RESUMO
Background: Nitrate is an acute and well-known hazardous contaminant, and its contamination of water sources has been a growing concern worldwide in recent years. This study evaluated the feasibility of nitrate removal from water using the traditional coagulants alum and ferric chloride with lower concentrations than those used in the conventional coagulation process
Methods: In this research, two coagulants, alum and ferric chloride, were compared for their efficiency in removing nitrate in a conventional water treatment system. The removal process was done in a batch system [jar test] to examine the effects of coagulant dosages and determine the conditions required to achieve optimum results
Results: The results revealed that ferric chloride at an initial dose rate of 4 mg/L reduced nitrate concentration from 70 mg/L to less than the World Health Organization [WHO] guideline value [50 mg/L N-NO[3]]. However, the removal efficiency of alum was not salient to significant nitrate reduction
Conclusion: In conclusion, ferric chloride was more effective than alumin removing NO[3], even in common dosage range, and can be considered a cost-effective and worthy treatment option to remediate nitrate-polluted water. Furthermore, the removal of nitrate by coagulation can be simple and more economical than other treatment alternatives
RESUMO
Eutrophication is one of the detrimental environmental problems in water reser-voirs dye to the irregular introducing nutrients [phosphorus and nitrogen]. This study aimed to explore the eutrophication state of Ekbatan Reservoir, Hamadan, western Iran. Monthly sampling was conducted during April 2010 to March 2011. Seven sampling stations were selected in the various locations of the reservoir and the samples were collected in the depth of 50 cm. The grab sampling of water for nitrogen, phosphorous and chlorophyll-a was carried out at all localities by Hatch sampler. The trophic state of the dam was determined by Carlson's Trophic State Index [TSI] and Chapra's classification. The highest concentrations of phosphorus and chlorophyll-a were measured in August and the lowest concentration for both of the parameters was determined in February. The TSI index according phosphorus concentration showed that the reservoir was in eutrophic status during May to November and was in mesotrophic status over November to May. It seems that the eutrophication process in the lake was resulted from the rural wastewaters and agricultural fertilizers. Therefore, using long term management methods includ-ing prevent of uncontrolled discharge of agricultural wastewaters is recommended in order to reduce the eutrophication in the reservoir. Decrease of phosphorus concentration in the dam by 50% can convert the eutrophic state to mesotrophic state.