The feasibility of magnetic field was examined as a factor affecting sludge conditioning intensification. In the experiment sludge after preliminary anaerobic digestion was used, coming from a domestic wastewater treatment plant. Digested sludge was taken directly from a fermentation tank. The experiment was run in three phases. They were performed on a laboratory scale, at various experimental stands. Different dosages of iron chloride, hydrogen peroxide and Fenton's reagent were applied to determine their influence on the sludge properties as well as the effect of constant magnetic field on the conditioning parameters was determined. Straight dependence was found between dosage of the reagents and the way of sludge introduction in the magnetic activity zone, as well as physical and chemical parameters of the prepared sludge.
This paper presents the experimental data on the amount of available phosphorus in a sandy soil assessed by the Egner-Riehm (DL) method and water extraction method. Simultaneously, the effects of the addition to the soil of calcium oxide, calcium carbonate, powder super- phoshate, and soil incubation on the P content was assessed. It was found that available phosphorus content in the soil extracted by water was lower than that assessed by the Egner-Riehm method. The effect of lime application was different in the extracts obtained by the compared methods. As effect of liming, the available phosphorus content assessed by the water extraction method was smaller. The addition to the soil of powder superphosphate caused an increase of the available phosphorus recovery by both methods. The water extraction allowed 20% of the added phosphorus to be recovered.
Porównano chemiczną, instrumentalną i wskaźnikową metodą oznaczania zawartości azotanów w świeżych warzywach, zróżnicowanych w poziomie tych związków między 10 a 4000 mg N-NO3/kg. Stwierdzono bardzo wysoką korelację rzędu 0,99 między metodą zalecaną w normie PN-92/A-75112 (zmodyfikowana metoda kolorymetryczna wg Griessa) a metodą potencjometryczną. Metoda wskaźnikowa, chociaż powtarzalna, pozwala tylko na zakwalifikowanie warzyw do dość szerokich przedziałów zawartości azotanów.