Use of Continuous Aeration Respirometry Method for the Prediction of Slightly Saline Waste Water Biodegradation

AbstractThe microorganisms growth kinetics is determined by the physical and chemical characteristics of the environment in which they find themselves and multiply; It is therefore essential to understand the effect of these environmental factors to master cell multiplication and hence the pollution biodegradation. Respirometry has been used in recent years in the laboratory as an assessment technique of microbial activity and an effect detector of the contamination (presence of toxic, stress, increase or decrease in pH, temperature variation .) on bacterial respiration and hence on the biological waste water treatment plant. In this study respirometry has been used as a relatively quick and efficient means to detect the effect of the presence of a salt of up to 5g/l (low salt stress) on the degradation of carbon and nitrogen pollution and on bacterial floc aggregation

Sorption Study of a Basic Dye “Gentian Violet” from Aqueous Solutions Using Activated Bentonite

AbstractVarious industries like textiles, papers, food, plastics, leather, etc are great water and organic colorant users. Hence, the resulting effluents could be an important source of environmental problems, since they may contain stable and non biodegradable contaminants, like organic dyes. The treatment of which is the main scope of the present study. Different ways of dye removal from these effluents do exist, such as flotation, reverse osmosis, chemical flocculation and adsorption etc. Adsorption is used in this work for the removal of a particular basic dye, known as Gentian violet (GV) from an aqueous solution, by means of a natural clay material. The influence of various key parameters like contact time, temperature, ionic strength, etc. on the adsorbed amount of the dye was investigated, for batch conditions. A kinetic study was also carried out, the obtained experimental results were tested against the pseudo first order and the pseudo second order equations. An analysis of the obtained equilibrium data showed that the dye adsorption is best described by the Langmuir model. The obtained results showed that temperature did enhance the Gentian violet dye retention process onto the considered bentonite whereas the obtained thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. The simultaneous presence of methylene blue, which is another colorant compound, with the Gentian violet was also considered. The clay materials showed a better affinity for the first one i e. methylene blue. In conclusion and according to the obtained results, the clay material may be recommended as an industrial adsorbent for the treatment of effluents containing Gentian violet (GV)

Structure spatiale et statut dynamique dans une communauté végétale: cas d'une cocciféraie dunaire (Annaba, Algérie).

The quantity and the presence of thirty-six species are registred on a 4 kms transect in a dunary bush of the Kermes Oak (Annaba Algeria) . The spatial patterns are described and interpreted according to the series of degradation of the Kermes Oak and of the Oleo-Lentisc. The vegetal carpet appears to be structured by a superposition of scales of dynamic stages and mosaics or superpositions of ecologie associations . The article emphasizes the part that can be played by the description of the vegetal patterns in the interpretation of the contents of a floristic list.L'abondance et la présence de trente-six espèces sont enregistrées sur un transect de 4 km dans une cocciféraie dunaire (Annaba Algérie). Les structures spatiales sont décrites et interprétées en fonction des séries de dégradation du Chêne Kermès et de l'Oléo-Lentisque. Le tapis végétal apparaît structuré par une superposition d’ écailles de stades dynamiques et de mosaïques ou de superpositions de groupes écologiques. L'article souligne le rôle que peut jouer la description des structures végétales dans l'interprétation du contenu d'une liste floristique.Belair G. De, Chessel Daniel, Bencheikh-Lehocine M. Structure spatiale et statut dynamique dans une communauté végétale: cas d'une cocciféraie dunaire (Annaba, Algérie).. In: Ecologia mediterranea, tome 10 n°1-2, 1984. pp. 261-270

Effect of Chemical Coagulation Pretreatment on Anaerobic Digestion of Tannery Wastewater

Tanning factory is globally considered to be one of the most resource consuming and pollutants producing industries because it requires, for processing leather, large amounts of fresh water, chemical reagents, and energy, and in addition produces wastes, liquid as well solid, rich in organic matter and heavy metals (e.g., chromium). Such characteristics of tannery wastes make their biological treatment promising as well as challenging. This study deals with the effect of coagulation process as a pretreatment method on real tannery wastewater prior to anaerobic digestion (AD), with the aim of removing chromium and thus limiting its inhibitory effect on biological process. Different concentrations (100, 200, 400, 600, 800, and 1,000 mg/L) of the coagulant FeCl3 were tested, at pH 7.5, with an initial total chromium concentration of 150 mg/L. The efficiency of metal removal was in the range of 0.44-29.38%. Simultaneously, the chemical oxygen demand was reduced by 0.86-28.80%, with the detrimental effect of lowering the total biogas production potential from tannery wastewater. Nevertheless, coagulation pretreatment enhanced the AD process of tannery wastewater, resulting in an increase of the cumulative biogas production by 10% and in a reduction of the digestion time by approximately 25%, in comparison with untreated wastewater. After 37 days of incubation, the maximum specific cumulated volume of biogas produced from the wastewater pretreated with 800 mg/L of FeCl3 was 837 mL/g total volatile solids added with approximately 84% of methane

Application of the IWA ADM1 model to simulate anaerobic co-digestionof organic waste with waste activated sludge in mesophilic condition

Anaerobic digestion model no. 1 model of international water association was applied to a full scale anaerobic co-digestion process for the treatment of the organic fraction of municipal solid wastes along with activated sludge wastes originating from a municipal wastewater treatment plant. This operation was carried out in a digester of 2000 m3 in volume. It is operates at an average hydraulic retention time of 26.9 days with an average organic loading rate of 1.01 kg TVS/m3 day, at a temperature of 37 \ub0C with an average gas production rate of 0.296 m3/m3 day. The aim of the present study is to compare the results obtained from the simulation with the experimental values. The simulated results showed a good fit for pH, methane and carbon dioxide percentages, biogas volume, chemical oxygen demand, total volatile fatty acids, inorganic nitrogen and inorganic carbon

Leachate effluent COD removal using electrocoagulation A response surface methodology (RSM) optimization and modelling

International audienceThis study focused on electrocoagulation treatment of leachate effluent using aluminum electrodes in a discontinuous system, the modeling and optimization of which were carried out using the response surface methodology (RSM) basing on the central composite design (CCD). Moreover, individual and interaction effects of principal independent factors (current density (X1), initial pH (X2), electrolysis time (X3), and distance between electrodes (X4)), on chemical oxygen demand (COD) removal efficiency response, were investigated. The obtained results were in good agreement with the predicted ones with correlation factors R2 Dec = 0.94 and R2 Ajusted = 0.88. At the optimal conditions, maximal removal efficiency was achieved for values of chemical oxygen demand (COD), total organic carbon, total nitrogen, and turbidity of 79.8%, 78%, 45.4%, and 99.9%, respectively. The quite good agreement between the experimental values and the predicted results confirms the reliability of the RSM approach in the modeling and optimizing of the leachate treatment using an electrocoagulation process. © 2018 Desalination Publications. All rights reserved