Background and purpose: Nitrite and nitrate are considered as pollutant agents of ground water resources that cause several hygienic complications. Agricultural fertilizers that contain nitrate are widely used in north of Iran. This study was carried out to determine the concentrations of nitrite and nitrate in agricultural and drinking water wells in rural areas in Miandoroud, Iran.

Materials and methods: In this study, 276 samples were collected from 35 drinking water wells in Miandoroud (Mazandaran province, north of Iran) in March-September 2013. All experiments were performed according to the standard methods examination book. The results were analyzed in SPSS V.16 and Microsoft Excel.

Materials and methods: In this study, 276 samples were collected from 36 drinking water and agricultuer wells in Miandoroud (Mazandaran province, north of Iran) in March-September 2013. All experiments were performed according to the standard methods examination book. The results were analyzed in Microsoft Excel.

Results: According to the results, the concentration of nitrite was within standard levels established by national guidelines, while in some regions the nitrate concentration was found to be higher than standard levels. In all wells gradual increases were seen in nitrate concentrations. There was a direct relationship between nitrite and nitrate concentrations with depth and temperature.

Conclusion: The nitrate concentrations in some wells were higher than standard levels, therefore, more attention should be paid to nitrate pollution in this region.

Background and purpose: Laundry is one of the main wastewater producing units in hospitals. Most of detergent materials are hardly degradable and cannot be broken fast in the conventional treatment facilities. This research aimed at studying the possibility of hospital laundry wastewater pretreatment by electrocoagulation method using aluminum electrodes.

Materials and methods: Using composite sampling method, a total of 72 samples was taken from the effluent of a hospital laundry wastewater in Gorgan. The samples were analyzed according to standard methods of water and wastewater examination. After determining the quality of raw laundry wastewater, the wastewater was treated by electrocoagulation method with aluminum electrodes in different circumstances of pH, voltage and times. Process efficiency concerning the removal of COD, color, phosphate and surfactant was examined.

Results: In this study the mean density of COD, phosphate and surfactants in hospital laundry waste water were 848.8 ± 109.4, 1.03 ± 0.06 and 4.81 ± 0.93 mg per liter, respectively and the mean concentration of color was 759.3 ± 152.8 TCU. In optimal conditions, this process could remove 86, 98.8, 94.98, and 66.6% of COD, color, phosphate and surfactant, respectively. The efficiency removal of all parameters increased as the voltage and the contact time increased.

Conclusion: This study showed that laundry waste water was highly polluted and electrocoagulation process could be an efficient procedure in its pre-treatment.