Electro-ultrafiltration method with continuously increasing filtration efficiency and stepwise establishment of maximum current strengths for analysing the nutrients or the pollutants in soils, composted waste, sewage sludge etc.

摘要

In the electro-ultrafiltration methods for analysing the nutrients fractions of soils, interferences occur which can lead to an under estimation of readily available nutrient contents and to an overestimation of the nutrient reserves of lime-rich soils, as a result of which excessive or insufficient fertiliser rates are recommended. To avoid these interferences, according to the invention it is proposed to limit the maximum mA values during the ultrafiltration stepwise (0-30 min at 15, 30-35 min at 40 and 35-40 min at 150 mA). The advantages achievable by the novel method of establishing the mA values stepwise are in particular that the readily available nutrient contents, chiefly phosphorus contents, of lime-rich soils not determined at 15 mA values can be obtained at mA values of /= 40 and that the potassium reserves of lime-rich soils are still not overestimated at mA values of 40, so that K-selective minerals of the soils can be determined exactly.