Iranian Journal of

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Backgrounds and Objectives: Drinking water quality after treatment and before reaching  the consumer could be affected by distribution pipes, service lines and Home devices. The structure of water coolers, a home device that are widely used in warm months of the year, could potentially affect the quality of drinking water. The aim of this study was to assess the microbial and chemical quality of water from conventional water coolers.
Materials and Methods : Water samples were collected from 29 water cooler systems at the Isfahan  university of medical sciences. 29 control samples also obtained from the nearest drinking water taps. All samples were examined for total heterotrophic bacteria and physicochemical parameters including temperature, ph, turbidity and heavy metals.
Results: All samples from the water cooler systems complied with the EPA guidelines for total heterotrophic bacteria count. There were no significant differences between the levels of heavy metals in water samples from the water cooler systems and taps. There was only a significant difference between the level of Cu in the water samples from cooler systems and taps
Conclusion: The overall results of this study indicated that the use of water cooler systems from hygienic point of view could not cause any problems for consumers

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Background and Objectives: Legionella are gram-negative bacteria widely dispersed in natural and man-made water sources. Some Legionella species are pathogenic and could cause respiratory infections. Cultivation technique is the conventional method for the detection of Legionella spp. in aquatic samples. However, the method has low sensitivity and require prolonged incubation period. Therefore, Polymerase chain reaction (PCR) as a rapid method with extreme sensitivity is used. The present study was designed to evaluate the feasibility and sensitivity of PCR method for detection of Legionellas pp. in aquatic samples using three sets of primers.
Materials and Methods: In this study, 60 water samples were investigated for the presence of Legionella species using Nested- PCR technique. The sensitivity of this technique was evaluated for the detection of Legionella species in aquatic samples using three primer sets, including (LEG225-LEG858), (LEG448-LEG858), and (LEG448-JRP).
Results: The nested PCR assay revealed that detection percentage of Legionella in samples was 70 when LEG448-JRP primers were used, whereas this percentage reduced to 50 and 45 when we applied prime sets of LEG225-LEG858 and LEG448 - LEG858, respectively.
Conclusion: The results of the study showed that contamination of aquatic samples to the Legionella spp. could be easily and rapidly detected by nested PCR. However, selecting appropriate method for DNA extraction and choosing the primers are important factors in efficiency and sensitivity of detection method.

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MicrosoftInternetExplorer4 Background and Objectives: Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor.
Materials and Methods: After impregnating activated carbon by sulfur as a microorganism carriers and enrichment and inoculation of denitrifying bacteria, a laboratory-scale fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite, turbidity, hardness and TOC in the effluent were examined during the whole experiment under various conditions including constant influent nitrate concentration as 90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr.
Results: We found that  the denitrification rates was depended on the hydraulic retention time and the nitrate removal efficiency was up to 98%  and nitrite concentration was lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no difference in hardness between influent and effluent due to supplying sodium bicarbonate as carbon source for denitrifying bacteria.  However pH, TOC, hardness, and turbidity of the effluent met the W.H.O guidelines for drinking water. 
Conclusion: This study demonstrated that an innovative carrier as sulfur impregnated activated carbon could be used as both the biofilm carrier and energy source for treating nitrate contaminated drinking water in the lab-scale fluidized bed bioreactor.

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Background and Objective: The presence of pathogenic microorganisms in compost of solid waste can threat public health. Therefore, it is necessary to evaluate the safety of produced composts before its land application as a soil conditioner. This study was conducted to investigate the presence of pathogenic microorganisms in municipal solid waste (MSW) compost and health risks associated with accidental ingestion of compost by children.
Materials and Methods: In this study, sampling was done from compost piles at different public parks of Isfahan city during the period of compost spreading. Presence and concentration of pathogenic microorganisms including salmonella, campylobacter, cryptosporidium and adenovirus were investigated by culture or real-time PCR methods.
Results: All pathogenic microorganisms were detected in MSW compost in a frequency from 11%-62% with the highest frequency for detection of adenovirus. The health risk assessment showed that the highest risk of daily infection was for Cryptosporidium (7.67 × 10^-4 pppy) and the lowest risk was related to adenovirus (8.27 × 10^-10 pppy). The annual infection risk from gastrointestinal disease was calculated above guideline infection risk (10^-3 pppy).
Conclusion: The results showed contamination of produced compost to pathogenic microorganisms and potential health risks from applying MSW compost in urban green spaces. Therefore, the relevant organizations should pay more attention to the composting process and its microbial quality and application in public access areas.