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The study presents the level of air pollution by eleven polluting gases measured during six months in Draria (Algiers), a location influenced by the traffic emissions. The sampling of this pollution was done by a 24 hours and 7 days a week sampling station that we ourselves built based on an Arduino programmable board and a series of MQ-type sensors. During this study we have shown the interest of using such type of programmation in order to have an instantaneous evaluation of the air quality to allow making decisions about this pollution and take preventive measures and actions. The rate of benzene is on average lower than the international norms of 10µg/m³. The exploitation of the results has permitted to put into evidence the daily, weekly and monthly distribution of these polluting gases. The study of the compassrose and pollution rose has permitted to surround the most affected zones by the pollution. Various interrelationships between these polluting gases that have been established show that the benzene is a good indicator of the pollution by cars. [ABSTRACT FROM AUTHOR]

Biogas and methane yields, under different operating conditions, and chemical oxygen demand (COD) removal efficiencies were investigated in a mesophilic batch reactor (38°C) for the mixtures of dairy manure (DM) and cheese whey (CW) at 7% or 9% of total solids (TS). Biogas production of 401 L/kg of volatile solids (VS) and methane yield of 215.3 L/kg of VS was obtained after an operating time of 100 days for the mixture containing 7% of TS. A maximum increase in biogas production of 92% compared to the start-up phase was achieved with a volume of 3.6 L of biogas on day 55. The corresponding methane yield reached a maximum value of 80%. The removal efficiency of the COD was 73%. Results show that anaerobic co-digestion of cheese whey and dairy manure with 7% of TS gives better results compared to 9% of TS. [ABSTRACT FROM AUTHOR]

The highest biodegradation efficiency of petroleum hydrocarbons 50% was observed for a C:N:P ratio of 100:10:1 while it reached 28% for a C:N:P ratio of 60:2:1 and moisture of 15% for both of them. For a higher N:P molar ratio greater than or equal to 10, the recorded depletion and consequently biodegradation ratios decreased significantly. The monitoring of temporal evolution of the biomass and C:N:P ratios highlighted that the N: P molar ratio may be a factor limiting which concurs with several studies. In addition to the ability of the indigenous microbial population to oxide petroleum hydrocarbons to a large extent, the results highlighted the remediation feasibility in solid-phase bioreactors. [ABSTRACT FROM AUTHOR]

In the present work, solar energy conversion into electricity was evidenced by the Chlorophytum comosum-Microbial Fuel Cell (Chlorophytum-MFC). Our Chlorophytum-MFC had produced an Open Circuit Voltage (OCV) up to 1211 mV, without adding any nutrient or membrane. Plant biomass heigh and anodic bacterial number were proportional to OCV, current Icmax, and power Pmax, and were inversely proportional to the internal resistance Rint thus: 42 cm, 110.103 U/ml, 900 mV, 0.037 mA, 744 µW/m2 and 17 KΩ, respectively, at the 191th day of experiment. We had also highlighted that Chlorophytum-MFC had behaved like a typical fuel cell via polarization and power curves. Also, we had studied the photosynthesis effect on electrical energy production by measuring voltage fluctuation during three successive days and nights. The solar and temperatures influences were also highlighted by comparing weather software data to the measured Open Voltage. The electrogenous activity was clearly proportional to soil and climate temperature as well as to sunlight intensity. The obtained results showed that developing Chlorophytum-MFC could provide significant prospects for p-MFC and bioenergy recovery. [ABSTRACT FROM AUTHOR]

Chitin recovery by lactic acid fermentation was considered. It was previously shown that the use of glucose led to 61% of demineralization and 42% of deproteinization; while and unlike glucose, the inoculation of L. helveticus in date waste (200 g L-1 reducing sugars) led to a simultaneous demineralization and deproteinization of shrimp shells, 83 and 61 %, respectively. The purity of end-products were characterized by infrared (FTIR), X-ray diffraction and X-ray fluorescence. Analysis of the chemical composition of fermentation end-product by X-ray fluorescence showed that residual minerals are in trace except CaO and P2O5. The infrared spectra and the X-ray diffractograms of both samples compared to those of pure chitin showed a strong similarity. FTIR of fermented shells showed the appearance of characteristic peaks of a-chitin and the disappearance of calcite peaks. In addition and especially for the shells fermented using L. helveticus cultivated on date waste, a similarity with those of pure chitin should be noted. These results confirmed the efficiency of biological chitin recovery, and that a synthetic carbon source (glucose) can be replaced by a natural one, date waste, allowing a valorization of this latter. The relevance of subsequent works to improve yields of demineralization and deproteinization was therefore confirmed. [ABSTRACT FROM AUTHOR]

The aim of this work is to study and evaluate in situ, the Artemisia herba alba responses to hexavalent chromium stress in the arid and semi-arid steppe Algerian soil. This metallic pollutant was selected to its high toxicity and to its great release from several industrial and agricultural activities emissions in the area of the study region. Artemisia herba alba is a medicinal plant but also a forage species widely used in pasture. It has dominated then adapted to the arid and semi-arid climate of Algerian steppe region, due principally to their morphological and physiological characteristics. To establish this work, A. herba alba species were selected in the Algerian steppe region, and their soils were treated weekly with K2CrO4 solution for about three months. Chromium concentrations were determined in the soil and in the different plants' parts to verify its absorption and translocation with and without pollution simulation. This study demonstrated that A. herba alba has a strong resistance to high concentrations of hexavalent chromium. An increase in chromium concentrations at the different parts of plant's has been noticed, without affecting its growth and vegetative development. The results of physiological and elementary analysis indicated that chromium was absorbed by A. herba alba. Cr (VI) accumulation in plant increase when they are increasing in soil. Translocation factor results indicated that Cr (VI) was mainly accumulated by A. herba alba roots. Particle size analysis showed that the soil is poor in organic substances and mostly sandy loams with 79.77% of sand and 9.76% of clay minerals. [ABSTRACT FROM AUTHOR]

The main purpose of this work is to study the ability of the enzymatic reaction. For the performance of the experiment, it is desirable to control variations so that they are minimized to the maximum extend and therefore an optimum operating point can be maintained. To achieve this target, the central composite design takes into account all interaction effects that may be useful for creating a mathematical model in agreement with the validity criteria. The model showed to be more suitable for the saccharification experiments in batch mode than in continuous mode. In batch mode, a correlation coefficient close to unity ( R2 = .98) was obtained. Moreover, the resulting mathematical model was satisfactory in accordance with the validation criteria. For continuous mode, the coefficient value obtained was R2 = .83 indicating that the model to study the ability of the enzymatic reaction was inferior than the batch mode conditions of the analysis. Practical applications The ability of the enzymatic reaction to maintain its performance at small experimental condition variations was studied., The central composite design conformed to criterion validity., A correlation coefficient close to unity ( R2 = .98) was obtained. [ABSTRACT FROM AUTHOR]