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R Barat

Publications and source records attributed to R Barat.

7 recordsLinked to original sources
PubMed2006

Potential phosphorus recovery in a WWTP with the BCFS process: interactions with the biological process.

The BCFS process was developed to optimize the activity of denitrifying and P-removing bacteria. In this technology in combination with optimal operating conditions for biological nitrogen removal, chemical precipitation of phosphorus is used to ensure compliance with effluent standards regarding phosphorus. This work addresses the potential of the BCFS technology for phosphorus recovery and the interactions with the biological process. The TUD model calibrated for the Hardenberg WWTP was used. Nitrification was the biological process most influenced by the P stripper operation; however, further research is needed into the effect of limiting phosphate concentrations. Phosphate removal in the anaerobic reactor causes a decrease in the sludge poly-P content. The evaluation of the process operation under dynamic conditions showed that the P stripper use for phosphate recovery does not imply complicated control strategies. The use of the BCFS for phosphate recovery implies a change in the design philosophy not only to achieve the effluent requirements but also to maximize the anaerobic phosphate release and thereby recovery.

Anaerobiosis↗
PubMed2006

Calcium effect on enhanced biological phosphorus removal.

The role of calcium (Ca) in enhanced biological phosphorus removal and its possible implications on the metabolic pathway have been studied. The experience has been carried out in an SBR under anaerobic-aerobic conditions for biological phosphorus removal during 8 months. The variations of influent Ca concentration showed a clear influence on the EBPR process, detecting significant changes in Y(PO4). These Y(PO4) variations were not due to influent P/COD ratio, pH, denitrification and calcium phosphate formation. The Y(PO4) has been found to be highly dependent on the Ca concentration, increasing as Ca concentration decreases. The results suggest that high Ca concentrations produce "inert" granules of polyphosphate with Ca as a counterion that are not involved in P release and uptake. Furthermore, microbiological observations confirmed that appreciable changes in PAO and GAO populations were not observed. This behaviour could suggest a change in the bacterial metabolic pathway, with prevailing polyphosphate-accumulating metabolism (PAM) at low influent Ca concentration and glycogen-accumulating metabolism (GAM) at high concentration.

Aerobiosis↗
PubMed2006

A case of trisomy 12 mosaicism with pituitary malformation and polycystic ovary syndrome.

We report the case of a patient (followed from birth to 15 years) presenting with trisomy 12 mosaicism, and focus on the endocrine phenotype associating a pituitary malformation and ovarian abnormalities. We describe the dysmorphic features and their evolution, the growth retardation and ovarian symptoms. Complete growth hormone deficiency was confirmed on auxological data, stimulation test and was related to pituitary stalk interruption, diagnosed by magnetic resonance imaging. Effect of growth hormone treatment was satisfactory resulting in a normal adult height. She also presented premature thelarche associated with right ovarian hypertrophy (4 to 5 fold the volume of the left ovary) which remained constant until 15 years of age. Diagnosis of trisomy 12 mosaicism was made on skin and ovarian karyotypes. The possible relation between these endocine findings and some genes located on chromosome 12 involved in pituitary and ovarian development is discussed.

Abnormalities, Multiple↗
PubMed2005

The role of potassium, magnesium and calcium in the Enhanced Biological Phosphorus Removal treatment plants.

Cations as potassium and magnesium play an important role in maintaining the stability of Enhanced Biological Phosphorus Removal (EBPR) process. In this paper potassium, magnesium and calcium behaviour in EBPR treatment plants has been studied. An ASM2d model extension which takes into account the role of potassium and magnesium in the EBPR process has been developed. Finally, a simulation of the effect on P removal of a shortage of K and Mg was studied. The experimental results showed that K and Mg play an important role in the EBPR process being cotransported with P into and out of bacterial cells. It has been observed that calcium is not involved in P release and uptake. The values of the molar ratios K/P (0.28 mol K mol P(-1)) and Mg/P (0.36 mol Mg mol P(-1)) were obtained accomplishing the charge balance, with different K/Mg mass ratios and without phosphorus precipitation. Model predictions accurately reproduced experimental data. The simulations carried out showed the important effect of the K and Mg influent concentration for P removal efficiency. The results illustrate that the proposed ASM2d model extension must be considered in order to accurately simulate the phosphorus removal process.

Aerobiosis↗
PubMed2004

Use of biological and sedimentation models for designing Peñíscola WWTP.

This paper presents Peñíscola wastewater treatment plant design. Peñíscola is a tourist city in Castellón (Spain), whose population changes significantly between summer and the rest of the year. The design of the biological and settling treatment units has been confirmed by computer model simulations and provided for biological organic matter, nitrogen and phosphorus removal. Two different treatment schemes have been proposed in order to optimize the plant performance during both seasonal operations. During low-load season, the plant will be operated under extended aeration conditions, so further sludge stabilization will not be needed. During high-load season, the plant will be operated under conventional process conditions and excess sludge will be aerobically digested. Since the treated water will be reused for irrigation purposes, biological nutrient removal has been considered in this design. Phosphorus released during aerobic digestion must be removed by chemical precipitation in the supernatant from dewatering process. In this way, deterioration of the enhanced biological phosphorus removal process caused by phosphate recirculation can be avoided. Mathematical models have proven to be very useful to make decisions about plant design and operation, mainly in situations with significant variations in the influent load and flow-rate. Several operation conditions have been simulated to obtain optimum operation criteria for both seasons.

Geologic Sediments↗
PubMed2004

Monitoring pH and electric conductivity in an EBPR sequencing batch reactor.

This paper presents laboratory-scale experimentation carried out to study enhanced biological phosphorus removal. Two anaerobic aerobic (A/O) sequencing batch reactors (SBR) have been operated during more than one year to investigate the information provided by monitoring pH and electric conductivity under stationary and transient conditions. Continuous measurements of these parameters allow detecting the end of anaerobic phosphorus release, of aerobic phosphorus uptake and of initial denitrification, as well as incomplete acetic acid uptake. These results suggest the possibility of using pH and electric conductivity as control parameters to determine the length of both anaerobic and aerobic phases in an A/O SBR. More valuable information provided by monitoring pH and electric conductivity is the relation between the amount of phosphorus released and the conductivity increase observed during the anaerobic stages and which group of bacteria (heterotrophic or polyphosphate accumulating) is carrying out the denitrification process.

Acetic Acid↗