Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 6 Articles
Biological treatment of sulphate-rich wastewaters\nemploying dissimilatory sulphate reducing bacteria as\nremedial agents is an attractive technique and has gained\nimportance in the last few years. Industrial effluents enriched\nwith sulphates are generally deficient in electron\ndonors. And thus cannot be treated biologically without\nsupplementation of carbon through an external source. For\nscalable operations, however, the carbon source must not be\nexpensive. In this context, present study reports the efficiency\nof biological sulphate reduction using sugarcane\nbagasse as a cost-effective carbon source. An average\n0.00391 �± 0.001 gL-1 day-1 (3.91 mgL-1 day-1) sulphate\nreduction was observed reaching maximally to 0.00466 �±\n0.001 gL-1 day-1 (4.66 mgL-1 day-1) while employing\nDesulfovibrio fructosovorans-HAQ2 and Desulfovibrio piger-\nHAQ6 in a 60-day trial of anaerobic incubation using\nsugarcane bagasse as growth substrate. These findings will\nbe helpful in developing economical bioremediation processes\ntending to operate for a longer period of time to\nreduce sulphate contents of contaminated waters....
One of the key parameters influencing sprinkler\nirrigation performance is water quality. In this study, the\nspatial variability of groundwater quality parameters (EC,\nSAR, Na?, Cl-, HCO3\n- and pH) was investigated by\ngeostatistical methods and the most suitable areas for\nimplementation of sprinkler irrigation systems in terms of\nwater quality are determined. The study was performed in\nFasa county of Fars province using 91 water samples.\nResults indicated that all parameters are moderately to\nstrongly spatially correlated over the study area. The spatial\ndistribution of pH and HCO3\n- was mapped using\nordinary kriging. The probability of concentrations of EC,\nSAR, Na? and Cl- exceeding a threshold limit in\ngroundwater was obtained using indicator kriging (IK).\nThe experimental indicator semivariograms were often\nfitted well by a spherical model for SAR, EC, Na? and Cl-.\nFor HCO3\n- and pH, an exponential model was fitted to the\nexperimental semivariograms. Probability maps showed\nthat the risk of EC, SAR, Na? and Cl- exceeding the given\ncritical threshold is higher in lower half of the study area.\nThe most proper agricultural lands for sprinkler irrigation\nimplementation were identified by evaluating all\nprobability maps. The suitable areas for sprinkler irrigation\ndesign were determined to be 25,240 hectares, which is\nabout 34 percent of total agricultural lands and are located\nin northern and eastern parts. Overall the results of this\nstudy showed that IK is an appropriate approach for risk\nassessment of groundwater pollution, which is useful for a\nproper groundwater resources management....
The study was conducted on the status of the\nquality of water from the Owabi water treatment plant that\nsupplies drinking water to Kumasi, a major city in Ghana,\nto ascertain the change in quality of water from source to\npoint-of-use. Physico-chemical, bacteriological water\nquality parameters and trace metal concentration of water\nsamples from five different treatment points from the\nOwabi water treatment plant were investigated. The raw\nwater was moderately hard with high turbidity and colour\nthat exceeds the WHO guideline limits. Nutrient concentrations\nwere of the following order: NH3\\NO2\n-\\-\nNO3\n-\\PO4\n3-\\SO4\n2- and were all below WHO\npermissible level for drinking water in all the samples at\ndifferent stages of treatment. Trace metal concentrations of\nthe reservoir were all below WHO limit except chromium\n(0.06 mg/L) and copper (0.24 mg/L). The bacteriological\nstudy showed that the raw water had total coliform\n(1,766 cfu/100 mL) and faecal coliform (257 cfu/100 mL)\nthat exceeded the WHO standard limits, rendering it unsafe\nfor domestic purposes without treatment. Colour showed\nstrong positive correlation with turbidity (r = 0.730), TSS\n(r C 0.922) and alkalinity (0.564) significant at p\\0.01.\nThe quality of the treated water indicates that colour, turbidity,\nCr and Cu levels reduced and fall within the WHO\npermissible limit for drinking water. Treatment process at\nthe water treatment plant is adjudged to be good....
Background: Newfoundland and Labrador (NL) has one of the highest waste disposal rates in Canada and it has\n200 small communities without access to central composting facilities. During Municipal solid waste (MSW)\ncomposting, the selection of bulking agents is critical. Bench-scale composting systems plus locally available bulking\nagents are thus desired for economic and effective MSW management in NL communities. This study evaluated the\nperformance of locally available bulking agents (i.e., NL sawdust and peat) during MSW composting in a bench-scale\nsystem. Physiochemical (temperature, oxygen uptake rate, pH, electrical conductivity, moisture and ash content,\nand C/N ratio) and biological (enzyme activities and germination index) parameters were monitored to evaluate\ncompost maturity and stability.\nResults: In peat composting, higher temperature for a longer duration was observed, indicating more effective\npathogen removal and sterilization. High enzyme activities of dehydrogenase, ?-glucosidase, and phosphodiesterase\nin the third week of composting imply high microbial activity and high decomposition rate. The low C/N ratio for\ncompost product implies acceptable stability states. In sawdust composting, higher temperature and oxygen uptake\nrate (OUR) were observed in the third week of composting, and higher enzyme activities in the second week. Sawdust\ncomposting generated a higher germination index, indicating higher maturity.\nConclusions: Both sawdust and peat are effective bulking agents for the bench-scale composting. The choice of a\nbulking agent for a particular community depends on the availability of the agent and land in the region, convenience\nof transportation, price, and the expected quality of the compost product....
Background: The aim of this work is to propose a new river water quality index using fuzzy logic. The proposed\nfuzzy index combines quality indicatorsâ�� prescribed thresholds extracted mainly from the Moroccan and the Quebec\nwater legislations. The latter is reputed for its strict water quality assessment. The proposed index combines six\nindicators, and not only does it exhibit a tool that accounts for the discrepancy between the two base indices, but\nalso provides a quantifiable score for the determined water quality. These classifications with a membership grade\ncan be of a sound support for decision-making, and can help assign each section of a river a gradual quality\nsub-objective to be reached.\nResults: To demonstrate the applicability of the proposed approach, the new index was used to classify water\nquality in a number of stations along the basins of Bouregreg-Chaouia and Zizi-Rh�©ris. The obtained classifications\nwere then compared to the conventional physicochemical water quality index currently in use in Morocco. The\nresults revealed that the fuzzy index provided stringent classifications compared to the conventional index in 41%\nand 33% of the cases for the two basins respectively. These noted exceptions are mainly due to the big disparities\nbetween the different quality thresholds in the two standards, especially for fecal coliform and total phosphorus.\nConclusions: These large disparities put forward an argument for the Moroccan water quality legislation to be\nupgraded to align water and environmental assessment methods with other countries in order to mitigate the risks\nof failing to achieve a good ecological status....
In the present study, a coagulation process was\nused to treat paper-recycling wastewater with alum coupled\nwith poly aluminum chloride (PACl) as coagulants. The\neffect of each four factors, viz. the dosages of alum and\nPACl, pH and chemical oxygen demand (COD), on the\ntreatment efficiency was investigated. The influence of these\nfour parameters was described using response surface\nmethodology under central composite design. The efficiency\nof reducing turbidity, COD and the sludge volume index\n(SVI) were considered the responses. The optimum conditions\nfor high treatment efficiency of paper-recycling\nwastewater under experimental conditions were reached\nwith numerical optimization of coagulant doses and pH, with\n1,550 mg/l alum and 1,314 mg/l PACl and 9.5, respectively,\nwhere the values for reduction of 80.02 %in COD, 83.23 %\nin turbidity, and 140 ml/g in SVI were obtained....
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