12 research outputs found
Technosols designed for rehabilitation of mining activities using mine spoils and biosolids. Ion mobility and correlations using percolation columns
The restoration technologies in areas degraded by extractive activities are more efficient under the use of their own spoils. Reducing deficiencies in physical properties, organic matter, and nutrients with a contribution of treated sewage sludge is proposed. This experiment was based on a controlled study using columns. The work was done with two limestone quarry spoils, both very rich in calcite. Two biosolid doses were undertaken (30,000 and 90,000 kg/ha of sewage sludge) in addition to different quarry spoils used as substrates. The water contribution was provided by a device simulating short duration rain. The leached water was collected 24 h after the last application. Nitrate, ammonium, phosphate, sulfate, and chloride ions were determined, as well as Ca, Mg, Na and K, the pH and electrical conductivity. The electrical conductivity limit value is < 1000 μS/cm. These values will be met from the fourth irrigation application onward, while the values up to that point were far superior. Significant nitrate concentrations appeared that may pose an environmental contamination risk. A comparison between the concentrations of the chemical elements obtained in the leachates from our experiment and the established limit values for water of the third quality group has been performed. The electrical conductivity correlated well with the cations, with the exception of potassium. For sulfates, significant correlations were obtained with the Mg2 +, Ca2 +, and K+ cations. The chlorides showed excellent correlation with the sodium. The good correlations obtained for some physical–chemical parameters can help to establish indicators of environmental quality of leachates over time
Technosols designed for rehabilitation of mining activities using mine spoils and biosolids. Ion mobility and correlations using percolation columns
The restoration technologies in areas degraded by extractive activities are more efficient under the use of their own spoils. Reducing deficiencies in physical properties, organic matter, and nutrients with a contribution of treated sewage sludge is proposed. This experiment was based on a controlled study using columns. The work was done with two limestone quarry spoils, both very rich in calcite. Two biosolid doses were undertaken (30,000 and 90,000 kg/ha of sewage sludge) in addition to different quarry spoils used as substrates. The water contribution was provided by a device simulating short duration rain. The leached water was collected 24 h after the last application. Nitrate, ammonium, phosphate, sulfate, and chloride ions were determined, as well as Ca, Mg, Na and K, the pH and electrical conductivity. The electrical conductivity limit value is < 1000 μS/cm. These values will be met from the fourth irrigation application onward, while the values up to that point were far superior. Significant nitrate concentrations appeared that may pose an environmental contamination risk. A comparison between the concentrations of the chemical elements obtained in the leachates from our experiment and the established limit values for water of the third quality group has been performed. The electrical conductivity correlated well with the cations, with the exception of potassium. For sulfates, significant correlations were obtained with the Mg2 +, Ca2 +, and K+ cations. The chlorides showed excellent correlation with the sodium. The good correlations obtained for some physical–chemical parameters can help to establish indicators of environmental quality of leachates over time
Potencial poluidor de rejeitos carboníferos: I - Caracterização química da água de lixiviação
A non-selective (amitriptyline), but not a selective (citalopram), serotonin reuptake inhibitor is effective in the prophylactic treatment of chronic tension-type headache.
Acute and continuation therapy in unipolar depression: observations from the run-in phase of a maintenance trial
Repeating boundaries – repertoires of landscape regulations in southern Scandinavia in the Late Bronze Age and Pre-Roman Iron Age
Towards the end of the Late Bronze Age, linear boundaries such as enclosed farmsteads, field divisions, and pit zone alignments emerged and gradually permeated the landscapes of southern Scandinavia on multiple scales. This article suggests the concept of a ‘repertoire’ as a way of approaching this phenomenon. The repertoire consisted of different topological operations (e.g. plot definition, demarcation, and enclosure), constructed by different materials (e.g. fences, pit zones, and earthen banks) on different scales (e.g. farmstead, settlement, and landscape). Such linear boundaries were applied as technological solutions to the new social and economic problems that occurred at this time in prehistory. A number of chronological and regional preferences can be demonstrated within this repertoire, and during the Late Bronze Age and Pre-Roman Iron Age, a range of new applications and combinations were developed in a creative exploration of the repertoire of linear boundaries