Reducing Pollution of Stabilized Landfill Leachate by Mixing of Coagulants and Flocculants: A Comparative Study

The physico-chemical process of coagulation-flocculation is very efficient and economical for the treatment of leachate. The latter can have considerable impacts on the environment. The leachate from the landfill of the city of Mohammedia is characterized by a high COD content which varies between 2200 and 2700 mg/l, a total Kjeldahl nitrogen concentration varying from 1080 to 1405 mg/l while the ammonium content has a concentration varying between 587 and 1410 mg/l. Organic matter is not readily biodegradable (BOD5/COD: 0.2 to 0.13). Metal concentrations ranged from 0.1 to 4.2 mg/l for Cr, 40 to 5 mg/l for Cd, and 0.3 to 0.8 mg/l for lead. For monitoring the leachate treatment, several coagulants and flocculants were used (FeCl3, Al2(SO4)3, Alginate, cationic flocculants, anionic flocculants). In parallel with the monitoring of the physicochemical parameters we followed the production of the volume of the settled sludge over time. Treatment with all coagulants and flocculants used is pH dependent. Ferric Chloride has been shown to be effective at a pH of 6.5 while for Aluminum Sulfate the optimum pH is 5.3. The results showed that coagulation-flocculation by Ferric Chloride and Aluminum Sulfate is very effective in reducing turbidity. This reduction reaches 95 and 98% respectively for FeCl3 and Al2(SO4)3, while the reduction in COD for the two coagulants is around 60%. Organic flocculants alone do not lead to a significant reduction in turbidity and COD, while their combination with coagulants marks a good reduction in pollution. Hydrated iron hydroxides precipitate more easily than flocs formed by aluminum, resulting in more efficient removal of pollutants than that obtained at lower pH values. The order of introduction strongly influences the coagulation flocculation. The optimal doses of the various coagulants and flocculants chosen for the study vary from one reagent to another. FeCl3 remains the most suitable coagulant to further eliminate organic and metal pollution. The cost associated with the treatment using flocculants remains much higher when the flocculant is used in admixture with a coagulant

Pollution diffuse ou localisée des eaux de la Senne en amont de Tubize (Belgique) par les nutriments

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Pollution diffuse ou localisée des eaux de la Senne en amont de Tubize (Belgique) par les nutriments

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Changes in physico-chemical conditions in Ouesd Sebou, what are the risks?

L'Oued Sebou reçoit une charge importante en éléments en trace métallique liée aux activités artisanales de la ville de Fés, largement piégés dans les sédiments. La mise en service d'une station d'épuration est susceptible de modifier radicalement les conditions physico-chimiques dans cet Oued. La recherche menée a consisté à reproduire en laboratoire cette modification pour évaluer le risque de mobilisation des éléments métalliques piégés. Des phénomènes de solubilisations importants de métaux ont étés mis en évidence, mais également des processus conduisant à leur précipitation dans d'autres phases solides, limitant le risque d'observer des concentrations importantes

Etude de mise en place d’un tri sélectif à l’université de Mohammedia, Maroc

The present research work is a contribution to the decision-making support in the management of domestic and assimilated waste produced by Hassan 2 University in Mohammedia. It supplies the reference data on the composition and the flow of production waste then identifies the various constraints (institutional, legal, financial, technical and/or educational), which limits the implementation of a continuous management and the establishment of a selective collection to the source. Besides, it allows us to determine the sustainable solutions and to propose an approach of development of this service.Therefore, we conducted five days for the collection and sorting of waste generated by the various institutions, which showed that the university is one of the largest producers of waste, (3900 euros are spent for the collection and processing of 113 tons each year). Also, the study exposed that the University household waste contains more than 60.70% of fermentable waste fully recyclable by simple methods, and 30.26% of reusable materials (glass, plastic, paper / cardboard, and metal).Le présent travail de recherche est une contribution d’aide à la décision dans la gestion des déchets ménagers et assimilés produits par l’université Hassan 2 de Mohammedia. Il fournit les données de référence sur la composition et le flux de production desdits déchets et identifie les différentes contraintes (institutionnelles, juridiques, financières, techniques et/ou éducationnelles) qui limitent la mise en place d’une gestion continue et l’instauration d’une collecte sélective à la source. En outre, cela permet de déterminer les solutions durables adéquates et de proposer une approche de développement de ce service.À cet effet, on a procédé durant cinq jours à la collecte et triage des déchets générés par cinq institutions universitaires. Ce travail a montré que l’université est parmi les gros producteurs de déchets, et que 3900 euros sont dépensés pour la collecte et traitement d’environ 113 tonnes produites chaque année. D’autre part, l’étude a permis de montrer que les ordures ménagères de l’université contiennent plus de 60,70 % de déchets fermentescibles entièrement valorisables par des simples procédés, 30,26 % de matériaux valorisables directement par recyclage (verre, plastique, papier / carton, et métal)

Early Forecasting Hydrological and Agricultural Droughts in the Bouregreg Basin Using a Machine Learning Approach

Water supply for drinking and agricultural purposes in semi-arid regions is confronted with severe drought risks, which impact socioeconomic development. However, early forecasting of drought indices is crucial in water resource management to implement mitigation measures against its consequences. In this study, we attempt to develop an integrated approach to forecast the agricultural and hydrological drought in a semi-arid zone to ensure sustainable agropastoral activities at the watershed scale and drinking water supply at the reservoir scale. To that end, we used machine learning algorithms to forecast the annual SPEI and we embedded it into the hydrological drought by implementing a correlation between the reservoir’s annual inflow and the annual SPEI. The results showed that starting from December we can forecast the annual SPEI and so the annual reservoir inflow with an NSE ranges from 0.62 to 0.99 during the validation process. The proposed approach allows the decision makers not only to manage agricultural drought in order to ensure pastoral activities “sustainability at watershed scale” but also to manage hydrological drought at a reservoir scale

Optimization of coagulation-flocculation for landfill leachate treatment: An experimental design approach using response surface methodology

The present work aims to optimize the leachate treatment of the Mohammedia-Benslimane landfill by coagulation-flocculation using the central composite design. The independent variables studied were pH, coagulant dose, flocculant dose, and stirring time. The response variables studied were turbidity, COD, and absorbance at a wavelength of 254 nm. The results showed that the optimal pH was 6.87, the optimal coagulant dose was 7.89 g/L, the optimal flocculant dose was 12 ml/L, and the optimal stirring time was 22.8 min. These optimal conditions provided the best results for the responses studied. Indeed, turbidity was reduced by 90.38%, COD was reduced by 85.50%, and absorbance at a wavelength of 254 nm was decreased by 55.53%. The analysis of variance indicated that the established models were significant and that they are characterized by a good fit (R2 in the order of 0.97, 0.96, and 0.94 for turbidity, COD, and UV254, respectively). In conclusion, optimizing landfill leachate treatment by flocculation coagulation using the central composite design within response surface methodology yielded promising results for reducing turbidity, COD, and absorbance at a wavelength of 254 nm. This method can be used to optimize landfill leachate treatment in other settings

Quality assessment of surface and sediment pore waters and their behaviours using WQI index and geostatistics approaches. Case study: El Malleh dam reservoir, Morocco

The El Malleh dam reservoir is an important water source for irrigation and protection against flooding in the Mohammedia region of the kingdom of Morocco. However, flash floods threaten the sustainability of the reservoir by sedimentation and water quality contamination. Pollution sources could arise from sediment mobilization in the reservoir bottom, or carry by water flow from the watershed to the dam reservoir. The current study evaluates the surface and pore water quality, focuses on their behaviour based on the laboratory results, the Water Quality Index (WQI) and statistical analysis. The results show that the concentration of nutrients was not significant. The concentrations of major elements differ from surface waters to pore waters and from one parameter to another. For instance, the Cl concentration in the surface water ranged from 852 mg L−1 to 1065 mg L−1, and from 10 mg L−1 to 7810 mg L−1 for pore water. Besides that, the calculation of WQI indicated that the sediment pore water quality was unsuitable, and the surface waters quality was in a poor and very poor category

Assessment of Groundwater Quality in the Berrechid Aquifer, Central Morocco, Using Multivariate Statistics and Water Quality Indices

Groundwater salinity is a serious problem for water quality in the irrigated parts of arid and semi-arid regions, especially in the aquifers of Berrechid, Morocco. This study used a variety of techniques, including the Water Quality Index (WQI) and World Health Organization (WHO) recommended limits, Principal Component Analysis (PCA), and Geographic Information System (GIS) to evaluate the quality of the groundwater for irrigation and domestic use in the Berrechid region in central Morocco. The goal of this study was to evaluate the quality of groundwater for irrigation and human consumption. The collection and analysis of twenty-two samples for ions was carried out, including, EC, Cl-, NO3-, NH4+, NO2-, Ca2+, Mg2+, pH, SO42-, Na+, K+, CO3-, HCO3-, and Mn2+. The Water Quality Index (WQI) was used to classify the water quality vis: excellent, good, average, poor and very poor. The research area's water quality index (WQI) ranges from 43.89 to 439.34, with around 40.90% of samples having excellent water quality, 45.45% having poor water quality, 4.54% showing extremely bad water quality, and 9.09% having unsuitable quality for human consumption. The principal component analysis reveals that the average concentration of cations in groundwater was Na+> Mg2+> Ca2+> K+> Mn2+> NH4+, whereas the concentration of anions was Cl-> HCO3-> SO42-> NO3-> NO2-> CO32-. The correlation matrix was created and analyzed to determine its significance in groundwater quality assessment. The primary sources of pollution are household waste, exposed septic tanks, landfill leachate, and excessive fertilizer usage in agriculture and industrial operations. The current analysis demonstrates that the deteriorating groundwater quality in the region needs pre-consumption treatment and contamination risk prevention

Risk factors of acute renal failure in patients with protective ileostomy after rectal cancer surgery

Abstract Background Despite the potential benefits of protective ileostomy in rectal surgery, diverting loop ileostomy construction is not free of specific medical consequences implying unplanned hospital readmissions. The most common reason for readmission in these patients is a dehydration with a prevalence of acute renal failure (ARF) of 20%. The objective of this study was to establish the predictive factors of ARF in patients with protective ileostomy after surgery for rectal cancer from a bicentric study. Methods we conducted a bicentric retrospective cohort study to identify the risk factor of ARF. This study was carried out on 277 patients operated for rectal cancer with necessity of a protective ileostomy during the study period. ARF was measured at any endpoint between ileostomy creation and reversal. Multiple logistic regressions were performed to identify independent risk factors. Results A total of 277 patients were included, and 18% (n = 50) were readmitted for ARF. In multivariate logistic regression, increased age (OR 1.02, p = 0.01), Psychiatric diseases (OR 4.33, p = 0.014), Angiotensin II receptor blockers (OR 5.15, p < 0.001) and the ASA score ≥ 3 (OR 9.5, p < 0.001) were significantly associated with ARF. Conclusion Acute renal failure is a prevalent and significant event in the postoperative course of ileostomy patients. Patients at risk should be risk stratified before discharge and targeted for intensive preventive measures