Diagnosis and optimization of WWTPs using the PWM library: full-scale experiences.

Given the shift in perception of wastewater treatment plants as water resource recovery facilities, conventional mathematical models need to be updated. The resource recovery perspective should be applied to new processes, technologies and plant layouts. The number and level of models proposed to date give an overview of the complexity of the new plant configurations and provides a wide range of possibilities and process combinations in order to construct plant layouts. This diversity makes the development of standard, modular and flexible tools and model libraries that allow the incorporation of new processes and components in a straightforward way a necessity. In this regard, the plant-wide modelling (PWM) library is a complete model library that includes conventional and advanced technologies and that allows economic and energetic analyses to be carried out in a holistic way. This paper shows the fundamentals of this PWM library that is built upon the above-mentioned premises and the application of the PWM library in three different full-scale case studies.

Lessons learnt from the application of a multi-variable controller for nitrogen removal in the Mekolalde wastewater treatment plant: good simulation practices in control.

Although often perceived as tools for use by scientists, mathematical modelling and simulation become indispensable when control engineers have to design controllers for real-life wastewater treatment plants (WWTPs). Nonetheless, the design of effective controllers in the wastewater domain using simulations requires effects, such as the nonlinearity of actuators, the time response of sensors, plant model uncertainties, etc. to have been reproduced beforehand. Otherwise, control solutions verified by simulation can completely underperform under real conditions. This study demonstrates that, when all the above effects are included at the outset, a systematic use of simulations guarantees high quality controllers in a relatively short period of time. The above is exemplified through the Mekolalde WWTP, where a comprehensive simulation study was conducted in order to develop a control product for nitrogen removal. Since its activation in May 2011, the designed controller has been permanently working in the plant which, from this time onwards, has experienced significant improvements in the quality of water discharges combined with a lower utilization of electricity for wastewater treatment.

Add Control: plant virtualization for control solutions in WWTP.

This paper summarizes part of the research work carried out in the Add Control project, which proposes an extension of the wastewater treatment plant (WWTP) models and modelling architectures used in traditional WWTP simulation tools, addressing, in addition to the classical mass transformations (transport, physico-chemical phenomena, biological reactions), all the instrumentation, actuation and automation & control components (sensors, actuators, controllers), considering their real behaviour (signal delays, noise, failures and power consumption of actuators). Its ultimate objective is to allow a rapid transition from the simulation of the control strategy to its implementation at full-scale plants. Thus, this paper presents the application of the Add Control simulation platform for the design and implementation of new control strategies at the WWTP of Mekolalde.

[Right-left shunt caused by sarcoma of the right atrium]. / Shunt droit-gauche secondaire à un sarcome de l'oreillette droite.

A 70 year old woman was admitted for right ventricular failure and cyanosis of recent onset. Echocardiography showed a very large, homogenous, immobile, smooth-contoured mass filling the right atrium. Right atrial pressures were raised but the other intracardiac pressures were normal at catheterisation. Right heart angiography confirmed the voluminous right atrial mass and dilatation of the hepatic veins and showed early opacification of the left heart chambers. A right-to-left shunt was confirmed by oximetry which showed significant desaturation of the blood in the left atrium and ventricle (saturation 78% in the left ventricle). The tumour was also documented by a thoracic CT scan. At surgery, a very large, malignant right atrial tumour was resected which histological examination showed to be an angiosarcoma. The interatrial septum seemed to be intact: there was no true atrial septal defect but a persistent foramen ovale was found. After resection of the tumour the right atrium was reconstructed. The initial postoperative period was uncomplicated but the patient died nine months later of metastatic disease particularly affecting the liver and brain. The clinical presentation of malignant cardiac tumour is very variable but a right-to-left interatrial shunt through a patent foramen ovale has only been reported previously in 2 cases of primary malignant tumours (a rhabdomyosarcoma and an angiosarcoma) and in 1 case of a secondary cardiac metastasis.

[Abdominal manifestations in hereditary acute angioneurotic oedema. Value of study of the complement system (author's transl)]. / Manifestations abdominales aiguës de l'oedème angioneurotique héréditaire. Intérêt de l'exploration du système du complément.

Four individuals of the same family suffered from a functional deficiency in C1 esterase inhibitor. In three of them, the manifestations of hereditary angioneurotic oedema were abdominal, paroxystic and pseudo-surgical. They were related to the development of visceral or mucosal oedema. The measurement of total complement (and of its fractions) during the acute episode, as well as dynamic complement studies between attacks, represent a simple method for indicating the probable diagnosis. Only estimation of the functional activity of C1 esterase inhibitor provides definite evidence. Familiarity with the clinical and biological characteristics of these acute abdominal episodes makes it possible to avoid repeated, unnecessary operations in these patients. They should be treated medically, under surgical surveillance, since a patient with angioneurotic oedema may have nevertheless a specific lesion, in addition. In addition, the episode may spread at any time, resulting in oedema of the glottis requiring tracheotomy or immediate intubation.