The paper presents the problem of crystallization of hydrated magnesium ammonium phosphate (struvite), a chemical formula MgNH4PO4 ∙ 6H2O often formed in the line of wastewater treatment plant sludge. Struvite crystallization tests were performed on a laboratory scale, assuming three independent variables which were pH, concentration of phosphate ions PO43- and the concentration of ammonium ion NH4+. The size of a search was required concentration of magnesium ions Mg2+, which occurs when struvite precipitation. It was found that the crystallization of struvite occurs in a wide range of concentrations of phosphate and ammonium ions, but most depend on the reaction. In the analyzed conditions, struvite is not precipitated at pH 7.0 from 7.5 and precipitated an increasing range of concentrations of individual components.
...
The research was conducted in the years 2007 -2009. The trial was set up as split -plot with four replication. Experience related to the impact of mulching - the use black synthetic mulches (polyethylene film, polypropylene fabric and polypropylene nonwoven) on the yield and fruit biometric features and the content of selected nutrients in the cultivation of two cultivars peppers: 'Denis F1' and 'King Arthur F1'. Seedlings planted permanently in place in mid-June at a spacing of 50 to 50 cm. Harvesting were made gradually as of fruit ripening. Based on the of the obtained results it was found that the yield of peppers depended on the weather conditions and was variated in the years of experience. Higher yields fruits collected from the 'Denis F1' especially grown on leaf litter of black polyethylene film. The longest fruits were collected from plants mulched nonwoven polypropylene. Thicker pericarp had a variety of ‘King Arthur F1' mulching with polyethylene film. Mulching the soil favored the accumulation of L-ascorbic acid, total and reducing sugars in the fruits of peppers.The results showed that all types of mulches have contributed to a reduction in dry matter content in fruits compared to the control ...
