Model tehnologic de valorificare ca îngrășământ a nămolului orășenesc tratat și deshidratat în geotuburi

Abstract

The article reflects the key points on the use of dehydrated urban sludge in geotubes as organic fertilizer in agriculture. The technological model was developed based on the results of the testing the urban sludge from geotubes during the 2011 – 2019 yrs. In field experiments, on leached chernozem with clay loam texture, two application doses were tested – 18 and 36 t/ha calculated based on the nitrogen quantity applied with these doses – 170 kg and 340 kg N/ha. The chemical composition shows that urban sludge is an important source of organic matter and nutrients and is characterized as a complex organic fertilizer containing all biophilic elements. Compared to bovine manure with bedding (conventional), urban sludge from geotubes contains two times more nitrogen, three times more phosphorus and about 20% more organic matter. The application of 20 t/ha of sludge during eight years ensured a specific annual income per ton of sludge of 81 MDL. The specific income spent per 1 MDL was about 1.24 MDL.

Keywords

• urban sludge
• geotubes
• dehydration
• chemical composition
• fertilizer application
• efficiency