A. Hosseinpour; Gh. Haghnia; A. Alizadeh; A. Fotovat
Abstract
Abstract
Population increase, limitation of water resources, and increasing volume of municipal wastewater, has caused the necessity of wastewater reuse. Application of wastewater on soils seems to be the most economical method of its disposal and by percolating wastewater through the soil, its chemical ...
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Abstract
Population increase, limitation of water resources, and increasing volume of municipal wastewater, has caused the necessity of wastewater reuse. Application of wastewater on soils seems to be the most economical method of its disposal and by percolating wastewater through the soil, its chemical quality is improved. For this purpose, a greenhouse experiment was carried out with polyethylene columns (150 cm in length and 11 cm in diameter) during 7 periods of 15 days in Ferdowsi University of Mashhad. A statistical completely randomized design was used. Raw and treated wastewaters from Parkandabad Treatment Plant were applied intermittent in columns filled with sandy loam soil. At The end of experiment, sampled of leachate were analyzed for parameters sach as pH, salinity, SAR, NO3-N, PO4-P, TOC, and two heavy metals of Cd and Ni. The results showed that the mean values of each of the above mentioned parameters, with the exception of pH, were lower in the leachate compared to the wastewaters entering the soil. However, with continuous application of wastewaters increase in the amount of these components was observed. Considering the effect of type of wastewater on values of above parameters, mean of pH value was significantly lower for raw wastewater (7.65) in the leachate as compared to the treated wastewater (7.71). NO3-N, PO4-P and Ni showed an opposite trend. The mean values of these parameters leached out from soil columns were 21.96, 0.055 and 0.015 (mg/l) for raw wastewater and 20.48, 0.024 and 0.012 (mg/l) for treated wastewater, respectively. Type of wastewater did not have any significant effect on other parameters. In generall, with respeet to the amount of SAR, NO3-N and TOC in the leachate as well as Ni and Cd specially in the raw wastewater and their hazardous consequences, their long-term disposals on soils need sound and suitable management practices.
Key words: Raw wastewater, Treated wastewater, Chemical characteristics of leachate, Soilu column
A. Hosseinipour; Gh. Haghnia; A. Alizadeh; A. Fotovat
Abstract
Abstract
Due to the necessity of wastewater reuse in arid regions and the necessity of investigation on the fate of added materials into the soil, a greenhouse experiment was carried out with polyethylene columns (150 cm in length and 11 cm in diameter) filled with a sandy loam soil during 7 periods ...
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Abstract
Due to the necessity of wastewater reuse in arid regions and the necessity of investigation on the fate of added materials into the soil, a greenhouse experiment was carried out with polyethylene columns (150 cm in length and 11 cm in diameter) filled with a sandy loam soil during 7 periods of 15 days. A statistical factorial design was used. Raw and treated wastewaters from Parkandabad treatment plant were applied to the columns under continuous and intermittent flood irrigations. The results showed that PO4-P and Cd were retained by the soil while a large portion of soluble cations and anions, NO3-N and TOC as well as a part of Ni were leached out. The type of wastewater had a significant effect on transport percentage of elements except K and Mg. The transport percentage of all elements (with the exception of NO3-N and PO4-P) was higher for treated as compared to raw wastewater. Ca, HCO3 and Ni were significantly affected by the mode of application. For the intermittent flood conditions more Ca was leached out, while a reverse case was observed for the other two elements. Due to relatively rapid leaching of soluble cations especially Ca and Mg, NO3-N and TOC from the soil, and also high amount of heavy metals and TOC in raw wastewater, disposal of wastewaters (especially raw wastewater) should be managed carefully.
Key words: Column study, Raw and treated wastewater, Continuous flooding, Intermittent flooding,Transport perecentage