Applied Water Science (v.7, #1)

A review on characterization and bioremediation of pharmaceutical industries’ wastewater: an Indian perspective by Rajender Singh Rana; Prashant Singh; Vikash Kandari; Rakesh Singh; Rajendra Dobhal; Sanjay Gupta (1-12).
During the past few decades, pharmaceutical industries have registered a quantum jump contributing to high economic growth, but simultaneously it has also given rise to severe environmental pollution. Untreated or allegedly treated pharmaceutical industrial wastewater (PIWW) creates a need for time to time assessment and characterization of discharged wastewater as per the standards provided by the regulatory authorities. To control environmental pollution, pharmaceutical industries use different treatment plans to treat and reuse wastewater. The characterization of PIWW using advanced and coupled techniques has progressed to a much advanced level, but in view of new developments in drug manufacture for emerging diseases and the complexities associated with them, better sophisticated instrumentation and methods of treatment are warranted. The bioremediation process to treat PIWW has undergone more intense investigation in recent decade. This results in the complete mineralization of pharmaceutical industries’ wastewater and no waste product is obtained. Moreover, high efficiency and low operation cost prove it to be an effective tool for the treatment of PIWW. The present review focuses on the characterization as well as bioremediation aspects of PIWW.
Keywords: Pharmaceutical industries; Wastewater; Characterization and bioremediation

Research trends in electrochemical technology for water and wastewater treatment by Tianlong Zheng; Juan Wang; Qunhui Wang; Huimin Meng; Lihong Wang (13-30).
It is difficult to completely degrade wastewater containing refractory pollutants without secondary pollution by biological treatment, as well as physical–chemical process. Therefore, electrochemical technology has attracted much attention for its environmental compatibility, high removal efficiency, and potential cost effectiveness, especially on the industrial wastewater treatment. An effective bibliometric analysis based on the Science Citation Index Core Collection database was conducted to evaluate electrochemical technology for water and wastewater treatment related research from 1994 to 2013. The amount of publications significantly increased in the last two decades. Journal of the Electrochemical Society published the most articles in this field with a top h-index of 90, taking 5.8 % of all, followed by Electrochimica Acta and Journal of Electroanalytical Chemistry. The researchers focused on categories of chemistry, electrochemistry, and materials science. China and Chinese Academy of Sciences were the most productive country and institution, respectively, while the USA, with the most international collaborative articles and highest h-index of 130, was the major collaborator with 15 other countries in top 20 most productive countries. Moreover, based on the analysis of author keywords, title, abstract, and ‘KeyWords Plus’, a new method named “word cluster analysis” was successfully applied to trace the research hotspot. Nowadays, researchers mainly focused on novel anodic electrode, especially on its physiochemical and electrochemical properties.
Keywords: Scientometrics; Web of science core collection; Electrochemical technology; Research trends; Water and wastewater treatment

Oxidation pond for municipal wastewater treatment by Erick Butler; Yung-Tse Hung; Mohammed Suleiman Al Ahmad; Ruth Yu-Li Yeh; Robert Lian-Huey Liu; Yen-Pei Fu (31-51).
This literature review examines process, design, and cost issues related to using oxidation ponds for wastewater treatment. Many of the topics have applications at either full scale or in isolation for laboratory analysis. Oxidation ponds have many advantages. The oxidation pond treatment process is natural, because it uses microorganisms such as bacteria and algae. This makes the method of treatment cost-effective in terms of its construction, maintenance, and energy requirements. Oxidation ponds are also productive, because it generates effluent that can be used for other applications. Finally, oxidation ponds can be considered a sustainable method for treatment of wastewater.
Keywords: Oxidation pond; Waste stabilization pond; Tertiary treatment; Wastewater treatment; Sustainability treatment

Groundwater in the northeastern Amman-Zarqa basin is an important source of water for irrigation. The quality and quantity of water has deteriorated due to mismanagement and misunderstanding of the hydrogeological system. Overexploitation of groundwater resources upstream of the Khirbet Al-Samra wastewater treatment plant (KSWTP) has lowered the water table 43 m since the beginning of groundwater development in 1968. Heavy pumping of groundwater downstream of KSWTP has not dropped the water level due to constant recharge from the Zarqa river bed. The water level of groundwater is rising continuously at a rate of 20 cm per year since building the KSWTP in 1985. Groundwater salinity has also shifted the quality of the aquifer from fresh to brackish. Continual irrigation from the groundwater upstream of KSWTP dissolves accumulated salt from the soil formed by evaporation, and the contaminated water infiltrates back to the aquifer, thereby increasing both salt and nitrate concentrations. The intense irrigation from the reclaimed water downstream of KSWTP and leakage of treated wastewater from the Zarqa River to the shallow groundwater is a secondary source of salt and nitrates. The isotopic composition of groundwater varies over a wide range and is associated with the meteoric water line affected by Mediterranean Sea air moisture. The isotopic composition of groundwater is represented by evaporation line (EL) with a low slope of 3.6. The enrichment of groundwater in δ18O and δD is attributed mainly to the two processes of evaporation before infiltration of return flow and mixing of different types of water in KSWTP originating from different aquifers. The EL starts from a location more depleted than the weighted mean value of the Amman rainfall station on the Eastern Meteoric Water Line indicating that the recharge took place under the climate regime prevailing today in Jordan and the recharge of the groundwater originates from a greater elevation than that of the Amman station. Elevated high tritium levels observed in wells in close proximity to a regional fault system signify local recharge and short residence time. The Khaldyia dam is a local source for groundwater recharge.
Keywords: Salinity; Over-exploitation; Return flow; Recharge; Environmental isotope; Fault

Occurrence of nitrate in Tanzanian groundwater aquifers: A review by Eliapenda Elisante; Alfred N. N. Muzuka (71-87).
More than 25 % of Tanzanian depends on groundwater as the main source of water for drinking, irrigation and industrial activities. The current trend of land use may lead to groundwater contamination and thus increasing risks associated with the usage of contaminated water. Nitrate is one of the contaminants resulting largely from anthropogenic activities that may find its way to the aquifers and thus threatening the quality of groundwater. Elevated levels of nitrate in groundwater may lead to human health and environmental problems. The current trend of land use in Tanzania associated with high population growth, poor sanitation facilities and fertilizer usage may lead to nitrate contamination of groundwater. This paper therefore aimed at providing an overview of to what extent human activities have altered the concentration of nitrate in groundwater aquifers in Tanzania. The concentration of nitrate in Tanzanian groundwater is variable with highest values observable in Dar es Salaam (up to 477.6 mg/l), Dodoma (up to 441.1 mg/l), Tanga (above 100 mg/l) and Manyara (180 mg/l). Such high values can be attributed to various human activities including onsite sanitation in urban centres and agricultural activities in rural areas. Furthermore, there are some signs of increasing concentration of nitrate in groundwater with time in some areas in response to increased human activities. However, reports on levels and trends of nitrate in groundwater in many regions of the country are lacking. For Tanzania to appropriately address the issue of groundwater contamination, a deliberate move to determine nitrate concentration in groundwater is required, as well as protection of recharge basins and improvement of onsite sanitation systems.
Keywords: Groundwater contamination; Human activities; Nitrate concentration; Tanzania

In this study, intrinsic groundwater vulnerability for the shallow aquifer in northeastern Missan governorate, south of Iraq is evaluated using commonly used DRASTIC model in framework of GIS environment. Preparation of DRASTIC parameters is attained through gathering data from different sources including field survey, geological and meteorological data, a digital elevation model DEM of the study area, archival database, and published research. The different data used to build DRASTIC model are arranged in a geospatial database using spatial analyst extension of ArcGIS 10.2 software. The obtained results related to the vulnerability to general contaminants show that the study area is characterized by two vulnerability zones: low and moderate. Ninety-four percentage (94 %) of the study area has a low class of groundwater vulnerability to contamination, whereas a total of (6 %) of the study area has moderate vulnerability. The pesticides DRASTIC index map shows that the study area is also characterized by two zones of vulnerability: low and moderate. The DRASTIC map of this version clearly shows that small percentage (13 %) of the study area has low vulnerability to contamination, and most parts have moderate vulnerability (about 87 %). The final results indicate that the aquifer system in the interested area is relatively protected from contamination on the groundwater surface. To mitigate the contamination risks in the moderate vulnerability zones, a protective measure must be put before exploiting the aquifer and before comprehensive agricultural activities begin in the area.
Keywords: Vulnerability map; DRASTIC model; ArcGIS; Missan governorate; South of Iraq

Climate change impact on forest cover and vegetation in Betwa Basin, India by S. S. Palmate; Ashish Pandey; Dheeraj Kumar; R. P. Pandey; S. K. Mishra (103-114).
This paper evaluates the effect of climate change (described in terms of temperature and rainfall) on forest cover and vegetation (described in terms of Normalized Difference Vegetation Index) in the Betwa river basin, a tributary of River Yamuna in Central India. Temperature and rainfall data of 18 stations, forest cover and vegetation (derived using 5 years data from Landsat images employing ERDAS Imagine and ArcGIS) were used in the analysis. The effect of climate change was studied for both the pre-monsoon and post-monsoon seasons. In this study, the simple regression method was used to evaluate their relationship. In pre-monsoon season, temperature and forest cover analysis shows regression coefficient value of 0.6876 and, temperature and vegetation analysis shows regression coefficient value of 0.5751. Further, in post-monsoon season analysis rainfall and forest cover shows regression coefficient value of 0.8417 and, temperature and vegetation analysis shows regression coefficient value of 0.6854. The study reveals that, in pre-monsoon season temperature was significantly related with forest cover and vegetation. In post-monsoon season rainfall exhibited positive response to forest cover and, temperature exhibited negative response to vegetation in the Betwa river basin.
Keywords: Climate; Betwa river basin; Climate parameters; Forest cover; Vegetation; NDVI

Enhanced photocatalytic activity of metal oxides/β-cyclodextrin nanocomposites for decoloration of Rhodamine B dye under solar light irradiation by Subramanian Rajalakshmi; Sakthivel Pitchaimuthu; Nagarathinam Kannan; Ponnusamy Velusamy (115-127).
We present the photocatalytic decoloration of Rhodamine B (RhB) dye with the nanocomposites such as TiO2, ZnO, TiO2/β-cyclodextrin (β-CD) and ZnO/β-CD. Band gap energy of nanocomposites was calculated by UV-DRS analysis and the results showed that the band gap energy of ZnO/β-CD nanocomposite is lower than that of other catalysts. The microstructures of the nanocomposites have been characterized by PXRD and FE-SEM analyses. The results showed that crystallinity and surface morphology of metal oxides (MO) (say, TiO2 and ZnO) are not changed in MO/β-CD nanocomposite systems. GC–MS results showed that the photocatalytic decoloration of RhB follows the steps such as N-deethylation, cleavage of chromophore and mineralization of dye.
Keywords: RhB; TiO2 ; ZnO; TiO2/β-CD; ZnO/β-CD

Mg−Al oxide, obtained by the thermal decomposition of a CO3 2−-intercalated Mg−Al layered double hydroxide (CO3·Mg−Al LDH), simultaneously absorbed Cl and SO4 2− from seawater and generated a Mg−Al LDH intercalated with Cl and SO4 2−. The Mg−Al oxide with a molar ratio Mg/Al = 4 was more superior than the oxide with Mg/Al = 2 for Cl removal, whereas a reverse phenomenon was observed for SO4 2− removal. The removal of Cl and SO4 2− by the Mg−Al oxide with Mg/Al = 4 could be represented by first-order and pseudo second-order reactions, respectively. The removal of both Cl and SO4 2− by the Mg−Al oxide with Mg/Al = 2 could be represented by a pseudo second-order reaction. The removal of both Cl and SO4 2− by the Mg−Al oxides with Mg/Al = 4 and 2 was proceeded under chemical reaction control. The adsorption isotherms for Cl and SO4 2− adsorbed by the Mg−Al oxides could be expressed by Langmuir-type adsorption. These reactions were derived from monolayer adsorption, indicating the intercalation of Cl and SO4 2− in the interlayer space of Mg−Al LDH. The uptake of Cl and SO4 2− from seawater by Mg−Al oxide was proceeded spontaneously.
Keywords: Chloride ion; Sulfate ion; Mg−Al oxide; Simultaneous removal; Kinetics; Equilibrium

Analyses of freshwater stress with a couple ground and surface water model in the Pra Basin, Ghana by George Owusu; Alex B. Owusu; Ebenezer Forkuo Amankwaa; Fatima Eshun (137-153).
The optimal management of water resources requires that the collected hydrogeological, meteorological, and spatial data be simulated and analyzed with appropriate models. In this study, a catchment-scale distributed hydrological modeling approach is applied to simulate water stress for the years 2000 and 2050 in a data scarce Pra Basin, Ghana. The model is divided into three parts: The first computes surface and groundwater availability as well as shallow and deep groundwater residence times by using POLFLOW model; the second extends the POLFLOW model with water demand (Domestic, Industrial and Agricultural) model; and the third part involves modeling water stress indices—from the ratio of water demand to water availability—for every part of the basin. On water availability, the model estimated long-term annual Pra river discharge at the outflow point of the basin, Deboase, to be 198 m3/s as against long-term average measurement of 197 m3/s. Moreover, the relationship between simulated discharge and measured discharge at 9 substations in the basin scored Nash–Sutcliffe model efficiency coefficient of 0.98, which indicates that the model estimation is in agreement with the long-term measured discharge. The estimated total water demand significantly increases from 959,049,096 m3/year in 2000 to 3,749,559,019 m3/year in 2050 (p < 0.05). The number of districts experiencing water stress significantly increases (p = 0.00044) from 8 in 2000 to 21 out of 35 by the year 2050. This study will among other things help the stakeholders in water resources management to identify and manage water stress areas in the basin.
Keywords: PCRaster; GIS; River discharge; Water vulnerability; Groundwater; POLFLOW

Assessment of physico-chemical quality of borehole and spring water sources supplied to Robe Town, Oromia region, Ethiopia by Dagim Abera Shigut; Geremew Liknew; Dejene Disasa Irge; Tanweer Ahmad (155-164).
The study was carried out to find the physico-chemical water quality of borehole and spring water supplied to Robe Town. For this study, a total of six water samples were collected from three borehole and three spring water sources. The analyses for 14 physico-chemical parameters, pH, turbidity, electrical conductivity, total dissolved solids, total suspended solids total hardness cations (Ca2+, Mg2+), anions (NO2 , NO3 , SO4 2− and PO4 3−) and heavy metals (Fe and Mn), were done in the laboratory by adopting standard procedures suggested by the American Public Health Association (APHA). Descriptive statistics were used to describe data, while Pearson correlation was used to determine the influences of the physico-chemical variables. The single factor analysis of variance (t test) was used to determine possible differences between the borehole and spring water, while means plots were used for further structure detection. From the total samples analyzed, most of the samples comply with the water quality guidelines of Ethiopian limit, WHO and U.SEPA. The pH of the water samples from borehole groundwater source was found to be slightly acidic and bove the maximum permissible limit (MPL). High concentration of Fe and Mn that exceeds the MPL set by WHO was found in the three boreholes. The spring water sources were found to be better for drinking than borehole water sources.
Keywords: Robe Town; Water quality; Borehole; Groundwater; Spring water

Experiments in two laboratory-scale sequential batch reactors were carried out to investigate the effect of heterotrophic bacteria on nitrifying bacteria using external carbon sources. Partial nitrification of ammonium-rich wastewater during short-term acclimatization enriched the activity of ammonia-oxidizing bacteria in both reactors. Heterotrophic bacteria exhibited a minor effect on nitrifying bacteria, and complete removal of ammonium occurred at a rate of 41 mg L−1 h−1 in both reactors. The main strategy of this research was to carry out partial nitrification using high-activity ammonia-oxidizing bacteria with a high concentration of free ammonia (70 mg L−1). The NO2 /(NO3  + NO2 ) ratio was greater than 0.9 in both reactors most of the time.
Keywords: Nitrification; Nitrifying bacteria; Ammonium-rich wastewater; Partial nitrification

Changes in water quality in the Owabi water treatment plant in Ghana by Osei Akoto; Opoku Gyamfi; Godfred Darko; Victor Rex Barnes (175-186).
The study was conducted on the status of the quality of water from the Owabi water treatment plant that supplies drinking water to Kumasi, a major city in Ghana, to ascertain the change in quality of water from source to point-of-use. Physico-chemical, bacteriological water quality parameters and trace metal concentration of water samples from five different treatment points from the Owabi water treatment plant were investigated. The raw water was moderately hard with high turbidity and colour that exceeds the WHO guideline limits. Nutrient concentrations were of the following order: NH3 < NO2  < NO3  < PO4 3− < SO4 2− and were all below WHO permissible level for drinking water in all the samples at different stages of treatment. Trace metal concentrations of the reservoir were all below WHO limit except chromium (0.06 mg/L) and copper (0.24 mg/L). The bacteriological study showed that the raw water had total coliform (1,766 cfu/100 mL) and faecal coliform (257 cfu/100 mL) that exceeded the WHO standard limits, rendering it unsafe for domestic purposes without treatment. Colour showed strong positive correlation with turbidity (r = 0.730), TSS (r ≥ 0.922) and alkalinity (0.564) significant at p < 0.01. The quality of the treated water indicates that colour, turbidity, Cr and Cu levels reduced and fall within the WHO permissible limit for drinking water. Treatment process at the water treatment plant is adjudged to be good.
Keywords: Water quality; Treatment process; Owabi; Bacteriological; Physico-chemical

The most important weather variations are temperature (T), relative humidity (RH), and wind speed (u) for evapotranspiration models in limited data conditions. This study aims to compare three T-based formula, T/RH-based formula, and T/RH/u-based formula to detect the performance of them under limited data and different weather conditions. For this purpose, weather data were gathered from 181 synoptic stations in 31 provinces of Iran. The potential evapotranspiration was compared with the FAO Penman–Monteith method. The results showed that T-based formula, T/RH-based formula, and T/RH/u-based formula estimated potential evapotranspiration with R 2 >0.93 for 6, 12, and 30 provinces of Iran, respectively. They are more suitable for southeast of Iran (YA, KE, SB, and SK). The best precise method was the T/RH/u-based formula for SK and GO. Finally, a list of the best performance of each method has been presented to use other regions and next researches according to values of temperature, relative humidity, and wind speed. The best weather conditions to use the formulas are 14–26 °C and 2.50–3.50 m/s for temperature and wind speed, respectively.
Keywords: Evapotranspiration; Humidity; Iran; Radiation; Temperature; Wind

Sorption of mercury onto waste material derived low-cost activated carbon by Jatindra N. Bhakta; Sukanta Rana; Susmita Lahiri; Yukihiro Munekage (199-206).
The present study was performed to develop the low-cost activated carbon (AC) from some waste materials as potential mercury (Hg) sorbent to remove high amount of Hg from aqueous phase. The ACs were prepared from banana peel, orange peel, cotton fiber and paper wastes by pyrolysis and characterized by analyzing physico-chemical properties and Hg sorption capacity. The Brunauer Emmett and Teller surface areas (cotton 138 m2/g; paper 119 m2/g), micropore surface areas (cotton 65 m2/g; paper 54 m2/g) and major constituent carbon contents (cotton 95.04 %; paper 94.4 %) were higher in ACs of cotton fiber and paper wastes than the rest two ACs. The Hg sorption capacities and removal percentages were greater in cotton and paper wastes-derived ACs compared to those of the banana and orange peels. The results revealed that elevated Hg removal ability of cotton and paper wastes-derived ACs is largely regulated by their surface area, porosity and carbon content properties. Therefore, ACs of cotton and paper wastes were identified as potential sorbent among four developed ACs to remove high amount of Hg from aqueous phase. Furthermore, easily accessible precursor material, simple preparation process, favorable physico-chemical properties and high Hg sorption capacity indicated that cotton and paper wastes-derived ACs could be used as potential and low-cost sorbents of Hg for applying in practical field to control the severe effect of Hg contamination in the aquatic environment to avoid its human and environmental health risks.
Keywords: Waste material; Pyrolysis; Activated carbon; Mercury; Sorption; SEM–EDS

Degradation of endosulfan and lindane using Fenton’s reagent by Asfiya Begum; Prakhar Agnihotri; Amit B. Mahindrakar; Sumit Kumar Gautam (207-215).
Advanced oxidation of endosulfan and lindane was investigated using Fenton’s reagent (FeSO4/H2O2) in aqueous phase. A pH of 3 was chosen as optimum with the degradation efficiency of 83 % for endosulfan and 92 % for lindane. FeSO4 dose of 50 and 20 mg ml−1 was found to be optimum for endosulfan and lindane, respectively, with the degradation efficiency of ~83 % at pH 3. Further addition of FeSO4 remained unutilized and contributed to the dissolved solid content. FeSO4:H2O2 (w/w) ratio of 1:4.7 and 1:7 was optimized for endosulfan and lindane, respectively. First-order reaction kinetics (5, 7.5 and 10 ppm) were observed for both endosulfan and lindane degradations. Calculated rate constant values (k obs’) for initial endosulfan concentration of 5, 7.5 and 10 ppm were 0.021, 0.133, 0.046 min−1, respectively. While rate constant values (k obs’) of 0.057, 0.035 and 0.034 min−1 were observed for kinetics performed with 5, 7.5 and 10 ppm initial lindane concentrations, respectively. GC–MS analysis revealed that degradation process for endosulfan was sequential with the formation of methyl cyclohexane followed by 1-hexene. While lindane degradation process was spontaneous with the formation of 1-hexene formed by benzene ring fission.
Keywords: Dechlorination; Endosulfan; Lindane; Fenton’s reaction

A GIS-based approach in drainage morphometric analysis of Kanhar River Basin, India by Praveen Kumar Rai; Kshitij Mohan; Sameer Mishra; Aariz Ahmad; Varun Narayan Mishra (217-232).
The study indicates that analysis of morphometric parameters with the help of geographic information system (GIS) would prove a viable method of characterizing the hydrological response behaviour of the watershed. It is also well observed that remote sensing satellite data is emerging as the most effective, time saving and accurate technique for morphometric analysis of a basin. This technique is found relevant for the extraction of river basin and its stream networks through ASTER (DEM) in conjunction with remote sensing satellite data (Landsat etm+, 2013 and georeferenced survey of Indian toposheet, 1972). In this study, Kanhar basin a tributaries of Son River has been selected for detailed morphometric analysis. Seven sub-watersheds are also delineated within this basin to calculate the selected morphometric parameters. Morphometric parameters viz; stream order, stream length, bifurcation ratio, drainage density, stream frequency, form factor, circulatory ratio, etc., are calculated. The drainage area of the basin is 5,654 km2 and shows sub-dendritic to dendritic drainage pattern. The stream order of the basin is mainly controlled by physiographic and lithological conditions of the area. The study area is designated as seventh-order basin with the drainage density value being as 1.72 km/km2. The increase in stream length ratio from lower to higher order shows that the study area has reached a mature geomorphic stage.
Keywords: Drainage morphometry; Kanhar basin; Watershed; DEM; GIS

Groundwater characterization and selection of suitable water type for irrigation in the western region of Bangladesh by Mirza A. T. M. Tanvir Rahman; A. H. M. Saadat; Md. Safiqul Islam; Md. Abdullah Al-Mansur; Shamim Ahmed (233-243).
The main source of irrigation water in Bangladesh is groundwater, hence its quality needs to be ensured; otherwise, it can damage soil and reduce crop production. In current research, work by analyzing hydrogeochemical characteristics of groundwater different water types have been assessed to find out the suitable irrigation water of Godagari upazila in the western zone of Bangladesh. Studied parameters include pH, EC, TDS, K+, Na+, Ca2+, Mg2+, Fe2+, Cl, Br, NO3 and SO4 2− along with sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium bicarbonate (RSBC), permeability index (PI), magnesium adsorption ratio (MAR), Kelley’s ratio (KR), Mg:Ca and Na:Ca. XLSTAT and AquaChem software were used to perform factor analysis and determine water types of groundwater, respectively. The mean trends of cations and anions of the study area are Na+ > Ca2+ > Mg2+ > K+ > Fe2+ and Cl > HCO3  > SO4 2− > NO3 where silicate-weathered minerals influence the groundwater quality of the study area. Except PI all parameters satisfy irrigation water standards. However, Na–Ca–Mg and Na–Ca–Cl types of water need to be under observation for any future changes since SSP is not satisfied for both of them and considering KR Na–Ca–Cl water type is not suited. Except these two groups, Ca–Na–Mg and Ca–Na–Mg–Cl water types are suitable for irrigation.
Keywords: Factor analysis; Piper diagram; Rajshahi; Silicate; Wilcox’s diagram

Analysis of spatial–temporal patterns of water table change as a tool for conjunctive water management in the Upper Central Plain of the Chao Phraya River Basin, Thailand by Vitor Vieira Vasconcelos; Sucharit Koontanakulvong; Chokchai Suthidhummajit; Paulo Pereira Martins Junior; Renato Moreira Hadad (245-262).
A sustainable strategy for conjunctive water management must include information on the temporal and spatial availability of this natural resource. Because of water shortages in the dry seasons, farmers on the Upper Plain of the Chao Phraya River basin, Thailand, are increasingly using groundwater to meet their irrigation needs. To evaluate the possibilities of conjunctive water management in the area, the spatial–temporal changes in the water table of the Younger Terrace Aquifer were investigated. First, a regional geomorphological map based on field surveys, remote sensing and previous environmental studies was developed. Then, the well data were analyzed in relation to rainfall, streamflow, yield and pumpage, and the data were interpolated using geostatistical techniques. The results were analyzed via integrated zoning based on color theory as applied to multivariate visualization. The analysis results indicate areas that would be more suitable for groundwater extraction in a conjunctive management framework with regard to the natural hydrogeological processes and the effects of human interaction. The kriging results were compared with the geomorphological map, and the geomorphological areas exhibit distinct hydrogeological patterns. The western fans exhibit the best potential for the expansion of conjunctive use, whereas the borders of the northern fans exhibit the lowest potential.
Keywords: Kriging; Conjunctive Management of Water Resources; Multivariate visualization; Chao Phraya River; Thailand

Geochemical signatures of groundwater in the coastal aquifers of Thiruvallur district, south India by S. Senthilkumar; N. Balasubramanian; B. Gowtham; J. F. Lawrence (263-274).
An attempt has been made to identify the chemical processes that control the hydrochemistry of groundwater in the coastal aquifers of Thiruvallur coastal village of Thiruvallur district, Tamil Nadu, south India. The parameters such as pH, EC, TDS and major ion concentrations of Na, K, Ca, Mg, Cl, HCO3, SO4 and NO3 of the groundwater were analyzed. Abundances of these ions are in the following order Na > Ca > Mg > K and HCO3 > Cl > SO4 > NO3. The dominant water types are in the order of NaCl> mixed CaMgCl > CaHCO3 > CaNaHCO3. Water types (mixed CaHCO3, mixed CaMgCl and NaCl) suggest that the mixing of high salinity water caused from surface contamination sources such as irrigation return flow, domestic wastewater and septic tank effluents with existing water followed by ion exchange reaction processes, silicate weathering and evaporation are responsible for the groundwater chemistry of the study area. The above statement is further supported by Gibbs plot where most of the samples fall within the evaporation zone.
Keywords: Groundwater; Geochemical facies; Ionic ratios; Thiruvallur coastal village; Tamil Nadu

The present study makes an attempt to prioritize sub-watersheds based on Snyder’s synthetic unit hydrograph method. Snyder’s method of synthetic unit hydrograph calculates peak discharge and lag time of the unit hydrograph for each sub-watersheds. Compound values of ranking are calculated from assigned rankings to parameters, viz. peak discharge and lag time. Depending on the range of the compound values sub-watersheds are classified as high, medium and low soil-erosive sub-watersheds. The priorities obtained from Snyder’s synthetic unit hydrograph method are compared with the methods of morphometric analysis and land use/land cover analysis. On comparison of priorities for Dangri River watershed, Panchkula District, Haryana (India), among the three methods it was found that the sub-watershed (SW1) has the same priority. Among all the three methods, Snyder’s synthetic unit hydrograph is a better method, as it is easier to use and less data intensive.
Keywords: Watershed; Priority; Morphometry; Synthetic unit hydrograph; Land use; Land cover

Chemistry and quality of groundwater in a coastal region of Andhra Pradesh, India by N. Subba Rao; G. Vidyasagar; P. Surya Rao; P. Bhanumurthy (285-294).
The chemistry of groundwater in the coastal region between Chirala and Ongole of Andhra Pradesh, India shows pollution to varying extent. The relative contribution of ions in six zones divided based on TDS indicates unsuitability of groundwater here for drinking, irrigation and industrial use. The water is brackish except in first zone and further alkaline. TDS is less than 1,000 mg/L in first zone, while it is more in other zones. This classification of groundwater into zones is also investigated by hydrogeochemical facies, genetic classification, mechanisms of groundwater chemistry and geochemical signatures. Hydrogeochemical facies of Na+>Mg2+>Ca2+: $$ { ext{HCO}}_{3}^{ - } $$ HCO 3 -  > Cl > SO $$ _{4}^{2 - } $$ 4 2 - is observed from zone I, while that of Na+>Mg2+>Ca2+:Cl > HCO $$ _{3}^{ - } $$ 3 -  > SO $$ _{4}^{2 - } $$ 4 2 - from second to sixth zones. The genetic classification of groundwater in first and second zones is HCO $$ _{3}^{ - } $$ 3 - type and supported by good drainage conditions, while zones III to VI belong to Cl category evident from poor drainage scenario. The location of six zones on mechanisms of groundwater chemistry supports sluggish drainage conditions of second to six zones, while predominate rock-water interaction in first zone. The geochemical signatures (HCO $$ _{3}^{ - } $$ 3 - :Cl > 1 and Na+:Cl < 1) also endorse the pollution. The quantities of chemical species (Mg2+, Na+, K+, HCO $$ _{3}^{ - } $$ 3 - , Cl $$ ^{ - } $$ - , SO $$ _{4}^{2 - } $$ 4 2 - , NO $$ _{3}^{ - } $$ 3 - and F $$ ^{ - } $$ - ) and TDS in all zones are far greater than the stipulated limits for drinking. The United States Salinity Laboratory plots discriminated the suitability of groundwater in second to sixth zones for irrigation after only special soil treatment. Higher concentrations of TDS, HCO $$ _{3}^{ - } $$ 3 - , Cl and SO $$ _{4}^{2 - } $$ 4 2 - in all zones render it unsuitable for industry too. This information is crucial for public and civic authorities for taking up strategic management plan for preventing further deterioration of hydrogeochemical environmental conditions of this part of the coastal region.
Keywords: Groundwater chemistry; Quality; Coastal Region; Andhra Pradesh; India

The assessment of water quality has been carried out to determine the concentrations of different ions present in the surface waters. The Seybouse River constitutes a dump of industrial and domestic rejections which contribute to the degradation of water quality. A total of 48 surface water samples were collected from different stations. The first objective of this study is the use of water quality index (WQI) to evaluate the state of the water in this river. The second aim is to calculate the parameters of the quality of water destined for irrigation such as sodium adsorption ratio , sodium percentage, and residual sodium carbonate. A high mineralization and high concentration of major chemical elements and nutrients indicate inevitably a high value of WQI index. The mean value of electrical conductivity is about 945.25 µs/cm in the station 2 (Bouhamdane) and exceeds 1,400 µs/cm in station 12 of Nador. The concentration of sulfates is above 250 mg/l in the stations 8 (Zimba) and 11 (Helia). A concentration of orthophosphate over 2 mg/l was observed in the station 11. The comparison of the obtained and the WHO standards indicates a before using it use in agricultural purposes.
Keywords: Seybouse River; Hydrochemistry; Pollution; Algeria

Study the adsorption of sulfates by high cross-linked polystyrene divinylbenzene anion-exchange resin by Mahmoud Fathy; Th. Abdel Moghny; Ahmed E. Awadallah; Abdel-Hameed A-A El-Bellihi (309-313).
In response to rising concerns about the effect of sulfate on water quality, human health, and agriculture, many jurisdictions around the world are imposing tighter regulations for sulfate discharge. This is driving the need for environmental compliance in industries like mining, metal processing, pulp and paper, sewage treatment, and chemical manufacturing. The sulfate removal from synthetic water by high cross-linked polystyrene divinylbenzene resin was studied at batch experiments in this study. The effect of pH, contact time, sulfates concentration, and adsorbent dose on the sulfate sequestration was investigated. The optimum conditions were studied on Saline water as a case study. The results showed that with increasing of the absorbent amount; contact time, and pH improve the efficiency of sulfate removal. The maximum sulfates uptake was obtained in pH and contact time 3.0 and 120 min, respectively. Also, with increasing initial concentration of sulfates in water, the efficiency of sulfate removal decreased. The obtained results in this study were matched with Freundlich isotherm and pseudo-second-order kinetic. The maximum adsorption capacity (Qm) and constant rate were found 0.318 (mg/g) and 0.21 (mg/g.min), respectively. This study also showed that in the optimum conditions, the sulfate removal efficiency from Saline water by 0.1 mg/L sulfates was 65.64 %. Eventually, high cross-linked polystyrene divinylbenzene resin is recommended as a suitable and low cost absorbent to sulfate removal from aqueous solutions.
Keywords: Adsorption; Saline water; Adsorption capacity; Water; Hard

This study was performed to investigate the hydrological and the hydrogeological framework of the Lottenbachtal, Germany. Long-term climatic data were statistically analyzed, water and soil samples were collected and analyzed, stream flow discharge was measured and separated, the hydrological balance of this catchment was calculated and a hydrological and hydrogeological conceptual model was constructed. The study area is characterized mainly by the precipitation value ranged between 0.1 and 5 mm/day. The actual evapotranspiration constitutes 31.90 % of the total precipitation, the direct surface runoff constitutes 61.04 %, the soil storage constitutes 3 % and the groundwater recharge of the Lottenbachtal constitutes only 4 % of the total precipitation. The Lottenbachtal has largely affected the diversity of the land use, which includes forests, arable areas, abandoned coal mines and settlement areas. The soil of the forested area is represented by relatively high acidic conditions and relatively high sulfate concentrations, while the soil of the arable areas is represented by near-neutral conditions associated with relatively high concentrations of nutrients and other chemical elements (calcium, magnesium, sodium, potassium, chloride, sulfate, nitrate). The settlement areas are characterized by huge blocks of concrete and backfills, which are rich in calcium and magnesium carbonates. The effects of this diversity in the land use on groundwater and surface water quality resulting by leaching the chemical elements from the soil covers and the other materials. These effects are represented by the following complex water types of Ca–Na–Mg–Cl–SO4–HCO3, Ca–Mg–HCO3–SO4, Ca–Na–Mg–Cl–SO4, Ca–Na–Mg–Cl–SO4 and Ca–HCO3, which represent the diversity of the flow paths of the water as well as to mixing processes. The diversity of the land use also affected the physical hydrological-hydrogeological characteristics of the study area by increasing the direct surface runoff and decreasing the groundwater recharge. The impervious surfaces of the settlement areas and the low hydraulic conductivities of the soil covers are responsible for these conditions.
Keywords: Hydrological balance; Surface water hydrochemistry; Groundwater hydrochemistry; Hydrological and hydrogeological conceptual model; Groundwater recharge

Hydrological investigation and behavior of watershed depend upon geo-morphometric characteristics of catchment. Morphometric analysis is commonly used for development of regional hydrological model of ungauged watershed. A critical valuation and assessment of geo-morphometric constraints has been carried out. Prioritization of watersheds based on water plot capacity of Piperiya watershed has been evaluated by linear, aerial and relief aspects. Morphometric analysis has been attempted for prioritization for nine sub-watersheds of Piperiya watershed in Hasdeo river basin, which is a tributary of the Mahanadi. Sub-watersheds are delineated by ArcMap 9.3 software as per digital elevation model (DEM). Assessment of drainages and their relative parameters such as stream order, stream length, stream frequency, drainage density, texture ratio, form factor, circulatory ratio, elongation ratio, bifurcation ratio and compactness ratio has been calculated separately for each sub-watershed using the Remote Sensing (RS) and Geospatial techniques. Finally, the prioritized score on the basis of morphometric behavior of each sub-watershed is assigned and thereafter consolidated scores have been estimated to identify the most sensitive parameters. The analysis reveals that stream order varies from 1 to 5; however, the first-order stream covers maximum area of about 87.7 %. Total number of stream segment of all order is 1,264 in the watershed. The study emphasizes the prioritization of the sub-watersheds on the basis of morphometric analysis. The final score of entire nine sub-watersheds is assigned as per erosion threat. The sub-watershed with the least compound parameter value was assigned as highest priority. However, the sub-watersheds has been categorized into three classes as high (4.1–4.7), medium (4.8–5.3) and low (>5.4) priority on the basis of their maximum (6.0) and minimum (4.1) prioritized score.
Keywords: Geo-morphometric analysis; Prioritization; Watershed; RS and GIS

Accurate and reliable interpolation of groundwater depth over a region is a pre-requisite for efficient planning and management of water resources. The performance of two deterministic, such as inverse distance weighting (IDW) and radial basis function (RBF) and two stochastic, i.e., ordinary kriging (OK) and universal kriging (UK) interpolation methods was compared to predict spatio-temporal variation of groundwater depth. Pre- and post-monsoon groundwater level data for the year 2006 from 110 different locations over Delhi were used. Analyses revealed that OK and UK methods outperformed the IDW method, and UK performed better than OK. RBF also performed better than IDW and OK. IDW and RBF methods slightly underestimated and both the kriging methods slightly overestimated the prediction of water table depth. OK, RBF and UK yielded 27.52, 27.66 and 51.11 % lower RMSE, 27.49, 35.34 and 51.28 % lower MRE, and 14.21, 16.12 and 21.36 % higher R 2 over IDW. The isodepth-area curves indicated the possibility of exploitation of groundwater up to a depth of 20 m.
Keywords: Delhi; Groundwater depth; Inverse distance weighting; Ordinary kriging; Radial basis function; Universal kriging

Water wells’ exploitation and its impact on the drying up of foggaras by Bensaada Mohamed; Boualem Remini (349-359).
For a long time, man had to explore groundwater by constructing special hydraulic works. Thus, in ancient times, hydraulic civilizations such as the foggaras in Iran, Egypt, China and Latin America were born. In the Algerian Sahara, the foggara has played a leading role in the field of abstraction of groundwater distribution and sharing through formal and strict rules. Today, this technique has been disappearing and drying up. This decline does not only increase year by year, there were over a thousand foggaras in the early 1960s, but today only 915 foggaras have been listed for all those regions. Among the factors favoring the decline of foggara is the exploitation of water by deep holes drilled near the latter. In this article, we try to show the impact of drilling on the foggara.
Keywords: Foggara of Mghaer ; Timimoune; Aquifer; Drying up

The intention of this study was to appraise the spatial and temporal variations in the physico-chemical parameters of coastal waters of Rameswaram Island, Gulf of Mannar Marine Biosphere Reserve, south India, using multivariate statistical techniques, such as cluster analysis, factor analysis and principal component analysis. Spatio-temporal variations among the physico-chemical parameters are observed in the coastal waters of Gulf of Mannar, especially during northeast and post monsoon seasons. It is inferred that the high loadings of pH, temperature, suspended particulate matter, salinity, dissolved oxygen, biochemical oxygen demand, chlorophyll a, nutrient species of nitrogen and phosphorus strongly determine the discrimination of coastal water quality. Results highlight the important role of monsoonal variations to determine the coastal water quality around Rameswaram Island.
Keywords: Coastal water quality; Rameswaram Island; Physico-chemical variables; Factor analysis (FA); Principal component analysis (PCA) and cluster analysis (CA)

In this study, solar photo-Fenton reaction using compound parabolic collectors reactor was assessed for removal of phenol from aqueous solution. The effect of irradiation time, initial concentration, initial pH, and dosage of Fenton reagent were investigated. H2O2 and aromatic intermediates (catechol, benzoquinone, and hydroquinone) were quantified during the reaction to study the pathways of the oxidation process. Complete degradation of phenol was achieved after 45 min of irradiation when the initial concentration was 100 mg/L. However, increasing the initial concentration up to 500 mg/L inhibited the degradation efficiency. The dosage of H2O2 and Fe+2 significantly affected the degradation efficiency of phenol. The observed optimum pH for the reaction was 3.1. Phenol degradation at different concentration was fitted to the pseudo-first order kinetic according to Langmuir–Hinshelwood model. Costs estimation for a large scale reactor based was performed. The total costs of the best economic condition with maximum degradation of phenol are 2.54 €/m3.
Keywords: Compound parabolic collectors; Phenol; Photo-Fenton; Solar

The aim of this work was to remove the Cobalt ions from wastewater by three types of Saudi clay. These were collected from Tabbuk city (Tabbuk clay), Khiber city (Khiber clay), and Bahhah city (Bahhah clay). The paper also examined the effect of different activators on the enhancement of adsorption capacity of clays for cobalt ions. The results showed minor enhancement in the adsorption capacities of cobalt ions on three types of clays activated by acid treatment. The adsorption capacity of clays improved particularly for Tabbuk clay when treated with hydrogen peroxide as an activator. The adsorption capacity increased from 3.94 to 12.9 mg/g for the untreated and treated Tabbuk clay, respectively. Also, the adsorption capacity of Bahhah clay increased by activating with sodium chloride from 3.44 to 12.55 mg/g for untreated and treated sample, respectively. The equilibrium adsorption data were correlated using five equilibrium equations, namely, Langmuir, Freundlich, Langmuir–Freundlich, BET, and Toth isotherm equations. Langmuir isotherm agreed well with the experimental data of Khiber and Bahhah clay, while Freundlich model and Langmuir–Freundlich model fitted well with the experimental data of Tabbuk and Bahhah clay activated by NaCl. The results showed that Freundlich model fitted well with the experimental data of Tabbuk clay when activated by H2O2 and H2SO4. Finally, the BET model did not describe the experimental data well for the three types of clay after activation.
Keywords: Saudi clays; Adsorption capacity; Enhancement; Different activators; Hydrogen peroxide; Equilibrium models

Catalytic ozonation of pentachlorophenol in aqueous solutions using granular activated carbon by Ghorban Asgari; Fateme Samiee; Mohammad Ahmadian; Ali Poormohammadi; Bahman solimanzadeh (393-400).
The efficiency of granular activated carbon (GAC) was investigated in this study as a catalyst for the elimination of pentachlorophenol (PCP) from contaminated streams in a laboratory-scale semi-batch reactor. The influence of important parameters including solution pH (2–10), radical scavenger (tert-butanol, 0.04 mol/L), catalyst dosage (0.416–8.33 g/L), initial PCP concentration (100–1000 mg/L) and ozone flow rate (2.3–12 mg/min) was examined on the efficiency of the catalytic ozonation process (COP) in degradation and mineralization of PCP in aqueous solution. The experimental results showed that catalytic ozonation with GAC was most effective at pH of 8 with ozone flow rate of 12 mg/min and a GAC dosage of 2 g. Compared to the sole ozonation process (SOP), the removal levels of PCP and COP were, 98, and 79 %, respectively. The degradation rate of kinetics was also investigated. The results showed that using a GAC catalyst in the ozonation of PCP produced an 8.33-fold increase in rate kinetic compared to the SOP under optimum conditions. Tert-butanol alcohol (TBA) was used as a radical scavenger. The results demonstrated that COP was affected less by TBA than by SOP. These findings suggested that GAC acts as a suitable catalyst in COP to remove refractory pollutants from aqueous solution.
Keywords: Catalytic ozonation; Pentachlorophenol; Activated carbon; Ozone

Basic information about major elements in bottled drinking water is provided on product labels. However, more information is needed about trace elements in bottled drinking water and other sources of drinking water to assess its quality and suitability for drinking. This is the first such study to be carried out in Najran city in the Kingdom of Saudi Arabia (KSA). A total of 48 water samples were collected from different sources comprising wells, stations for drinking water treatment and bottled drinking water (purchased from local supermarkets). The concentrations of 24 elements [aluminum (Al), arsenic (As), barium (Ba), calcium (Ca), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), molydenum (Mo), sodium (Na), nickel (Ni), lead (Pb), rubidium (Rb), selenium (Se), strontium (Sr), titanium (Ti), vanadium (V), uranium (U) and zinc (Zn)] were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Anions (chlorine (Cl), fluoride (F), sulfate (SO4 2−) and nitrate (NO3 ) were determined by ion chromatography (IC). Electrical conductivity (EC), pH, total dissolved salts (TDS) and total hardness (TH) were also measured. All parameters of treated drinking water and bottled drinking water samples did not exceed the World Health Organization (WHO) 2008, US Environmental Protection Agency (USEPA 2009), Gulf Cooperation Council Standardization Organization (GSO) 2008 and Saudi Arabian Standards Organization (SASO) 1984 recommended guidelines. It is noteworthy that groundwater samples were not used for drinking purpose. This study is important to raise public knowledge about drinking water, and to promote public health.
Keywords: Groundwater; Treated drinking water; Bottled drinking water; Trace elements; Najran

A total of 20 groundwater samples were collected from both dug and bore wells of southern Tiruchirappalli district and analyzed for various hydrogeochemical parameters. The analyzed physicochemical parameters such as pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, carbonate, sulfate, chloride, nitrate, and fluoride are used to characterize the groundwater quality and its suitability for drinking and irrigational uses. The results of the chemical analysis indicates that the groundwater in the study area is slightly alkaline and mainly contains Na+, Ca2+, and Mg2+ cations as well as HCO3 2−, Cl, SO4 2−and NO3 anions. The total dissolved solids mainly depend on the concentration of major ions such as Ca, Mg, Na, K, HCO3, Cl, and SO4. Based on TDS, 55 % of the samples are suitable for drinking and rest of the samples are unsuitable for drinking. The total hardness indicates that majority of the groundwater samples are found within the permissible limit of WHO. The dominant hydrochemical facies for groundwater are Ca–Mg–Cl, Ca–HCO3, and Ca–Cl type. The USSL graphical geochemical representation of groundwater quality suggests that majority of the water samples belongs to high medium salinity with low alkali hazards. The Gibb’s plot indicates that the groundwater chemistry of the study area is mainly controlled by evaporation and rock–water interaction. Spearman’s correlation and factor analysis were used to distinguish the statistical relation between different ions and contamination source in the study area.
Keywords: Groundwater hydrochemistry; Quality assessment; Correlation analysis; Factor analysis; India

Groundwater in the Vietnamese Mekong Delta is facing the pollution and it needs to be protected. Searching literature reviews on economic valuation techniques, the contingent valuation method (CVM) has been popularly applied to estimate the economic value of water protection. This approach is based on a hypothetical scenario in which respondents are requested through questionnaires to reveal their maximum willingness to pay (WTP) for the water protection project. The study used the approach of CVM to analyze the households’ motivations and their WTP for the program of groundwater protection in the Mekong Delta. The study performed that the residents in the delta were willing to pay approximately 141,730 VND (US$6.74) per household a year. Groundwater could be an inferior good with the negative income effect found in the demanding for clean groundwater. Respondent’s gender and groundwater-related health risk consideration were factors sensitively affecting the probability of demanding for groundwater protection.
Keywords: Contingent valuation; Groundwater pollution; Probit model; Sensitivity analysis

An iterative procedure is worked out for estimating solute travel times in a subsurface system by making use of the velocity and streamline distributions pertinent to the system. The developed method is then being applied to study the solute travel times to ditch drains originating from a field being subjected to a uniform (1) recharge and (2) ponding field over the surface of the soil. For case (1), both single and layered soils are being considered to estimate the travel times. The developed mathematical procedure is simple to use, robust, reasonably accurate even if being used with a lesser division of a streamline and completely eliminates the necessity of determination of any integrals for estimating the travel times—integrals which, in the methods generally been employed for estimating the travel times from steady-state analytical groundwater models, would otherwise need be evaluated. The study shows that travel times of water particles traversing through a layered soil being subjected to a uniform recharge at the surface are sensitive to the directional conductivities, anisotropy ratio (defined here as the ratio between horizontal and vertical hydraulic conductivities of soil) and thickness of individual layers of a soil profile as well as to the magnitude of the steady-state recharge on the surface of the soil. For the ponded drainage scenarios also, directional conductivities and thickness of a soil profile, extent of partial penetration and width of the ditch drains, levels of water head at the surface of the soil as well as on the ditches are observed to influence the travel times in a noticeable way. The proposed method is important as it provides simple and accurate estimations of migration times of pollutants to subsurface drains under different drainage situations; it can also be used to assess the time of reclamation of a salt-affected or waterlogged soil being drained by a network of subsurface drains being installed for the purpose from the available hydraulic theory relevant to the concerned drainage situation.
Keywords: Fluid travel times; Subsurface drains; Anisotropy ratio; Directional conductivities of soil

Physico-chemical parameters and Ichthyofauna diversity of Arasalar estuary in southeast coast of India by C. Raju; G. Sridharan; P. Mariappan; G. Chelladurai (445-450).
The physico-chemical changes may have the tendency to accumulate in the various organs of estuarine organisms, especially fish which may in turn enter into the human metabolism through consumption causing serious hazards. Hence, the present study was carried out to dete rmine the physico-chemical characteristics of water and Ichthyofauna in Arasalar estuary in southeast coast of India for the period of 1 year during September 2012–August 2013. The environmental parameters such as, temperature, pH, salinity, DO, silicate, nitrate and phosphate were observed from Department of Zoology, Rajah Serfoji Goverment College, Thanjavur, Tamil Nadu, India. During the period of study, air temperature varied from 28.8 to 35 °C. The surface water temperature also varied from 25 to 31.5 °C. The monthly mean values of hydrogen ion concentration of water varied from 7.1 to 8.2. The salinity of water varied from 5.5 ‰ to 34. Dissolved oxygen in Arasalar estuary was varied from 3.5 to 7.2 mg/l. The total phosphorus varied from 0.29 to 2.15 µg/1. The nitrate varied from 0.47 to 3.75 µg/l. The silicate content varied from 28.25 to 98.74 µg/l. Totally 866 fishes were collected belonging to 4 orders and 5 families. Mystus gulio was found to be the dominant species (25.40 %) in the study area.
Keywords: Arasalar estuary; Physico-chemical parameters; Ichthyofauna diversity

Analysis and optimization of coagulation and flocculation process by V. Saritha; N. Srinivas; N. V. Srikanth Vuppala (451-460).
Natural coagulants have been the focus of research of many investigators through the last decade owing to the problems caused by the chemical coagulants. Optimization of process parameters is vital for the effectiveness of coagulation process. In the present study optimization of parameters like pH, dose of coagulant and mixing speed were studied using natural coagulants sago and chitin in comparison with alum. Jar test apparatus was used to perform the coagulation. The results showed that the removal of turbidity was up to 99 % by both alum and chitin at lower doses of coagulant, i.e., 0.1–0.3 g/L, whereas sago has shown a reduction of 70–100 % at doses of 0.1 and 0.2 g/L. The optimum conditions observed for sago were 6 and 7 whereas chitin was stable at all pH ranges, lower coagulant doses, i.e., 0.1–0.3 g/L and mixing speed—rapid mixing at 100 rpm for 10 min and slow mixing 20 rpm for 20 min. Hence, it can be concluded that sago and chitin can be used for treating water even with large seasonal variation in turbidity.
Keywords: Chitin; Sago; Mixing speed; Coagulation and Flocculation

Quality and management of wastewater in sugar industry by Pradeep Kumar Poddar; Omprakash Sahu (461-468).
Wastewater from sugar industries is one that has complex characteristics and is considered a challenge for environmental engineers in terms of treatment as well as utilization. Before treatment and recycling, determination of physicochemical parameter is an important mechanism. Many different types of techniques are introduced and modified for the purpose, but depend upon the water quality parameters. The main aim of this study is to determine the physicochemical characteristics of sugar industry waste water by the standard method and minimize the fresh water consumption in sugar industry by water pinch methodology.
Keywords: Effluent; Fresh water; Lime; Physicochemical; Steam

In order to characterize, classify and evaluate the suitability of Medjerda River water for irrigation, a hydrochemical assessment was conducted. It accounts for 80 % of the total Tunisian surface water. In this paper, hydrographical methods and PHREEQC geochemical program were used to characterize water quality of Medjerda River, whereas its suitability for irrigation was determined in accordance with its electrical conductivity (EC), sodium adsorption ratio (SAR) and sodium concentrations. It was established that the water samples were undersaturated with calcite, dolomite, aragonite, anhydrite, gypsum and halite except in one water sample which is supersaturated with carbonate minerals. The quality assessment of Medjerda River for irrigation purposes showed that some points belonged to the excellent-to-good and good-to-permissible irrigation water categories, while the remaining ones were classified as doubtful to unsuitable for irrigation making the river water use limited to plants with high salt tolerance. Moreover, based on FAO guidelines, almost all water samples may cause immediate salinity to gradual increasing problem but no soil infiltration problems except for two sampling points. However, immediate development or possible increasing of severe toxicity problems may be caused by the continuous use of this water for irrigation due to troublesome concentrations of chloride and sodium.
Keywords: Assessment; Analysis; Water quality; Irrigation; River

The flow net map is a basic tool for groundwater flow dynamics investigation. In areas where there are no boreholes or piezometers are not available, constructing flow net map may be difficult. This work proposes a simple methodology to construct flow net map without drilling boreholes. The flow net map constructed using the proposed approach represents an expected flow net map, which can draw conceptual flow model of the site. The major benefit from constructing the expected flow net map is it gives guidance for locating new boreholes for site investigation, carrying out investigation of the groundwater flow directions and estimating recharge/discharge from the site boundary. An illustrative example for the proposed approach was presented to show how the data required to construct the expected flow net map can be collected. The constructed, expected flow net map using the proposed methodology was compared with actual flow net map constructed from measured water levels. Both maps give consistent hydrological information about the site. The suggested approach represents a simple and cheap way to carry out investigation of groundwater flow dynamics in areas where there are no boreholes are available.
Keywords: Groundwater; Flow direction; Flow net construction; No boreholes

Shallow groundwater recharge mechanism and apparent age in the Ndop plain, northwest Cameroon by Mengnjo Jude Wirmvem; Mumbfu Ernestine Mimba; Brice Tchakam Kamtchueng; Engome Regina Wotany; Tasin Godlove Bafon; Asobo Nkengmatia Elvis Asaah; Wilson Yetoh Fantong; Samuel Ndonwi Ayonghe; Takeshi Ohba (489-502).
Knowledge of groundwater recharge and apparent age constitutes a valuable tool for its sustainable management. Accordingly, shallow groundwater (n = 72) in the Ndop plain has been investigated using the stable isotopes of oxygen (18O) and hydrogen (2H or D) and tritium (3H) to determine the recharge process, timing and rate of recharge, and residence time. The shallow groundwater showed low variability in δ18O values (−2.7 to −4.1 ‰) and 3H content (2.4–3.1 TU). The low variability suggests a similar origin, homogenous aquifer, good water mixing and storage capacity of the groundwater reservoir. Like surface water, a cluster of groundwater along the Ndop Meteoric Water Line (NMWL) and Global Meteoric Water Line indicates meteoric origin/recharge. The rainfall recharge occurs under low relative humidity conditions and negligible evaporation effect. About 80 % of the recharge is from direct heterogeneous/diffuse local precipitation at low altitude (<1,260 m) within the Ndop plain. Approximately 20 % is from high altitude precipitation (localised recharge) or is recharged by the numerous inflowing streams and rivers from high elevations. A homogenous cluster of δ-values in groundwater (and surface water) between May and June monsoon rains on the NMWL suggests dominant recharge during these months. The recharge represents at least 16 % (>251 mm) of the annual rainfall (1,540 mm) indicating high annual recharge; high enough for development of the groundwater resource for agriculture. The 3H content (>2.4 TU) in groundwater indicates post-1952 recharged water with an estimated residence time <30 years, suggesting short subsurface circulation, and subsequently a renewable aquifer.
Keywords: Stable isotopes; Tritium groundwater dating; Groundwater recharge; Residence time; Ndop plain; Northwest Cameroon

Groundwater plays an important role for socio-economic development of Comoro watershed in Timor Leste. Despite the significance of groundwater for sustainable development, it has not always been properly managed in the watershed. Therefore, this study seeks to identify groundwater potential zones in the Comoro watershed, using geographical information systems and remote sensing and analytic hierarchy process technique. The groundwater potential zones thus obtained were divided into five classes and validated with the recorded bore well yield data. It was found that the alluvial plain in the northwest along the Comoro River has very high groundwater potential zone which covers about 5.4 % (13.5 km2) area of the watershed. The high groundwater potential zone was found in the eastern part and along the foothills and covers about 4.8 % (12 km2) of the area; moderate zone covers about 2.0 % (5 km2) of the area and found in the higher elevation of the alluvial plain. The poor and very poor groundwater potential zone covers about 87.8 % (219.5 km2) of the watershed. The hilly terrain located in the southern and central parts of the study area has a poor groundwater potential zone due to higher degree of slope and low permeability of conglomerate soil type. The demarcation of groundwater potential zones in the Comoro watershed will be helpful for future planning, development and management of the groundwater resources.
Keywords: Groundwater; Potential zone; Comoro watershed; GIS and remote sensing; Analytic hierarchy process

RETRACTED ARTICLE: Hydrologic evaluation on the ERA-Interim output using observed river discharge data by L. A. Djiotang Tchotchou; A. Tompkins; F. Mkankam Kamga (521-521).

RETRACTED ARTICLE: Field measurements and neural network modeling of water quality parameters by Afishin Qishlaqi; Sediqeh Kordian; Abbas Parsaie (523-523).