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In this study, zoning and the effect of heavy metal concentration on the incidence of cancer, the effect of land use, the location of quifers, the assessment of carcinogenic and non-carcinogenic health risks of heavy metals for 104 drinking water sources and 1248 samples based on standard sampling methods (using It was measured by atomic absorption method equipped with graphite furnace) from drinking water sources. Then statistical indicators and spatial information system were used to compare and analyze the data. According to the obtained results, the highest concentrations of arsenic, chromium and zinc correspond to Bashet, Behmai and Cheram cities respectively (15.47 ± 10.52, 292.21 ± 312.29, 599.09 ± 320.74 micrograms per liter) Is; that the concentration of arsenic and chromium in some sources is higher than the standard. One-way analysis of variance showed that there is a significant difference between the average concentration of arsenic, chromium and zinc in the cities (P. Value < 0.05). The average health risk factor of arsenic in Bashet and Chrome in Behmai city is higher than 1. According to the results of the average cancer risk of arsenic in the drinking water sources of Basht, Gachsaran and Behmai and chromium in the water sources of Behmai and Gachsaran have a definite risk of cancer.

Background: Hydrogen gas is the cleanest energy carrier and could be produced by biological process. Dark fermentation is one of the biohydrogen production methods that carried out just on organic wastes conversion. Methods: In this study, the batch tests were conducted to compare the biohydrogen production and glucose fermentation via acetate-butyrate and acetate-ethanol metabolic pathway induced by NaOH and KOH (10 M) pretreatment. In batch test, the glucose concentration in the feed was varied from 3.75 to 15 g/L under mesophilic conditions (37°C ± 1°C). In order to sludge pretreatment, NaOH and KOH (as an alkaline agent) was used. Results: Batch tests showed that maximum biohydrogen production under NaOH (2.7 ± 0.5 L) and KOH (2.2 ± 0.7 L) pretreatment was achieved at 15 g/L of influent glucose. In the batch test, with increasing influent glucose concentration, the lower yields of hydrogen were observed. The biohydrogen reactions had good electron closure (5.2%-13.5%) for various glucose concentrations and pretreatments. For NaOH and KOH pretreatment, the biohydrogen yield decreased from 2.49 to 1.63 and from 2.22 to 1.2 mol H 2 /mol glucose, respectively, when glucose concentration increased from 3.75 to 15 g/L. Conclusions: By applying alkaline sludge pretreatment by NaOH and KOH, the glucose fermentation was followed with acetate-butyrate and acetate-ethanol metabolic pathway, respectively. The lower biohydrogen yields were observed under acetate-ethanol metabolic pathway and related to metabolically unfavorable for biohydrogen production.

The process of electrochemical denitrification is applied with the aim of converting nitrate ( NO 3 − ) to N2 gas by reducing nitrate and oxidizing by-products such as ammonia ( NH 4 + ). In this study, Ti/RuO2 and graphite were used as anode and cathode electrodes, respectively, to treat synthetic aqueous solutions containing different concentrations of nitrate ions. Nitrate initial concentration (2.75–55 mg NO3-N/lit), voltage (2.5–30 V), pH (3–13), electrode distance (ED = 0.5–3.5 cm), and reaction time (10–180 min) were the main studied operating parameters for the electrochemical denitrification (ECD) reactor. The experiments were designed using the central composite design (CCD) method. The experimental results were modeled with the response surface methodology (RSM) technique. Scanning electron microscope (SEM), X-ray diffraction analyzer (XRD), and Fourier transform infrared spectroscopy (FTIR) characterized electrodes were performed before and after all experiments. Optimization and sensitivity analysis was performed using the Monte Carlo simulation (MSC) approach. The energy consumption and current efficiency were calculated for the ECD reactor. Kinetic models of zero, first, and second order were evaluated, and the second-order model was selected as the best kinetic model. Also, the effect of adding monovalent, divalent salts, and organic compounds to the process was evaluated. Finally, three nitrate-contaminated water wells were selected near agricultural lands as real samples and investigated the performance of the ECD process on the samples. The performance of the ECD reactor for the real samples showed some decrease compared to the synthetic samples.

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