This study presents an evaluation of diatomite as a low cost adsorbent for Pb (II) removal from aqueous solutions under various conditions. The results demonstrate that adsorption of Pb (II) is strongly dependent on the pH of the solution. The effect of pH on adsorption of Pb (II) on diatomite was studied by varying pH from 2 to 12 at 20 oC. In the pH range of 2.0-4.0, the percentage of Pb (II) adsorbed increases slightly as the pH increases. At pH>4, the percentage of Pb (II) adsorbed decreases with increasing pH because hydrolysis and precipitation begin to play an important role in the sorption of Pb (II). At pH 4, the maximum adsorption capacity of diatomite was found to be 26 mg/g. The adsorption isotherms of Pb (II) on diatomite can be described well by the Freundlich model. The regression equation coefficients were calculated and the data fitted to a second-order kinetic equation for removal of Pb (II) ions. The high adsorption capacity of diatomite makes it a suitable low-cost material for the removal of Pb (II) from aqueous solutions.
Civilization has been experiencing frequent changes in the climate due to global warming.
The developing nations are worst affected as they are largely dependent on the local precipitation and soil moisture for their livelihood generations. The changing climate with extended summer, change in the rainfall pattern (intensity and duration) and variations of onset and departure of seasons are directly impacting the cultivation, status of natural vegetation, surface and sub-surface water, and other natural resources in a watershed area. Among the various efforts, watershed development approach, in which intervention is more site-specific in nature and can address the local requirements, is found to be more effective at micro levels. The vulnerability of climatic changes is mainly due to water stress, degradation of natural vegetations, degradation in the health and hygiene conditions, and poor information communication technology. The present article highlights these issues, impact of watershed development project in the Himalayan region and identifying the adaptation mechanism through watershed programs. A site specific action, research methods including primary and secondary data collections, GIS, remote sensing and statistical techniques were used. The study on the Jusho Bakro micro-watershed treated by TERI under the program DROP has been found to be effective in drawing possible adapting mechanism to withstand the changing climate and its severity on the natural resources and the livelihood of the community.
Biosorption is an emerging technique for water treatment utilizing abundantly available biomaterials.The potential feasibility of magnetic peanut hulls particle for removal of cationic dye (methylene blue) from aqueous solution was investigated. The effects of various experimental parameters were examined and optimal experimental conditions were decided. Characterization of biosorbent was carried out by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analyzer. FT-IR analysis showedthe presence of hydroxyl, carbonyl and carboxyl groups which can involve in the biosorption process. The results in this study indicated that peanut hull was an attractive candidate for removing cationic dyes from dye wastewater. Different kinetic and equilibrium models were applied to the experimental data. Tempkin model was the most fitted isotherm as R2= 0.963. While the resulting data for the different parameters studied was suitable to be pseudo second order.
This study was conducted to investigate the effect of praestol, as a coagulant-aid, to improve coagulation-flocculation process in the removal of disperse red 60 from aqueous solutions. The effect of various parameters including coagulants dose (10-1000 mg l-1), praestol dose (0-1000 mg l-1), solution pH (3-11), initial dye concentration (100-500 mg l-1), flocculation speed (30-60 rpm), flocculation time (15-30 min), settling time (5-60 min) and ionic strength (0-6 mg l-1) was evaluated on the dye removal. The dye removal efficiency was substantially increased by using praestol in the concentration of 80 mg l-1 and 400 mg l-1 for coagulation with alum and polyaluminum chloride (PACl), respectively. The maximum dye removal by alum coupled with praestol (Al-P) and PACl coupled with praestol (PA-P) was found to be 97.8% and 98.7%, respectively that were occurred at pH 7. The results showed that the application of PA-P or Al-P can be effectively used to remove disperse red 60 (DR 60) in aqueous solutions.
In this paper, ethylene glycol wastewater (EGW) treatment was studied by using one anaerobic polyvinyl alcohol (PVA) gel beads based biofilm reactor. Enhanced by PVA-gel beads based biofilm, organic loading rate (OLR) about 11 g COD l-1 d-1 was achieved at the end of this study. Black PVA-gel beads with an average settling velocity 322 m h-1 (9 cm s-1) and 0.24g VSS g-1 PVA gel mainly composed of Methanosarcina spp. were got, while no natural granules were found in this experiment. The COD removal efficiency in this study could reach a high value about 95%. Most COD removal was contributed by the PVA-gel beads based biofilm. It could be concluded that the PVA-gel beads based biofilm reactor is appropriate for EGW treatment.
The need for efficient and economical use of the world’s water requires the implimentation of modern methods to make decisions about water management. This inspired the principal philosophy of the management study of the Hellenic part of the Strymonas River catchment (6400 km2). An important issue in such studies is to simulate the hydrology of the river catchment. The state-of-the-art couple model MIKE SHE/MIKE 11 is a powerful, physically-based distributed hydrological and hydraulic simulation tool. To determine water balance, hydrology and hydraulic functions in the river catchment a water level monitoring network was established. Data collection was performed during 2004 and 2006. The philosophy and main assumptions that underlie the current work are described. Furthermore, the effectiveness of the irrigation networks in the Strymonas River basin is checked. Finally, the negative effect of the current irrigation network on the lake’s water level fluctuation is pointed out and simple but effective solutions are proposed.
In this study, the seasonal variation on drainage water quality of Çarşamba Plain, Turkey has been evaluated from June 2012 to January 2013 and determined the suitability of water for irrigation purpose. Water samples collected from 21 drainage canals during July and January were analysed for 12 water quality parameters including physico-chemical analyses. Piper diagram and United States Salinity Laboratory (USSL) diagram were prepared to investigate water quality. Sodium Adsorption Ratio (SAR), Percent Sodium (Na%), Residual Sodium Carbonate (RSC), Kelly Index (KI), Magnesium Ratio (MR), Langelier Saturation Index (LSI), Permeability Index (PI) and Potential Salinity (PS) were also used to assess suitability of waters for irrigation.
In July 2012, EC values varied between 0.45-4.23 dS/m. Waters of 7 drainage canals were found to be unsuitable for irrigation with regard to KI, 3 canals with regard to RSC and 13 canals with regard to MR. According to USSL diagram, 24% of drainage waters were classified in C2S1, 62% in C3S1, 4% in C4S2 and 10% in C4S4 class. In January 2013, EC values varied between 0.16-1.44 dS/m. Waters of one canal was found to be unsuitable for irrigation with regard to KI and 8 canals with regard to MR values.
The result obtained from paired sample t-test revealed that the drainage canal water quality varies significantly between June 2012 and January 2013 except for Ca, Mg and SO4. According to analysed parameters, some of the drainage canals were considered unsuitable for irrigation in june 2012. The water properties of all canals were observed as unsuitable to be used for drip irrigation in accordance to the LSI index. Classification of drainage water by USSL diagrams indicates a low sodium and high salinity hazard.
In this work, the effectiveness of electro-Fenton process degradation of sodium dodecylbenzene sulfonate (SDBS) anionic surfactant in acidic wastewater was investigated. Taguchi method was applied to study the effect of process parameters on oxidation of SDBS pollutant. An orthogonal array L9 experimental design that allows investigating the simultaneous variation of current density, initial acidity of wastewater, and the initial SDBS concentration was employed to evaluate the effect of these parameters as control factors. Taguchi experimental design in dynamic sense was carried out with electrolysis time chosen as signal factor. Each experiment comprises the addition of peroxide (170 mg l-1; 0.005M) as a fixed component of Fenton's reagent and NaCl (1.5 mg l-1) as supportive electrolyte. The results revealed that SDBS degradation in acidic aqueous phase, can reached high values by the electro-Fenton process. The estimation of linear model coefficients for S/N (signal to noise) ratios expression has acceptable fitness of 93.5% with the selected control and signal factors. Main effects and analysis of variance (ANOVA) indicates that the current density and the acidity have high impact on electro-Fenton degradation of SDBS process with high sum of squares and low p-values that signifies the 0.05 α-level. Moreover, Taguchi optimal analysis indicates that high S/N ratio of response can be obtained with 0.3 mA cm-2 current density,
pH=2 initial acidity of wastewater, and 10 mg l-1 initial SDBS surfactant concentration.
Jarosite waste released from the zinc production process during the hydrometallurgical leaching of concentrates in Trepça lead-zinc smelter, Kosovo has serious environmental problems due to the presence of toxic metals such as Pb, Cd, Zn, As etc. Its disposal in open tailing damps has become a major environmental concern with contamination effects of water, soil and vegetation. The current paper considers the jarosite waste in Mitrovica Industrial Park, Kosovo in order to evaluate the characteristics of jarosite waste, identify the potential environmental impacts and understand its potential for recycling or utilization as a challenge for the development of a positive “green” image environmental protection and sustainable hazard waste management in future. XRD, SEM and TG/DTA were used to analyze the characterization features of jarosite. The results give an initial understanding of the jarosite strengths and application potentials as recycled material. The potential application provides useful contribution towards proper environmental, social and economic management development.
Environmental pollution caused by heavy metals from different industrial activities constitutes a serious risk for the environment. Soils contaminated with metals, such as Cu, Cd and Zn, are often subjected to physical or chemical remediation procedures to purify soils from these metals. Typical chelating agents used for metal extraction and soil washing generally include ethylene-diaminetetraacetic acid nitrilotriacetic acid, diethylenetriaminepentaacetic acid and citric acid. The subject study evaluating the potential of soil washing methods using EDTA and ferric chloride on two types of soils (coarse grained, fine grained). The effects of operating parameters, such as liquid/solid ratio, soil washing chemicals and washing time were examined. In extraction procedure of Cd (266 mg kg-1), Cu (194 mg kg-1) and Zn (497 mg kg-1) from contaminated coarse grained soil with using 0.01 M FeCl3 washing solution (liquid/solid ratio 20) for 2 hours, contaminants were removed 96.66%, 90.02% and 98.25%, respectively. In extraction procedure of Cd (218 mg kg-1), Cu (153 mg kg-1) and Zn (441.6 mg kg-1) from contaminated fine grained soil with using 0.01 M FeCl3 washing solution (liquid/solid ratio 20) for 2 hours, contaminants were removed 98.18%, 97.48% and 98.05%, respectively. Better removal efficiencies have been obtained by using FeCl3. These results confirmed the effectiveness of the soil-washing method with FeCl3 in remediating heavy metals (Cu, Cd and Zn) from different types of soil.