In order to produce its agricultural soils correctors, Agrosistemi uses, as biological basis, sewage sludge resulting from residential and agricultural waste water treatment.
BIOSOLFATO and BIOCARBONATO are the trade names of two agricultural correctors, belonging to Italian fertilizers types “Precipitation gypsum ” and “Precipitation calcium carbonate”, as defined by the Italian Law (Legislative Decree n. 75/2010).
They are produced by:
- hydrolysis of biological sludge proteins with calcium oxide
- introduction of sulfuric acid for the calcium sulphate precipitation (BIOSOLFATO)
- introduction of carbon dioxide for the calcium carbonate precipitation (BIOCARBONATO)
- integration with additives
- possible metals or unwanted anions pretreatment extraction, through electro kinetics process
- possible organic pollutants reduction pretreatment, through Fenton process
Sludge treatment is carried out:
- with fixed systems, authorized in compliance with art. 208, paragraph 1 of Legislative Decree 152/06 (Piacenza and Cervia plants)
- with mobile systems, authorized in compliance with art. 208, paragraph 15 of Legislative Decree 152/06, which may be placed at sludge producers plants, performing task for a defined time
Alternatively, Agrosistemi is able to produce the same corrector through an innovative treatment of biological materials in liquid phase, to be inserted directly on the sludge line of the water purification plant (La Spezia plant). This method guarantees:
- managerial/administrative simplification, avoiding waste (the sewage sludge) production, as the treatment operates on the liquid line mud, not classified as “waste”, yet.
- reduction of the nitrogen present in purification process;
- separation of phosphorus;
- obtaining a corrective fertilizer for agricultural soils.
Again, in order to recover valuable biomass, Agrosistemi makes use of extraction methods for the ammoniac nitrogen from digestates of methanogenic fermentation, able to produce ammonium bicarbonate crystals, together with the already described agricultural correctors.