Applied Water Science (v.7, #4)

Parameters affecting the photocatalytic degradation of dyes using TiO2: a review by Khan Mamun Reza; ASW Kurny; Fahmida Gulshan (1569-1578).
Traditional chemical, physical and biological processes for treating wastewater containing textile dye have such disadvantages as high cost, high energy requirement and generation of secondary pollution during treatment process. The advanced oxidation processes technology has been attracting growing attention for the decomposition of organic dyes. Such processes are based on the light-enhanced generation of highly reactive hydroxyl radicals, which oxidize the organic matter in solution and convert it completely into water, CO2 and inorganic compounds. In this presentation, the photocatalytic degradation of dyes in aqueous solution using TiO2 as photocatalyst under solar and UV irradiation has been reviewed. It is observed that the degradation of dyes depends on several parameters such as pH, catalyst concentration, substrate concentration and the presence of oxidants. Reaction temperature and the intensity of light also affect the degradation of dyes. Particle size, BET-surface area and different mineral forms of TiO2 also have influence on the degradation rate.
Keywords: Photocatalytic degradation; Dye; Titanium dioxide; Parameters

What maintains the waters flowing in our rivers? by Vitor Vieira Vasconcelos (1579-1593).
This article discusses how new contributions from hydrogeological science in the 20th and 21st centuries have allowed for a better understanding of the processes that affect the maintenance of river flows. Moreover, the way in which this knowledge has been conveyed beyond academia and has been gradually incorporated into public policy for natural resource management is also discussed. This article explains the development of several approaches used to understand the relationships among the management of aquifers, vegetation and river flows, including water balance, aquifer recharge, the piston effect, seasonal effects, and safe and sustainable yields. Additionally, the current challenges regarding the modeling of hydrological processes that integrate groundwater and surface waters are discussed. Examples of studies applied in Brazil that demonstrate these processes and stimulate thought regarding water management strategies are presented. In light of the case studies, it is possible to propose different strategies, each adapted for specific hydrogeological context to maximize aquifer recharge or base flow maintenance. Based on these strategies, the role of infiltration ponds and other artificial recharge techniques is re-evaluated in the context of the mitigation of environmental impacts on the maintenance of river flows. Proposals for the improvement of public policies regarding the payment of related environmental services to stimulate investment in aquifer recharge and the maintenance of base flow, for which the goal is to attain win–win–win situations for the environment, farmers and water users, while preventing land speculation, are discussed. Lastly, a conceptual model for the dissemination of hydrogeological knowledge in public policies is provided, and its challenges and possibilities are discussed.
Keywords: Hydrology; Hydrogeology; Environmental management; Public Policies; Water resources management

Integrating remote sensing, geographic information systems and global positioning system techniques with hydrological modeling by Jay Krishna Thakur; Sudhir Kumar Singh; Vicky Shettigondahalli Ekanthalu (1595-1608).
Integration of remote sensing (RS), geographic information systems (GIS) and global positioning system (GPS) are emerging research areas in the field of groundwater hydrology, resource management, environmental monitoring and during emergency response. Recent advancements in the fields of RS, GIS, GPS and higher level of computation will help in providing and handling a range of data simultaneously in a time- and cost-efficient manner. This review paper deals with hydrological modeling, uses of remote sensing and GIS in hydrological modeling, models of integrations and their need and in last the conclusion. After dealing with these issues conceptually and technically, we can develop better methods and novel approaches to handle large data sets and in a better way to communicate information related with rapidly decreasing societal resources, i.e. groundwater.
Keywords: Hydrological modeling; Groundwater; Remote sensing; GIS; GPS

Hydrogeochemical analysis and evaluation of surface water quality of Pratapgarh district, Uttar Pradesh, India by Ashwani Kumar Tiwari; Abhay Kumar Singh; Amit Kumar Singh; M. P. Singh (1609-1623).
The hydrogeochemical study of surface water in Pratapgarh district has been carried out to assess the major ion chemistry and water quality for drinking and domestic purposes. For this purpose, twenty-five surface water samples were collected from river, ponds and canals and analysed for pH, electrical conductivity, total dissolved solids (TDS), turbidity, hardness, major cations (Ca2+, Mg2+, Na+ and K+), major anions (HCO3 , F, Cl, NO3 , SO4 2−) and dissolved silica concentration. The analytical results show mildly acidic to alkaline nature of surface water resources of Pratapgarh district. HCO3 and Cl are the dominant anions, while cation chemistry is dominated by Na+ and Ca2+. The statistical analysis and data plotted on the Piper diagram reveals that the surface water chemistry is mainly controlled by rock weathering with secondary contributions from agriculture and anthropogenic sources. Ca2+–Mg2+–HCO3 , Ca2+–Mg2+–Cl and Na+–HCO3 –Cl are the dominant hydrogeochemical facies in the surface water of the area. For quality assessment, values of analysed parameters were compared with Indian and WHO water quality standards, which shows that the concentrations of TDS, F, NO3 , Na+, Mg2+ and total hardness are exceeding the desirable limits in some water samples. Water Quality Index (WQI) is one of the most effective tools to communicate information on the quality of any water body. The computed WQI values of Pratapgarh district surface water range from 28 to 198 with an average value of 82, and more than half of the study area is under excellent to good category.
Keywords: Pratapgarh; Major ion chemistry; Hydrogeochemical facies; Surface water quality; PCA; WQI; GIS

Magnesium oxide-impregnated tuff soil-derived ceramic: a novel cadmium(II) adsorbing media by Md Salim; Jatindra N. Bhakta; Namburath Maneesh; Yukihiro Munekage; Kevin Motomura (1625-1633).
The contamination of cadmium (Cd) in the aquatic environment is one of the serious environmental and human health’s risks. The present study attempted to develop the potential magnesium oxide (MgO)-impregnated tuff soil-derived ceramic (MITDC)-based novel adsorbent media for adsorbing higher rate of cadmium [Cd(II)] from water phase. A potential MITDC adsorbent media was developed using volcanic raw tuff soil and its Cd(II) adsorption capacity from water phase was evaluated comparing with the raw tuff soil. A series of studies were carried out in an agitated batch method at 20 ± 2 °C to characterize the adsorption capacity of MITDC under different conditions of factors, such as contact time (0–360 min), initial pH (3–11) of solution, dose of MITDC (2, 5, 7.5 and 10 g/L), and initial concentration of Cd(II) (5, 10, 20, 30, and 40 mg/L), influencing the adsorption mechanism. MITDC exhibited the equilibrium state of maximum Cd(II) adsorption at the contact time 120 min and pH 4.7 (removed 98.2 % Cd) when initial Cd(II) concentration was 10 mg/L in the present study. The dose of 7.5 g MITDC/L showed maximum removal of Cd(II) from water. Experimental data were described by the Freundlich and the Langmuir isotherms and equilibrium data fitted well with the Langmuir model (R 2 = 0.996). The Cd(II) adsorption capacity of MITDC was 31.25 mg/g. The high Cd(II) adsorption capacity indicated that novel MITDC could be used as a potential ceramic adsorbent media to remove high rate of Cd(II) from aqueous phase.
Keywords: Magnesium oxide; Tuff soil; Impregnation; Cadmium ion; Adsorption; Isotherm

Microbiological evaluation of drinking water sold by roadside vendors of Delhi, India by Abhishek Chauhan; Pankaj Goyal; Ajit Varma; Tanu Jindal (1635-1644).
Delhi has emerged as one of the greenest capital city of the world. Microbiological assessment of drinking water emphasizes estimation of the hygienic quality of the water sold with reference to community health significance. This study was conducted to evaluate the quality of drinking water sold by roadside vendors in east, west, north and south zones of capital of India. A total number of 36 samples (nine from each zone) were collected as per national guidelines and studied for microbiological assessment. All the drinking water samples were collected in gamma-sterilized bottles and were kept in an ice pack to prevent any significant change in the microbial flora of the samples during the transportation. The water samples were transported to the laboratory in vertical position maintaining the temperature 1–4 °C with ice pack enveloped conditions. Samples were analyzed for total MPN coliform per 100 ml and for the presence and absence of common human pathogenic bacteria such as Escherichia coli, Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa. All the samples were found to be contaminated with coliform organisms in the range of 14 to >1600 per 100 ml of sample. Out of 36 water samples, the occurrence of E. coli was 61 %, Salmonella 25 % S. aureus 14 % and P. aeruginosa 53 % as 22, 9, 5 and 19 samples were found contaminated, respectively. The numbers of coliform bacteria and presence of some common pathogenic bacteria suggested that the quality of drinking water sold by roadside vendors is not within the Indian standard and WHO guidelines laid down for drinking water quality. Hence, there is a vital need to study the root cause in terms of hygiene, sanitation of vendors and source of contamination to prevent waterborne diseases.
Keywords: Quality of drinking water; Microbiological assessment; Coliform; Bacterial disease and human health

Geochemistry and quality parameters of dug and tube well water of Khipro, District Sanghar, Sindh, Pakistan by Erum Bashir; Syed Nawaz-ul Huda; Shahid Naseem; Salma Hamza; Maria Kaleem (1645-1655).
Thirty-nine (23 dug and 16 tube well) samples were geochemically evaluated and investigated to ascertain the quality of water in Khipro, Sindh. The analytical results exhibited abundance of major cations and anions in Na+ > Ca2+ > Mg2+ > K+ and Cl > HCO3  > SO4 2− sequence. Stiff diagram showed dug well sample have high Na–Cl and moderate Mg–SO4 content as compared to tube well samples. Majority of dug well samples appeared as Na–Cl type on Piper diagram while tube well samples are mixed type. Gibbs diagram reflected evaporation as a dominant phenomenon in dug well; however, tube well samples are declined toward rock dominance. Process of ion exchange was witnessed from Na+ versus Cl and Ca2+ + Mg2+ versus HCO3  + SO4 2− plots. Principal component analysis also discriminates dug well and tube well water by means of positive and negative loading based on physical and chemical composition of the groundwater. Studied and computed parameters like pH, EC, TDS, TH, Na+, K+, Ca2+, Mg2+, Cl, SO4 2−, HCO3 , sodium adsorption ratio, magnesium adsorption ratio, potential salinity, residual sodium carbonate, Na%, Kelly’s ratio, and permeability index were compared with WHO to evaluate studied water for drinking and agricultural purposes. Except Na+ and K+, all chemical constrains are within the allowed limits, set by WHO for drinking water. Similarly, most of the groundwater is moderately suitable for irrigation uses, with few exceptions.
Keywords: Drinking and irrigation water quality; PCA; WHO standards; Khipro; Sanghar

Mineral dissolution reactions actively participate in controlling the composition of mineral water. In this study, water soluble, acidic–alkaline and carbonated solution experiments were designed, and mineral reaction mechanisms were researched using chemical kinetics and the minimum free-energy method. The results showed that the release of metasilicate was controlled by pH, CO2, and rock characteristics. In the water soluble experiment, the release process of metasilicate in powdered rocks reached equilibrium after 40 days, while metasilicate in solid rocks took 170 days. The release process of metasilicate in solid rocks satisfied an asymptotic model, while in powdered rocks it accorded with the Stanford reaction kinetic model. In the acidic–alkaline experiment, metasilicate was released earlier under acidic conditions (2.46 < pH < 7) than under alkaline conditions (7 < pH < 10.61). The release process of metasilicate under acidic conditions reached equilibrium in 40 days, compared with 60 days for alkaline conditions. The addition of CO2 to the water solution was beneficial to the formation of metasilicate. Under neutral pH conditions, the reaction barely occurred. Under alkaline conditions, metasilicate was produced by the hydrolysis of metasilicate minerals. Under acidic and additional CO2 conditions, metasilicate formation was mainly via the reaction of H+, CO2, and metasilicate minerals. From these results, we concluded that the metasilicate mineral water from the Changbai Mountains, Jingyu County, is generated by a combination of the hydrolysis of metasilicate minerals and the reaction of H+, CO2, and metasilicate minerals. These results can contribute to a better development and protection of the mineral water resources in the Changbai Mountains.
Keywords: Mineral water; Metasilicate; pH; CO2 ; Chemical kinetics analysis; Minimum free energy; Changbai Mountain

Bottom sediment in a river often acts as a sink and indicator of changes in water column and magnitude of anthropogenic influences through air and watersheds. Heavy metal concentration in sediments of Ganga River was studied along a 37-km stretch to assess whether there is a significant difference between sites situated upstream and downstream of Varanasi urban core. Metal concentration increased consistently along the study gradient, indicating the influence of urban sources. Concentration in the river sediment was found highest for Fe followed by Mn, Zn, Cr, Cu, Ni, Pb, and Cd. Mann–Kendall trend analysis showed marked seasonality in the concentration with values being highest in summer and lowest in rainy season. Enrichment factor revealed severe enrichment of Cd and Pb at downstream sites, and principal component analysis segregated sites into four distinct groups indicating source relationships. Concentrations of Cd, Pb, Ni, Cu, and Cr did exceed WHO standards. The study has relevance designing control measures and action plans for reducing sediment contamination in anthropogenic impacted rivers.
Keywords: Atmospheric deposition; Ganga River basin; Enrichment factor; Heavy metal; Sediment

Located in the extreme northwest of Africa, the Kingdom of Morocco is increasingly affected by drought. Much of the country is characterised by an arid to semi-arid climate and the demand for water is considerably higher than the supply, particularly on the Haouz Plain in the centre of the country. The expansion of agriculture and tourism, in addition to industrial development and mining, have exacerbated the stress on water supplies resulting in drought. It is therefore necessary to adopt careful management practices to preserve the sustainability of the water resources in this region. The aquifer recharge rate in the piedmont region that links the High Atlas and the Central Haouz Plain was estimated using the chloride mass balance hydrochemical method, which is based on the relationship between the chloride concentrations in groundwater and rainwater. The addition of a geographical information system made it possible to estimate the recharge rate over the whole 400 km2 of the study area. The results are presented in the form of a map showing the spatialized recharge rate, which ranges from 13 to 100 mm/year and the recharge percentage of the total rainfall varies from 3 to 25 % for the hydrological year 2011–2012. This approach will enable the validation of empirical models covering areas >6200 km2, such as the Haouz nappe.
Keywords: Groundwater recharge; Semi-arid regions; Chloride mass-balance method (CMB); Geographic information system (GIS); Haouz Plain (Morocco)

Viability of karezes (ancient water supply systems in Afghanistan) in a changing world by G. L. Macpherson; W. C. Johnson; Huan Liu (1689-1710).
The Afghanistan population living far from rivers relies upon groundwater delivered from karezes (sub-horizontal tunnels). Karezes exploit unconfined groundwater in alluvial fans recharged largely by snowmelt from the Hindu Kush, the central mountain range of the country. Since the multi-year drought that began in 1998, many karezes have stopped flowing. This study characterizes the hydraulics of a kariz, the potential for reduced groundwater recharge because of climate change, and the impact of increasing population on kariz water production. A typical kariz in Afghanistan is 1–2 km long with a cross-section of 1–2 m2 and gradient of 1 m km−1. MODFLOW simulations show that water delivery from a kariz can be modeled by imposing a high ratio of kariz hydraulic conductivity to aquifer hydraulic conductivity on the cells representing the kariz. The model is sensitive to hydraulic conductivity, kariz gradient, and length of the kariz in contact with the water table. Precipitation data are scarce in Afghanistan, but regional data show a long-term trend of decreased snow cover, and therefore strong likelihood of decreased aquifer recharge. Population in Afghanistan has increased at a rate of about 2.2 % over the past several decades. An assessment of a six-district region within Kandahar Province where karezes are the most likely source of water indicates that water demand could have caused water tables to decline by 0.8–5.6 m, more than enough to cause karezes to stop flowing. These results suggest that kariz water production is not sustainable under current climate- and population-growth trends.
Keywords: Kariz; Qanat; Water resources; Arid regions; Climate change; Population growth

Electrocoagulation was used for the removal of basic dye rhodamine B from aqueous solution, and the process was carried out in a batch electrochemical cell with steel electrodes in monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process, were investigated. Equilibrium was attained after 10 min at 30 °C. Pseudo-first-order, pseudo-second-order, Elovich and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic adsorption process; pseudo-first-order and Avrami models best fitted the data. Experimental data were analysed using six model equations: Langmuir, Freudlinch, Redlich–Peterson, Temkin, Dubinin–Radushkevich and Sips isotherms and it was found that the data fitted well with Sips isotherm model. The study showed that the process depends on current density, temperature, pH and initial dye concentration. The calculated thermodynamics parameters ( $$Delta G^circ ,;Delta H^circ ;{ ext{and}};Delta S{^circ }$$ Δ G ∘ , Δ H ∘ and Δ S ∘ ) indicated that the process is spontaneous and endothermic in nature.
Keywords: Electrocoagulation; Steel electrodes; Rhodamine B; Kinetics; Thermodynamics; Isotherms

The process of delineating areas that are more susceptible to pollution from anthropogenic sources has become an important issue for groundwater resources management and land-use planning. In this study, an attempt was made to delineate aquifer vulnerability zones for nitrate contamination at Galal Badra basin, east of Iraq using Dempster–Shafer method of evidence in GIS platform. First, an inventory map of the wells with elevated nitrate concentration (>3 mg/L) was prepared. The map showed that there are 63 wells with elevated nitrate concentrations in the study area. These data were partitioned randomly into two sets, for training and testing. The partition criterion was 70/30, 44 wells for training and 19 wells for testing. Then, the most influencing evidential thematic factors in determining aquifer vulnerability were selected depending on the availability of data. These factors were groundwater depth, hydraulic conductivity, slope, soil, and land use land cover (LULC). The spatial association between well locations and evidential thematic layers was investigated by means of mass functions (belief, disbelief, uncertainty, and plausibility) of Dempster–Shafer method. The integrated belief function was used to produce groundwater aquifer vulnerability index (GVI) for the study area. The pixel values of GVI were reclassified into five categories: very low, low, moderate, high, and very high using Jenks classification scheme. The very low–low zones cover 32 % (209 km2). These classes mainly concentrate on the eastern parts of the study area and occupy small zone in the central part. The moderate zone extends over an area of 42 % (279 km2) and mainly encompasses the western part of the study area. The high–very high zones cover 26 % (170 km2) and these zones concentrate on the central part of the study area. The results indicate that the aquifer system in the study area is moderately vulnerable to contamination by nitrate. The model was validated by using relative operating characteristic technique. The success and prediction rates for area under the curve (AUC) were 0.86 and 0.77, respectively, indicating that the model has good capability to delineate aquifer vulnerability zones for nitrate contamination in the study area.
Keywords: Aquifer vulnerability; Dempster–Shafer method of evidence; GIS; Galal Badra area; Iraq

Springs are the gifts of nature on the earth as they contribute about eighty essential nutrients that are involved in more than 7000 enzymatic processes in the human body. European balneologists have recommended spring mineral waters for different therapeutic applications. In the present investigation, Aab-e-Shifa (Punjab Pakistan) spring water was analyzed due to its therapeutic behavior in the healing of various skin diseases via atomic absorption spectroscopy (AAS). It was found that besides other important minerals (Ca, Mg, K, and Na), the spring water contains the most significant antioxidant, i.e., Zn which is probably one of the major features of the curative behavior of Aab-e-Shifa. Other trace elements (Cr, Cd, Ni, Mn, Fe, and Cu) were also found to be present in the spring water under the permissible limits of various national and international organizations.
Keywords: Aab-e-Shifa Spring; AAS; Zn Concentration; Trace Elements

Acid and base recovery from brine solution using PVP intermediate-based bipolar membrane through water splitting technology by Krishnaveni Venugopal; Minnoli Murugappan; Sangeetha Dharmalingam (1747-1759).
Potable water has become a scarce resource in many countries. In fact, the world is not running out of water, but rather, the relatively fixed quantity is becoming too contaminated for many applications. Hence, the present work was designed to evaluate the desalination efficiency of resin and glass fiber-reinforced Polysulfone polymer-based monopolar and bipolar (BPM) ion exchange membranes (with polyvinyl pyrrolidone as the intermediate layer) on a real sample brine solution for 8 h duration. The prepared ion exchange membranes (IEMs) were characterized using FTIR, SEM, TGA, water absorption, and contact angle measurements. The BPM efficiency, electrical conductivity, salinity, sodium, and chloride ion concentration were evaluated for both prepared and commercial-based IEM systems. The current efficiency and energy consumption values obtained during BPMED process were found to be 45 % and 0.41 Wh for RPSu-PVP-based IEM system and 38 % and 1.60 Wh for PSDVB-based IEM system, respectively.
Keywords: Brine water desalination; Reinforced IEM; PVP intermediate based BPM; Water dissociation reaction; BPM efficiency

Use of artificial neural networks for electrical conductivity modeling in Asi River by Mohammad Ali Ghorbani; Mohammad Taghi Aalami; Leila Naghipour (1761-1772).
This study aims to model monthly electrical conductivity (EC) values in the Asi River using artificial neural networks (ANNs) to evaluate water quality conditions using pH, temperature, water discharge, sodium, sum of calcium and magnesium concentrations. The results are compared using multiple linear regression (MLR). Recorded data are available at a gauging site in Antakya, Turkey, for the period from 1984 to 2008. Comparing the modeled values by ANNs with the experimental data indicates that neural network model with seven neurons in hidden layer provides accurate results (R 2 = 0.968, RMSE = 46.927 µS/cm, MAE = 32.462 µS/cm and MRSE = 0.0029 for the training data and R 2 = 0.965, RMSE = 50.810 µS/cm, MAE = 37.495 µS/cm and MRSE = 0.0024 for the testing data). The Garson method of the connection weights of the network was used to study the relative % contribution of each of the input variables. It was found that the sum of calcium and magnesium concentration and temperature had the most effect on the predicted EC. The results indicate that two proposed models were able to approximate the EC parameter reasonably well; however, the ANN was found to perform better than the MLR model.
Keywords: Artificial neural networks; Asi River; Multiple linear regression; Relative importance; Water quality

Watershed is an ideal unit for planning and management of land and water resources (Gajbhiye et al., IEEE international conference on advances in technology and engineering (ICATE), Bombay, vol 1, issue 9, pp 23–25, 2013a; Gajbhiye et al., Appl Water Sci 4(1):51–61, 2014a; Gajbhiye et al., J Geol Soc India (SCI-IF 0.596) 84(2):192–196, 2014b). This study aims to generate the curve number, using remote sensing and geographical information system (GIS) and the effect of slope on curve number values. The study was carried out in Kanhaiya Nala watershed located in Satna district of Madhya Pradesh. Soil map, Land Use/Land cover and slope map were generated in GIS Environment. The CN parameter values corresponding to various soil, land cover, and land management conditions were selected from Natural Resource Conservation Service (NRCS) standard table. Curve number (CN) is an index developed by the NRCS, to represent the potential for storm water runoff within a drainage area. The CN for a drainage basin is estimated using a combination of land use, soil, and antecedent soil moisture condition (AMC). In present study effect of slope on CN values were determined. The result showed that the CN unadjusted value are higher in comparison to CN adjusted with slope. Remote sensing and GIS is very reliable technique for the preparation of most of the input data required by the SCS curve number model.
Keywords: SCS-CN; Runoff; Watershed; Remote sensing; Geographical information system

In this study, the photocatalytic activity of polypyrrole-TiO2 nanocomposite was studied experimentally for the degradation of methylene blue (MB) dye under simulating solar light irradiation. To improve the photocatalytic activity of TiO2 under sunlight irradiation, conducting polymers such as polypyrrole (PPy) and its derivatives are generally used as photosensitizers. The PPy-TiO2 nanocomposite was prepared by the chemical oxidative polymerization method. The prepared nanocomposite showed better photocatalytic activity than bare TiO2 under sunlight irradiation for the degradation of MB dye. The prepared nanocomposite was subjected to characterization techniques such as SEM-EDAX, FT-IR, UV-DRS, XRD, TGA and PL spectral analysis. Different influencing operating parameters like initial concentration of dye, irradiation time, pH and amount of PPy-TiO2 nanocomposite used have also been studied. The optical density of the dye degradation was measured by UV–Visible spectrophotometer. The repeatability of photocatalytic activity was also tested. A plausible mechanism was proposed and discussed on the basis of experimental results.
Keywords: PPy-TiO2 nanocomposite; Methylene blue; Sun light; Scanning Electron Microscopy; Photocatalysis

Impact of physicochemical parameters on 2 compositions and abundances in Selameko Reservoir, Debre Tabor, South Gondar from August 2009 to May 2010 was assessed. Water quality parameters, such as temperature, water transparency, water depth, dissolved oxygen, pH, total dissolved solids, phosphate, nitrate, and silicate were measured in situ from two sites (littoral and open water zone) of the reservoir. Phytoplankton compositions and abundances were analyzed in Tana fisheries and other aquatic organisms’ research center. ANOVA result of the physicochemical parameters included chlorophyll-a showed the presence of significance difference among seasons and between sites (P < 0.05). A total of seven families, 36 genera from three groups (Diatom, Blue green algae and Green algae) of phytoplankton were identified during the study period. From all groups, diatoms were the most abundant at both sites and Blue green algae were the least abundant. ANOVA of all phytoplankton showed highly significant difference among seasons and between sites (P < 0.05). ANOVA of all phytoplankton showed highly significant difference among seasons and between sites (P < 0.05). Based on the stepwise regression, a total number of phytoplanktons had positive correlation with some of the physicochemical parameters (R2 = 0.99, P < 0.001, N = 16). The study concluded that some of physicochemical parameters (NO3-N and PO4-P) indicated the presence of reservoir water pollution. This is supported by the presence of pollution-resistant phytoplankton species such as Melosira and Microcystis. The reservoir water was eutrophic (productive) throughout the year. To avoid such pollution, basin and reservoir management are recommended.
Keywords: Physico-chemical parameters; Phytoplankton composition; Abundance

Development of a simplified biofilm model by Sushovan Sarkar; Debabrata Mazumder (1799-1806).
A simplified approach for analyzing the biofilm process in deriving an easy model has been presented. This simplified biofilm model formulated correlations between substrate concentration in the influent/effluent and at biofilm–liquid interface along with substrate flux and biofilm thickness. The model essentially considered the external mass transport according to Fick’s Law, steady state substrate as well as biomass balance for attached growth microorganisms. In substrate utilization, Monod growth kinetics has been followed incorporating relevant boundary conditions at the liquid–biofilm interface and at the attachment surface. The numerical solution of equations was accomplished using Runge–Kutta method and accordingly an integrated computer program was developed. The model has been successfully applied in a distinct set of trials with varying range of representative input variables. The model performance was compared with available existing methods and it was found an easy, accurate method that can be used for process design of biofilm reactor.
Keywords: Biofilm process; Modelling; Monod growth; Simplified approach

Morphometric evaluation of Swarnrekha watershed, Madhya Pradesh, India: an integrated GIS-based approach by Abhishek Banerjee; Prafull Singh; Kamleshwar Pratap (1807-1815).
The quantitative analysis of the watershed is vital to understand the hydrological setup of any terrain. The present study deals with quantitative evaluation of Swarnrekha Watershed, Madhya Pradesh, India based on IRS satellite data and SRTM DEM. Morphometric parameters of the watershed were evaluated by computations of linear and areal aspect using standard methodology in GIS environment. ARC GIS software was utilized for morphometric component analysis and delineation of the watershed using SRTM digital elevation model (DEM). The watershed is drained by a fifth-order river and shown a dendritic drainage pattern, which is a sign of the homogeneity in texture and lack of structural control. The drainage density in the area has been found to be low which indicates that the area possesses highly permeable soils and low relief. The bifurcation ratio varies from 3.00 to 5.60 and elongation ratio is 0.518 which reveals that the basin belongs to the elongated shape basin and has the potential for water management. The main objective of the paper is to extract the morphometric parameters of the watershed and their relevance in water resource evaluation management. The results observed from this work would be useful in categorization of watershed for future water management and selection recharge structure in the area.
Keywords: Morphometric analysis; GIS; Swarnrekha watershed; Madhya Pradesh; India

Groundwater arsenic and fluoride in Rajnandgaon District, Chhattisgarh, northeastern India by Khageshwar Singh Patel; Bharat Lal Sahu; Nohar Singh Dahariya; Amarpreet Bhatia; Raj Kishore Patel; Laurent Matini; Ondra Sracek; Prosun Bhattacharya (1817-1826).
The groundwater of Ambagarh Chouki, Rajnandgaon, India, shows elevated levels of As and F, frequently above the WHO guidelines. In this work, the concentrations of As, F, Na+, Mg2+, Ca2+, Cl, SO4 2−, HCO3 , Fe, dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the groundwater of Ambagarh Chouki are described. The sources of dissolved components in the groundwater are investigated using the cluster and factor analysis. Five factors have been identified and linked to processes responsible for the formation of groundwater chemistry. High concentrations of dissolved As seems to be linked to high concentrations of DOC, suggesting reductive dissolution of ferric oxyhydroxides as arsenic mobilization process. Fluoride is found in shallow depth water, presumably as a consequence of evaporation of water and removal of Ca2+ by precipitation of carbonates.
Keywords: Arsenic; Fluoride; Trace element; Groundwater

Site-specific functionalizations are the emergent attention for the enhancement of sorption latent of heavy metals. Limited chemistry has been applied for the fabrication of diafunctionalized materials having potential to tether both environmentally stable oxidation states of chromium (Cr(III) and Cr(VI). Polyaniline impregnated nanocellulose composite (PANI-NCC) has been fabricated using click chemistry and explored for the removal of Cr(III) and Cr(VI) from hydrological environment. The structure, stability, morphology, particle size, surface area, hydrophilicity, and porosity of fabricated PANI-NCC were characterized comprehensively using analytical techniques and mathematical tools. The maximum sorption performance of PANI-NCC was procured for (Cr(III): 47.06 mg g−1; 94.12 %) and (Cr(VI): 48.92 mg g−1; 97.84 %) by equilibrating 0.5 g sorbent dose with 1000 mL of 25 mg L−1 chromium conc. at pH 6.5 and 2.5 for Cr(III) and Cr(VI), respectively. The sorption data showed a best fit to the Langmuir isotherm and pseudo-second-order kinetic model. The negative value of G° (-8.59 and -11.16 kJ mol−1) and H° (66.46 × 10−1 and 17.84 × 10−1 kJ mol−1), and positive value of S° (26.66 and 31.46 J mol−1K−1) for Cr(III) and Cr(VI), respectively, reflect the spontaneous, feasibility, and exothermic nature of the sorption process. The application of fabricated PANI-NCC for removing both the forms of chromium in the presence of other heavy metals was also tested at laboratory and industrial waste water regime. These findings open up new avenues in the row of high performance, scalable, and economic nanobiomaterial for the remediation of both forms of chromium from water streams.
Keywords: Site-specific functionalization; Click reaction; Cr(III) and Cr(VI) remediation; Waste water treatment

Biosorption is becoming a promising alternative to replace or supplement the present dye removal processes from dye containing waste water. In this work, adsorption of Congo Red (CR) from aqueous solution on burned root of Eichhornia crassipes (BREC) biomass was investigated. A series of batch experiments were performed utilizing BREC biomass to remove CR dye from aqueous systems. Under optimized batch conditions, the BREC could remove up to 94.35 % of CR from waste water. The effects of operating parameters such as initial concentration, pH, adsorbent dose and contact time on the adsorption of CR were analyzed using response surface methodology. The proposed quadratic model for central composite design fitted very well to the experimental data. Response surface plots were used to determine the interaction effects of main factors and optimum conditions of the process. The optimum adsorption conditions were found to be initial CR concentration = 5 mg/L−1, pH = 7, adsorbent dose = 0.125 g and contact time = 45 min. The experimental isotherms data were analyzed using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) isotherm equations and the results indicated that the Freundlich isotherm showed a better fit for CR adsorption. Thermodynamic parameters were calculated from Van’t Hoff plot, confirming that the adsorption process was spontaneous and exothermic. The high CR adsorptive removal ability and regeneration efficiency of this adsorbent suggest its applicability in industrial/household systems and data generated would help in further upscaling of the adsorption process.
Keywords: Adsorption; Congo Red; E. crassipes biomass; Central composite design; Regeneration

Biosorptive removal of divalent nickel from aqueous solution using Carissa Carandas and Syzygium aromaticum was investigated in batch mode and the observations were correlated with the pH variation, agitation time, dose of the adsorbent and initial metal ion concentration in the solution. In the course of this study Sorption efficiency of C. carandas leaf powder found higher than that of S. aromaticum under identical experimental conditions. The maximum adsorption capacities estimated for Ni(II) through Freundlich isotherm model were 3.76 and 2.96 mg/g for C. carandas and S. aromaticum, respectively. In kinetic studies the correlation coefficient (R 2 = 0.99) for the pseudo-second order kinetics modal was higher than that of pseudo-first order kinetics model and the calculated value of q e for the pseudo-second order kinetic model resulted very close to the experimental value, which indicates that it fits well with the equilibrium data for Ni(II) sorption from aqueous solutions on biosorbents.
Keywords: Green Chemistry; Divalent nickel; Adsorption; Biosorption; Carissa carandas ; Syzygium aromaticum ; Langmuir isotherm; Freundlich isotherm; Kinetics

Assessment of Groundwater quality in Krishnagiri and Vellore Districts in Tamil Nadu, India by A. Shanmugasundharam; G. Kalpana; S. R. Mahapatra; E. R. Sudharson; M. Jayaprakash (1869-1879).
Groundwater quality is important as it is the main factor determining its suitability for drinking, domestic, agricultural and industrial purposes. The suitability of groundwater for drinking and irrigation has been assessed in north and eastern part of Krishnagiri district, South-western part of Vellore district and contiguous with Andhra Pradesh states, India. A total of 31 groundwater samples were collected in the study area. The groundwater quality assessment has been carried out by evaluating the physicochemical parameters such as pH, EC, TDS, $$ ext{HCO}_{3}^{ - }$$ HCO 3 - , Cl, $$ ext{SO}_{4}^{2 - }$$ SO 4 2 - , Ca2+, Mg2+, Na+ and K+. The dominant cations are in the order of Na+ > K+ > Ca2+ > Mg2+ while the dominant anions have the trends of Cl > $$ ext{HCO}_{3}^{ - }$$ HCO 3 -  > $$ ext{SO}_{4}^{2 - }$$ SO 4 2 -  > CO3. The quality of the water is evaluated using Wilcox diagram and the results reveals that most of the samples are found to be suitable for irrigation. Based on these parameters, groundwater has been assessed in favor of its suitability for drinking and irrigation purpose.
Keywords: Groundwater; Major ions; Quality assessment

Seasonal variations in physico-chemical characteristics of Tuticorin coastal waters, southeast coast of India by S. Balakrishnan; G. Chelladurai; J. Mohanraj; J. Poongodi (1881-1886).
Physico-chemical parameters were determined along the Vellapatti, Tharuvaikulam and Threspuram coastal waters, southeast coast of India. All the physico-chemical parameters such as sea surface temperature, salinity, pH, total alkalinity, total suspended solids, dissolved oxygen and nutrients like nitrate, nitrite, inorganic phosphate and reactive silicate were studied for a period of 12 months (June 2014–May 2015). Sea surface temperature varied from 26.4 to 29.7 °C. Salinity varied from 26.1 and 36.2 ‰, hydrogen ion concentration ranged between 8.0 and 8.5. Variation in dissolved oxygen content was from 4.125 to 4.963 mg l−1. Total alkalinity ranged from 64 to 99 mg/l. Total suspended solids ranged from 24 to 97 mg/l. Concentrations of nutrients, viz. nitrates (2.047–4.007 μM/l), nitrites (0.215–0.840 μM/l), phosphates (0.167–0.904 µM/l), total phosphorus (1.039–3.479 μM/l), reactive silicates (3.737–8.876 μM/l) ammonia (0.078–0.526 μM/l) and also varied independently.
Keywords: Physico-chemical parameters; Nutrients; Southeast coast; Bay of Bengal

In the present study, amino-functionalized Mobil Composite Material No. 41 (MCM-41) was used as an adsorbent to remove nitrate anions from aqueous solutions. Mono-, di- and tri-amino functioned silicas (N-MCM-41, NN-MCM-41 and NNN-MCM-41) were prepared by post-synthesis grafting method. The samples were characterized by means of X-ray powder diffraction, FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy and nitrogen adsorption–desorption. The effects of pH, initial concentration of anions, and adsorbent loading were examined in batch adsorption system. Results of adsorption experiments showed that the adsorption capacity increased with increasing adsorbent loading and initial anion concentration. It was found that the Langmuir mathematical model indicated better fit to the experimental data than the Freundlich. According to the constants of the Langmuir equation, the maximum adsorption capacity for nitrate anion by N-MCM-41, NN-MCM-41 and NNN-MCM-41 was found to be 31.68, 38.58 and 36.81 mg/g, respectively. The adsorption kinetics were investigated with pseudo-first-order and pseudo-second-order model. Adsorption followed the pseudo-second-order rate kinetics. The coefficients of determination for pseudo-second-order kinetic model are >0.99. For continuous adsorption experiments, NNN-MCM-41 adsorbent was used for the removal of nitrate anion from solutions. Breakthrough curves were investigated at different bed heights, flow rates and initial nitrate anion concentrations. The Thomas and Yan models were utilized to calculate the kinetic parameters and to predict the breakthrough curves of different bed height. Results from this study illustrated the potential utility of these adsorbents for nitrate removal from water solution.
Keywords: MCM-41; Nitrate; Amine functionalized; Isotherm; Breakthrough analysis

Major ions, trace elements, and isotope concentrations were measured in 11 representative groundwater samples that were collected from a series of aquifers in the Wugou coal mine, Anhui Province. The geochemical characteristics of the groundwater samples were examined using conventional graphical and multivariate statistical approaches, and the results showed that almost all of the groundwater samples collected from the coal-bearing aquifer were the Na-SO4 type, whereas the samples from the Quaternary and the limestone aquifer were the Ca-SO4 and Na-Cl types, respectively. The groundwater in the study area is not suitable for drinking without treatment because of the higher values of total dissolved solids and other parameters, whereas the lower value of the sodium adsorption ratio indicates that it can be used for irrigation. The total rare earth element concentrations ranged from 0.0398 to 0.1874 mg/L, and had an average of 0.075 mg/L. There were negative cerium and positive europium anomalies in the groundwater. The δD and δ 18O values in groundwater ranged from −9.01 to −8.81 ‰, and from −74.7 to −71.4 ‰, respectively. Meteoric water with variable degrees of evaporation is the main source of the groundwater in the coal-bearing aquifer.
Keywords: Hydro-geochemistry; Groundwater; Wugou coal mine; REE; Isotopes

The proper evaluation of evapotranspiration is essential in food security investigation, farm management, pollution detection, irrigation scheduling, nutrient flows, carbon balance as well as hydrologic modeling, especially in arid environments. To achieve sustainable development and to ensure water supply, especially in arid environments, irrigation experts need tools to estimate reference evapotranspiration on a large scale. In this study, the monthly reference evapotranspiration was estimated by three different regression models including the multivariate fractional polynomial (MFP), robust regression, and Bayesian regression in Ardestan, Esfahan, and Kashan. The results were compared with Food and Agriculture Organization (FAO)-Penman–Monteith (FAO-PM) to select the best model. The results show that at a monthly scale, all models provided a closer agreement with the calculated values for FAO-PM (R 2 > 0.95 and RMSE < 12.07 mm month−1). However, the MFP model gives better estimates than the other two models for estimating reference evapotranspiration at all stations.
Keywords: Evapotranspiration; Iran; Multivariate fractional polynomial; Bayesian regression; Robust regression

Characterization of a fluoride-resistant bacterium Acinetobacter sp. RH5 towards assessment of its water defluoridation capability by Shraboni Mukherjee; Vaibhav Yadav; Madhumanti Mondal; Soumya Banerjee; Gopinath Halder (1923-1930).
The present study investigates the defluoridation capability of fluoride-resistant bacteria from contaminated groundwater collected from Asanjola and Madhabpur, West Bengal, India. Seven strains of fluoride-resistant bacteria were isolated employing culture media containing 10–250 mg/L of fluoride to evaluate their ability in reducing fluoride concentration in water. Five isolates exhibited significant amount of reduction in fluoride. Isolate RH5 achieved a maximum fluoride removal of 25.7 % from the media at 30 °C and pH 7 after 8 days of incubation. Based on morphological, physiological characteristics and analysis of 16S rDNA gene sequence, isolate RH5 was identified as Acinetobacter sp. RH5. Growth of RH5 was analysed at a diverse pH range, and it could thrive at pH 5–10. The present investigation revealed that the selective pressure of fluoride results in growth of fluoride-resistant bacteria capable of secreting high-affinity anion-binding compounds. This bacterium played a dominant bioremediative role by concentrating the anions so that they become less available. Hence, the fluoride-resistant bacteria, Acinetobacter sp. RH5, could be used as a promising strain for application in water defluoridation from contaminated sites.
Keywords: Bioremediation; Defluoridation; Xenobiotic; Characterization; Acinetobacter

New biosorbent in removing some metals from industrial wastewater in El Mex Bay, Egypt by Maha Ahmed Mohamed Abdallah; Mohamed E. Mahmoud; Maher M. Osman; Somaia B. Ahmed (1931-1942).
Biosorption is an extensive technology applied for the removal of heavy metal ions and other pollutants from aqueous solutions. In the present study, the biosorption of cadmium, lead, chromium and mercury ions from polluted surface seawater in El-Max Bay was determined using hybrid active carbon sorbents. These sorbents were treated chemically by acid, base and redox reaction followed by surface loading of baker’s yeast biomass for increasing their biosorption capacity and the highest metal uptake values. The surface function and morphology of the hybrid immobilized sorbents were studied by Fourier Transform Infrared analysis and scanning electron microscope imaging. Metal removal values proved that the vital role of baker’s yeast as a significant high removable due to functional groups at baker’s yeast cell wall surface that have the ability to forming various coordination complexes with metal ions. A noticeable increase in the removal of all studied metals was observed and reached to 100 %.
Keywords: Activated carbon; Baker’s yeast; Wastewater; El Mex Bay; Egypt

FeCl3 coagulation was used to achieve maximum reduction of COD, phosphate, sulfate and color and process optimization (FeCl3 dosage, pH, reaction time) was done by BBD-RSM. Responses were recorded in terms of EC, COD, phosphate, color and sulfate removal. Variables A (pH) and B (reaction time) were negatively related to removal of COD and phosphate, whereas, C (FeCl3 dosage) was positive in case of COD removal and negative for phosphate removal. pH and coagulant dosage had negative relationship with color removal; however, reaction time showed positive relationship. In case of percent sulfate removal, variable A (pH) demonstrated negative relationship whereas B (reaction time) and C (FeCl3 dosage) were found to be positively related. Numerical optimization of the model revealed a maximum reduction of 71, 93, 86 and 99.6 % COD, phosphate, color and sulfate at optimal FeCl3 dosage = 3 g/l, pH 8, and reaction time = 95 min.
Keywords: Landfill leachate; Ferric chloride; Response surface methodology; Box–Behnken design; Coagulation; Optimization; COD; Decolorization; Phosphate removal; Sulfate removal

Identification of pollutant sources for river pollution incidents is an important and difficult task in the emergency rescue, and an intelligent optimization method can effectively compensate for the weakness of traditional methods. An intelligent model for pollutant source identification has been established using the basic genetic algorithm (BGA) as an optimization search tool and applying an analytic solution formula of one-dimensional unsteady water quality equation to construct the objective function. Experimental tests show that the identification model is effective and efficient: the model can accurately figure out the pollutant amounts or positions no matter single pollution source or multiple sources. Especially when the population size of BGA is set as 10, the computing results are sound agree with analytic results for a single source amount and position identification, the relative errors are no more than 5 %. For cases of multi-point sources and multi-variable, there are some errors in computing results for the reasons that there exist many possible combinations of the pollution sources. But, with the help of previous experience to narrow the search scope, the relative errors of the identification results are less than 5 %, which proves the established source identification model can be used to direct emergency responses.
Keywords: Water pollution incident; Basic genetic algorithm (BGA); Pollutant amount; Pollution source position; Identification model

Kinetic modeling of liquid-phase adsorption of Congo red dye using guava leaf-based activated carbon by Adedamola Titi Ojedokun; Olugbenga Solomon Bello (1965-1977).
Guava leaf, a waste material, was treated and activated to prepare adsorbent. The adsorbent was characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infra Red (FTIR) and Energy-Dispersive X-ray (EDX) techniques. The carbonaceous adsorbent prepared from guava leaf had appreciable carbon content (86.84 %). The adsorption of Congo red dye onto guava leaf-based activated carbon (GLAC) was studied in this research. Experimental data were analyzed by four different model equations: Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms and it was found to fit Freundlich equation most. Adsorption rate constants were determined using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion model equations. The results clearly showed that the adsorption of CR dye onto GLAC followed pseudo-second-order kinetic model. Intraparticle diffusion was involved in the adsorption process. The mean energy of adsorption calculated from D-R isotherm confirmed the involvement of physical adsorption. Thermodynamic parameters were obtained and it was found that the adsorption of CR dye onto GLAC was an exothermic and spontaneous process at the temperatures under investigation. The maximum adsorption of CR dye by GLAC was found to be 47.62 mg/g. The study shows that GLAC is an effective adsorbent for the adsorption of CR dye from aqueous solution.
Keywords: Adsorption; Congo red; Guava leaf-based activated carbon (GLAC); Kinetics; Exothermic; Thermodynamics

Flood frequency analysis of Ganga river at Haridwar and Garhmukteshwar by Vikas Kamal; Saumitra Mukherjee; P. Singh; R. Sen; C. A. Vishwakarma; P. Sajadi; H. Asthana; V. Rena (1979-1986).
The Ganga River is a major river of North India and is known for its fertile alluvium deposits formed due to floods throughout the Indo-Gangetic plains. Flood frequency analysis has been carried out through various approaches for the Ganga River by many scientists. With changes in river bed brought out by anthropogenic changes the intensity of flood has also changed in the last decade, which calls for further study. The present study is in a part of the Upper Indo-Ganga plains subzone 1(e). Statistical distributions applied on the discharge data at two stations found that for Haridwar lognormal and for Garhmukteshwar Gumbel EV1 is applicable. The importance of this study lies in its ability to predict the discharge for a return period after a suitable distribution is found for an area.
Keywords: Discharge; Flood frequency; Generalized extreme value; Goodness of fit tests; Gumbel distribution; Lognormal 3P; Log Pearson type III

Biosorption studies on waste cotton seed for cationic dyes sequestration: equilibrium and thermodynamics by N. Sivarajasekar; R. Baskar; T. Ragu; K. Sarika; N. Preethi; T. Radhika (1987-1995).
The immature Gossypium hirsutum seeds—an agricultural waste was converted into a novel adsorbent and its effectiveness for cationic dyes removal was discussed in this study. Characterization revealed that sulfuric acid activated waste Gossypium hirsutum seed (WGSAB) contains surface area 496 m2 g−1. The ability of WGSAB to adsorb basic red 2 (BR2) and basic violet 3 (BV3) from aqueous solutions has been studied. Batch adsorption studies were carried out at different initial dye concentrations (100–300 mg l−1), contact time (1–5 h), pH (2–12) and temperature (293–323 K) to understand the adsorption mechanism. Adsorption data were modeled using Langmuir, Freundlich and Toth adsorption isotherms. Equilibrium data of the adsorption process fitted very well to the Toth model for both dyes. The Langmuir maximum adsorption capacity was 66.69 mg g−1 for BV3 and 50.11 mg g−1 for BR2 at optimum conditions. The near unity value of Toth isotherm constant (BR2: 0.999 and BV3: 1.0) indicates that WGSAB surface is heterogeneous in nature. The maximum adsorption capacity predicted by Toth isotherm of BV3 (66.699 mg g−1) is higher than BR2 (50.310 mg g−1). The kinetic investigation revealed that the BR2 and BV3 were chemisorbed on WGSAB surface following Avrami fractional order kinetics. Further, the fractional order and rate constant values are almost similar for every concentration in both the dyes. The thermodynamic parameters such as ΔH 0, ΔS 0 and ΔG 0 were evaluated. The dye adsorption process was found to be spontaneous and endothermic for the two dyes. Regeneration of WGSAB exhausted by the two dyes could be possible via acetic acid as elutant.
Keywords: Adsorption; Gossypium hirsutum seed; Isotherm; Kinetic; Thermodynamic

Spatial variability of groundwater quality of Sabour block, Bhagalpur district (Bihar, India) by D. K. Verma; Gouri Sankar Bhunia; Pravat Kumar Shit; S. Kumar; Jajati Mandal; Rajeev Padbhushan (1997-2008).
This paper examines the quality of groundwater of Sabour block, Bhagalpur district of Bihar state, which lies on the southern region of Indo-Gangetic plains in India. Fifty-nine samples from different sources of water in the block have been collected to determine its suitability for drinking and irrigational purposes. From the samples electrical conductivity (EC), pH and concentrations of Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Potassium (K+), carbonate ion (CO 3 2− ), Bicarbonate ion (HCO 3 - ), Chloride ion (Cl), and Fluoride (F) were determined. Surface maps of all the groundwater quality parameters have been prepared using radial basis function (RBF) method. RBF model was used to interpolate data points in a group of multi-dimensional space. Root Mean Square Error (RMSE) is employed to scrutinize the best fit of the model to compare the obtained value. The mean value of pH, EC, Ca2+, Mg2+, Na+, K+, HCO3 , Cl, and F are found to be 7.26, 0.69, 38.98, 34.20, 16.92, 1.19, 0.02, and 0.28, respectively. Distribution of calcium concentration is increasing to the eastern part and K+ concentrations raise to the downstream area in the southwestern part. Low pH concentrations (less than 6.71) occur in eastern part of the block. Spatial variations of hardness in Sabour block portraying maximum concentration in the western part and maximum SAR (more than 4.23) were recorded in the southern part. These results are not exceeding for drinking and irrigation uses recommended by World Health Organization. Therefore, the majority of groundwater samples are found to be safe for drinking and irrigation management practices.
Keywords: Groundwater quality; Spatial distribution; GIS; RBF model

Effect of process variables interaction on simultaneous adsorption of phenol and 4-chlorophenol: statistical modeling and optimization using RSM by Kwok-Yii Leong; Sylvia See; Jun-Wei Lim; Mohammed J. K. Bashir; Choon-Aun Ng; Leony Tham (2009-2020).
Results of the interaction of process variables and the consequential mixture of phenolic compounds adsorption study are expected to shed brighter light on the wastewater treatment applications. Accordingly, the aims of this research are to model and optimize the process variables which impinged on the simultaneous adsorption of phenol and 4-chlorophenol (4-CP) in the binary solution by spherical activated carbon (SAC). Batch assessments were designed using response surface methodology software. The process variables, namely SAC dosage and pH were varied over the 1.50–3.50 g/L and 4.00–9.00 g/L ranges, respectively, were experimented. The analysis of variance results showed the significant models could precisely predict the percentage removals of phenol and 4-CP, indicating models reliability. The interaction of process variables was inconspicuous for the case of phenol adsorption. However, increasing the pH would deteriorate the 4-CP adsorption which was partially offset by raising the SAC dosage. Considering the environmental benefits, optimization taken place at the SAC dosage and pH of 3.50 g/L and 7.60 g/L, respectively, was selected. By employing the optimized conditions of SAC dosage of 3.50 g/L at pH 7.60 for the adsorption process, the predicted phenol and 4-CP removal percentages were found to be 85.4 % (73.1 mg/g) and 96.2 % (82.6 mg/g), respectively, which were in agreement with the experimental runs.
Keywords: Simultaneous adsorption; Process variable; Modeling; Optimization; Binary solution

In this article, the adsorption process of cadmium and copper using natural Jordanian (NJ) zeolite as adsorbent has been experimentally estimated. The samples of NJ zeolite were obtained from Al Mafraq discrete, north east of Jordan. The influence of the bulk concentration (C o), contact time (t) and different adsorbent masses (m) of NJ zeolite on the removal of heavy metal were evaluated. These variables had a considerable function in promoting the sorption process of heavy metal using the NJ zeolite. The initial concentration of heavy metals in the stock solution was extended between 80 and 600 mg/L. The batch adsorption method was employed to investigate the adsorption process. The experimental data were correlated using Freundlich and Langmuir empirical formula. The ability of NJ zeolite to eliminate cadmium and copper was estimated according to Langmuir isotherm empirical formula and found 25.9 and 14.3 mg/g for cadmium and copper, respectively. The kinetics of adsorption of cadmium and copper have been analyzed and correlated by first-order and second-order reaction model. It was noticed that adsorption of cadmium and copper was better correlated with pseudo-second-order kinetic model. The results presented that NJ zeolite is practical adsorbent for removing cadmium and copper ion metal.
Keywords: NJ zeolite; Batch process; Cadmium; Copper; Isotherm; Kinetic

Climate change impact assessment on hydrology of a small watershed using semi-distributed model by Brij Kishor Pandey; A. K. Gosain; George Paul; Deepak Khare (2029-2041).
This study is an attempt to quantify the impact of climate change on the hydrology of Armur watershed in Godavari river basin, India. A GIS-based semi-distributed hydrological model, soil and water assessment tool (SWAT) has been employed to estimate the water balance components on the basis of unique combinations of slope, soil and land cover classes for the base line (1961–1990) and future climate scenarios (2071–2100). Sensitivity analysis of the model has been performed to identify the most critical parameters of the watershed. Average monthly calibration (1987–1994) and validation (1995–2000) have been performed using the observed discharge data. Coefficient of determination ( $$R^{2}$$ R 2 ), Nash–Sutcliffe efficiency (ENS) and root mean square error (RMSE) were used to evaluate the model performance. Calibrated SWAT setup has been used to evaluate the changes in water balance components of future projection over the study area. HadRM3, a regional climatic data, have been used as input of the hydrological model for climate change impact studies. In results, it was found that changes in average annual temperature (+3.25 °C), average annual rainfall (+28 %), evapotranspiration (28 %) and water yield (49 %) increased for GHG scenarios with respect to the base line scenario.
Keywords: Hydrological modeling; Climate change; HadRM3; SWAT; Armur; Emission scenarios

Assessment of combined toxicity of heavy metals from industrial wastewaters on Photobacterium phosphoreum T3S by BibiSaima Zeb; Zheng Ping; Qaisar Mahmood; Qiu Lin; Arshid Pervez; Muhammad Irshad; Muhammad Bilal; Zulfiqar Ahmad Bhatti; Shahida Shaheen (2043-2050).
This research work is focusing on the toxicities of heavy metals of industrial origin to anaerobic digestion of the industrial wastewater. Photobacterium phosphoreum T3S was used as an indicator organism. The acute toxicities of heavy metals on P. phosphoreum T3S were assessed during 15-min half inhibitory concentration (IC50) as indicator at pH 5.5–6. Toxicity assays involved the assessment of multicomponent mixtures using TU and MTI approaches. The results of individual toxicity indicated that the toxicity of Cd, Cu and Pb on P. phosphoreum increased with increasing concentrations and there was a linear correlation. The 15-min IC50 values of Cd, Cu and Pb were 0.537, 1.905 and 1.231 mg/L, respectively, and their toxic order was Cd > Pb > Cu. The combined effects of Cd, Cu and Pb were assayed by equivalent concentration mixing method. The results showed that the combined effects of Cd + Cu, Cd + Pb, Cu + Pb, Cd + Cu + Pb were antagonistic, antagonistic and partly additive. The combined effect of three heavy metals was partly additive.
Keywords: Heavy metals; Photobacterium; Acute toxicity; Wastewater treatment

Adsorption studies were done on Boston fern leaves for the effective removal of Cu(II) ions from aqueous solution. It has been tested for the first time for heavy metal adsorption from aqueous solution. This promising material has shown remarkable adsorption capacity towards Cu(II) ions which confirm its novelty, ease of availability, non-toxic nature, cheapness, etc., and give the main innovation to the present study. The adsorbent was analyzed by FT-IR, SEM and EDS. The effect of pH, contact time, initial metal ion concentration and temperature on the adsorption was investigated using batch process to optimize conditions for maximum adsorption. The adsorption of Cu(II) was maximum (96 %) at pH 4. The experimental data were analyzed by Langmuir, Freundlich and Tempkin isotherms. The kinetic studies of Cu(II)were carried out at room temperature (30 °C) in the concentration range 10–100 mg L−1. The data obtained fitted well with the Langmuir isotherm and pseudo-second-order kinetics model. The maximum adsorption capacity (q m) obtained from Langmuir adsorption isotherm was found to be 27.027 mg g−1 at 30 °C. The process was found to be exothermic and spontaneous in nature. The breakthrough and exhaustive capacities were found to be 12.5 and 37.5 mg g−1, respectively. Desorption studies showed that 93.3 % Cu(II) could be desorbed with 0.1 M HCl by continuous mode.
Keywords: Adsorption; Boston fern; Isotherms; Thermodynamic; Kinetics; Breakthrough capacity

Batch and fixed-bed adsorption of tartrazine azo-dye onto activated carbon prepared from apricot stones by H. I. Albroomi; M. A. Elsayed; A. Baraka; M. A. Abdelmaged (2063-2074).
This work describes the potential of utilizing prepared activated carbon from apricot stones as an efficient adsorbent material for tartrazine (TZ) azo-dye removal in a batch and dynamic adsorption system. The results revealed that activated carbons with well-developed surface area (774 m2/g) and pore volume (1.26 cm3/g) can be manufactured from apricot stones by H3PO4 activation. In batch experiments, effects of the parameters such as initial dye concentration and temperature on the removal of the dye were studied. Equilibrium was achieved in 120 min. Adsorption capacity was found to be dependent on the initial concentration of dye solution, and maximum adsorption was found to be 76 mg/g at 100 mg/L of TZ. The adsorption capacity at equilibrium (q e) increased from 22.6 to 76 mg/g with an increase in the initial dye concentrations from 25 to 100 mg/L. The thermodynamic parameters such as change in free energy (ΔG 0), enthalpy (ΔH 0) and entropy (ΔS 0) were determined and the positive value of (ΔH) 78.1 (K J mol−1) revealed that adsorption efficiency increased with an increase in the process temperature. In fixed-bed column experiments, the effect of selected operating parameters such as bed depth, flow rate and initial dye concentration on the adsorption capacity was evaluated. Increase in bed height of adsorption columns leads to an extension of breakthrough point as well as the exhaustion time of adsorbent. However, the maximum adsorption capacities decrease with increases of flow rate. The breakthrough data fitted well to bed depth service time and Thomas models with high coefficient of determination, R 2 ≥ 94.
Keywords: Adsorption of tartrazine azo-dye; Apricot stones; Fixed-bed column; Breakthrough curve

Effects of rainfalls variability and physical–chemical parameters on enteroviruses in sewage and lagoon in Yopougon, Côte d’Ivoire by Kouassi Julien Momou; Chantal Akoua-Koffi; Karim Sory Traoré; Djako Sosthène Akré; Mireille Dosso (2075-2087).
The aim of this study was to assess the variability of the content of nutrients, oxidizable organic and particulate matters in raw sewage and the lagoon on the effect of rainfall. Then evaluate the impact of these changes in the concentration of enteroviruses (EVs) in waters. The sewage samples were collected at nine sampling points along the channel, which flows, into a tropical lagoon in Yopougon. Physical–chemical parameters (5-day Biochemical Oxygen Demand, Chemical Oxygen Demand, Suspended Particulate Matter, Total Phosphorus, Orthophosphate, Total Kjeldahl Nitrogen and Nitrate) as well as the concentration of EV in these waters were determined. The average numbers of EV isolated from the outlet of the channel were 9.06 × 104 PFU 100 ml−1. Consequently, EV was present in 55.55 and 33.33 % of the samples in the 2 brackish lagoon collection sites. The effect of rainfall on viral load at the both sewage and brackish lagoon environments is significant correlate (two-way ANOVA, P < 0.05). Furthermore, in lagoon environment, nutrients (Orthophosphate, Total Phosphorus), 5-day Biochemical Oxygen Demand, Chemical Oxygen Demand and Suspended Particulate Matter were significant correlated with EVs loads (P < 0.05 by Pearson test). The overall results highlight the problem of sewage discharge into the lagoon and correlation between viral loads and water quality parameters in sewage and lagoon.
Keywords: Enteroviruses; Correlation; Oxidizable organic matters, suspended matters; Nutrients; Yopougon, Côte d’Ivoire