جستجوی مقالات مرتبط با کلیدواژه « آلودگی میکروبی » در نشریات گروه « آب و خاک »

Shortage of fresh water resources is a major concern all over the world. Availability of water for irrigation is one of the most important factors in arid and semiarid regions، and treated domestic wastewater becomes an important source. Even after treatment، wastewater may contain a great variety of microorganisms that are hazardous for humans and environment. Thereafter the potential transmission of pollution is a principle concern associated with the agricultural use of treated wastewater. Thereafter various irrigation techniques can be used associated with treated wastewater for agriculture. Accordingly، the present study was conducted on Fecal Coliform in the wastewater treatment in laboratory columns، having 30 cm diameter and 60 cm height irrigated using surface (DI) and subsurface drip irrigation systems (SDI). Samples of the effluent and soil solutions were collected from each column after each irrigation events. Results represented that crowd of bacteries increased in both columns. There were no significant difference between crowds of bacteries in the effluent columns of two irrigation systems. It was observed that contamination of 15 cm layer in SDI was lower than DI column.

A field study was conducted at the College of Agriculture, Ferdowsi University of Mashhad, to investigate the effect of irrigation with treated municipal wastewater on the yield and quality of lettuce and some soil characteristics. Five irrigation treatments were applied to a clay loam soil, classified as fine loamy mixed mesic Calcixerollic Xerochrepts, in a randomized block design with 5 replications. The treatments consisted of T1 (Irrigation with treated wastewater over all growing season), T2 (Alternate irrigation with treated wastewater and well water), T3 (Irrigation with well water and application of cattle manure), T4 (Irrigation with well water plus fertilizer N and P), and T5 (Irrigation with well water only as control). Chemical analysis of well water proved to be a suitable source for agriculture. The results showed that the yield was higher in T1, T2, T3 and T4 as compared to the control treatment. Maximum fresh and dry yields were obtained from T3 & T1 and T1 & T3, respectively. Plant tissue analysis showed an increase in macronutrients (N, P, K) and heavy metal concentrations in shoots and roots of lettuce in the first four treatments as compared to the control. In T1, iron concentration was maximum while that of cadmium was minimum. Furthermore, microbial contamination was considerably higher in T1 and T2. Soil analysis indicated that in plots treated with wastewater, electrical conductivity, total nitrogen, available phosphorus, soluble boron and heavy metal concentration increased. However, their values were all below international standards. More experiments seem to be necessary in this regard.