Applied Water Science (v.1, #1-2)
New journal: Applied Water Science by Abdulrahman I. Alabdulaaly; Enrico Drioli (1-2).
Membranes and the water cycle: challenges and opportunities by A. G. Fane (3-9).
Membrane technology for the water cycle has been around for about 50 years and is taking an increasingly important role in the provision of safe water supply and treatment and reuse of wastewater. It is timely to examine the challenges and the future of the technology. The challenges are both technical and socio-political and they provide the drivers for new developments. This paper summarizes the status of membranes in the water industry and discusses the major challenges and possible responses that will determine the possible futures.
Keywords: Membrane technology; Water; Wastewater; Climate change; Future
An ambitious step to the future desalination technology: SEAHERO R&D program (2007–2012) by Suhan Kim; Byung Soo Oh; Moon-Hyun Hwang; Seungkwan Hong; Joon Ha Kim; Sangho Lee; In S. Kim (11-17).
In Republic of Korea, seawater engineering and architecture of high efficiency reverse osmosis (SEAHERO) research and development (R&D) program started from 2007 to lead the top seawater reverse osmosis (SWRO) plant technologies for desalination with the fund of US $165 million for 6 years including test-bed plant construction. There are three technical strategies for SEAHERO R&D program called 3L, which represents large scale, low fouling, and low energy, respectively. Large scale means design, construction, and operation of the largest unit SWRO train [daily water production rate = 8 MIGD (36,000 m3/day)] in the world. Low-fouling strategy targets the decrease of RO membrane fouling by 50%. The specific target for low energy is total energy consumption of whole SWRO plant (including intake, pretreatment, SWRO systems, and so on) less than 4 kWh/m3. The core parts for SWRO plant, such as 16 in. diameter RO membrane and energy recovery device, were developed and will soon be introduced to a test-bed including the largest unit SWRO train. The next step of SEAHERO is real field scale test-bed application of the unit technologies developed for the past 4 years (2007–2010) such as strategic pretreatment, energy-saving technology, and reliable system monitoring.
Keywords: Desalination; Reverse osmosis; SEAHERO; Large scale; Low fouling; Low energy
Photodegradation of bromophenol blue with fluorinated TiO2 composite by L. N. Dlamini; R. W. Krause; G. U. Kulkarni; S. H. Durbach (19-24).
Fluorinated TiO2 composites were prepared by the sol–gel method. The photocatalytic activities of the composites were evaluated with bromophenol blue (BPB). Composites which contained carbon nanotubes showed the highest photodegradation (98%) of BPB at 20 min as compared to pure TiO2. Photodegradation by-products of BPB such as Br− and [SO4]2− ions were monitored with ion chromatography. All catalysts were characterized with microscopic techniques, including transmission electron microscopy and scanning electron microscopy which were both equipped with an energy dispersive X-ray spectrophotometer. The polymorph of TiO2 was verified by the use of Raman spectroscopy and powder X-ray diffraction.
Keywords: Bromophenol blue; Fluorinated TiO2Photodegradation; Carbon nanotubes
Textile wastewater purification through natural coagulants by J. Beltrán-Heredia; J. Sánchez-Martín; M. T. Rodríguez-Sánchez (25-33).
A new coagulant obtained through polymerization of Acacia mearnsii de Wild tannin extract has been characterized in the removal of two dangerous dye pollutants: Alizarin Violet 3R and Palatine Fast Black WAN. This coagulant is lab-synthesized according to the etherification of tannins with glycidyltrimethylammonium chloride and formaldehyde and its performance in dye removal in terms of efficiency was high. Reasonably low coagulant dosages (ca. 50 mg L−1) reaches high capacity levels (around 0.8 for Alizarin Violet 3R and 1.6 for Palatine Fast Black WAN mg dye mg−1 of coagulant) and pH and temperature are not extremely affecting variables. The systems coagulant dyes were successfully modeled by applying the Langmuir hypothesis. qmax and b parameters were obtained with an adjusted correlation factor (r2) above 0.8.
Keywords: Dyes; Coagulation; TanninsAcacia mearnsii de Wild
Aerobic digestion of tannery wastewater in a sequential batch reactor by salt-tolerant bacterial strains by G. Durai; M. Rajasimman; N. Rajamohan (35-40).
Among the industries generating hyper saline effluents, tanneries are prominent in India. Hyper saline wastewater is difficult to treat by conventional biological treatment methods. Salt-tolerant microbes can adapt to these conditions and degrade the organics in hyper saline wastewater. In this study, the performance of a bench scale aerobic sequencing batch reactor (SBR) was investigated to treat the tannery wastewater by the salt-tolerant bacterial strains namely Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and Styphylococcus aureus. The study was carried out under different operating conditions by changing the hydraulic retention time, organic loading rate and initial substrate concentration. From the results it was found that a maximum COD reduction of 90.4% and colour removal of 78.6% was attained. From this study it was found that the salt-tolerant microorganisms could improve the reduction efficiency of COD and colour of the tannery wastewater.
Keywords: Tannery; Salt tolerant; Sequential batch reactor; Organic loading rate
Physico-chemical quality of boreholes in Densu Basin of Ghana by J. Amoako; A. Y. Karikari; O. D. Ansa-Asare (41-48).
Physico-chemical characteristics of 74 boreholes from communities within Densu Basin were assessed following procedures outlined in Standard Methods for the Examination of Water and Wastewater. The aim was to assess the status of the boreholes water quality for any contamination for management action to ensure the quality of health of the people in the area. The water quality parameters analyzed included conductivity, pH, turbidity, color, major ions, nutrients, and metals. The study showed that most of the physico-chemical constituents were within the WHO guideline limits. pH values ranged from 6.0 to 8.21, while conductivity varied between 117 and 3,500 μS/cm and turbidity from 0.6 to 19.0 NTU. However, a few of the parameters fell outside the limits prescribed by the World Health Organization (WHO 2004). Fourteen, 9, and 7% of the boreholes exceeded the WHO guideline values for nitrate (NO3), fluoride (F−) and iron (Fe), respectively. Locations where high concentration of Fe and Mn occurred, efforts must be made to remove them to discourage the use of surface waters which may be contaminated by harmful bacteria.
Keywords: Borehole; Ghana; Water quality; Physico-chemical; Densu Basin
Disinfection and reduction of organic load of sewage water by electron beam radiation by Y. Avasn Maruthi; N. Lakshmana Das; Kaizar Hossain; K. S. S. Sarma; K. P. Rawat; S. Sabharwal (49-56).
The efficacy of electron beam radiation for the disinfection and reduction of organic load of sewage water was assessed with ILU-6 Accelerator at Radiation Technology Development Division of the Bhabha Atomic Research Centre, Mumbai India. The current problem on environmental health in relation to water pollution insists for the safe disposal of sewage water. In general, sewage water comprises heterogeneous organic based chemicals as well as pathogens. EB treatment of the wastewater has found to be very effective in reducing the pathogens as well as organic load. EB dose of 1.5 kGy was sufficient for complete elimination of total coli forms. The experimental results elucidated the reduction of biological oxygen demand—BOD (35 and 51.7%) in both inlet and outlet sewage samples. Similarly reduction of chemical oxygen demand—COD was observed (37.54 and 52.32%) in both sewage samples with respect to increase in irradiation doses (0.45–6 kGy). The present study demonstrated the potential of ionizing radiation for disinfection of sewage and to increase the water quality of the wastewater by decreasing BOD and COD. So, the irradiation sewage water can find its application either in agriculture for irrigation, in industry for cooling purpose and some selected domestic purposes.
Keywords: Coliform and organic load of sewage water; Electron beam radiation
Assessment of reclaimed water irrigation on growth, yield, and water-use efficiency of forage crops by S. A. Alkhamisi; H. A. Abdelrahman; M. Ahmed; M. F. A. Goosen (57-65).
Field experiments were conducted to determine the effect of water quality (reclaimed and fresh water), water quantity, and their interactions on the growth, yield, and water use efficiency of forage maize during two winter seasons in the Arabian Gulf. The plants irrigated with the reclaimed water had higher plant height than those irrigated with the fresh water. The leaf length and leaf area (cm2) did not show any significant differences among the interaction. Reclaimed water had shorter time for 50% male and female flowering of forage maize plants, indicating earlier maturity. Plants irrigated with reclaimed water had higher chlorophyll content for all levels of water applications. A significant difference in green forage yield was found among the interactions. Reclaimed water gave the highest green forage yield of 72.12 and 59.40 t/ha at 1.4ETo and 1.0ETo, respectively. Plants irrigated with the reclaimed water used water more efficiently [3.65 kg/m3 of DM (dry matter)] than those irrigated with the fresh water [2.91 kg/m3 of DM (dry matter)] for all water quantities. The enhanced growth in wastewater-irrigated crops, compared with fresh water-irrigated crops, was attributed primarily to higher nutrient content (e.g., nitrogen) and lower salinity of the reclaimed water. The study concluded that treated wastewater irrigation increased yields of forage crops and their water use efficiency. Cost-benefit analysis, studies on the use these forage crops as animal feed, and more in depth evaluation of possible crop and soil contamination were recommended.
Keywords: Reclaimed Water; Zea mays ; Forage crops; Wastewater Management; Nutrients
Application of dc and mark-space bias differential electrolytic potentiometry for determination of cyanide using a programmable syringe pump by Tawfik A. Saleh; A. M. Abulkibash (67-72).
This paper describes a rapid sequential injection titration method for the determination of cyanide in aqueous solutions. Mercuric nitrate was used as a titrant and a pair of gold-amalgam electrodes as an indicating system. The technique of differential electrolytic potentiometry using both mark-space bias (m.s.b.) and dc current for polarization was employed. The optimum values of current and percentage bias were 5 μA and 13%, respectively. The effects of dispense time, volume of analyte, supporting electrolyte, and the concentration of titrant were investigated. The results obtained are in agreement with those of the standard method (APHA), with a relative standard deviation of 1.43%, t = 0.783, F = 1.713. A sampling rate of about 20 samples per hour was achieved with good reproducibility and lower consumption of reagents.
Keywords: Cyanide; Mercuric nitrate; Syringe pump