PL233754B1 - Organic fertiliser and method for obtaining it - Google Patents

Description

The subject of the invention is a method of obtaining organic fertilizer from stabilized municipal sewage sludge and fertilizer from stabilized municipal sewage sludge.

From the Polish patent application P. 297,619 a method of producing calcium fertilizer from transformed sewage sludge of the food industry is known, consisting in adding to the sludge containing from 8 to 30% of dry weight of ground calcium oxide in the amount of 30 to 70% of the sludge, and then mixing, stabilizing and granulating this mixture. This solution is difficult to apply in practice due to the high reactivity of the fertilizer. A large amount of reactive lime introduced into the soil with fertilizers disturbs the dynamic balance in the soil ecosystem, which in turn may lead to a deterioration in the efficiency of yield growth.

Patent description PL 169 896 describes a method of producing a mineral-organic fertilizer with an increased content of magnesium and potassium from a mixture of post-fermentation sludge with a dry matter content of 18% and partially roasted dolomite, roasted basalt weathered and cement dust. The disadvantage of the fertilizer produced by this method is its high plasticity and susceptibility to caking.

The Polish patent specification PL 184434 describes a method of producing loose mineral-organic fertilizers, consisting in mixing hydrated sewage sludge (with 60-90% hydration) with powdered quicklime (up to 25% by volume), semi-aqueous gypsum (up to 5% by volume) , ash from heat plants / combined heat and power plants, nitrogen and phosphorus compounds in the form of alkali and alkaline earth metal compounds (up to 5% in terms of N and P2O5) and potassium compounds in the amount of 5% in terms of K2O. Lime, calcium carbonate or post-saturation lime is added to the above mixture to facilitate granulation of the fertilizer by giving the mixture a moisture content of 25-44%. After the granulation process, the excess water is evaporated, which leads to a reduction in the reactivity of the quicklime present in the fertilizer.

The aim of the invention is to eliminate the above-mentioned shortcomings of the known and currently used methods of producing fertilizers from stabilized municipal sewage sludge and to create a new quality by using the technique of dynamic counter-mixing and the selection of a favorable mixture of substrates to facilitate the granulation process.

Stabilized municipal sewage sludge is waste which, due to the dry matter calorific value above 6 MJ / kg, cannot be stored. Sewage sludge is characterized by a high content of organic substances and minerals, in particular sewage sludge from areas not covered by industrial activities and with separate sewage systems, show high suitability for their use for reclamation or agricultural purposes.

The essence of the invention is a method of obtaining organic fertilizer from stabilized municipal sewage sludge containing: organic carbon in the amount of 10-65% by weight, nitrogen in the amount of 1-15% by weight, phosphorus compounds in the amount of 0.5-15% by weight and potassium compounds in the amount of 0 , 1-1% by weight, characterized in that the mixture is made of dolomite flour with a grain size of 0.2-0.4 mm, preferably 0.2 mm, and a weight concentration of 10-40%, preferably 30%, of a calcium oxide by weight 5-10%, preferably 5%, of cellulose fibers with a concentration of 0.1-3%, preferably 1%, and from sewage sludge with 60-90% hydration, preferably 75% in addition to 100% by weight of the mixture, are subjected to the mixing process in in a dynamic counter-rotating mixer and then granulated, preferably in a disc granulator, for 1 to 60 minutes, and dried preferably in a belt drier at 105-140 ° C, preferably 120 ° C, for 1-5 h, preferably 2 h. stabilized municipal sewage sludge, meal d olomite, calcium oxide and cellulose fibers are mixed in the following proportions by weight: 64%: 30%: 5%: 1%.

The essence of the invention is also an organic fertilizer made of stabilized municipal sewage sludge containing: organic carbon in the amount of 10-65% by weight, nitrogen in the amount of 1-15% by weight, phosphorus compounds in the amount of 0.5-15% by weight and potassium compounds in the amount of 0, 1-1% by weight, characterized by the fact that it contains 10-40% by weight of dolomite flour, 5-10% of calcium oxide, 0.1-3% by weight of cellulose fibers and, in addition to 100% by weight, sewage sludge with 60-90% hydration preferably 75%. Preferably, the fertilizer is in the form of granules with a diameter not greater than 8 mm, preferably 2-4 mm.

The invention is illustrated in the following examples.

P r z k ł a d I

640 g of sewage sludge with a hydration of 75% containing:

• 62% (m / m) of organic matter in the form of organic carbon • 5.5% (m / m) of total nitrogen (N),

PL 233 754 B1 • 7.1% (m / m) of phosphorus in terms of phosphorus pentoxide (P2O5), • 0.69% (m / m) of potassium in terms of potassium oxide (K2O) was mixed with 300 g of dolomite flour, 50 g of quicklime and 10 g of cellulose fibers to give a mixture which was granulated by feeding it into a counter rotating dynamic mixer and then granulated on a disk granulator. After 5 minutes, the granulated material is sent to a belt-type dryer and dried at 120 ° C for 2 hours.

The obtained was 650 g of organic fertilizer containing 90% dry matter, particle diameter 1.6-4 mm, containing 47% (m / m) of organic matter and:

• 3.3% (m / m) of total nitrogen (N), • 1.9% (m / m) of phosphorus in terms of phosphorus pentoxide (P2O5), • 0.4% (m / m) of potassium in terms of potassium oxide (K2O).

P r z x l a d II

Fertilizer from municipal sewage sludge stabilized in aerobic conditions containing; 70% by weight organic carbon, 20% dolomite powder, 7% calcium oxide and 3% cellulose fibers. The fertilizer is in the form of granules with a diameter of 4 mm.

700 g of sewage sludge with a hydration of 75% containing:

• 65% (m / m) of organic matter in the form of organic carbon, • 6.3% (m / m) of total nitrogen (N), • 7.5% (m / m) of phosphorus expressed as phosphorus pentoxide (P2O5), • 0.7% (m / m) of potassium in terms of potassium oxide (K2O) was mixed with 200 g of dolomite flour, 70 g of quicklime and 30 g of cellulose fibers, and a mixture was obtained, which was granulated by introducing it into an offshore dynamic mixer, and then granulated on a disc granulator. After 5 minutes, the granulated material is sent to a belt-type dryer and dried at 120 ° C for 2 hours.

The obtained was 680 g of organic fertilizer containing 90% of dry matter, particle diameter 1.6-4 mm, containing 50% (m / m) of organic matter and:

• 3.9% (m / m) of total nitrogen (N), • 2.1% (m / m) of phosphorus in terms of phosphorus pentoxide (P2O5), • 0.5% (m / m) of potassium in terms of potassium oxide (K2O).

P r x l a d III

Fertilizer from municipal sewage sludge stabilized in aerobic conditions, containing: 65% by weight of organic carbon, 25% of dolomite flour, 7% of calcium oxide and 2% of cellulose fibers. The fertilizer is in the form of granules with a diameter of 4 mm.

650 g of sewage sludge with a hydration of 75% containing:

• 65% (m / m) of organic matter in the form of organic carbon • 6.1% (m / m) of total nitrogen (N), • 7.7% (m / m) of phosphorus expressed as phosphorus pentoxide (P2O5), • 0.7% (m / m) of potassium in terms of potassium oxide (K2O) was mixed with 280 g of dolomite flour, 50 g of quicklime and 20 g of cellulose fibers to obtain a mixture which was granulated by introducing it into a counter-rotating dynamic mixer, and then granulated on a disc granulator. After 5 minutes, the granulated material is sent to a belt dryer and dried at 120 ° C for 2 hours.

The obtained was 650 g of organic fertilizer containing 90% of dry matter and a particle diameter of 1.6-4 mm, containing 49% (m / m) of organic matter and:

• 3.8% (m / m) of total nitrogen (N), • 2.1% (m / m) of phosphorus expressed as phosphorus pentoxide (P2O5).

• 0.4% (m / m) of potassium expressed as potassium oxide (K2O).

Patent claims

Claims (4)

1. Method of obtaining organic fertilizer from stabilized municipal sewage sludge containing: organic carbon in the amount of 10-65% by weight, nitrogen in the amount of 1-15% by weight, phosphorus compounds in the amount of 0.5-15% by weight and potassium compounds in the amount of 0, 1-1% by weight, characterized in that the mixture is made of dolomite flour with a grain size of 0.2-0.4 mm, preferably 0.2 mm, and a weight concentration of 10-40%, preferably 30%, of calcium oxide PL 233 754 B1 with a concentration by weight of 5-10%, preferably 5%, cellulose fibers with a concentration of 0.1-3%, preferably 1%, and sewage sludge with a hydration of 60-90%, preferably 75%, in addition to 100% by weight the mixtures, are subjected to a mixing process in a dynamic counter-rotating mixer, followed by granulation, preferably in a disk granulator, for 1 to 60 minutes and drying, preferably in a belt dryer, at a temperature of 105-140 ° C, preferably 120 ° C, for a period of 1- 5 h, preferably 2 h. 2. The method according to p. The process of claim 1, characterized in that stabilized municipal sewage sludge, dolomite flour, calcium oxide and cellulose fibers are mixed in the proportions by weight: 64%: 30%: 5%: 1%. 3. Organic fertilizer from stabilized municipal sewage sludge containing: organic carbon in the amount of 10-65% by weight, nitrogen in the amount of 1-15% by weight, phosphorus compounds in the amount of 0.5-15% by weight and potassium compounds in the amount of 0.1- 1% by weight, characterized in that it contains 10-40% by weight of dolomite flour, 5-10% of calcium oxide, 0.1-3% of cellulose fibers and, in addition to 100% by weight, of sewage sludge with 60-90% hydration, preferably 75% %. 4. Fertilizer according to claim 3. The method according to claim 3, characterized in that the fertilizer is in the form of granules with a diameter of not more than 8 mm, preferably 2-4 mm.