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P Jaouen

Publications and source records attributed to P Jaouen.

8 recordsLinked to original sources
PubMed2003

Coupling ultrafiltration with an activated carbon cloth for the treatment of highly coloured wastewaters: a techno-economic study.

This work investigates the coupling of a membrane technique, ultrafiltration, with a recent adsorbent, activated carbon cloth for the treatment of industrial highly coloured wastewaters. A first experimental part shows the high treatment ability of this process for fountain-pen inks effluents arising from the rinsing of vats in which inks were produced. Whereas ultrafiltration enables more than 97% of colour removal, COD and DOC are not completely retained and a residual value of 1,700 mg l(-1) of DOC is obtained in the permeate. The second step of the process, activated carbon cloth, allows residual organic matter to be removed and a complete discolouring of the permeate. Adsorption capacities of COD and DOC are high, equal to 500 and 250 mg g(-1) respectively. Furthermore, this adsorbent induces a complete removal of glycol compounds (acting as antifreeze) which were not retined by a nanofiltration technique. A second part is an evaluation of the economic feasibility of such an integrated process. Only direct costs are considered at this phase of the study, and are divided into fixed costs (equipment, depreciation, maintenance), variable costs (electricity and consumption) and labour costs. The technical-economic study is carried out for two configurations: a low capacity unit (the UF membrane area is 2.4 m2) and an industrial capacity unit (with a 100 m2 UF membrane). Costs per treated m3 are respectively 111 and 32 euros, with costs partitioning which are dependent on the unit capacity.

Absorption↗
PubMed2002

The role of exopolysaccharides in fouling phenomenon during ultrafiltration of microalgae (Chlorellasp. and Porphyridium purpureum): advantage of a swirling decaying flow.

Ultrafiltration of two microalgae species, Chorellasp. and Porphyridium purpureum, has been performed in two filtration units of different configurations: a module generating a classical tangential-plane flow and another one inducing a swirling decaying flow. The swirling motion is generated by a unique tangential inlet at the bottom of an annulus. Permeation flux obtained in each ultrafiltration unit depends on the filtered species, and specific deposits are associated to each species and module. Enhancement in permeation flux in the swirling configuration compared with that obtained in the plane unit can reach 40% during the ultrafiltration of Porphyridium purpureum and is negligible for the suspensions of Chlorella sp. The experimental data revealed the significant role of the soluble compounds in the medium culture in terms of flux limitation. It seems that the soluble products and their interactions with the microalgal cells are strongly involved in the fouling mechanism.

Journal Article↗
PubMed2001

Stabilized landfill leachate treatment by combined physicochemical-nanofiltration processes.

Landfill leachate is a complex wastewater which the composition and concentration of contaminants are influenced by the type of waste deposited and the age of landfill. In the last years, several processes or process combinations were developed and tested to reach requirements for the discharge of leachate. Among the new processes, membrane processes are considered as promising: reverse osmosis is one of the most widely used treatment in the Northwestern European countries and nanofiltration is gained in popularity during the last 5 years. Successful application of membrane technology for the treatment of landfill leachates, requires efficient control of membrane fouling. Two organic membranes of nanofiltration were used for pilot-scale testing. Leachates were subject to several pretreatments (pH modification, prefiltration and coagulation with FeCl3) to remove potential foulants including dissolved organic and inorganic substances, colloidal and suspended particles. These pretreatments do not enhance the performances (retention and permeation flux) of membranes because the pH range and the presence of Fe3+ ions contribute greatly to change the characteristics of organic matter and the surface charges of membranes. However, the results show that nanofiltration is sufficient to eliminate refractory COD, the permeates have a COD lower than the requirements for discharge.

Adsorption↗
PubMed1999

Effects of shear on two microalgae species. Contribution of pumps and valves in tangential flow filtration systems.

The circulation of microorganisms in tangential flow filtration systems induces perturbations and then the damage of brittle cells. This work is focused on the shearing of two marine microalgae species (Skeletonema costatum and Haslea ostrearia), both largely cultivated in western France (Région des Pays de la Loire). We have studied the effects of the circulation of these cells in pumps and valves. For the pumps, it is shown that shear stress is due to the type of pump, but that mechanical shear can have different effects even if the pumps and the number or frequency of loops are the same. Hence other intrinsic parameters of the pump must be taken into account: rotating velocity (omega), capacity (Cyl = output flow/rotating velocity) or internal leakage (K = inner volume/capacity). In throttling valves, the aim is to correlate the effect of shear to a parameter related to the inner geometry of the valve and to operating conditions. An overall parameter is then evaluated: the pressure drop coefficient Kv which integrates both the type of valve (ball valve or globe valve type) and its opening degree. Kv is derived from the relationship DeltaH = Kvu2/2g. The modelling of the shear effects is now conceivable: basic descriptive data used so far (type of pump, geometry or opening degree of the valve, etc.) being completed and partially substituted by quantitative parameters (rotating velocity, capacity, or internal leakage for the pumps, Kv coefficient for the valves).

Biomass↗
PubMedDate not supplied

[Screening of deafness at birth (author's transl)].

The authors studied different parameters of the hearing test proposed to detect deafness among new-borns. These parameters belong to the technic of the test itself (intensity of stimulus, repetition of the test five minutes later, during the day and the following days, characters of the reactions) and to the infant (gestational age birth weight age, disease). They found that the noise in the resuscitation room and in the usual incubators is high and perhaps injurious. Following their own experience and the results published in France and abroad, they think that the test is difficult and cannot be generalised for the moment to all newborns.

Deafness↗
PubMedDate not supplied

[Noise in incubators].

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Evaluation Studies as Topic↗