Applied Water Science (v.3, #3)
Biosorption of lead (II) from water using heartwood charcoal of Areca catechu: equilibrium and kinetics studies by Nabanita Haloi; H. P. Sarma; P. Chakravarty (559-565).
Present study was conducted to investigate the removal of Pb(II) from water by using heartwood charcoal of Areca catechu (HCAC). Batch experiments were conducted to determine the adsorption properties at different contact times (5–30 min), concentrations (0.1–10 mg/L), amounts of adsorbents (0.1–0.6 g), and in a range of pH 2–7. Most favorable biosorption condition was found at pH 5.0, 0.5 g biomass dosage and at 25 min equilibrium time. The experimental results were fitted to the Langmuir and Freundlich isotherm models; the Freundlich isotherm was found to well represent the measured sorption data implying HCAC has heterogeneous surface. Lagergren first-order and pseudo-second-order kinetic model were used to analyze the biosorption data; it was observed that the pseudo-second-order model best represented the relationship. Scanning electron microscopy image and energy dispersive X-ray analysis were also incorporated in support of the study. The result shows that HCAC has the potentiality to remove Pb(II) from water.
Keywords: Biosorption; Lead (II); Heartwood charcoal; Equilibrium study; Kinetic study
Evaluation of the use of an alkali modified fly ash as a potential adsorbent for the removal of metals from acid mine drainage by P. K. Sahoo; S. Tripathy; M. K. Panigrahi; Sk. Md. Equeenuddin (567-576).
The coal fly ash (FA), mainly containing high unburnt carbon was modified by alkali hydrothermal treatment. The modified fly ash (MFA) contains lower amounts of Si and Al and has a higher surface area and pH than the untreated fly ash (FA). The objective of this study is to investigate the potential of MFA as a low cost adsorbent material for the removal of Al, Fe, Ni, Pb, Zn and Mn from acid mine drainage (AMD). The effect of dose, contact time and competing cations on the adsorption of metals was investigated. The results showed that the sorption process onto MFA was initially rapid, but slowed down thereafter. The optimum time for metal uptake was 180 min while the optimum dose of MFA for metal removal was 120 g/L. The adsorption data best fit to the Freundlich isotherm model, which demonstrates that the adsorption process is controlled by the heterogeneous nature of the adsorbent. Adsorption kinetics of Al, Fe, Ni, Pb, and Zn onto MFA follow a pseudo second-order reaction, which implies that chemisorption is the adsorption rate-limiting step for them, while for Mn it is intra-particle diffusion. Preliminary treatment of real mine drainage from Jaintia Hills coalfield indicates that MFA can be an effective and low-cost adsorbent for the treatment of AMD. The desorption data show that most of the metal ions were substantially desorbed in the acidic media, implying that the adsorbent can be regenerated and reused efficiently.
Keywords: Modified coal fly ash; Acid mine drainage; Adsorption; Heavy metals
Hydrogeochemistry and isotope studies of groundwater in the Ga West Municipal Area, Ghana by David Saka; Tetteh T. Akiti; Shiloh Osae; Michael K. Appenteng; Abass Gibrilla (577-588).
This paper assesses groundwater in the Ga West Municipal Area of Ghana using hydrogeochemistry and isotope approaches. High salinity groundwaters are obtained in the municipality which poses problems for current and future domestic water supply exploitation. The increase in salinity is related to the dissolution of minerals in the host rocks and the evaporative concentration of solutes. The dominant groundwater composition in both shallow and deep wells sampled is Na–Cl. The concentration of the Na–Cl was observed to increase substantially with well depths. The mixing of freshwater of the shallow hand dug wells with that of saline water of the deep boreholes was noted in the shift from Ca–HCO3 facies to Ca–Cl facies. Schoeller diagram showed that groundwater in the study area is recharged from a similar source. The Schoeller diagram also showed the gradual increase in concentration of the major ions with depth. This leads to salinization in the deep boreholes. The oxygen and hydrogen isotope compositions in the groundwater samples suggest that groundwater recharge is of meteoric origin with few samples showing evidence of evaporation. An average deuterium excess of rainfall of 14.2 ‰ was observed, which indicates the significance of kinetic evaporation due to low humidity conditions prevalent in the study area. The d-excess also indicates modern recharge along the foothills of the Akwapim-Togo Ranges.
Keywords: Deuterium excess; Major ions; Schoeller diagram; Salinity; Ghana
Occurrence of fluoride in ground waters of Saudi Arabia by Abdulrahman I. Alabdulaaly; Abdullah I. Al-Zarah; Mujahid A. Khan (589-595).
The presence of elevated levels of fluoride in groundwater is considered a global problem. Fluoride in water derives mainly from dissolution of natural minerals in the rocks and soils with which water interacts. The most common fluorine-bearing minerals are fluorite, apatite and micas. Anthropogenic sources of fluoride include agricultural fertilizers and combustion of coal. In the present research, a survey of wells (n = 1,060) was undertaken in all the 13 regions of the Kingdom of Saudi Arabia to assess the contained fluoride (F) levels. The results indicated variation in fluoride levels from 0.10 to 5.4 mg/L as F throughout the kingdom. The average fluoride levels in milligrams per liter as F were as follows in descending order: 1.80 (Hadwood Shamalyah), 1.37 (Hail), 1.33 (Eastern Province), 1.16 (Al Jouf), 1.11 (Qassim), 1.01 (Riyadh), 0.90 (Madina Al Munnawara), 0.81 (Tabouk), 0.74 (Makkah Al- Mukaramma), 0.73 (Jizan), 0.66 (Asir), 0.64 (Najran), and 0.60 (Al Baha). The results indicated that fluoride levels exceeded the USEPA maximum contaminant limits for drinking water (4 mg/L) in several wells (n = 7) in different regions of the kingdom and that 13.96 % of the wells exceeded the World Health Organization recommended levels (1.5 mg/L). The results were also compared with the secondary USEPA contaminant standards of 2.0 mg/L for fluorides.
Keywords: Fluoride; Ground water; Saudi Arabia; Occurrence; Health effects
Variogram-based approach for selection of grid size in groundwater modeling by Zargham Mohammadi (597-602).
In this paper a geostatistical approach based on the variogram concept is used for decisions about the size of a grid network applicable to a groundwater model. One of the important properties of the variogram function is the range of influence, which is interpreted as a measure of similarity and correlation distance between spatial phenomena. Taking the concept of range into account, several available spatial variables of the under study aquifer were used to plot the variogram in different directions. The study area is an unconfined aquifer (Boushkan Plain in southwest Iran) with an average thickness of 50 m and area of 100 km2. The variables used for computing the variogram include aquifer thickness (D), groundwater pumping rate (Q) and electrical resistivity (R) of the aquifer material. The range of influence was estimated to be 2,000, 2,500, and 2,000 m for D, Q and R, respectively. Comparisons of statistical parameters of spatial variables over a grid size ranging from 1,000 to 5,000 m were done to confirm the proposed grid size according to variogram plots. The bounded area of each cell could be considered as homogenous media according to the spatial variation of the variables used. The optimum size of the grid network was selected according to the minimum of the variance and coefficient of variation over each cell size. Results suggest a 2,500 × 2,500 m grid size for the modeling process in the studied aquifer. The results emphasize the role of variogram function in selection of grid size for the groundwater model.
Keywords: Geostatistics; Variogram; Groundwater modeling; Boushkan; Iran
Hydrochemical characteristics of coastal aquifers of Kadaladi, Ramanathapuram District, Tamilnadu, India by P. Sivasubramanian; N. Balasubramanian; John Prince Soundranayagam; N. Chandrasekar (603-612).
Geochemical signatures of groundwater in the coastal aquifers of Kadaladi block of Ramanathapuram District, Tamilnadu, India were used to identify the chemical processes that control hydrochemistry. The parameters such as pH, EC, TDS and major ion concentrations Na, K, Ca, Mg, Cl, HCO3, SO4, PO4 and NO3 of the groundwater were analyzed. Abundances of these ions are in the following order Na > Ca > Mg > K and Cl > HCO3 > SO4 > NO3 > PO4. Na–Cl is the dominant hydrochemical facies of the study area. Interpretation of the hydrochemical data suggests that hydrochemistry of the study area is controlled by mixing of fresh water with relict saline water, ion-exchange processes, silicate weathering and evaporation are responsible for the groundwater chemistry of the study area. Above statement is further supported by Gibbs plot where most of the samples fall within the evaporation zone. Good quality groundwater is restricted to coastal sand dunes running parallel to the coast and it is important to conserve these dunes.
Keywords: Groundwater; Geochemical facies; Ionic ratios; Kadaladi; Tamilnadu
Design of a groundwater model to determine the feasibility of extending an artificial salmon-spawning stream: case study for Marx Creek, near Hyder, Alaska by T. P. Nelson; T. E. Lachmar (613-624).
Marx Creek is a groundwater-fed, artificial salmon-spawning stream near Hyder, Alaska. The purpose of this project was to develop a groundwater flow model to predict baseflow to a proposed 450-m extension of Marx Creek. To accomplish this purpose, water levels were monitored in 20 monitor wells and discharge measurements were recorded from Marx Creek. These data were used to create a three-dimensional groundwater flow model using Visual MODFLOW. Three predictive simulations were run after the model was calibrated to groundwater levels and stream discharge measurements. The proposed extension was added to the calibrated model during the first simulation, resulting in simulated baseflow to the extension stream exceeding simulated baseflow to the existing Marx Creek by 39 %. Sections of Marx Creek were removed from the model during the second simulation, resulting in a 5 % increase in simulated baseflow to the extension stream. A 32-cm reduction in the water table was simulated during the third simulation, resulting in an 18 % decrease in simulated baseflow to the extension stream. These modeling results were used by Tongass National Forest personnel to determine that baseflow to the proposed extension would likely be sufficient to provide habitat conducive to salmon spawning. The extension stream was constructed and portions of Marx Creek were decommissioned during the summer of 2008. It was observed that there is comparable or greater discharge in the extension stream than there was in the decommissioned sections of Marx Creek, although neither discharge nor stream stage measurements have yet been collected.
Keywords: Groundwater; Groundwater modeling; Chum salmon; Alaska; Tongass National Forest; Artificial salmon-spawning stream
Seasonal bacteriological analysis of Barak River, Assam, India by Bibhas Rajkumar; G. D. Sharma (625-630).
The present study was aimed at estimating the seasonal variation of human pathogenic bacteria in different sites of the Barak River. Water samples were collected in different seasons of the year from four sites of the river for physico-chemical and bacteriological analysis. Total alkalinity showed a rising trend during summer and winter seasons. In contrast, the values declined during monsoon season. pH values, however, showed a narrow range of fluctuations over the seasons as well as among the study sites. In the site Panchgram higher value of dissolved oxygen was observed during monsoon season which gradually declined attaining minimum during winter season. During monsoon season, the free carbon dioxide (FCO2) value was found to be high whereas lower values of FCO2 were observed during summer and winter seasons. All samples were found to have total viable count (TVC) higher than those prescribed by Bureau of Indian Standards (ISI, 1991). The TVC was higher in monsoon season as compared to summer and winter. The total coliform count was also relatively higher in monsoon season than summer and winter in all the sites. Pseudomonas spp. was recorded from all sites in all seasons which were higher in monsoon in comparison to other seasons. The highest value of MPN was found in the site Panchgram and Annapurnaghat (1,600 MPN/100 ml) during monsoon season and lowest was found in the site Katakhal (110 MPN/100 ml) during winter season.
Keywords: Barak River; Faecal coliforms; Pollution indicator
Evaluation of groundwater quality in and around Nagercoil town, Tamilnadu, India: an integrated geochemical and GIS approach by Y. Srinivas; D. Hudson Oliver; A. Stanley Raj; N. Chandrasekar (631-651).
This study was made to find the ground water quality for samples of the town located in the southern most end of India. The study was carried out to evaluate the major ion chemistry, the factors controlling water composition, and suitability of water for both drinking and irrigation purposes. Totally, 21 ground water samples were collected randomly from bore wells and hand pumps throughout the Nagercoil town and its surroundings. The collected samples were analyzed for major ions and the analytical data were interpreted according to published guide lines. The spatial maps show that the concentration of the chemical constituent in ground water varies spatially and temporarily. Sodium is the most dominant cation with Cl− and HCO3− as the dominant anion. The abundant of the major is as follows: Na+ > Cl− > Mg2+ > K+ which is equal to HCO3− > Cl− > SO4. Only one-third of the samples best fit for both consumption and agricultural purposes. The spatial maps show high contamination along the southern region of the study area. Total hardness of the collected samples lies between 60 and 490 mg/l reveals that the 33 % groundwater samples exceeds the safe limit of 300 mg/l. Total dissolved solids (TDS) in the study area ranges between 67 and 2,086 mg/l with a mean value of 523 mg/l. High total hardness and TDS in few places identified that the ground water is unsuitable for drinking and irrigation. In these places, the aquifers are subject to contamination from sewage effluents and excess use of fertilizer and pesticides in agriculture. Such areas require adequate drainage and introduction of alternative salt tolerance cropping.
Keywords: Ground water; Drinking and irrigation water quality; Spatial distribution; Water quality index; Nagercoil; India
Removal of Cr(VI) and As(V) ions from aqueous solutions by polyacrylate and polystyrene anion exchange resins by Justyna Jachuła; Zbigniew Hubicki (653-664).
The sorption of Cr(VI) and As(V) from the aqueous solutions with the polyacrylate anion exchangers of the strong base functional groups Amberlite IRA 458 and Amberlite IRA 958 was studied. The studies were carried out by the static-batch method. The concentration of Cr(VI) and As(V) ions in the aqueous solution was determined by the UV–VIS spectrophotometer. The influence of several parameters was studied with respect to sorption equilibrium. The phase contact time and the concentration affect the sorption process. The equilibrium state was established already after 15 min of phase contact time. Maximum uptake of Cr(VI) and As(V) occurred at pH 5 and 10, respectively. The determined kinetic parameters imply that the sorption process proceeds according to the equation type of pseudo second-order. Sorption equilibrium data were correlated with the Langmuir and Freundlich isotherms. Removal of As(V) ions on macroporous Amberlite IRA 900 decreased about 12 % in presence of other anions (Cl−, NO3−, SO42−) in the solution. The sorption was temperature dependent.
Keywords: Chromium; Arsenic; Anion exchangers; Sorption; Removal; Langmuir isotherm
Adsorption of Pb(II) ions onto biomass from Trifolium resupinatum: equilibrium and kinetic studies by Makshoof Athar; Umar Farooq; Muhammad Aslam; M. Salman (665-672).
The present study provides information about the binding of Pb(II) ions on an eco-friendly and easily available biodegradable biomass Trifolium resupinatum. The powdered biomass was characterized by FTIR, potentiometric titration and surface area analyses. The FTIR spectrum showed the presence of hydroxyl, carbonyl and amino functional groups and Pb(II) ions bound with the oxygen- and nitrogen-containing sites (hydroxyl and amino groups). The acidic groups were also confirmed by titrations. Effects of various environmental parameters (time, pH and concentration) have been studied. The biosorption process achieved equilibrium in a very short period of time (25 min). Non-linear approach for Langmuir and Freundlich models was used to study equilibrium process and root mean-square error was used as an indicator to decide the fitness of the mathematical model. The biosorption process was found to follow pseudo-second-order kinetics and was very fast. Thus, the biomass can be cost-effectively used for the binding of Pb(II) ions from aqueous solutions.
Keywords: Trifolium resupinatum biomass; Langmuir model; Pseudo-second-order lead(II) ions