On Reconciliation of Traditional Water Quality Models and Activated Sludge Models

Models of the oxidation of organic material developed for river water quality management and for biological wastewater treatment differ widely in state variables and process descriptions due to their development history, environmental conditions and the objectives of the two approaches. The IAWPRC/IAWQ Activated Sludge Model No. 1 (ASM-I) resulted from a coordinated effort of a dedicated specialist group at the mid 1980s and thus free of the inconsistencies inherent in ambient water quality models such as QUAL2E developed in the course of the past three decades. The reconciliation of the ASM-1 and QUAL2E attempted in the present work may help in developing integrated pollution abatement strategies considering treatment and riverine processes in a unified way. It is shown that, after some modifications, a model similar to ASM-1 can be successfully applied to riverine conditions. It is also demonstrated that simple first-order kinetics models (such as the Streeter-Phelps and extended Streeter-Phelps ones) can be derived from the ASM-1 and QUAL2E as their asymptotic forms under the assumption that "fast" variables attain their long-term equilibrium levels. Models of ASM-1 type should, therefore, be applied when there are abrupt temporal or spatial changes in the system, otherwise simpler models adequately reflect the behavior of the oxidation system. Finally, an international effort to develop a standardized and improved river water quality model following the procedure of ASM-I looks more than desirable

Wind-induced Sediment Resuspension and its Impact on Algal Growth for Lake Balaton

This report includes two articles which were published concerning IIASA's joint study with the Hungarian Academy of Sciences on eutrophication management of Lake Balaton. The first one, "Dynamic Behavior of Suspended Sediment Concentrations in a Shallow Lake Perturbed by Episodic Wind Events," by Luettich, Jr. et al, deals with the understanding and modeling of physical processes influencing resuspension, while the second one, "Influence of Sediment Resuspension on the Light Conditions and Algal Growth in Lake Balaton," by Somlyody and Koncsos, builds on its achievements and estimates the impact on light conditions and algae biomass. Due to an increased internal phosphorus load and the appearance of nitrogen-fixing blue-green algae, nowadays nutrients are not a limiting factor for Lake Balaton (in spite of the significant load reduction realized since 1983). The short-term dynamics of algae biomass are primarily determined by light, as described in the second article

Primary care obesity management in Hungary: evaluation of the knowledge, practice and attitudes of family physicians

BACKGROUND: Obesity, a threatening pandemic, has an important public health implication. Before proper medication is available, primary care providers will have a distinguished role in prevention and management. Their performance may be influenced by many factors but their personal motivation is still an under-researched area. METHOD: The knowledge, attitudes and practice were reviewed in this questionnaire study involving a representative sample of 10% of all Hungarian family physicians. In different settings, 521 practitioners (448 GPs and 73 residents/vocational trainees) were questioned using a validated questionnaire. RESULTS: The knowledge about multimorbidity, a main consequence of obesity, was balanced.Only 51% of the GPs were aware of the diagnostic threshold for obesity; awareness being higher in cities (60%) and the highest among residents (90%). They also considered obesity an illness rather than an aesthetic issue.There were wider differences regarding attitudes and practice, influenced by the the doctors' age, gender, known BMI, previous qualification, less by working location.GPs with qualification in family medicine alone considered obesity management as higher professional satisfaction, compared to physicians who had previously other board qualification (77%vs68%). They measured their patients' waist circumference and waist/hip ratio (72%vs62%) more frequently, provided the obese with dietary advice more often, while this service was less frequent among capital-based doctors who accepted the self-reported body weight dates by patients more frequently / commonly. Similar reduced activity and weight-measurement in outdoor clothing were more typical among older doctors.Diagnosis based on BMI alone was the highest in cities (85%). Consultations were significantly shorter in practices with a higher number of enrolled patients and were longer by female providers who consulted longer with patients about the suspected causes of developing obesity (65%vs44%) and offered dietary records for patients significantly more frequently (65%vs52%). Most of the younger doctors agreed that obesity management was a primary care issue.Doctors in the normal BMI range were unanimous that they should be a model for their patients (94%vs81%). CONCLUSION: More education of primary care physicians, available practical guidelines and higher community involvement are needed to improve the obesity management in Hungary

Practical guidelines for rigor and reproducibility in preclinical and clinical studies on cardioprotection

The potential for ischemic preconditioning to reduce infarct size was first recognized more than 30 years ago. Despite extension of the concept to ischemic postconditioning and remote ischemic conditioning and literally thousands of experimental studies in various species and models which identified a multitude of signaling steps, so far there is only a single and very recent study, which has unequivocally translated cardioprotection to improved clinical outcome as the primary endpoint in patients. Many potential reasons for this disappointing lack of clinical translation of cardioprotection have been proposed, including lack of rigor and reproducibility in preclinical studies, and poor design and conduct of clinical trials. There is, however, universal agreement that robust preclinical data are a mandatory prerequisite to initiate a meaningful clinical trial. In this context, it is disconcerting that the CAESAR consortium (Consortium for preclinicAl assESsment of cARdioprotective therapies) in a highly standardized multi-center approach of preclinical studies identified only ischemic preconditioning, but not nitrite or sildenafil, when given as adjunct to reperfusion, to reduce infarct size. However, ischemic preconditioning—due to its very nature—can only be used in elective interventions, and not in acute myocardial infarction. Therefore, better strategies to identify robust and reproducible strategies of cardioprotection, which can subsequently be tested in clinical trials must be developed. We refer to the recent guidelines for experimental models of myocardial ischemia and infarction, and aim to provide now practical guidelines to ensure rigor and reproducibility in preclinical and clinical studies on cardioprotection. In line with the above guideline, we define rigor as standardized state-of-the-art design, conduct and reporting of a study, which is then a prerequisite for reproducibility, i.e. replication of results by another laboratory when performing exactly the same experiment

An analysis on parameters of suspended sediment models for a shallow lake

The objective of the present paper was to clarify the inconsistencies on parameters of two formerly developed resuspension models for Lake Balaton. With the aid of a new scale analysis based on the Richardson law it was demonstrated that the settling velocity of the resuspended sediment particles is primarily dependent on the hydrodynamic conditions and the water content of the sediment. On the other hand the particle size distribution of the bottom sediment does not play a significant role in influencing the settling velocity

River water quality modelling: III. Future of the art.

This paper is the third of a three-part series summarizing the background to and objectives of the activity of the IAWQ Task Group on River Water Quality Modelling (RWQM). On the basis of the two other papers and a comparison between the best known state of the art river model, QUAL2, and the IAWQ Activated Sludge Model (ASM) No. 1, the Task Group proposes to develop improved conversion models for inclusion in a river water quality model. The model should describe the cycling of oxygen, nitrogen, and phosphorus in both water and sediment, and should be compatible with the ASM to support the development of integrated emission reduction strategies. The model should be particularly well suited to handle problems characterized by significant temporal and spatial influences (e.g. CSOs and NPSs). It should serve for research, education, improved communication, knowledge transfer, regulatory applications such as catchment planning, and improved data collection. Anticipated results of the Task Group effort include (i) standardized conversion sub-models; (ii) a decision support tool to guide model construction and usage; and (iii) case study applications. The model development, which is not intended to result in a software product, is intended to be an open-ended and flexible process to encourage the participation of interested professionals

River water quality modelling: I. state of the art

River water quality models are used extensively in research as well as in the design and assessment of water quality management measures. The application of mathematical models for that purpose dates back to the initial studies of oxygen depletion due to organic waste pollution. Since then, models have been constantly refined and updated to meet new and emerging problems of surface water pollution, such as eutrophication, acute and chronic toxicity, etc. In order to handle the complex interactions caused by the increased influence of human activities in rivers it is today mandatory to couple river water quality models with models describing emissions from the drainage and sewerage system (such as the IAWQ Activated Sludge model No.1). In this paper—which is the first of a three-part series by the IAWQ Task Group on River Water Quality Modelling— the state of the art is summarized with the above aim in mind. Special attention is given here to the modelling of conversion processes but also the methods and tools to work with the models, i.e. parameter estimation, measurement campaign design, and simulation software, are discussed

River water quality modelling: II.:Problems of the art

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