Position paper - progress towards standards in integrated (aerobic) MBR modelling.

Membrane bioreactor (MBR) models are useful tools for both design and management. The system complexity is high due to the involved number of processes which can be clustered in biological and physical ones. Literature studies are present and need to be harmonized in order to gain insights from the different studies and allow system optimization by applying a control. This position paper aims at defining the current state of the art of the main integrated MBR models reported in the literature. On the basis of a modelling review, a standardized terminology is proposed to facilitate the further development and comparison of integrated membrane fouling models for aerobic MBRs.

Survival Benefit From Kidney Transplantation Using Kidneys From Deceased Donors Aged ≥75 Years: A Time-Dependent Analysis.

Patients with end-stage renal disease have longer survival after kidney transplantation than they would by remaining on dialysis; however, outcome with kidneys from donors aged ≥75 years and the survival of recipients of these organs compared with their dialysis counterparts with the same probability of obtaining an organ is unknown. In a longitudinal mortality study, 2040 patients on dialysis were placed on a waiting list, and 389 of them received a first transplant from a deceased donor aged ≥75 years. The adjusted risk of death and survival were calculated by non-proportional hazards analysis with being transplanted as a time-dependent effect. Projected years of life since placement on the waiting list was almost twofold higher for transplanted patients. Nonproportional adjusted risk of death after transplantation was 0.44 (95% confidence interval [CI] 0.61-0.32; p < 0.001) in comparison with those that remained on dialysis. Stratifying by age, adjusted hazard ratios for death were 0.17 (95% CI 0.47-0.06; p = 0.001) for those aged <65 years, 0.56 (95% CI 0.92-0.34; p = 0.022) for those aged 65-69 years and 0.82 (95% CI 1.28-0.52; p = 0.389) for those aged ≥70 years. Although kidney transplantation from elderly deceased donors is associated with reduced graft survival, transplanted patients have lower mortality than those remaining on dialysis.

Experimental early pathogenesis of Streptococcus agalactiae infection in red tilapia Oreochromis spp.

Streptococcus agalactiae causes a severe systemic disease in fish, and the routes of entry are still ill-defined. To address this issue, two groups of 33 red tilapia Oreochromis spp. each of 10 g were orally infected with S. agalactiae (n = 30), and by immersion (n = 30), six individuals were control-uninfected fish. Three tilapias were killed at each time point from 30 min to 96 h post-inoculation (pi); controls were killed at 96 h. Samples from most tissues were examined by haematoxylin-eosin (H&E), indirect immunoperoxidase (IPI) and periodic acid-Schiff; only intestine from fish infected by gavage was evaluated by transmission electron microscopy. The results of both experiments suggest that the main entry site of S. agalactiae in tilapia is the gastrointestinal epithelium; mucus seems to play an important defensive role, and environmental conditions may be an important predisposing factor for the infection.

Validation of a decision support tool for wastewater treatment selection.

Wastewater treatment selection is a complex task usually addressed by applying separate tools for the correct assessment of multi-criteria evaluation. Novedar_EDSS integrates technical, environmental, economic and social assessment capabilities in one single platform. The aim of this work is to evaluate and demonstrate the capabilities of this environmental decision support system (EDSS). For that purpose, 4 case studies of real projects were selected to validate the results in the EDSS by comparing them with those from the study of alternatives performed by the decision makers. Moreover, 1 conceptual case study was applied to support the selection of the most properly strategy for plant retrofitting. Results have demonstrated that the EDSS provides key aspects when deciding the retrofitting process to apply and, when compared to real projects, it recommends analogue treatments as those applied in the projects, ranking them in the same order. Therefore, results in the validation process performed show that this tool provides a reliable basis to support decision makers to select properly treatment alternatives in wastewater treatment plant pre-design.

Feasibility and safety of biventricular repair in neonates with hypoplastic left heart complex.

Hypoplastic left heart syndrome is a spectrum of structural cardiac malformations characterized by variable underdevelopment of the left heart-aorta complex. A minority of patients having a milder degree of left ventricular hypoplasia, described as hypoplastic left heart complex (HLHC), may be selected for biventricular repair. The objective of this study was to assess the outcome of the biventricular approach in HLHC. We evaluated retrospectively 30 neonates diagnosed with HLHC from the "12 de Octubre" University Hospital, following established criteria. We analyzed the echocardiographic data recorded just after birth and at last follow-up after surgery. All patients were operated on in the neonatal period using various surgical techniques. There were no early deaths and only 1 late death after a mean follow-up of 62.9 ± 43.8 months. All patients presented a significant growth of the left ventricular structures, with a Z-score increase of 1.17 ± 1.05 for mitral annulus, 1.72 ± 1.23 for aortic annulus, and 1.33 ± 1.46 for left ventricular end-diastolic diameter. Postoperatively, 18 patients showed a left valvular stenosis, and 17 patients underwent a reoperation and/or an interventional procedure. Freedom from surgery or interventional catheterizations at 1, 3 and 5 years was 53, 49 and 43%, respectively. The 29 current survivors are all in a good functional status. In our experience, we achieved good results from biventricular repair in patients with HLHC, with a significant growth of left heart structures and an excellent clinical status at a medium-term follow-up. Nevertheless, there was a high rate of reoperations and/or interventional catheterizations.

Assessment of energy-saving strategies and operational costs in full-scale membrane bioreactors.

The energy-saving strategies and operational costs of stand-alone, hybrid, and dual stream full-scale membrane bioreactors (MBRs) with capacities ranging from 1100 to 35,000 m(3) day(-1) have been assessed for seven municipal facilities located in Northeast Spain. Although hydraulic load was found to be the main determinant factor for the energy consumption rates, several optimisation strategies have shown to be effective in terms of energy reduction as well as fouling phenomenon minimization or preservation. Specifically, modifications of the biological process (installation of control systems for biological aeration) and of the filtration process (reduction of the flux or mixed liquor suspended solids concentration and installation of control systems for membrane air scouring) were applied in two stand-alone MBRs. After implementing these strategies, the yearly specific energy demand (SED) in flat-sheet (FS) and hollow-fibre (HF) stand-alone MBRs was reduced from 1.12 to 0.71 and from 1.54 to 1.12 kW h(-1) m(-3), respectively, regardless of their similar yearly averaged hydraulic loads. The strategies applied in the hybrid MBR, namely, buffering the influent flow and optimisation of both biological aeration and membrane air-scouring, reduced the SED values by 14%. These results illustrate that it is possible to apply energy-saving strategies to significantly reduce MBR operational costs, highlighting the need to optimise MBR facilities to reconsider them as an energy-competitive option.

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.

Representative taxa in field trials for environmental risk assessment of genetically modified maize.

When assessing the benefits and risks of transgenic crops, one consideration is their relative effects on non-target arthropod (NTA) abundance and functions within agroecosystems. Several laboratory and field trials have been conducted in Spain since the late 1990s to assess this issue. A consideration in the design of field trials is whether it is necessary to sample most NTAs living in the crop or only representative taxa that perform main ecological functions and have a good capacity to detect small changes in their abundance. Small changes in the field abundance of an effective representative taxon should be detectable using standard experimental protocols. The ability of a species to reveal differences across treatments may be analysed by examining the detectable treatment effects for surveyed non-target organisms. Analysis of data from several NTAs recorded in 14 field trials conducted over 10 years using complete block designs allowed us to select a number of representative taxa capable of detecting changes in the density or activity of arthropod herbivores, predators, parasitoids and decomposers in transgenic and non-transgenic maize varieties. The most suitable NTA as representative taxa (with detectable treatment effects below 50%) included leafhoppers among arthropod herbivores, Orius spp., Araneae, and Carabidae among predators, chalcidids, particularly the family Mymaridae, among parasitoids and Chloropidae as decomposer. Details of sampling techniques for each sampled taxa and their advantages and disadvantages are discussed. It is concluded that abundance of taxa is the most influential factor determining their capacity to detect changes caused by genetically modified varieties.

Taxonomic identification of Macrolophus pygmaeus and Macrolophus melanotoma based on morphometry and molecular markers.

Two Macrolophus species, M. melanotoma (=M. caliginosus) and M. pygmaeus, have been referred to as efficient predators of several key pests on vegetable crops in Europe. However, due to the great morphological similarity of these species, they have been confused, with important consequences for inoculative releases of these predators in greenhouses and for the conservation of their natural populations on greenhouse and outdoor crops. In this work, we developed tools to identify these morphologically very similar species. We first confirmed the specific status of two Macrolophus populations collected on their respective host plants (Dittrichia viscosa and tomato) through crossing experiments. Then, using multivariate morphometric analysis, we proposed a linear discriminant function that combines head measurements separating males from the two species without error. Finally, we designed specific primers for a mitochondrial DNA region that were able to distinguish field-collected Macrolophus individuals through conventional PCR. In conclusion, the tools developed in the present study will allow reliable identification of the Macrolophus species present in crops and in the native flora that are the source of populations that colonise them. They will also allow correct identification of mass reared Macrolophus to be introduced in greenhouse crops in inoculative releases.

Ex-ante determination of the capacity of field tests to detect effects of genetically modified corn on nontarget arthropods.

Field trials may be required to assess risks of genetically modified crops (GMCs) for nontarget arthropods. One critical point of these trials is their capacity to detect differences between the density of one taxon in the GMC and that in the comparator. The detection capacity of a trial depends on the abundance and variability of the taxon, the values assumed for type I (alpha) and II (beta) errors, and the characteristics of the trial and statistical design. To determine the optimal trial layout and statistical analysis, 20 field trials carried out in Spain from 2000 to 2009 to assess risks of GMCs on nontarget arthropods were examined with alpha and beta fixed at 0.05 and 0.20, respectively. Under the experimental conditions tested, taxon variability is the most influential component determining test detection capacity; the maximum acceptable values of taxon variability to achieve a certain detection capacity were calculated for different numbers of replicates (blocks), treatments, and years. A close relationship between taxon variability and mean abundance in visual counts, pitfall traps, and yellow sticky traps allowed minimal critical abundance thresholds to be estimated to guarantee a certain detection capacity and to establish abundance criteria for selecting focal taxa. The number of replications (blocks), treatments, sites, and years has a lesser influence on detection capacity once minimal values in taxon abundance in field trials are ensured. Conclusions reached on the detection capacity of field trials with the experimental data obtained under Mediterranean conditions should be contrasted with those of other regions.

Ragging phenomenon characterisation and impact in a full-scale MBR.

Although there are few studies about clogging phenomenon in the peer-reviewed literature, it is considered one of the main operational challenges by membrane bioreactor (MBR) practitioners. This study presents data from the performance of a full-scale MBR affected by clogging, and ragging in particular. An evaluation of the efficiencies of different applied cleaning methods revealed the acid recovery cleaning to be more efficient than the basic recovery cleanings, although all maintenance cleanings were largely ineffective in recovering membrane permeability. Only declogging cleaning through the manual removal of the accumulated solids was found to be efficient, indicating that such solids were substantially unremoved by chemical cleaning. Moreover, reclogging following manual cleaning demonstrated a propensity for rapid clogging - within a period of 10 days over which the permeability returned to 68 and 88% of the pre-cleaned state. The analysis of the feedwater indicated suspended textile fibres (>70% cotton) to be present at a concentration of more than 40 mg·L(-1), ∼90% being smaller than 1 mm (0.06-0.4 mm). These small lengths of filaments evidently pass through pre-treatment and are retained on the membrane surface, forming 'rags' within the membrane module, notwithstanding the routine high quality of sludge reflected in the capillary suction time and filterability measurements. Pre-treatment improvement, manual cleaning and permeate flux reduction are the only options to minimise ragging impact over MBR performance.

Characterisation of RO fouling in an integrated MBR/RO system for wastewater reuse.

Membrane filtration has gradually gained acceptance as the preferred pre-treatment for reverse osmosis (RO). In this paper, an integrated membrane bioreactor (MBR)/RO system for wastewater reuse treating real sewage water has been evaluated and the RO fouling has been characterised. The MBR achieved low values of organic matter, total nitrogen, PO(4)(3-), total organic carbon, turbidity and conductivity. Filtration with two different RO commercial membranes was performed after the MBR pre-treatment and the same average fouling rate (0.08 bar day(-1)) was noted. These results gained from the characterisation of the high quality MBR/RO permeate show its potential for water reuse. Inorganic precipitation appears to be the predominant form of fouling in the RO membranes. Calcium phosphate and alumino-silicates were identified by a scanning electron microscope combined with an energy dispersive X-ray and polysaccharides, amide and aliphatic structures were detected with attenuated total reflection infrared microspectroscopy.

Benchmark simulation models, quo vadis?

As the work of the IWA Task Group on Benchmarking of Control Strategies for wastewater treatment plants (WWTPs) is coming to an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to provide their insights, highlighting areas where knowledge may still be deficient and where new opportunities are emerging, and to propose potential avenues for future development and application of the general benchmarking framework and its associated tools. The paper focuses on the topics of temporal and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity.

Data quality validation of the Spanish Incisional Hernia Surgery Registry (EVEREG): pilot study.

PURPOSE: The Spanish Incisional Hernia Surgery Registry (EVEREG) was promoted by the Abdominal Wall Section of the Spanish Association of Surgeons, starting data collection in July 2012 and currently has more than 14,000 cases. The objective of this study was to validate the data collected through a pilot audit process. METHODS: A sample of hospitals participating in the EVEREG registry since the beginning was selected. Patients registered in these centers in the 2012-2020 period were included. A stratified random sampling was carried out, with the inclusion of 10% of registered cases per center with a minimum of 20 cases per center. At each participating center, two researchers not belonging to the center undergoing the audit checked (on site or telematically) the concordance between the data in the registry and the data contained in the case history of each patient. RESULTS: 330 patients have been analyzed, out of a total of 2673 registered, in 9 participating centers. The average accuracy has been 95.7%. Incorrect data 1.5% and missing data 2.3% CONCLUSION: The group of pilot hospitals from this EVERG incisional hernia surgery registry shows a very high precision of 95.7%. The confirmation of these findings in all the centers participating in the registry will make it possible to guarantee the quality of the studies made and their comparability with other similar national registries. TRIAL REGISTRATION: nnTrial registration number: ClinicalTrials.gov ID:NCT03899012.

Identification of de novo mutations and rare variants in hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) is one of the most severe congenital heart malformations, characterized by underdevelopment of the structures in the left heart-aorta complex. The majority of cases are sporadic. Although multiple genetic loci have been tentatively implicated in HLHS, no gene or pathway seems to be specifically associated with the disease. To elucidate the genetic basis of HLHS, we analyzed 53 well-characterized patients with isolated HLHS using an integrated genomic approach that combined DNA sequencing of five candidate genes (NKX2-5, NOTCH1, HAND1, FOXC2 and FOXL1) and genome-wide screening by high-resolution array comparative genomic hybridization. In 30 patients, we identified two novel de novo mutations in NOTCH1, 23 rare patients inherited gene variants in NOTCH1, FOXC2 and FOXL1, and 33 rare patients mostly inherited copy-number variants. Some of the identified variations coexisted in the same patient. The biological significance of such rare variations is unknown, but our findings strengthen the role of NOTCH pathway in cardiac valve development, indicating that HLHS is, at least in part, a 'valve' disease. This is the first report of de novo mutations associated with isolated HLHS. Moreover, the coexistence of multiple rare variants suggests in some cases a cumulative effect, as shown for other complex disease.

A knowledge-based control system for air-scour optimisation in membrane bioreactors.

Although membrane bioreactors (MBRs) technology is still a growing sector, its progressive implementation all over the world, together with great technical achievements, has allowed it to reach a mature degree, just comparable to other more conventional wastewater treatment technologies. With current energy requirements around 0.6-1.1 kWh/m3 of treated wastewater and investment costs similar to conventional treatment plants, main market niche for MBRs can be areas with very high restrictive discharge limits, where treatment plants have to be compact or where water reuse is necessary. Operational costs are higher than for conventional treatments; consequently there is still a need and possibilities for energy saving and optimisation. This paper presents the development of a knowledge-based decision support system (DSS) for the integrated operation and remote control of the biological and physical (filtration and backwashing or relaxation) processes in MBRs. The core of the DSS is a knowledge-based control module for air-scour consumption automation and energy consumption minimisation.

Nature-based solutions in the urban context: terminology, classification and scoring for urban challenges and ecosystem services.

The concept of Nature-Based Solutions (NBS) has emerged to foster sustainable development by transversally addressing social, economic, and environmental urban challenges. However, there is still a considerable lack of agreement on the conceptualization of NBS, especially concerning typologies, nomenclature, and performance assessments in terms of ecosystem services (ES) and urban challenges (UC). Therefore, this article consolidates the knowledge from 4 European projects to set a path for a common understanding of NBS and thus, facilitate their mainstreaming. To do so, firstly, we performed elicitation workshops to develop an integrative list of NBS, based on the identification of overlaps among NBS from different projects. The terminologies were formalized via web-based surveys. Secondly, the NBS were clustered, following a conceptual hierarchical classification. Thirdly, we developed an integrative assessment of NBS performance (ES and UC) based on the qualitative evaluations from each project. Afterwards, we run a PCA and calculated the evenness index to explore patterns among NBS. The main conceptual advancement resides in providing a list of 32 NBS and putting forward two novel NBS categories: NBS units (NBSu) that are stand-alone green technologies or green urban spaces, which can be combined with other solutions (nature-based or not); NBS interventions (NBSi) that refer to the act of intervening in existing ecosystems and in NBSu, by applying techniques to support natural processes. The statistical analysis suggests that NBSu are more versatile than NBSi in terms of UC and ES. Moreover, the results of the integrative assessment of NBS performance suggest a greater agreement concerning the role of NBS in addressing environmental UC, cultural and regulating ES than regarding socio-economic UC and supporting and provision ES. Finally, the 'green factor' and the replication of non-intensive practices occurring in nature seem to be key criteria for practitioners to identify a particular solution as an NBS.

Knowledge-based system for automatic MBR control.

MBR technology is currently challenging traditional wastewater treatment systems and is increasingly selected for WWTP upgrading. MBR systems typically are constructed on a smaller footprint, and provide superior treated water quality. However, the main drawback of MBR technology is that the permeability of membranes declines during filtration due to membrane fouling, which for a large part causes the high aeration requirements of an MBR to counteract this fouling phenomenon. Due to the complex and still unknown mechanisms of membrane fouling it is neither possible to describe clearly its development by means of a deterministic model, nor to control it with a purely mathematical law. Consequently the majority of MBR applications are controlled in an "open-loop" way i.e. with predefined and fixed air scour and filtration/relaxation or backwashing cycles, and scheduled inline or offline chemical cleaning as a preventive measure, without taking into account the real needs of membrane cleaning based on its filtration performance. However, existing theoretical and empirical knowledge about potential cause-effect relations between a number of factors (influent characteristics, biomass characteristics and operational conditions) and MBR operation can be used to build a knowledge-based decision support system (KB-DSS) for the automatic control of MBRs. This KB-DSS contains a knowledge-based control module, which, based on real time comparison of the current permeability trend with "reference trends", aims at optimizing the operation and energy costs and decreasing fouling rates. In practice the automatic control system proposed regulates the set points of the key operational variables controlled in MBR systems (permeate flux, relaxation and backwash times, backwash flows and times, aeration flow rates, chemical cleaning frequency, waste sludge flow rate and recycle flow rates) and identifies its optimal value. This paper describes the concepts and the 3-level architecture of the knowledge-based DSS and details the knowledge-based control module. Preliminary results of the application of the control module to regulate the air flow rate of an MBR working with variable flux demonstrates the usefulness of this approach.

Role playing games: a methodology to acquire knowledge for integrated wastewater infrastructures management in a river basin scale.

Current management of sanitation infrastructures (sewer systems, wastewater treatment plant, receiving water, bypasses, deposits, etc) is not fulfilling the objectives of up to date legislation, to achieve a good ecological and chemical status of water bodies through integrated management. These made it necessary to develop new methodologies that help decision makers to improve the management in order to achieve that status. Decision Support Systems (DSS) based on Multi-Agent System (MAS) paradigm are promising tools to improve the integrated management. When all the different agents involved interact, new important knowledge emerges. This knowledge can be used to build better DSS and improve wastewater infrastructures management achieving the objectives planned by legislation. The paper describes a methodology to acquire this knowledge through a Role Playing Game (RPG). First of all there is an introduction about the wastewater problems, a definition of RPG, and the relation between RPG and MAS. Then it is explained how the RPG was built with two examples of game sessions and results. The paper finishes with a discussion about the uses of this methodology and future work.

[Hepatopulmonary syndrome in children: evaluation and treatment]. / Síndrome hepatopulmonar en niños: evaluación y tratamiento.

Hepatopulmonary syndrome is a rare disease that affects patients of any age with acute or chronic liver disease. Its diagnosis is based on the presence of hypoxemia and the demonstration of an intrapulmonary shunting by echocardiography with contrast or perfusion lung scanning. Pulmonary angiography is useful to demonstrate macroscopic arteriovenous communications. We describe five paediatric cases with a different natural history and evolution. Two of them were diagnosed with hepatopulmonary syndrome type 1, another two with type 2 and a fifth one with type 1 and 2, which required a different therapeutic approach in each case.