Four techniques (microscope sizing, calculation from settling velocities. image and laser analysis) are available nowadays for determining the particle size distribution of upflow anaerobic sludge blanket (UASB) reactor sludge. These techniques present however the disadvantage of being either tedious, imprecise or expensive and hardly applicable in full scale treatment plants. There was then the need for a simple and low cost technique. In this study, a granulometry procedure based on manual humïhsievïng was evaluated. It was shown that no solid loss occured during the screening and that the particle size profiles were reproducible when performed with sludge samples of 5. 10.25 and 150 ml. but not I ml. Only the results between 10 and 25 ml were however fully identical. It was shown also that the sieving could be performed on sludge samples stored for as long as 50 days at refrigerator temperature and that tap water could be use for [he wash' and backwash operations without any impact ori the particle size profile. The granulometry obtained by image analysis was not comparable to that given by sieving. Ne\,ertheless. no evidence of granule erosion could be found. In any case, the technique allowed us to follow [he evolution of sludge granulometry perfectly over lime. As a consequence. the manual humid sieving appears to be an adequate technique for determining the granule size distribution of UASB sludges. Q 1999 Published by Elsevier Science Lid on behalf of the IAWQ. All rights reserved.

The adsorption of textile dyes such as Direct Red 75 and Direct Red 80 onto calcined bone was studied for their removal from aqueous solutions. The adsorption of Direct Red 75 and Direct Red 80 occurred by studying the effects of adsorbent amount, dye concentration, contact time, pH media and temperature. The adsorption rate data were analyzed using the intraparticle diffusion model, pseudo first order and the pseudo second order kinetic models to determine adsorption rate constants. The isotherms of adsorption data were analyzed by various adsorption isotherm models such as Langmuir, Freundlich and Tempkin. All results found concluded that calcined bone could be effectively employed as an effective new low cost adsorbent for the removal of textile dyes from aqueous solutions.

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-The aim of the present investigation is to compare the chemical characterization of four monovarietal virgin olive oils obtained from fruits of olive trees grown in Morocco (Picholine, Picual, Arebiquine, Koroneiki) with kinetic parameters of oxidation based on Rancimat measurements and finally to assess the oxidative stabilities. The examined oils from different varieties showed a chemical composition within the regulatory limits. Rancimat measurements of induction times were carried out under isothermal conditions in an air atmosphere at temperatures from 373 to 423 K with intervals of 10 K. Using the Arrhenius-type correlation between the inverse induction times and the absolute temperature of the measurements, E a , Z, and k values for oil oxidation under Rancimat conditions were calculated. The primary kinetic parameters derived from this method were qualitatively consistent and help to evaluate the oxidative stabilities of oils at increased temperatures.