## 3 Results and Discussion  
All the above raw materials were mixed in various ratios and granulated by wet granulation with a drum granulator to obtain spherical granules. Different amounts of liquid binder (MS or BE) were used to improve the agglomeration of organic raw materials. Eight different fertiliser compositions were created from the above-mentioned dry raw materials and a binder:  
I. 20% BHA + 40% BH + 40% BBM + BE II. 20% BHA + 40% BH + 40% BBM + MS III. 40% BHA + 30% BH + 30% BBM + BE IV. 40% BHA + 30% BH + 30% BBM + MS V. 20% BHA + 20% BH + 20% BBM + 40% BM +BE VI. 20% BHA + 20% BH + 20% BBM + 40% BM +MS VII. 40% BHA + 10% BH + 10% BBM + 40% BM +BE VIII. 40% BHA + 10% BH + 10% BBM + 40% BM +MS  
Percentages of raw materials in the initial stage (compositions I-IV) were selected based on the amount of relevant waste generated in the industry. After analysing the properties of the granulated product with this composition, it was determined that the granules are not strong enough (less than 5 N/gram), so bone meal was additionally added to their composition (compositions V-VIII). Based on the chemical composition of bone meal [59; 60] and personal experimental experience, it was assumed that its addition to the composition will increase the strength of granules and enrich organic biofertilisers with phosphorus and calcium. According to compositions I-IV, when the moisture content of the raw material mixture ranged from 34% to 46%, the amount of commercial fraction (2-4 mm) of granulated fertilisers was up to 60%. The main properties of these granules vary depending on the ratio of solid raw materials, the binder used, and its amount. After granulating the mixtureof raw materials, which contained less BHA than BH and BBM (compositions V, VI), the moisture content of the commercial product (2-4 mm) after drying was 5-7% with BE binder and 4-6% with MS binder. Prevalence of BHA over BH and BBM (compositions VII, VIII) resulted in similar (4-6%) moisture content of the commercial product. The pH value of the 10% solution of the granular product was slightly higher when more ash was used compared to the product containing less ash, i.e., 10 and 8-9%, respectively. This is completely understandable and explained by the high alkalinity of the ash. It was observed that the binder does not affect the pH of the product. The bulk density of the commercial product is slightly higher in the case where the mixture of raw materials contains more BHA than BH and BBM, i.e., in compositions III and IV, because the initial bulk density of ash is higher than that of other waste from the buckwheat groats industry. However, when measuring the strength of the granules, it was found that the granules are very plastic and their static crushing strength is lower than the measuring limit of the device, i.e., less than 5 N/granule. Such plastic granules are not suitable for storage and transportation, so the fertiliser composition was changed by adding BM (compositions V-VIII). Granulated and dried biertifilisers of compositions V-VIII were fractionated to determine the dependence of the granulometric composition and the amount of the commercial fraction on the composition of the raw material mixture (V-VIII) and moisture. As can be seen from Figure 1, the granulometric composition of individual compositions differs, but common features can also be found. In the case when the moisture content of the raw material mixture is between 31 and 34%, the 2-3.15 mm size fraction prevails, but many 1-2 mm size granules are also formed. As the moisture content of the raw material mixture increases (35-36%), the number of larger granules increases. The highest quantities (57-68%) of the commercial fraction of biertifilisers of different compositions (2-3.15 and 3.15-4 mm size granules) are obtained at a 32-35% moisture content of raw materials. It can also be concluded from the presented results that, when a lower amount of BHA is used (composition V and VI), more binder is needed to obtain a large amount of commercial fraction.