplish part selection with an eye to choosing those that are sufficiently SEU radiation “hard” for the particular electronics system application, within the constraints of ever fewer hardened part lines from vendors since the end of the cold war c maintaining a knowledge of part-function hierarchy with respect to SEU phenomena consequences within the context of the system being built d staying aware of the implication of test results as correlated with the needs of the system program e understand SEP in terms of appropriate weight given to it as compared with other system engineering and radiation requirements

To audit current practice regarding selection and use of graduated elastic compression stockings (GECS) in the authors' Trust. Following a literature review it was important for the Trust that the authors audited current practice before the development and implementation of any new guidelines. A literature review enabled the authors to establish best practice principles for the use of GECS and develop guidelines for use across their Trust. However, feedback from various sources highlighted conflicting practices regarding the methods by which patients either did or did not receive stockings, and which lengths and brands were used. As the guidelines aimed to allow implementation of standardized change across the Trust, it was important to establish current practice with regard to GECS selection and use. Therefore, an audit tool was developed carried out on the use of GECS. An audit tool was developed and implemented to establish the practices before the implementation of the guidelines. The audit demonstrated that there was no consistent policy within the surgical services directorate for the correct use of GECS. It is important that all healthcare providers have a local policy for GECS use, which makes it clear how an assessment for patients requiring GECS needs to be conducted and how that assessment is documented.

Purpose: The objective of this paper is to investigate how environmental improvements can be achieved through operational practices of Lean Manufacturing.Design/methodology/approach: A literature review was conducted to analyze the relationship between operational practices of Lean and reduction of environmental impact in organizational contexts. Verified theoretically, this relationship was observed in a company of the electronics industry, through an exploratory research which contemplated a mixed approach. The adopted research method consisted of a single case study, by providing greater depth and detail of the study. Utilized a research protocol, validated test pilot. The instruments for data collection were semi-structured interviews, direct observation and document analysis. The information was examined qualitatively considering the technique for content analysis.Findings: As a result of the study, it was found that there is evidence for the existence of relationship between the practices of Lean, for example, Kaizen, PDCA (plan, do, check, act), Ishikawa Diagram, Poka-Yoke, Standardized Work and Value Stream Mapping, with the reduction of environmental impacts of an organization. This reduction was observed after application of these practices that resulted in the reduction of energy consumption, water and waste generation. These results were accounted for financially, contributing to a reduction of annual costs by about US$ 20,900.Originality/value: The study presents in detail, the application of operational practices of Lean Manufacturing, with an effective view to reducing the environmental impact and cost reduction. The literature review, a detailed description of the application process and financial results are important information that contributes to the scientific studies that address traditional operating practices and the search for better environmental performance.

BackgroundAdvanced systemic mastocytosis (AdvSM), indolent systemic mastocytosis (ISM), and smoldering systemic mastocytosis (SSM) are rare diseases characterized by neoplastic mast cell infiltration of more than one organ. A content-valid patient-reported outcome (PRO) questionnaire that assesses relevant signs and symptoms that are important and understandable to individuals with a condition is critical for assessing new treatment benefit as well as supporting product labeling claims. Notably, no such PRO questionnaire has been developed in accordance with regulatory and scientific guidelines for use in AdvSM, ISM, and SSM patient populations. To fill that gap, this study documents the development and content validity of instruments evaluating signs and symptoms of systemic mastocytosis.MethodsA review of peer-reviewed literature, advice meetings with clinical therapeutic area experts, patient concept elicitation interviews, concept selection and questionnaire construction meetings, and patient cognitive debriefing interviews were conducted, and regulatory feedback was incorporated.ResultsFor AdvSM, 26 sign- and symptom-level concepts were identified in literature, 39 by clinicians, and 33 by patients. For ISM/SSM, 38 sign- and symptom-level concepts were identified in the literature, 39 by clinicians, and 57 by patients. Two patient-reported instruments, the Advanced Systemic Mastocytosis Symptom Assessment Form (AdvSM-SAF) and Indolent Systemic Mastocytosis Symptom Assessment Form (ISM-SAF)(©Blueprint Medicines Corporation), were developed based on consolidated findings. Cognitive debriefing interviews with AdvSM and ISM patients showed the AdvSM-SAF and ISM-SAF were understood and interpreted as intended by the majority of patients.ConclusionThe AdvSM-SAF and ISM-SAF are content-valid tools measuring symptoms from AdvSM and ISM patients’ perspective.

To examine available evidence on prehospital care in human and veterinary trauma and emergency medicine and develop best practice guidelines for use by both paramedical and nonparamedical personnel in the approach to the prehospital care of dogs and cats. Systematic evaluation of the literature gathered via medical databases searches of Medline, CAB abstracts, and Google Scholar. From a review and systematic evaluation of the available evidence, consensus guidelines on the approach to prehospital care of dogs and cats in 18 scenarios were developed. Due to the lack of current evidence in the veterinary prehospital arena, best practice guidelines were developed as an initial platform. Recommendations were based on a review of pertinent human and available veterinary literature as well as a consensus of the authors' professional opinions. It is anticipated that evidence-based additions will be made in the future.

Complementary and Alternative Medicine Use and Initiatives in Europe