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Solar wastewater treatment (SOWAT) was the subject of experiment between April and September using low cost and mastery equipment: ‘hot-box’ stills. Using a separate still, treated wastewater (i.e. distillate) production was recorded between 2.4 and 6 l m−2 day−1. Treatment efficiency was comparable to the activated sludge treatment process. Biological oxygen demand (BOD) recorded between 86 and 90% of abatement. Raw wastewater turbidity was reduced by 99%, from 181 nephelometric turbidity units (NTU) to 1.6 NTU. The treatment also allowed wastewater disinfection. The inactivation of total coliforms, faecal coliforms and faecal streptococci was estimated at about 99%. SOWAT offers the advantage of grouping, in a separate piece of equipment, three steps of conventional wastewater treatment: (i) the pre-treatment, (ii) the biological and (iii) disinfection treatments. Also, this sustainable treatment does not consume electricity and consequently does not emit greenhouse gases (GHGs). Used on a medium and large scale, SOWAT would be promising for safe wastewater reuse in agriculture. This could secure food production of poor and low-income countries, especially those that are very sunny. Copyright © 2017 John Wiley & Sons, Ltd.

Nowadays, water availability and quality represent a major challenge. In 2050, the United Nations Organization predicts that 44% of the world population will face severe water scarcity. Countries located in sub-humid and semi-arid regions of the world will be especially concerned for this problem, because of their low supply of rainwater. The aim of this study is to suggest the disinfection treatment by irradiation as a complement wastewater treatment to obtain a safe microbial quality of water and permit its reuse. This last is limited to 1.000 CFU/100 ml (i.e. equivalent to 3 log) of fecal coliforms by the Algerian and WHO standards. The experiments were conducted to disinfect wastewater by UVA, UVC, and solar radiation. The UVA and UVC disinfection treatments were carried out using an experimental bench composed of three flat-bottom flasks and three Erlenmeyers of 2 L each. The solar disinfection treatment was experimented using a 30 L-tubular photoreactor in a stationary and a dynamic flow. Th...

Wastewater treatment sector, in Algeria, uses exclusively two processes: the activated sludge applied in the north and the lagooning in the highlands and the south. In the operating balance of the National Sanitation Office (ONA), the activated sludge wastewater treatment plants are characterized by a high electricity consumption which induced high cost and greenhouse gas (GHG) emission. In 2010, about 104.32 million m3 of wastewater was treated. This operation consumed 30,900 MWh of electricity which cost 1.04 million Euros (€) and emitted 18,761 tons of CO2-equivalent. In 2013, the treated wastewater increased by 35.2% and the electricity consumption by 45.8%. To establish an exhaustive diagnostic, this study evaluated the electricity consumed during 2009/2010 in an activated sludge wastewater treatment plant of 70,000 population equivalents (PE) (i.e. Unit of a pollution load produced daily per person, fixed at 60 grams of DBO5, which is used for the sizing of the wastewater treatment plants). ...

Resume Differents melanges bentonite/kieselguhr obtenus par simple melange mecanique et avec differents rapports ont ete prepares et caracterises afin d’etudier leurs proprietes physiques et chimiques. L’evaluation de leurs proprietes catalytiques est conduite dans un premier temps sur des molecules modeles, puis sur une fraction petroliere reelle. Un melange bentonite/kieselguhr 30/70 montre que la competition entre des catalyseurs de craquage a base de platine est encore d’actualite pour des raisons d’efficacite a l’heure des attentions environnementales.

The wastewater reuse, especially for irrigation, requires a safer microbial quality. However, the tertiary treatment is often nonexistent, especially in developing countries where, unfortunately, wastewater treatment needs to be more systematic. Solar water disinfection processes could be appropriate treatments for improving the microbial quality of the wastewater reuse. This study evaluates the effectiveness of both solar photolysis and solar photocatalysis processes in disinfecting secondary-treated wastewater recovered from an activated sludge wastewater treatment plant where the disinfection treatment is not applied. The best parameters of the solar disinfection processes were determined. The experiments were conducted in a bench test composed of 4 flat-bottom flasks with a volume of 2 L each. Then, the disinfection efficiency of both processes was evaluated by a comparative study where 250 Wh/m2 of UV radiation was cumulated. The disinfection efficiency of studied pathogenic (1) total colifor...

Fe-TUD-1 catalysts with Si/Fe ratios of 85, 65 and 45 were prepared via hydrothermal one-pot synthesis. The samples were characterized by XRD, N2 physisorption, UV–vis and XPS spectroscopies, which show the incorporation of Fe3 + in tetrahedral coordination. The ability of these catalysts was tested by examining the conversion of the reaction of methylcyclopentane (MCP) with hydrogen at atmospheric pressure and temperatures between 200 and 400 °C. The active sites, tetrahedrally coordinated Fe and isolated atomic Fe sites, were responsible for the endocyclic C C bond rupture between substituted secondary-tertiary carbon atoms, while the small clusters serve as active sites for the successive C C bond rupture.

In Algeria, the activated sludge processes and the aerated lagoons and are mainly applied to treat wastewater. Worldwide, these treatment processes are recognized for their high electricity consumption and significant sewage sludge production. So, to reduce the electricity consumption, the management of the wastewater treatment plants had integrated the sewage sludge electricity generation. Recently, the sludge conditioning by solar energy is also widely applied.

A groupcontribution method was developed to predict critical tempertaures, pressures and volumes of hydrocarbon compounds. The method was tested with satisfactory accuracy. The absolute average deviations obtained between experimental and calculated values are 0.36%, 4.6% and 1.7% respectively for critical temperature, critical pressure and critical volume.

Preparation, textural and structural characterizations as well as acid properties of some aluminium, zirconium pillared montmorillonite (from Algerian bentonite) and including alumina or zirconium pillared montmorillonite supported palladium are reported. Heat resistant basal spacings of 1.7 nm, surface areas in the range of 250–300 m 2 /g and micropore volumes of about 0.1 cm 3 /g were obtained. The acid activation of montmorillonite prior pillaring conduces to a resulting material with significantly higher pore volume and acidity. The improvement in acidity is mainly of the Bronsted acid type. The modification of zirconium-pillared montmorillonite with sulfate ions affects the structural properties of the pillared sample but gives a material with strong acid properties and both Lewis and Bronsted acid types are enhanced. It is reported also that textural and structural properties are not affected by the impregnation of a metallic function (1 wt.% Pd loading) but the acid properties changed. The pillared montmorillonite supported palladium has more Bronsted acidity than does the pillared montmorillonite. Decomposition of isopropanol was studied on these systems at low reaction temperature.

The present work is an evaluation of 1 wt.% Pd/sulfated zirconium pillared montmorillonite catalyst in the hydroisomerization reaction of two fractions of light naphtha composed mainly of C 5 and C 6 paraffins (feeds 1 and 2). Catalyst activity test was carried out in a fixed-bed flow reactor at reaction temperature of 300 °C, under atmospheric hydrogen pressure and weight hourly space velocity of 0.825 h −1 . The reaction products showed high isomer and cyclane selectivity. Monobranched and multibranched isomers were formed as well as C5 and C6 cyclane products. After the catalytic reaction, the total amount of benzene and cyclohexane decreased by 30% for the “feed 1” and by 40% for the “feed 2” leading to methylcyclopentane formation in the products. A long-term performance test catalyst for the two light naphtha fractions was also performed and we observed an improving of the research octane number (RON) by 15–17 for, respectively, feeds 1 and 2.

'Une nouvelle methode de contribution de groupes pour l'estimation des tensions superficielles, facteurs acentriques et indices de correlation des hydrocarbures purs a ete etablie. Les deviations absolues moyennes (average absolute deviations, AAD) enregistrees entre les valeurs tabulees et celles calculees sont de 2,5 %, 4,1 % et 1,5 % respectivement pour les tensions superficielles, les facteurs acentriques et les indices de correlation.

In the present work, we propose a new group-contribution method to estimate the boiling point, freezing point and the liquid density at 20°C of hydrocarbons. The method was tested with satisfactory accuracy, and when compared with other group-contribution methods, it reveals better results in terms of average standard deviations.

Stable and active hydroisomerisation catalysts have been prepared by impregnating acid pillared clay minerals with hydrogenation–dehydrogenation functions due to palladium. Contact reactions of hexanes on 1 wt.% Pd/alumina pillared acid-activated montmorillonite and 1 wt.% Pd/sulphated zirconium pillared sodium montmorillonite exhibit much better activities and isomerisation selectivities compared to those obtained on conventional pillared montmorillonite. The sulphated zirconium pillared sodium montmorillonite catalyst is two to three times more active than the other catalysts. The use of C6 cycoalkanes as reactants is a good indicator to quantify and to determine which parameters governs the reaction pathway either, the metal sites or the acid sites located on the support. Thus, it permits us to determine which mechanism will dominate. We propose for the adsorption step an associative mechanism between the hydrocarbon and the adsorbed hydrogen which leads on metal, on acid or on both metal plus acid catalysts to the formation of [CnH2n+3] as intermediate.

The dependence on temperature and acentric factor of the attractive term of the Redlich–Kwong equation of state has been modified. A new alpha function is expressed in a generalized form. The new equation allows a good representation of vapor pressure data of a great variety of compounds, as well as thermodynamic properties such as the enthalpy of vaporization and the entropy of vaporization.