Process for the production of a product based on faecals produced by animals as well as a plant for the production of the product, especially a fertilizer product

Abstract

The present disclosure relates to a process for producing a product based on faecals produced by animals, characterized in that faecals from mammals are wholly or partially dissolved using an oxidizing acid, solid acid-insoluble components are separated, if necessary, and the liquid component is neutralized with a base. Moreover, the invention relates to a plant for producing a product, the plant comprising a faecal reactor for receiving animal faecals, wherein the reactor is provided with means for supplying an oxidizing acid, possibly a separator unit for separating solid, acid-insoluble components, and a neutralizing reactor for neutralizing the part of the faecals dissolved by means of the oxidizing acid, wherein the neutralizing reactor is provided with means for supplying a base. The invention provides a substantially odourless product for use as fertilizer for a crop.

1 . A process for the production of a fertilizer product based on faecals produced by animals, wherein:
 a. faecals from mammals are wholly or partially dissolved using an oxidizing acid,   b. solid acid-insoluble components are separated, if necessary,   
       and
 c. the liquid component is neutralized with a base. 
 
     
     
         2 . A process according to  claim 1 , wherein the oxidizing acid is selected from the group consisting of nitric acid (HNO 3 ), nitric acid mixed with NO 2  (fuming nitric acid), peroxynitric acid (HNO 4 ), peroxophosphoric acid (H 3 PO 5 , H 4 P 2 O 5 ), hypophosphoric acid (H 4 P 2 O 5 ), pyrophosphoric acid (H 4 P 2 O 7 ), peroxodiphosphoric acid (H 4 P 2 O 8 ), peroxosulphuric acid (H 2 SO 5 ), thiosulphuric acid (H 2 S 2 O 3 , H 2 S 2 O 4 , H 2 S 2 O 5 , H 2 S 2 O 6 ), pyrosulphuric acid (H 2 S 2 O 7 ), peroxydisulphuric acid (H 2 S 2 O 8 ), hypochlorous acid (HCIO), chlorous acid (HCIO 2 ), chloric acid (HCIO 3 ), perchloric acid (HCIO 4 ), bromic acid (HBrO 3 ), iodic acid (HIO 3 ), periodic acid (HIO 4 , H 5 IO 6 ), peroxalic acid, performic acid, peracetic acid and perbenzoic acid or a mixture of two or more thereof. 
     
     
         3 . A process according to  claim 1 , wherein the oxidizing acid is used in admixture with a further acid selected from the group consisting of hydrochloric acid, sulphuric acid, formic acid, chloroformic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, oxalic acid and maleinic acid. 
     
     
         4 . A process according to  claim 1 , wherein the oxidizing acid is nitric acid. 
     
     
         5 . A process according to  claim 1 , wherein the oxidizing acid is used in a concentrated form. 
     
     
         6 . A method according to  claim 1 , wherein the oxidizing acid is nitric acid in a concentration of 10 percent by weight or more. 
     
     
         7 . A process according to  claim 1 , wherein the quantity and type of oxidizing acid added to the faecals in step a are sufficient to dissolve at least 50 percent by weight of the faecals, calculated on the basis of the dry matter content. 
     
     
         8 . A process according to  claim 1 , wherein the volume and type of oxidizing acid added to the faecals in step a are sufficient to dissolve at least 70 percent by weight of the faecals, calculated on the basis of the dry matter content. 
     
     
         9 . A process according to  claim 1 , wherein any solid, acid-insoluble components separated in step bare treated with a strong base in order to dissolve these components at least partially. 
     
     
         10 . A process according to  claim 9 , wherein the strong base is selected from alkali metal hydroxide, alkaline earth metal hydroxide or an aqueous solution of alkali metal phosphate. 
     
     
         11 . A process according to  claim 9 , wherein the strong base is sodium hydroxide (NaOH) or potassium hydroxide (KOH). 
     
     
         12 . A process according to  claim 1 , wherein the neutralization in step c is carried out with a base selected from the group consisting of ammonia water (NH 4 OH), alkali metal hydroxide, alkaline earth metal hydroxide, an aqueous solution of alkali metal phosphate and an aqueous solution of ammonium (hydrogen) phosphate. 
     
     
         13 . A process according to  claim 1 , wherein the component dissolved with a base and obtained is used for at least partial neutralization in step c. 
     
     
         14 . A process according to  claim 1 , wherein the content of nitrogen, phosphorus and potassium is measured after step b or c. 
     
     
         15 . A process according to  claim 1 , wherein components containing phosphorus, potassium or nitrogen are added so that a predetermined ratio between nitrogen, phosphorus and potassium (NPK) is obtained. 
     
     
         16 . A process according to  claim 14 , wherein the content of one of more substances selected from calcium (Ca), sulphur (S), magnesium (Mg), manganese (Mn), copper (Cu), boron (B), chlorine (Cl) and iron (Fe) is measured, and a source of one or more of these substances is then added if necessary to obtain a predetermined ratio between the substances. 
     
     
         17 . A process according to  claim 1 , wherein the neutralization made in step c is carried out with a quantity and type of base so that the final pH of the fertilizer is in the interval of 4 to 10. 
     
     
         18 . A process according to  claim 17 , wherein the pH of the fertilizer is in the interval of 6 to 8. 
     
     
         19 . A process according to  claim 1 , wherein the faecals used are produced by pigs. 
     
     
         20 . A process according to  claim 1 , wherein pig faecals are obtained by separating the liquid fraction (liquid manure) from slurry. 
     
     
         21 . A process according to  claim 1 , wherein the process further comprises:
 d. drying of the fertilizer product to obtain a concentrate or a solid product.   
     
     
         22 . A process according to  claim 21 , wherein the drying is carried out at least partially by evaporation using the heat developed in step a. 
     
     
         23 . A process according to  claim 21 , wherein the drying is carried out by spray drying. 
     
     
         24 . A fertilizer product obtainable through a process according to  claim 1 . 
     
     
         25 . A plant for the production of a fertilizer product according to  claim 24 , comprising
 (i) a faecal reactor for receiving animal faecals, wherein the reactor is provided with means for supplying an oxidizing acid;   (ii) possibly a separator unit for separation of solid acid-insoluble components; and   (iii) a neutralizing reactor for neutralizing the part of the faecals dissolved by the oxidizing acid, wherein the neutralizing reactor is provided with means for supplying a base.   
     
     
         26 . A plant according to  claim 25 , wherein the faecal reactor is further provided with means for venting off gases produced during the treatment of faecals with oxidizing acid. 
     
     
         27 . A plant according to  claim 25 , wherein the faecal reactor through the means for venting off produced gases is connected to a vacuum pump, in order to maintain a pressure in the faecal reactor below the atmospheric pressure. 
     
     
         28 . A plant according to  claim 25 , comprising a gas collector connected to the faecal reactor for collection of the vented gases. 
     
     
         29 . A plant according to  claim 25 , wherein the faecal reactor is made of or lined inside with a material not substantially degraded by an oxidizing acid. 
     
     
         30 . A plant according to  claim 25 , wherein the faecal reactor is provided with a stirrer. 
     
     
         31 . A plant according to  claim 1 , wherein the filter in is a drum filter. 
     
     
         32 . A plant according to  claim 1 , further comprising one or more chemical silos and associated dosing pumps for the addition of further substances to the fertilizer product. 
     
     
         33 . A plant according to  claim 1 , wherein the faecal reactor is provided with means for recovering heat developed at the addition of the oxidizing acid to the faecals. 
     
     
         34 . A plant according to  claim 25 , further comprising a device for drying the fertilizer product.