Applied Water Science (v.2, #1)
A comparative study for prediction of direct runoff for a river basin using geomorphological approach and artificial neural networks by S. K. Mondal; S. Jana; M. Majumder; D. Roy (1-13).
Traditional techniques for estimation of flood using historical rainfall–runoff data are restricted in application for small basins due to poor stream gauging network. To overcome such difficulties, various techniques including those involving the morphologic details of the ungauged basin have been evolved. The geomorphologic instantaneous unit hydrograph method belongs to the latter approach. In this study, a gamma geomorphologic instantaneous unit hydrograph (GGIUH) model (based on geomorphologic characteristics of the basin and the Nash instantaneous unit hydrograph model) was calibrated and validated for prediction of direct runoff (flood) from the catchment of the Dulung-Nala (a tributary of the Subarnarekha River System) at Phekoghat station in the state of West Bengal in the eastern part of India. Sensitivity analysis revealed that a change in the model parameters viz., n, RA and RB by 1–20% resulted in the peak discharge to vary from 1.1 to 27.2%, 3.4 to 21.2% and 3.4 to 21.6%, respectively, and the runoff volume to vary from 0.3 to 12.5%, 2.1 to 2.6% and 2.2 to 2.7%, respectively. The Nash–Sutcliffe model efficiency criterion, percentage error in volume, the percentage error in peak, and net difference of observed and simulated time to peak which were used for performance evaluation, have been found to range from 74.2 to 95.1%, 2.9 to 20.9%, 0.1 to 20.8% and −1 to 3 h, respectively, indicating a good performance of the GGIUH model for prediction of runoff hydrograph. Again, an artificial neural network (ANN) model was prepared to predict ordinates of discharge hydrograph using calibrative approach. Both the ANN and GGIUH models were found to have predicted the hydrograph characteristics in a satisfactory manner. Further, direct surface runoff hydrographs computed using the GGIUH model at two map scales (viz. 1:50,000 and 1:250,000) were found to yield comparable results for the two map scales. For a final clarification, the probability density function of the actual and predicted data from the two models was prepared to compare the pattern identification ability of both the models. The GGIUH model was found to identify the distribution pattern better than the ANN model, although both the models were found to be ably replicating the data patterns of the observed dataset.
Keywords: GGIUH; ANN; Direct surface runoff hydrograph; Morphological parameters; Probability density function
Perched groundwater at the northwestern coast of Egypt: a case study of the Fuka Basin by Mohamed Yousif; Olaf Bubenzer (15-28).
Perched groundwater resources on the northwestern coast of Egypt have thus far been little studied. However, if replenished by rainwater, they can provide a considerable amount of renewable water, i.e., for sustainable irrigation. These resources are limited, show different salinity contents and are endangered by overuse, pollution and by the sea level rising in the context of global warming. This paper presents new climatic data, geomorphologic, geologic, geochemical and hydrological researches in combination with remote sensing and GIS applications from Fuka Basin. Fuka constitutes a special synclinal basin where the interbedded limestone and clays have been folded into gentle synclinal structures. Fractured Middle Miocene limestone represents the bearing formation for the perched groundwater. According to the hydrogeochemical analysis and the PHREEQC model, the aquifer is recharged during the winter season by rainwater from the surrounding tableland and the chemical evolution of the perched water is attributed to water–rock interaction and mixing of fresh water with sea water. The salinity of the perched water ranges from 2,126 to 2,644 mg/L whereas for the deep groundwater it reaches 9,800 mg/L. The study explores origin and potential of the perched groundwater of Fuka Basin and gives recommendations for a future sustainable use and further investigations.
Keywords: Fuka Basin (Egypt); Perched groundwater; Groundwater recharge; Rainfall/runoff; Hydrochemistry
Defluoridation from aqueous solution using stone dust and activated alumina at a fixed ratio by Iohborlang M. Umlong; Bodhaditya Das; Rashmi Rekha Devi; Kusum Borah; Lakhshya Bijoy Saikia; Prasanta Kumar Raul; Saumen Banerjee; Lokendra Singh (29-36).
Easily available stone dust and alumina were acid activated, mixed in the ratio of 9:1 and studied for fluoride removal capacity. Batch and continuous studies were performed to test the efficiency of the adsorbents. Batch study revealed that the mixed adsorbents can remove up to 19.30 mg fluoride per gram of mixed adsorbent and is best removed at pH 6.5. Adsorption studies showed that the mechanism of adsorption is physical sorption. Flow rate plays a significant role in removing fluoride. Breakthrough study of a continuous operated unit tested at three different flow rates showed that decreasing efficiency took place at higher flow rate. The regeneration study shows that this adsorbent can be desorbed following a simple base–acid rinsing procedure.
Keywords: Defluoridation; Stone dust; Activated alumina; Adsorption isotherms; Sorption unit
Development of polyaniline-modified polysulfone nanocomposite membrane by Javed Alam; Lawrence Arockiasamy Dass; Mansour Saleh Alhoshan; Mostafa Ghasemi; Abdul Wahab Mohammad (37-46).
In the present investigation, polyaniline (PANI) nanoparticles were used to improve the separation figures of merit of polysulfone (PSu) membrane. Polyaniline nanoparticles were dispersed into polysulfone matrix for the development of PSu/PANI nanocomposites through solution blending. A wet phase inversion method was used to fabricate a flat sheet polysulfone (PSu) and PSu/PANI nanocomposite membranes. The structure and characteristic properties of the membranes were investigated in terms of the surface and cross-section morphologies, roughness, and hydrophilicity, which were interpreted by scanning electron microscope, atomic force microscope, and water contact angle meter, respectively. Apart from these, the uniform dispersion of polyaniline nanoparticles (<20 nm) into polysulfone matrix was ascertained by transmission electron microscope. Compared with polysulfone membrane, PSu/PANI nanocomposite membranes had more hydrophilicity and smooth surface, and honeycomb cross-section structure. Therefore, the nanoparticles inclusion in the polysulfone membrane showed a significant effect on hydrophilic property as well as membrane morphology, which resulted in improvement of the permeability characteristics of polysulfone membrane.
Keywords: Separation figures of merit; Hydrophilic surface; Phase inversion method; Permeability characteristics
Ethanol production potential from fermented rice noodle wastewater treatment using entrapped yeast cell sequencing batch reactor by Sumana Siripattanakul-Ratpukdi (47-53).
Fermented rice noodle production generates a large volume of starch-based wastewater. This study investigated the treatment of the fermented rice noodle wastewater using entrapped cell sequencing batch reactor (ECSBR) compared to traditional sequencing batch reactor (SBR). The yeast cells were applied because of their potential to convert reducing sugar in the wastewater to ethanol. In present study, preliminary treatment by acid hydrolysis was performed. A yeast culture, Saccharomyces cerevisiae, with calcium alginate cell entrapment was used. Optimum yeast cell loading in batch experiment and fermented rice noodle treatment performances using ECSBR and SBR systems were examined. In the first part, it was found that the cell loadings (0.6–2.7 × 108 cells/mL) did not play an important role in this study. Treatment reactions followed the second-order kinetics with the treatment efficiencies of 92–95%. In the second part, the result showed that ECSBR performed better than SBR in both treatment efficiency and system stability perspectives. ECSBR maintained glucose removal of 82.5 ± 10% for 5-cycle treatment while glucose removal by SBR declined from 96 to 40% within the 5-cycle treatment. Scanning electron microscopic images supported the treatment results. A number of yeast cells entrapped and attached onto the matrix grew in the entrapment matrix.
Keywords: Bioethanol production; Calcium alginate; Cell entrapment; Fermented rice noodle wastewater treatment; Saccharomyces cerevisiae
Characteristics of the event mean concentration (EMCs) from rainfall runoff on mixed agricultural land use in the shoreline zone of the Yamuna River in Delhi, India by Deepshikha Sharma; Ruchi Gupta; Ram Karan Singh; Arun Kansal (55-62).
This paper is focused on the monitoring of the diffuse pollution characteristics from the agricultural land confining the River Yamuna in Delhi (capital of India). Agricultural fields surrounding the Yamuna river are direct nonpoint source of pollution impacting the river quality. The study includes watershed delineation for the River Yamuna using SWAT (2005) and land use classification for the city using GIS and remote sensing. Thereafter, the rainfall-runoff pollutant concentrations from the mixed agricultural land use were assessed for the 2006 and 2007 monsoon period (July–September). Runoff was measured using SCS method and grab samples of rainfall runoff were collected at three stations namely Old Delhi Railway Bridge (ODRB), Nizamuddin and Okhla bridge in Delhi. The samples were analysed for physico-chemical and biological parameters. Rainfall runoff and event mean concentrations (EMCs) for different water quality parameters were characterized and the effect of land use was analyzed. The average EMCs for BOD, COD, ammonia, nitrate, TKN, hardness, TDS, TSS, chlorides, sulfates, phosphate, fluorides and TC were 21.82 mg/L, 73.48 mg/L, 72.68 μg/L, 229.87 μg/L, 15.32 μg/L, 11.36 mg/L, 117.44 mg/L, 77.60 mg/L, 117.64 mg/L, 135.82 mg/L, 0.08 mg/L, 0.85 mg/L and 2,827.47 MPN/100 mL, respectively. The EMCs of TSS, nitrogen and its compounds, phosphate and BOD were high.
Keywords: Watershed; Land use; Digital elevation model; Diffuse pollution; Surface runoff