CC BY
20DOI: 10.24412/2181-144X-2020-2-59-67 Temirov U.Sh., Doniyarov N.A., Usanbaev N.Kh., Tagaev I.A., Juraqulov B.A.
ORGANOMINERAL FERTILIZERS BASED ON SEDIMENTS OF WASTE WATERS AND PHOSPHORITES OF CENTRAL KYSILKUM
Temirov Uktam Shavkatovich - doctoral student, Department of Chemical Technology, Navoi State Mining Institute, Doctor of Philosophy (PhD),
Doniyarov Nodir Abduhakimovich - Dean of the Faculty of Chemistry and Metallurgy of Navoi State Mining Institute, Doctor of Technical Sciences,
Usanbayev Nazimuddin Khalmurzaevich - Chief Research Fellow of the Institute of General and Inorganic Chemistry of the Academy of Sciences of the Republic of Uzbekistan, Doctor of Technical Sciences,
Tagaev Ilhom Akhrorovich - Associate Professor of Chemical Technology, Navoi State Mining Institute, Candidate of Agricultural Sciences,
Jurakulov Bakhrom Azamatovich - junior researcher of the Institute of General and Inorganic Chemistry of the Academy of Sciences of the Republic of Uzbekistan, Doctor of Technical Sciences.
Annotation. This paper presents the results of incomplete decomposition of Central Kyzylkum non-conditioned phosphorites with sulfuric acid (30-70% stoichiometric norm relative to CaO) and its subsequent processing into phosphorus-humus fertilizers with active turbidity. Optimal ratios of starting materials in the production of phosphorus-humus fertilizers on the basis of active turbid and non-conditioned phosphorites and the rate of sulfuric acid for the decomposition of Central Kyzylkum non-conditioned phosphorite were determined. Keywords: Active sludge, simple phosphorite flour, sulfuric acid, phosphorus, calcium, organic mineral fertilizer.
ОКАВА СУВЛАР ЧУКИНДИЛАРИ ВА МАРКАЗИЙ КИЗИЛКУМ ФОСФОРИТЛАР АСОСИДА ОРГАНИК МИНЕРАЛ УГИТЛАР
Темиров Уктам Шавкатович - Навоий давлат кончилик институти Кимё технология кафедраси докторанти, техника фанлари фалсафа доктори (PhD),
Донияров Нодир Дбду^акимович - Навоий давлат кончилик институти "Кимё-металлургия" факултети декани, техника фанлари доктори,
Усанбайев Назимуддин Халмурзаевич - Узбекистон Республикаси Фанлар академияси Умумий ва ноорганик кимё институти бош илмий ходими, техника фанлари доктори, Тагаев Илдом Дхрорович - Навоий давлат кончилик институти Кимё технологиялари кафедраси доценти, кишлок хужалиги фанлар номзоди,
Журакулов Бахром Азаматович - Узбекистон Республикаси Фанлар академияси Умумий ва ноорганик кимё институти кичик илмий ходими.
Аннотатсия. Ушбу маколада Марказий ^изилкум фосфоритларни сульфат кислота билан туликсиз меъёрда парчалаш ( СаО нисбатан 30-70% стехиометрик меъёрда) ва сунгра уни фаол лойка билан фосфор-гумусли угитларга кайта ишлаш натижалари келтирилган. Фаол лойка ва фосфоритлар асосида фосфор-гумусли угитлар олишда дастлабки моддаларнинг макбул нисбаталари ва Марказий ^изилкум фосфоритни парчалаш учун сульфат кислотанинг меъёри аникланган.
Калит сузлар. Фаол лойка, оддий фосфорит уни, сульфат кислота, фосфор,калтций, органоминерал угитлар.
ОРГАНОМИНЕРАЛЬНЫЕ УДОБРЕНИЯ НА ОСНОВЕ ОТЛОЖЕНИЙ СТОЧНЫХ ВОД И ФОСФОРИТОВ ЦЕНТРАЛЬНОГО КИСИЛКУМА
Темиров Уктам Шавкатович - докторант, кафедра Химическая технология, Навоийский государственный горный институт, PhD
Донияров Нодир Абдухакимович - декан "Химико-металлургического" факультета Навоийский государственный горный институт, док. тех. наук,
Усанбаев Нажимуддин Халмурзаевич - ведуший научный сотрудник, Институт общей и неорганической химии АН РУз, док. тех. наук,
Тагаев Ильхам Ахрорович - доцент кафедры «Химичекая технология» Навоийский государственный горный институт, канд. сель-хоз. наук.
Журакулов Бахром Азаматович - младший научный сотрудник, Институт общей и неорганической химии АН РУз.
Аннотация. В данной работе представлены результаты неполного разложения фосфоритов Центральных Кызылкумов серной кислотой (стехиометрическая норма 3070% по СаО) и их последующая переработка в фосфорно-гумусовые удобрения с активным помутнением. Определены оптимальные соотношения исходных веществ при производстве фосфорно-гумусовых удобрений на основе активной мутности и фосфоритов и нормы серной кислоты для разложения фосфоритов Центральных Кызылкумов.
Ключевые слова: активный ил, простая фосфоритная мука, серная кислота, фосфор, кальций, органо-минеральные удобрения.
In terms of chemical composition, the precipitates formed during the treatment of urban wastewater are classified as raw materials for the production of organic fertilizers. These sediments contain a wide range of various organic and inorganic substances of biogenic and abiogenic origin, including toxic elements, pathogenic microorganisms, helminth eggs, etc. Despite the presence of pollutants in sediments, they are characterized by a high content of many elements for plant nutrition - up to 50% organic matter, 1-2% of total nitrogen, 3-5% of phosphorus, as well as other macro- and microelements that can be converted into an accessible and safe form for plants. Agricultural use of sewage sludge (SS) is limited by the presence of heavy metals in them, the amount of which can exceed the permissible concentration. However, in recent years, due to the improvement of wastewater treatment technologies and a decrease in emissions due to the reduction of a number of industries, the newly formed sludge has a lower content of heavy metals. Therefore, many research institutions are developing efficient, environmentally friendly technologies for the production and use of fertilizers based on sewage sludge and their application, taking into account the doses, timing of application and the selection of appropriate crops. The use of SS after rational processing for fertilizers will reduce the deficit of mineral fertilizers and humus in soils [1,2]. Technological schemes of urban wastewater treatment operating in cities of different countries have a similar structure. However, the methods of disposal and recycling of waste generated in the process of water treatment are very diverse. The work [2] presents the results of an experimental study of the process of anaerobic microbiological destruction of sludge sediments with the reduction and removal of phosphorus compounds from them. The regularities and mechanisms of biochemical transformations of phosphorus compounds in silt sediments during processing have been determined. Shown is a process flow diagram for the extraction of phosphorus compounds from sludge sediments and waste streams In works [3,4], an analysis of existing methods of wastewater sludge disposal is given, according to which the most effective are thermal methods of SS utilization with the subsequent use of secondary waste in the production of building materials, and the most undesirable waste management method is the method of wastewater sludge disposal on sludge ponds or polygons. The popularity of this wastewater sludge management method is due to both its ease of use and its low cost. Sewage sludge deposition facilities cause great damage to the environment and occupy large areas. Therefore, a number of European countries are legally prohibited from depositing precipitation in areas. The work [5] also indicates the advantages of wastewater sludge processing in order to obtain products used in industrial production and heat power engineering, due to the absence of strict sanitary restrictions on the presence of toxic compounds of the resulting products. The work [2] shows the state of disposal and recycling as well as use by country (table 1). The table clearly shows that the main amount of precipitation is used in agriculture, although many works indicate that incineration is considered a more rational method for processing SS.
In works [6, 7] practically all possibilities of utilization and processing are given, as well as their use as fertilizer in liquid, dehydrated, dry forms, obtaining feed products based on excess sludge, obtaining commercial products by pyrolysis, (pyrocarbonate, resin, gasoline , kerosene, wax), production of commercial products (soap and fats), production of materials for the construction industry (ash for cement additives), production and utilization of digester gas (biogas) in installations for obtaining thermal, mechanical and electrical energy, preparation of fuel briquettes from raw precipitation and activated sludge. It is also shown that a large amount of excess activated sludge is formed during biological wastewater treatment. Since the bacterial nature of activated sludge determines the high content of protein substances, amino acids, microelements, B vitamins, including B12, this product is highly effective in feeding animals, birds, fish, fur animals. In many countries of the world, one of the areas of wastewater sludge use is their processing into fertilizers with the addition of lime, peat, manure, sawdust by composting [8-10]. In [11], in order to study the effect of sewage sludge on the yield of agricultural crops and their quality, a field experiment was laid. In the experiments, two types of sediments were studied - long-term storage and fresh, used against the background of liming and without it. The introduction of sewage sludge provided a reliable increase in yield in almost all variants of the experiment. SS contributed to an increase in the yield of hay by 1.3-1.6 times
Table 1.
The main methods of disposal of sewage sludge (in%) in modern conditions
Country Used in agriculture Landfill disposal Incineration Discharge into the sea, ocean
England 53 16 7 24
Austria 20 49 31 -
Germany 25 55 15 5
Denmark 45 28 18 9
USA 25 25 35 15
Italy 20 60 - 20
Finland 40 41 - 19
Switzerland 50 30 20 -
Sweden 60 30 - 10
France 23 46 31 -
compared with the control option, and the combination of lime with the introduction of sewage sludge was more effective. From the above, it can be seen that one of the main ways of using SS is their processing for fertilizers. It should be noted that at present in many countries of the world there is a decrease in the resources of phosphate raw materials and the content of humic substances in soils cultivated by agricultural crops. In 2018, the enterprises of Uzkimyosanoat JSC of the Republic of Uzbekistan produced 153.8 thousand tons of phosphate fertilizers (in terms of 100% P2O5). And the need for agriculture is 691.7 thousand tons of P2O5. These figures indicate that the provision of agriculture with phosphate fertilizers is insufficient. At present, at the Kyzylkum phosphorite plant, during the enrichment of highly carbonated phosphorites of the Central Kyzylkum, waste is generated in the form of off-balance ore with a content of 13-15% P2O5
and sludge phosphorites with a content of 8-12% P2O5. The total volume of accumulated waste phosphorites already reaches 15 million tons. In the conditions of an acute shortage of high-quality phosphate raw materials, the most affordable way to use substandard phosphorites is its combined processing with sewage sludge. Combined processing of sewage sludge and substandard phosphorites allows using the capabilities of activated sludge microorganisms to convert indigestible forms of phosphorus of substandard phosphorites into an assimilable form for plants, since microorganisms contained in sewage sludge are able to use many minerals, including phosphate, for their growth and development, in addition to this, sewage sludge contains a significant amount of carboxylic acids capable of binding calcium ions contained in partially degraded phosphorites with mineral acids. That is, under the influence of organic acids formed during the decomposition of sewage sludge, phosphorus, which is part of substandard phosphorites, passes from an indigestible form to a form assimilable for plants and thereby will exhibit its fertilizing properties. In addition, activated phosphorite with mineral acids binds (NH4)2CO3, free NH3 and other organic volatile organic substances into non-volatile forms. To study the processes of obtaining organomineral fertilizers, wastewater sludge from the city of Navoi was used with the following composition (wt.%): Moisture - 65.43; ash - 9.74; organic substances - 24.83; humic acids - 3.05; fulvic acids - 7.47; water-soluble organic substances - 2.13; P2O5 - 1.39; N 1.17; K2O - 0.44; CaO - 4.14 [12-15].
Table 2 shows the results of mass spectrometric analysis (ICP - MS) of sewage sludge ash. It follows from the table that the sewage sludge contains in its composition a number of trace elements necessary for the growth and development of plants.
Table 2
Results of mass spectrometric analysis of ash from sewage sludge in the city of
Navoi
Name and content of elements t/year
Poultry manure ash composition
Li 600 Si 10000 0 B 3000 Na 4000 0 Mg 30000 Al 80000 P 62310 K 3200 0 Ca 303608 Sr 2000
Mn 1000 Fe 11312 Co 80 Ni 130 Cu 1000 Zn 30 Mo 1,46 Ag 3,01 Hg 2,0 Ti 500
Simple phosphate rock (SPR) was used as a phosphate raw material. It was ground to a particle size of 0.25 mm before use. The composition of the SPR is given in table. 3.
Table 3
Chemical composition of phosphorite
Content of components, weig ht. %
P205 CaO Al2O3 Fe2°3 MgO F CO2 SO3 H.O.
16,6 48,62 0,98 0,78 1,42 1,48 13,02 1,09 4,85
From table. 3, it can be seen that SHF is characterized by a low phosphorus content (16.6% P2O5), a high carbonate content (13.02% C02) and a high calcium modulus (CaO : P2O5 = 2.93). Chemical analysis of sewage sludge from the city of Navoi, sludge phosphorite and products of their processing was carried out by the methods below. Humidity was determined according to GOST 26712-85, ash content according to GOST 26714-85 and organic matter according to GOST 27980-80. The amount of the water-soluble fraction of organic substances extracted from the products with water was determined by filtration and evaporation in a water bath, drying the solid residue to
constant weight, followed by its combustion to determine the ash content and subtract it. Humic acids were isolated by treating the products with 0.1 N alkali solution followed by acidification of the solution with mineral acid [16]. The solid phase after separation of alkali-soluble organic substances from it contains residual organic matter. It was thoroughly washed with disc water, dried to constant weight, and the content of organic matter was determined. The difference between the amounts of alkali-soluble organic substances and humic acids gives us the fulvic acid content. The determination of all forms of P2O5 was carried out by the gravimetric method by precipitation of a phosphate ion with a magnesian mixture in the form of magnesium ammonium phosphate, followed by calcining the precipitate at 1000-1050 ° C in accordance with GOST 20851.2-75. The assimilable forms of P2O5 were determined by their solubility both in 2% citric acid and in 0.2 M Trilon B. The determination of the CaO content was carried out complexometrically: by titration with 0.05 N solution of Trilon B in the presence of the fluorexon indicator. For the decomposition of slurry phosphorite, sulfuric acid with a concentration of 92% was used. The rate of sulfuric acid was varied in the range of 30-70% of the stoichiometry for the decomposition of CaO of phosphate raw materials. The experiments were carried out in the following way, sulfuric acid was slowly poured into a glass reactor, in which a sample of phosphate raw materials was located. The duration of the interaction of the components was 30 minutes, after which the waste water sludge was added to the pulp, and stirring was continued for 60 minutes. Drying was carried out at 80 ° C to a moisture content of 10-15% in the finished product. The processing of the products of sulfuric acid decomposition by sewage sludge was carried out in the range of weight ratios of sewage sludge to sludge phosphorite from 100: 10 to 100: 40. The results are shown in Tables 4-6 4. From Tables 4-6, it can be seen that the higher the rate of sulfuric acid and the more wastewater sludge is taken, the less P2O5total in the product, but the greater the relative content of the assimilable form of P2O5, the water-soluble form of CaO, organic substances and humic substances. As you can see from the table. 4, when the ratio of SS: SPR = 100: 10 and the rate of sulfuric acid is 30% of the stoichiometry, an organomineral fertilizer containing P2O5total is obtained. - 5.17%; P2O5 ass. by lim. to-those - 2.24%, P2O5 ass. : P2O5total. - 39.25 %; P2O5 water : P2O5total. - 4.78%; CaOtotal. - 14.99%; CaOwater. - 1.73%, CaOass. : CaOtotal. - 60.59%; CaOwater. : CaOtotal. - 11.53%, organic matter - 42.83%; humic substances - 23.70%; humic acids - 5,63%, fulvo acid -13,78%, water soluble organic matter - 3,93%, SO3общ. - 3,63%, SO3вод. - 1,11%, азот - 2,16%. With the same ratio of SS to mineralized mass, but at a rate of 70% acid, a fertilizer containing P2O5total. - 5.43%; P2O5 ass. by lim. to-those - 4.66%; P2O5 ass. : P2O5total. - 85.78%; P2Os water : P2Ostotal. - 40.28%; CaOtotal. - 13.39%; CaOwater. -6.07%, CaO ass. : CaOtotal. - 40.28%; CaOwater. : CaOtotal. - 50.47%, organic matter -40.72%; humic substances - 22.53%; humic acids - 5,32%, fulvo acid - 13,04%, water soluble organic matter- 3,80%, SO3total. - 7,73%, SO3water. - 2,01%, nitrogen - 2,04%.
At the request of agriculture, phosphate fertilizer must have a high content of the total and assimilable forms of P2O5, and the relative content of the water-soluble form of P2O5 must be at least 50%. Based on this requirement, the optimal rate of sulfuric acid for decomposition non-codic phosphorites is 40% of stoichiometry, and the optimal ratio of SS: substandard phosphorite can be considered 100 : 30, at which the relative content of P2O5ass. is 51.36%. In this case, organomineral fertilizer using SHF has a composition (wt%): P2O5total. - 7.76; P2Os ass. - 3.65; CaOtotal. - 21.59; CaOwater. - 5.95; organic substances - 27.85; humic substances - 15.41. Thus, the studies carried out convincingly show that on the basis of sewage sludge after dehydration, or without it, using a small amount of sulfuric acid or other mineral acids used in the production of mineral fertilizers, it is possible to intensively process sewage sludge and sludge phosphorite into organomineral fertilizers.
Table 4
The composition of organomineral fertilizer obtained by activation of
phosphorite wi th sulfuric acid and sewage sludge from the city ol Navoi
Mass ratio of SS to phosphorite P2O5 total% P2O5 yCB. % P2O5 water.% CaO total% CaO ycB % CaO water.%
H2SO4 norm from stoichiometry for decomposition CaO , 30 %
100: 10 5,71 2,24 0,27 14,99 9,08 1,73
100 : 20 7,06 2,72 0,39 19,29 11,29 2,49
100 : 25 7,55 2,85 0,48 20,85 11,80 2,81
100 : 30 7,96 2,97 0,57 22,16 12,23 3,20
100 : 40 8,61 3,11 0,70 24,21 12,90 3,74
H2SO4 norm from stoichiometry for decomposition CaO , 40 %
100: 10 5,64 2,85 0,42 14,80 8,14 3,40
100 : 20 6,92 3,39 0,59 18,90 10,24 4,77
100 : 25 7,38 3,55 0,70 20,37 10,86 5,37
100 : 30 7,76 3,65 0,80 21,59 11,26 5,95
100 : 40 8,36 3,82 0,94 23,51 11,90 6,91
H2SO4 norm from stoichiometry for decomposition CaO , 50 %
100: 10 5,57 3,55 0,95 14,61 7,22 4,78
100 : 20 6,78 4,15 1,30 18,52 8,90 6,48
100 : 25 7,21 4,31 1,47 19,92 9,45 7,25
100 : 30 7,57 4,39 1,65 21,07 9,83 7,87
100 : 40 8,12 4,61 1,97 22,85 10,28 9,02
H2SO4 norm from stoichiometry for decomposition CaO , 60 %
100: 10 5,50 4,15 1,53 14,43 6,40 6,10
100 : 20 6,65 4,86 2,02 18,16 7,62 8,02
100 : 25 7,06 5,03 2,24 19,48 7,97 8,71
100 : 30 7,39 5,08 2,42 20,56 8,26 9,47
100 : 40 7,90 5,32 2,77 22,23 8,49 10,86
H2SO4 norm from stoichiometry for decomposition CaO , 70 %
100: 10 5,43 4,66 2,09 14,25 5,74 7,19
100 : 20 6,52 5,44 2,68 17,81 6,88 9,40
100 : 25 6,90 5,63 2,90 19,06 7,21 10,31
100 : 30 7,21 5,85 3,15 20,08 7,43 11,15
100 : 40 7,69 6,03 3,52 21,64 7,72 12,40
Table 5
The composition of organomineral fertilizer obtained by activation of phosphorite with sulfuric acid and sewage sludge from the city of Navoi
Mass ratio of SS to phosphorite P2O5ass. /P2Ostotal. *100% P2O5 water. /P2O5total. *100% CaO ass / CaO total *100% CaO water./ CaO total *100% organic substances Humic substances
H2SO4 norm from stoichiometry for decomposition CaO , 30 %
100 : 10 39,25 4,78 60,59 11,53 42,83 23,70
100 20 38,51 5,47 58,54 12,89 34,28 18,97
100 25 37,68 6,38 56,59 13,49 31,17 17,25
100 30 37,25 7,18 55,21 14,42 28,58 15,81
100 40 36,18 8,14 53,29 15,45 24,50 13,56
H2SO4 norm from stoichiometry for decomposition CaO , 40 %
100 10 50,56 7,45 55,02 22,98 42,28 23,40
100 20 48,99 8,54 54,18 25,22 33,58 18,58
100 25 48,05 9,47 53,29 26,37 30,45 16,85
100 30 47,03 10,34 52,14 27,54 27,85 15,41
100 40 45,66 11,26 50,63 29,38 23,79 13,16
H2SO4norm from stoichiometry for decomposition CaO , 50 %
100 10 63,78 17,10 49,39 32,69 41,75 23,10
100 20 61,25 19,22 48,04 34,97 32,91 18,21
100 25 59,72 20,41 47,47 36,42 29,77 16,47
100 30 57,98 21,77 46,68 37,36 27,17 15,03
100 40 56,80 24,25 44,99 39,47 23,13 12,80
H2SO4 norm from stoichiometry for decomposition CaO , 60 %
100 10 75,41 27,85 44,34 42,29 41,23 22,81
100 20 73,13 30,41 41,98 44,15 32,27 17,86
100 25 71,26 31,81 40,94 44,71 29,11 16,11
100 30 68,81 32,82 40,19 46,05 26,51 14,67
100 40 67,31 35,09 38,21 48,86 22,50 12,45
H2SO4 norm from stoichiometry for decomposition CaO , 70 %
100 10 85,78 38,54 40,28 50,47 40,72 22,53
100 20 83,44 41,03 38,60 52,76 31,65 17,52
100 25 81,53 42,01 37,81 54,09 28,48 15,76
100 30 81,02 43,70 36,99 55,55 25,89 14,33
100 40 78,33 45,80 35,67 57,32 21,90 12,12
Table 6
The composition of organomineral fertilizer obtained by activation of phosphorite with sulfuric acid and sewage sludge from the city of Navoi
Mass ratio of SS to phosphorite fulvo acid humic acids water soluble organic matter SO3total. SO3water. SO3water. / SO3total. *100 % nitrogen
H2SO4 norm from stoichiometry for decomposition CaO, 30 %
100 10 13,78 5,63 3,93 3,63 1,11 30,62 2,16
100 20 11,02 4,50 3,14 5,81 1,88 32,42 1,73
100 25 10,02 4,09 2,86 6,61 2,18 33,05 1,57
100 30 9,19 3,75 2,62 7,27 2,49 34,28 1,44
100 40 7,87 3,21 2,25 8,30 3,00 36,15 1,23
H2SO4 norm from stoichiometry for decomposition CaO, 40 %
100 10 13,58 5,55 3,87 4,70 1,38 29,35 2,13
100 20 10,78 4,40 3,07 7,46 2,35 31,47 1,69
100 25 9,77 3,99 2,79 8,45 2,75 32,57 1,53
100 30 8,93 3,65 2,55 9,27 3,09 33,29 1,40
100 40 7,63 3,11 2,17 10,55 3,74 35,44 1,19
H2SO4 norm from stoichiometry for decomposition CaO, 50 %
100 10 13,40 5,47 3,82 5,74 1,57 27,35 2,10
100 20 10,55 4,31 3,01 9,03 2,66 29,41 1,65
100 25 9,53 3,89 2,72 10,20 3,12 30,54 1,49
100 30 8,69 3,55 2,48 11,17 3,54 31,72 1,36
100 40 7,40 3,02 2,11 12,67 4,26 33,61 1,16
H2SO4 norm from stoichiometry for decomposition CaO, 60 %
100 10 13,22 5,40 3,77 6,75 1,81 26,78 2,07
100 20 10,32 4,21 2,94 10,54 2,99 28,35 1,62
100 25 9,30 3,80 2,65 11,87 3,50 29,47 1,46
100 30 8,47 3,46 2,41 12,97 3,95 30,43 1,33
100 40 7,18 2,93 2,05 14,66 4,80 32,78 1,12
H2SO4 norm from stoichiometry for decomposition CaO, 70 %
100 10 13,04 5,32 3,72 7,73 2,01 25,95 2,04
100 20 10,11 4,13 2,88 11,98 3,24 27,02 1,58
100 25 9,09 3,71 2,59 13,47 3,87 28,71 1,42
100 30 8,25 3,37 2,35 14,68 4,29 29,24 1,29
100 40 6,97 2,85 1,99 16,53 5,21 31,52 1,09
REFERENCES
1. Frozen G.E. Use of organic waste in agriculture. Russian Chemical Journal 2005, v. XI.IX. №. 3, - Pp. 48-54.
2. Zainullin R.R., Galyautdinov A.A. Current state and prospects for the utilization of sediment from fine waters. International scientific journal "Innovative Science" №. 6. 2016. - Pp. 74-75.
3. Chernysh E.Yu. Ecobiotechnology of sludge treatment: removal of phosphorus compounds. Sumy State University. 2014 . Pp. 6.
4. Krupnova T.G., Kostryukova A.M., Mashkova I.V. Review of modern technologies for urban wastewater sludge treatment // Agriculture, forestry and water management. 2014. №.7 [Electronic resource]. URL: http://agro.snauka.ru/
5. Valetov D.S., Kashchenko O.V. Analysis of methods for utilization of urban wastewater sludge. Environmental protection journal. Human ecology. 2018 .-pp. 16-19.
6. Zainullin R.R., Galyautdinov A.A. Features of utilization and processing of urban wastewater sludge. International scientific journal "Innovative Science" №. 6. 2016. Pp. 6970.
7. Zainullin R.R., Galyautdinov A.A. Current state and prospects for the utilization of sediment from fine waters. International scientific journal "Innovative Science" №. 6. 2016. Pp. 74-75.
8. Blagorazumova A.M. Treatment and dehydration of urban wastewater sludge: textbook, part 1. - Novokuznetsk: Siberian State Institute of Management, 2010. Pp.139
9. Kalimullina D.D., Bagautdinov I.E. Utilization of municipal waste water sludge. International scientific journal "Innovative Science" №. 5. 2016. Pp. 115-116.
10. Pokrovskaya S.F., Kasatikov V.A. Use of urban wastewater sludge in the spruce economy / VNIITEIAagroprom. M., 1987. Pp.60.
11. Kasatikov V.A. Use of sewage sludge and composts from municipal solid waste / Chemicalization of agriculture. 1989. №. 11. Pp. 39-41.
12. Temirov Uktam, Namazov Shafoat, Najimuddin Usanbayev Intensive technology for processing bird litter in organomineral fertilizers // Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. [Russ. J. Chem. & Chem. Tech.]. 2020. V. 63. N 12. P. 85-94. DOI: https://doi.org/10.6060/ivkkt.20206312.6210
13. Temirov, U. S., Namazov, S. S., Usanbaev, N. H., Sultonov, B. E., & Reymov, A. M. (2018). Organic-mineral Fertilizer Based on Chicken Manure and Phosphorite from Central Kyzylkum. Chemical Science International Journal, 24(3), 1-7. https://doi.org/10.9734/CSJI/2018/43452
14. У.Ш.Темиpов, П.Х.Ганиев, Ш.С.Намазов, Н.Х.Усанбаев. Особенности компостиpования навоза фупного poraToro скота и фосфоpитного шлама с добавкой фосфогипса. // Эле^онный научный жуpнaл. Universum: химия и биология: -Нoвoсибиpск, 2018. - № 8(50) - С. 25-33. http://7universum.com/ru/nature/archive/item/6202
15. Ilkhom Tagaev, Nodirjon Doniyarov, Anvar Asrorov, Islom Murodov, N.KH. Usanbaev & Uktam Temirov. Distinctive IR-Spectroscopic Features of Functional Groups of Low-Grade Phosphorites After Microbiological and Acid Processing // Land Science, 2020, Vol. 2, No. 1, pp. 43-54. DOI: https://doi.org/10.30560/ls.v2n1p43
16. Dragunov S.S. Methods of analysis of humic fertilizers // Humic fertilizers. Theory and practice of their application. - Kharkov: Publishing house of Kharkiv State University, 1957. PP. 42-55.
