جستجوی مقالات مرتبط با کلیدواژه "پساب های شهری" در نشریات گروه "محیط زیست"

Given the scarcity of water resources in many parts of the country, the increasing need for water, and increased volume of urban wastewater, planning to use the effluent of urban wastewater treatment plants by considering the environmental aspects as an appropriate solution is regarded to compensate for some of these scarcities and to reduce the pollutions. The recycled urban wastewater effluent is associated with many benefits and risks for human and environmental health. This research is aimed to evaluate the risk of using effluent in demanding sectors with respect to the priority of risk reduction.

In 2016, this research was conducted with the aim of assessing the risk of using the output effluent of the Northern Isfahan wastewater treatment plant. The statistical information of effluent quality was collected monthly and averaged from the laboratories of the relevant organizations. Considering six major qualitative parameters (pH, COD, BOD, TSS, TDS, and TC) and using environmental standards related to these parameters, an index was evaluated to assess the quality of treated wastewater as the Comprehensive Pollution Index (CPI). Then, using the library studies, regional studies, as well as specialized meetings with experts with knowledge about the status of output effluent of this treatment plant, risk and control checklists were prepared in the form of a questionnaire. The checklists were completed by 69 experts, and by generalizing the Frank and Morgan method, the Risk Index (RI) was calculated for potential effluent use in the study area and compared with the pollution index.

Results of the completed checklists showed that the agricultural sector had the highest risk score against the industrial sector and the industrial sector had the highest control score against the agricultural sector. In general, the mean score of 6-item risk checklist in the agricultural sector was higher than all sectors and the risks posed to humans in all four sectors had a higher score than other risks. Comparison of the qualitative standards of using effluent and quality of output effluent of the wastewater treatment plant also showed that the measured coliform parameter had the highest distance to its standard limit compared to other parameters. Therefore, the significance of this parameter in public health and community safety had a great impact on the calculation of pollution and risk indices. Hence, the risk index for the four sectors of agriculture, green space, natural resources, and industry was 54.71%, 23.97%, 15.1%, 6.22%, respectively, and the relative pollution index was 43%, 28%, 21%, and 8%, respectively. The results of these two indices were completely matched and the agricultural sector had the highest pollution and risk indices and accounted for the priority of risk reduction, and the effluent usage in the industrial, natural resources, and green space sectors will have lower risks to humans and the environment.

According to the results of this study, using the effluent of the wastewater treatment plant in the current conditions has lower risks for industrial use and natural resources (non-desertification) than agricultural use and green space irrigation. In general, the effluent use in water-based industries and growing unproductive plants will be followed by increased access of farmers to higher quality water resources and improved human and environmental health.

Declining water resources caused usage of recycled water that sometimes not purified well.  The growing population and consequently increasing water demand, along with a shortage of available freshwater resources have inevitably led to the use of unconventional water resources. Irrigation lands with urban wastewater requires quality and quantity control for achieving food security. Therefore, the present study was conducted to investigate the effects of irrigation with urban wastewater on the concentration of Nickel and Cadmium in soils and their effects on plant, root, shoot, and functional characteristics of wheat.

  Field sampling was carried out at random from a depth of 0 to 20 cm. Wheat samples were taken at harvest from a 1-meter by 1-meter area. A total of 20 samples for Cadmium metal and 20 samples of Nickel metal were taken.

The results showed that the average concentration of Cadmium and Nickel was 10.6 and 49.43 kg, respectively, which resulted in an accumulation in various parts of the wheat plant. Increasing the concentration of Cadmium and Nickel in the soil increases the accumulation in the root, upper parts, and wheat seeds. Also, increasing the concentration of Cadmium and Nickel in the soil decreases the dry weight of the root, the shoot, and the weight of the thousand seed. However, there was no significant effect on two traits, number of grains per spike and number of spikes per square meter. The effect of Cadmium concentration was higher than that of Nickel.

Increasing 1 mg of soil Cadmium caused increasing, 0.81, 0.56, 0.6 mg Cadmium in root, upper parts and seed. For Nickel increasing the soil concentrations caused 0.29, 0.29, 0.11 mg in root, upper parts and seed.