Assessment of aeration control strategies for biofilm-based partial nitritation/anammox systems.

The objective of this work was to compare the nitrogen removal in mainstream, biofilm-based partial nitritation anammox (PN/A) systems employing (1) constant setpoint dissolved oxygen (DO) control, (2) intermittent aeration, and (3) ammonia-based aeration control (ABAC). A detailed water resource recovery facility (WRRF) model was used to study the dynamic performance of these aeration control strategies with respect to treatment performance and energy consumption. The results show that constant setpoint DO control cannot meet typical regulatory limits for total ammonia nitrogen (NHx-N). Intermittent aeration shows improvement but requires optimisation of the aeration cycle. ABAC shows the best treatment performance with the advantages of continuous operation and over 20% lower average energy consumption as compared to intermittent aeration.

The difference between energy consumption and energy cost: Modelling energy tariff structures for water resource recovery facilities.

The objective of this paper is to demonstrate the importance of incorporating more realistic energy cost models (based on current energy tariff structures) into existing water resource recovery facilities (WRRFs) process models when evaluating technologies and cost-saving control strategies. In this paper, we first introduce a systematic framework to model energy usage at WRRFs and a generalized structure to describe energy tariffs including the most common billing terms. Secondly, this paper introduces a detailed energy cost model based on a Spanish energy tariff structure coupled with a WRRF process model to evaluate several control strategies and provide insights into the selection of the contracted power structure. The results for a 1-year evaluation on a 115,000 population-equivalent WRRF showed monthly cost differences ranging from 7 to 30% when comparing the detailed energy cost model to an average energy price. The evaluation of different aeration control strategies also showed that using average energy prices and neglecting energy tariff structures may lead to biased conclusions when selecting operating strategies or comparing technologies or equipment. The proposed framework demonstrated that for cost minimization, control strategies should be paired with a specific optimal contracted power. Hence, the design of operational and control strategies must take into account the local energy tariff.

Instrumentation, control and automation in wastewater--from London 1973 to Narbonne 2013.

Key developments of instrumentation, control and automation (ICA) applications in wastewater systems during the past 40 years are highlighted in this paper. From the first ICA conference in 1973 through to today there has been a tremendous increase in the understanding of the processes, instrumentation, computer systems and control theory. However, many developments have not been addressed here, such as sewer control, drinking water treatment and water distribution control. It is hoped that this review can stimulate new attempts to more effectively apply control and automation in water systems in the coming years.

Thrombopoietin modulates the proliferation, migration and cytokine profile of decidual cell subsets during early gestation.

During early gestation, a considerable increase in different leukocyte subsets can be observed in the decidualized endometrium concomitantly to the invasion of cytotrophoblast cells (CTB). To date, it is still in question which factors induce this accumulation of immune cells and whether it is evoked by an in situ proliferation or by a migratory process. Studies on hepatoblastoma cells identified thrombopoietin (TPO) as a novel factor, which elicits dose-dependent chemotactic and chemokinetic effects. However, the impact and function of TPO on decidual cells has not been clarified yet. This study analyses the expression and function of TPO and its receptor c-Mpl in decidua during early gestation. Applying western blot analysis, we detected that TPO is expressed by decidual immune cells (uNK cells and CD14+ monocytes) as well as CTB and decidual stromal cells (DSCs). Expression of the different isoforms of c-Mpl was found in uNK cells, CD14+ monocytes and DSC. Studying the signalling pathway proteins in the uNK cells, an activation of STAT3/Tyr by TPO, was detected. The investigation of the proliferative effects of TPO on the decidual cell subsets revealed that TPO enhances the proliferation of uNK cells and CTB. No change of the proliferative activity after TPO incubation was found in DSC and even a decrease in CD14+ monocytes. In addition, TPO was observed to induce significantly the migratory activity of uNK cells, CD14+ monocytes and CTB. Investigating the effects of TPO on the cytokine profile of the isolated decidual cells, we observed a decrease in the secretion of IL-8, IL-10 and IL-1ß of isolated uNK cells, CD14+ monocytes and CTB, although these changes did not reach statistical significance. Thus, we here identified TPO as a novel factor modulating the proliferation, migration and possibly cytokine secretion of decidual cell subsets.

Critical review of activated sludge modeling: state of process knowledge, modeling concepts, and limitations.

This work critically reviews modeling concepts for standard activated sludge wastewater treatment processes (e.g., hydrolysis, growth and decay of organisms, etc.) for some of the most commonly used models. Based on a short overview on the theoretical biochemistry knowledge this review should help model users to better understand (i) the model concepts used; (ii) the differences between models, and (iii) the limits of the models. The seven analyzed models are: (1) ASM1; (2) ASM2d; (3) ASM3; (4) ASM3 + BioP; (5) ASM2d + TUD; (6) Barker & Dold model; and (7) UCTPHO+. Nine standard processes are distinguished and discussed in the present work: hydrolysis; fermentation; ordinary heterotrophic organisms (OHO) growth; autotrophic nitrifying organisms (ANO) growth; OHO & ANO decay; poly-hydroxyalkanoates (PHA) storage; polyphosphate (polyP) storage; phosphorus accumulating organisms PAO) growth; and PAO decay. For a structured comparison, a new schematic representation of these processes is proposed. Each process is represented as a reaction with consumed components on the left of the figure and produced components on the right. Standardized icons, based on shapes and color codes, enable the representation of the stoichiometric modeling concepts and kinetics. This representation allows highlighting the conceptual differences of the models, and the level of simplification between the concepts and the theoretical knowledge. The model selection depending on their theoretical limitations and the main research needs to increase the model quality are finally discussed.

[Severe maternal hepatopathies in the peripartum period--a case series with review of the literature focusing on pathogenesis and differential diagnosis]. / Lebensbedrohliche, maternale Leberaffektionen in der späten Schwangerschaft und im Wochenbett--eine Fallserie mit Überblick über Pathogenese und differenzialdiagnostische Abgrenzung.

BACKGROUND: A severe hepatopathy constitutes a serious threat during pregnancy and poses considerable challenges to the treating physicians. A broad spectrum of pregnancy-dependent or independent diseases like HELLP-syndrome, liver infection or acute fatty liver of pregnancy (AFLP) is characterized by these affections of the liver. In this study, we present a series of 3 cases with life-threatening hepatopathies and discuss the current state of the literature. A special focus is placed on pathogenesis and differential diagnosis. METHODOLOGY: Pathological, radiological and gynaecological/surgical procedures were performed according to the current German guidelines. Laboratory tests were conducted in the clinics' routine diagnostics section. The existing literature was reviewed via the US National Library of Medicine database "PubMed.gov". RESULTS: The first patient had been afflicted by a fulminant HELLP syndrome causing delivery after 32 weeks of pregnancy. Consecutively, she suffered a sub-total liver infarction followed by a severe coagulopathy and septic peritonitis. The second patient was diagnosed with HELLP syndrome at 36 weeks of pregnancy. The initially mild syndrome exacerbated after delivery leading to haemorrhagic shock and acute renal failure. In the third case, a woman with asymptomatic hepatitis B delivered in the 36th week of pregnancy. Post partum, her pre-existing condition worsened fulminantly resulting in sub-acute liver dystrophy and massive coagulopathy. DISCUSSION AND CONCLUSION: Whenever a hepatopathy occurs during pregnancy, several divergent diagnoses with severe implications and different aetiopathologies have to be considered. Diagnostic and therapeutic strategies have to be weighed quickly to enable a fast, interdisciplinary cooperation in order to prevent fatal outcomes.

MIC-1 (a multifunctional modulator of dendritic cell phenotype and function) is produced by decidual stromal cells and trophoblasts.

BACKGROUND: Macrophage inhibitory cytokine-1 (MIC-1) is a multifunctional cytokine produced in high amounts by placental tissue. Inhibiting trophoblast invasion and suppressing inflammation through inhibition of macrophage activation, MIC-1 is thought to provide pleiotropic functions in the establishment and maintenance of pregnancy. So far, little is known about the decidual cell subsets producing MIC-1 and the effect of this cytokine on dendritic cells (DCs), which are known to play a distinct role in the development of pro-fetal tolerance in pregnancy. METHODS: To identify the decidual cell types expressing and secreting MIC-1, immunohistochemical staining, PCR experiments, western blot analysis and ELISAs were performed. Immature DCs (iDCs) were generated from peripheral blood-derived monocytes and differentiated in the presence of MIC-1 or dexamethasone (Dex) for control. Migratory and proliferative activity of DCs after MIC-1 exposure was investigated by migration and proliferation assay. Cytokine secretion after MIC-1 exposure was tested in isolated uNK cells, isolated CD14+ monocytes, monocyte-derived iDCs and mature DCs. Subsequently, the phenotype of DCs was studied using FACS analysis. To test the T-cell stimulatory capacity of pre-incubated DCs, mixed lymphocyte reaction was applied. Finally, the expression of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) after the exposure of MIC-1 to maturing DCs was analysed by western blot. RESULTS: Immunohistochemical staining, PCR and western blot experiments demonstrated that MIC-1 is mainly expressed by trophoblast cells and decidual stromal cells. Analysis of the MIC-1 secretion of decidual cell types by ELISA again characterized trophoblast and stromal cells as main producers. The migratory activity of iDCs was significantly induced by MIC-1. No changes in proliferative activity of DCs were observed after MIC-1 pre-incubation. The secretion of pro- or anti-inflammatory cytokines was not affected significantly by MIC-1. Studying the phenotype of DCs after MIC-1 exposure by FACS analysis, we observed that MIC-1 suppresses the expression of typical maturation molecules such as CD25 and CD83 as well as of CD86 during cytokine-induced DC maturation similar to Dex. In addition, T-cell stimulatory capacity of DCs was significantly reduced after MIC-1 exposure. MIC-1 was also able to increase slightly the expression of IDO (a key immunomodulatory enzyme promoting periphereal tolerance) in maturing DCs. CONCLUSIONS: We have identified MIC-1 as a novel factor (secreted by decidual cells in early pregnancy) that could promote the increase of a tolerogenic subtype of DC in decidua.

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

This study aims at synthesizing experiences in the practical application of ASM type models. The information is made easily accessible to model users by creating a database of modelling projects. This database includes answers to a questionnaire that was sent out to model users in 2008 to provide inputs for a Scientific and Technical Report of the IWA Task Group on Good Modelling Practice - Guidelines for use of activated sludge models, and a literature review on published modelling projects. The database is analysed to determine which biokinetic model parameters are usually changed by modellers, in which ranges, and what values are typically used for seven selected activated sludge models. These results should help model users in the calibration step, by providing typical parameter values as a starting point and ranges as a guide. However, the proposed values should be used with great care since they are the result of averaging practical experience and not taking into account specific parameter correlations.

[Patient-controlled intravenous analgesia with remifentanil as an alternative to epidural analgesia during labor: case series and discussion of medicolegal aspects]. / Remifentanil zur geburtshilflichen Schmerzerleichterung per patientenkontrolliertem Analgesieverfahren: Fallserie und Diskussion medikolegaler Aspekte.

BACKGROUND: Epidural analgesia is considered as the standard method for labor analgesia by inducing a minimal negative impact on labor while providing effective analgesia. Labor analgesia in the absence of epidural analgesia is difficult to achieve with the commonly used analgesic interventions. If epidural analgesia is not feasible due to coagulation disorders, anticoagulation, inability to insert an epidural catheter or due to the mother''s refusal to accept neuraxial analgesia, there is a need for interventions to cope with labor pain. So far, pethidine, diamorphine, meptazinol and spasmolytics remain the most widely used substances for IM and IV use. Unfortunately, in addition to not being very effective, these interventions may be associated with undesirable side effects for the parturient and the newborn. For a decade, anaesthesiologists have experienced the unique properties of remifentanil in the settings of surgical anaesthesia and conscious sedation since it was introduced for labor analgesia. Unfortunately, remifentanil is not licensed for administration to the pregnant patient, and it is unlikely that the manufacturers would consider the cost justified. METHODS: Therefore, relevant concerns, legal issues and precautions are discussed based on the presentation of case series and a protocol is presented on how the use of remifentanil can be safely implemented for labor analgesia in selected situations. RESULTS AND CONCLUSIONS: Proper informed consent, appropriate monitoring for the mother and the newborn, one-to-one nursing or midwifery care as well as the availability of an attending physician experienced in neonatal resuscitation and an anaesthesiologist with experience regarding the use of remifentanil are important to ensure that this method retains its good reputation for obstetric analgesia.

A systematic approach for model verification: application on seven published activated sludge models.

The quality of simulation results can be significantly affected by errors in the published model (typing, inconsistencies, gaps or conceptual errors) and/or in the underlying numerical model description. Seven of the most commonly used activated sludge models have been investigated to point out the typing errors, inconsistencies and gaps in the model publications: ASM1; ASM2d; ASM3; ASM3 + Bio-P; ASM2d + TUD; New General; UCTPHO+. A systematic approach to verify models by tracking typing errors and inconsistencies in model development and software implementation is proposed. Then, stoichiometry and kinetic rate expressions are checked for each model and the errors found are reported in detail. An attached spreadsheet (see http://www.iwaponline.com/wst/06104/0898.pdf) provides corrected matrices with the calculations of all stoichiometric coefficients for the discussed biokinetic models and gives an example of proper continuity checks.

New framework for standardized notation in wastewater treatment modelling.

Many unit process models are available in the field of wastewater treatment. All of these models use their own notation, causing problems for documentation, implementation and connection of different models (using different sets of state variables). The main goal of this paper is to propose a new notational framework which allows unique and systematic naming of state variables and parameters of biokinetic models in the wastewater treatment field. The symbols are based on one main letter that gives a general description of the state variable or parameter and several subscript levels that provide greater specification. Only those levels that make the name unique within the model context are needed in creating the symbol. The paper describes specific problems encountered with the currently used notation, presents the proposed framework and provides additional practical examples. The overall result is a framework that can be used in whole plant modelling, which consists of different fields such as activated sludge, anaerobic digestion, sidestream treatment, membrane bioreactors, metabolic approaches, fate of micropollutants and biofilm processes. The main objective of this consensus building paper is to establish a consistent set of rules that can be applied to existing and most importantly, future models. Applying the proposed notation should make it easier for everyone active in the wastewater treatment field to read, write and review documents describing modelling projects.

Wastewater treatment modelling: dealing with uncertainties.

This paper serves as a problem statement of the issues surrounding uncertainty in wastewater treatment modelling. The paper proposes a structure for identifying the sources of uncertainty introduced during each step of an engineering project concerned with model-based design or optimisation of a wastewater treatment system. It briefly references the methods currently used to evaluate prediction accuracy and uncertainty and discusses the relevance of uncertainty evaluations in model applications. The paper aims to raise awareness and initiate a comprehensive discussion among professionals on model prediction accuracy and uncertainty issues. It also aims to identify future research needs. Ultimately the goal of such a discussion would be to generate transparent and objective methods of explicitly evaluating the reliability of model results, before they are implemented in an engineering decision-making context.

Activated sludge modelling in practice: an international survey.

The Good Modelling Practice Task Group (GMP-TG) of the International Water Association (IWA) is developing guidelines for the use of Activated Sludge Models (ASM). As part of this work the group created and sent out a questionnaire to current and potential activated sludge model users in 2007. The objectives of the questionnaire were (i) to better define the profile of ASM users, (ii) to identify the tools and procedures that are actually used and (iii) to highlight the main limitations while building and using ASM-type models. Ninety-six answers were received from all over the world, from several types of organisation. The results were analysed to identify the modellers' perceptions of models depending on their profile. The results also highlighted the main topics of interest for improving modelling procedures which are standardisation of the available modelling guidelines and better experience and knowledge transfer.

Inhibition of biological phosphorus removal in a sequencing moving bed biofilm reactor in seawater.

A new process was developed to achieve denitrifying biological phosphorus removal in wastewaters containing high levels of nitrate and phosphate with a low level of organic matter. This could particularly be useful in recirculating systems such as aquariums or fish farms to prevent accumulation of nitrate and phosphates and to avoid regular cost extensive and polluting water replacement. Phosphorus (P) was removed from the influent in a sequencing moving bed biofilm reactor, stored in the attached biomass and then cyclically removed from the biomass by filling the reactor with anaerobic water from a stock tank. Phosphate was accumulated in the stock tank which allowed for use as fertilizer. The feasibility of the experimental design was demonstrated by using the activated sludge model No. 3 (ASM3) complemented by the EAWAG Bio-P module implemented in the WEST simulation software. A pilot scale experiment was conducted in two identical reactors in two runs: one to treat water from a marine mesocosm, the other to treat a synthetic freshwater influent. No biological phosphorus removal was achieved during the seawater run. During the freshwater run, average P removal efficiency was 20%, of which 80% was attributed to biological removal and 20% to chemical precipitation. The absence of efficiency in seawater was attributed to the high concentration of calcium.

Potential of in-situ sensors with ion-selective electrodes for aeration control at wastewater treatment plants.

A pilot-scale activated sludge wastewater treatment plant (WWTP) operated with nitrification and pre-denitrification was monitored with a set of on-line sensors for over 3 years. Wet-chemistry ex-situ analyzers, UV and UV-Visible in-situ sensors and in-situ sensors based on ion-selective electrodes (ISE) were used. New ISE sensors for ammonium, nitrate and nitrite, adapted to water and wastewater matrices, have been released in recent years, With adequate quality control they proved to be highly accurate and reliable in WWTP influents and activated sludge (AS) reactors even at the end of the biological treatment zone, working at low ammonium concentrations (1-2 mgN/l). The ammonium measurement was used to test several feed-forward and feed-back aeration control strategies. The first aim was to keep inorganic nitrogen compounds, i.e. ammonium, nitrate and particularly nitrite, as low as possible in the effluent, and within Swiss national standards (<2.0 mgNH(4)-N/l, <0.3 mgNO(2)-N/l, 24 h average). All the strategies were successful at keeping ammonium low and subsequently at gaining denitrification capacity to significantly reduce the total nitrogen discharge. Some control strategies however generated temporary peaks of ammonium or even accumulation of nitrite.

Long-term evaluation of a spectral sensor for nitrite and nitrate.

A spectral in-situ UV sensor was investigated to measure nitrite and nitrate concentrations in the effluent of the EAWAG pilot-scale plant. The sensor was used with a calibration that was based on data from another WWTP and was operated over a period of 1.5 years. The results showed constant accuracy although the sensor was operated with minimal maintenance (manual cleaning once a month). It could be shown that the sensor was able to accurately predict the nitrite and nitrate concentration with a precision of 0.32 mg N/l (95% prediction interval at mean lab value of 1.15 mg N/l) and 1.08 mg N/l (at 5.55 mg N/l) for nitrite and nitrate, respectively. The UV sensor showed good results for nitrite in the low concentration range and very accurate results for higher concentrations (up to 10 mg N/l). This allows using the sensor for alarm systems as well as for control concepts at WWTPs.

monEAU: a platform for water quality monitoring networks.

Continuous monitoring of water quality creates huge amounts of data and therefore requires new concepts to guarantee high data quality and to prevent data graveyards. Monitoring stations commonly used in practice today suffer from insufficient flexibility and a lack of standardization. That is, although a lot of monitoring tasks are comparable and should lead to robust and powerful platforms, most monitoring stations are case specific developments. In this paper the underlying ideas of a new generation of monitoring networks is described. First a problem analysis of monitoring stations typically seen in current river monitoring practice is outlined, then the monEAU vision on monitoring networks will be discussed together with an overview of a planned system set-up with innovative data evaluation concept.

Adding realism to simulated sensors and actuators.

In this paper, we propose a statistical theoretical framework for incorporation of sensor and actuator faults in dynamic simulations of wastewater treatment operation. Sensor and actuator faults and failures are often neglected in simulations for control strategy development and testing, although it is well known that they represent a significant obstacle for realising control at full-scale facilities. The framework for incorporating faults and failures is based on Markov chains and displays the appealing property of easy transition of sensor and actuator history into a model for fault generation. The paper briefly describes Markov theory and how this is used together with models for sensor and actuator dynamics to achieve a realistic simulation of measurements and actuators.

[Severe foetal growth retardation in a patient with uterus bicornis, velamentous insertion and partial placental abruption in the 26th week of gestation--a case report]. / Schwere intrauterine Wachstumsretardierung bei Uterus bicornis, Insertio velamentosa und vorzeitiger partieller Plazentalösung in der 26. Schwangerschaftswoche - eine Kasuistik.

Foetal growth retardation (IUGR) occurs in approximately 3-10 % of all pregnancies and may result from foetal, maternal or placenta-related conditions. In IUGR, the placental weight is often reduced and the placental capacity, reflected by the organ's weight, is impaired. Uterine malformations have an incidence of 3-4 % and may be the cause of placental abruptions occurring in 0.4-1.3 % of all pregnancies. We report on a patient in the 26 (th) week of pregnancy who was admitted with vaginal bleeding. A uterus bicornis had been found previously. Sonography showed severe foetal growth retardation and a pathological foetal Doppler signal. A haematoma located cranial of the os uteri was sonographically diagnosed, and a partial placental abruption was suspected. Due to a pathological cardiotocography, a primary Caesarean section was performed. Intraoperative evaluation confirmed the presence of a uterus bicornis. In addition, the placenta showed an insertio velamentosa. The growth retarded foetus - 490 g birth weight - was anaemic. Respiratory therapy and surfactant substitution were performed because of a respiratory distress syndrome. At a corrected age of 8 weeks the boy was sent home without neurological sequelae. In the case reported, a malformation of the uterus was the cause of a pathologically altered placenta. The multiple factors responsible for the described severe intrauterine growth retardation were a low placental weight and thus a reduced placental capacity, an impaired foetal circulation caused by the velamentous insertion, as well as a partial placental abruption. In normotensive pregnancies with IUGR, macroscopic and histopathological examinations of the placenta are therefore strongly recommended. Prior to getting pregnant, the therapeutic options should be explained to women with uterine malformations.