RU2513558C1 - Method of preparation compost from sewage sludge (versions) - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: method of preparation compost from sewage sludge comprises mixing of fresh sewage sludge with the retention period of less than 3 years with the organic component, which is used as sawdust of any tree species, with the addition of bioactivator and subsequent aerobic composting of the resulting mixture, and prior to mixing the components the layering of sawdust with humidity of 30-40% and sewage sludge, which humidity is 79-81% is carried out, in a ratio of 3:1, at that the dust is subjected to bioactivation by spraying with the working solution of preparation EM-1 "Baikal" at a consumption rate of 5 liters per 1 t at its concentration in the working fluid of 0.0001%, in addition, the aerobic composting of the resulting mixture is carried out in storage pits, at that when the temperature of the composted mixture reaches 50-60°C the mixture is incubated for 20 days, after which the break-in of the storage pit is repeatedly carried out for 2 months with the intervals of 15-20 days, followed by aging of compost for 14-15 days.

EFFECT: invention enables to provide the low-cost environmentally friendly organic fertiliser, to resolve the problem of disposal of sewage sludge.

4 cl, 3 tbl, 2 ex

Description

The invention relates to the field of agriculture and environmental biotechnology and can be used for the preparation of fertilizers from sewage sludge, as well as the disposal of sewage sludge.

In modern society, a huge amount of anthropogenic waste is generated, the storage and disposal of which is one of the most important problems in the modern world. Among these wastes, an increasing amount of sewage sludge should be noted. One of the solutions to the problem may be the use of this type of waste as a material for the production of organic fertilizer.

Sewage sludge from the city has high fertilizer value, as it is 40% composed of humic substances and their precursors and contains all the substances necessary for soil formation. The presence of heavy metals in them negatively affects the biological activity of the soil. However, at present technological measures allow normalizing the content of trace elements in compost and the amount of salts of heavy metals.

The compost, which includes sewage sludge, contains a huge amount of organic substances, the decomposition of which produces carbon dioxide, which is necessary for plant life. These substances are not only a source of nutrition for crops, but also a source of biological activators of soil processes, stimulate the development and activity of soil microorganisms, which play a large role in soil nutrition of plants, eliminate the negative effects of podzolic acidity and alkalinity of saline soils. The introduction of raw sewage sludge into compost increases the content of fats, carbohydrates and their decay products. Carbohydrates are the primary products of photosynthesis and the main starting products of the biosynthesis of other substances, and fats are structural components of the cytoplasm of cells and perform various functions.

There are many technical solutions aimed at creating technologies for the production of organic fertilizers using this type of waste - sewage sludge as a material for producing organic fertilizer (AS USSR No. 685653, Cl. C05F 11/00, C05F 3/00, 1978 ; AS USSR No. 948993, CL C05F 7/00, C05F 11/02, 1979; AS USSR No. 1213017, CL C05F 7/00, C05F 11/02, 1984; Pat. Of the Russian Federation No. 2159756 , Cl. C05F 7/00, 1999; Pat. RF No. 2252205, Cl. C05F 7/00, 2003; Pat. RF No. 2414444, Cl. C05F 7/00, 2009; Pat. RF No. 2299872, Cl. C05F 7 / 00, 2005, etc.).

The known methods for producing compost using sewage sludge are based on the aerobic method of bioconversion of sewage sludge with moisture-consuming and gas-absorbing additives (sawdust, peat, wood chips, beer pellets, straw, etc.), including mixing the components and forming a compost heap from the resulting mixture . Composting a mixture (converting mixtures into ready-made compost) depends both on the ratio of components, their high-quality mixing, and on factors contributing to the course of enzymatic processes in the mixture. Biological disinfection of compost is possible as a result of self-heating of the mixture to a certain temperature (50-60 ° C). The introduction of bioactive additives accelerates fermentation.

Known methods for producing compost using sewage sludge are aimed at improving the quality of the compost obtained, reducing its cost, reducing compost time, but at the same time, known methods for producing compost (Pat. RF No. 2159756, Cl. C05F 7/00, 1999; Wesner J. M. Composting of sewage sludge. - In the book: Treatment and disposal of sewage sludge. - Vol. 2. - M .: Stroyizdat, 1985, p. 62-100) are not very effective in removing heavy metals from compost, since separation of heavy metals from compostable mass occurs only due to gravitational forces, therefore, in the prepared compost heavy metals are preserved that degrade the quality of the compost and pollute the environment, some with the duration of the composting process (AS USSR No. 1213017, Cl. C05F 7/00, C05F 11/02, 1984) and high cost (Pat. RF No. 2252205, Cl. C05F 7/00, 2003).

A known method of preparing organic fertilizer from sewage sludge (Pat. RF No. 2299872, CL. C05F 7/00 (2006.01), 2005, a prototype of option 4. A method of preparing organic fertilizer according to option 1 includes mixing a mineralized sewage sludge with beer pellet and subsequent aerobic composting of the mixture; the method according to option 2 includes mixing fresh sewage sludge with a carbon-containing moisture-absorbing component (sawdust of any tree species or peat) with the addition of beer grains and also subsequent aerobic compostiro mixture; the method according to option 3 includes mixing fresh sewage sludge with a carbon-containing moisture-absorbing component (sawdust of any tree species or peat) with the addition of beer grains and bioactivator and subsequent aerobic composting of the mixture; the method according to option 4 includes mixing fresh sewage sludge with a carbon-containing moisture-absorbing component (sawdust of any tree species or peat) with the addition of a bioactivator and subsequent aerobic composting of the mixture.

A known method of preparing organic fertilizers from sewage sludge (options) solves the problem of disposal of sewage sludge. Its disadvantage is the somewhat increased cost of finished compost due to the disposal of expensive brewing waste.

The problem solved by this invention is to develop a simple and cheap method of producing organic fertilizer, expanding the range of organic fertilizers, while solving the problem of disposal of sewage sludge.

The technical result obtained from the solution of the problem lies in the possibility of obtaining inexpensive environmentally friendly organic fertilizer and in solving the problem of disposal of sewage sludge.

The object of the invention is solved by the fact that in the method for preparing compost from sewage sludge (option 1), which involves mixing fresh sewage sludge with a shelf life of less than 3 years with an organic component, which uses sawdust of any tree species, with the addition of a bioactivator and the subsequent aerobic composting of the resulting mixture, before mixing the components, layered sawdust is laid with a moisture content of 30-40% and sewage sludge, the moisture content of which is 79-81%, in a ratio of 3: 1, while sawdust p they bioactivate by spraying with a working solution of the EM-1 Baikal preparation at a consumption rate of 5 l per 1 ton with a concentration of 0.0001% in the working fluid, in addition, aerobic composting of the resulting mixture is carried out in collars, while reaching a temperature of the compostable mixture 50-60 ° C, the mixture is kept for 20 days, after which the shoulder is repeatedly beaten for 2 months with an interval of 15-20 days, followed by compost exposure for 14-15 days.

According to option 2, in a method for preparing compost from a sewage sludge, comprising mixing fresh sewage sludge with a shelf life of less than 3 years with an organic component, which is used for sawdust of any tree species, with the addition of a bioactivator and subsequent aerobic composting of the resulting mixture, before mixing the components layer-by-layer laying of sawdust with a moisture content of 30-40% and sewage sludge, the humidity of which is 79-81%, in a ratio of 3: 1, while bird droppings are used as bioactivator 55-58% in the amount of 5% of the compostable mass, which is applied to each layer of sawdust, in addition, aerobic composting of the resulting mixture is carried out in collars, while when the compostable mixture reaches a temperature of 50-60 ° C, the mixture is incubated for 20 days, after which the bead is repeatedly interrupted for 2 months with an interval of 15-20 days, followed by compost exposure for 14-15 days.

Bird droppings with a moisture content of 55-58% are applied to the sawdust layer with a feed dispenser of the KTP-6 brand. Aerobic composting of the mixture is carried out in collars having a cross-section in the form of an isosceles triangle with a base of 4 m and a height of 3 m

One of the most rational ways to dispose of sewage sludge is to include them in various organic composts. The use of fresh sewage sludge directly from sludge chambers as an organic fertilizer is limited by sanitary indicators due to the possible content of helminth eggs, intestinal pathogenic protozoa cysts, pathogens and E. coli bacteria in it. Waste disinfection methods using chemicals or heat treatment are expensive. Natural disinfection of WWS by long-term storage (more than 3 years) leads to the mineralization of organic matter below the standard level (organic content <10-15%), and therefore such WWS cannot be used as fertilizer.

To optimize the chemical composition (carbon to nitrogen ratio) and control humidity, a carbon-containing, moisture-absorbing component in the form of sawdust is introduced into the mixture. This is due to the fact that as a filler materials that are available in sufficient quantities in this region are usually used. In the non-chernozem zone of Russia, peat, straw, sawdust are most often used. Currently, due to minimization of peat harvesting volumes and reduction of sown areas of cereal crops, the cheapest and most affordable filler may be sawdust, which has high hygroscopicity and good sorption properties and creates an acidic environment.

The claimed technology for producing compost from sewage sludge is based on the aerobic method of bioconversion of fresh sewage sludge with a moisture content of 79-81% with sawdust, the moisture content of which is 30-40%, in shoulders. The introduction of bioactive additives - the drug EM-1 Baikal or bird droppings - accelerates fermentation. When moving the composted mixture from one place to another (breaking the shoulder), the heat and mass transfer processes intensify due to aeration of the shoulder. The processes of biochemical oxidation are sharply intensified, the particle size of the biomaterial is reduced, and the composting period is reduced.

The drug EM-1 Baikal, used as a bioactivator, is a set of strains of many tens of beneficial microorganisms with a predominance of lactic acid bacteria. It is produced by the company EM-Center LLC, located in Ulan-Ude, Kirova St., 19. The norms and methods for introducing the bioactivator into the composted mixture were selected experimentally.

Processing sawdust with a working solution of the EM-1 Baikal preparation and their subsequent mixing with sewage sludge allows the bioactivator to be introduced more evenly into the composted mixture.

Bird droppings used as bioactivators were taken at the Upper Volga poultry farm in the Tver Region, where 23-25 thousand tons of it accumulate during the year. On the layer of sawdust, bird droppings are introduced with a feed dispenser of the KTP-6 brand fairly evenly. The norms and the method of introducing it into the compostable mixture are selected experimentally.

Aerobic composting of the resulting mixture is carried out in collars having a cross-section in the form of an isosceles triangle with a base of 4 m and a height of 3 m.The shape and dimensions of the collar are due to the technique used for its formation, as well as the convenience of subsequent interruption and are also selected experimentally.

Due to the uniform distribution of the components in the mixture, their optimal ratio and the height of the pile for composting, the resulting compost has a fairly high quality (table 1).

The invention is illustrated in tables.

Table 1 presents the chemical composition of compost prepared from sewage sludge (options); table 2 is presented, showing the content of heavy metals in compost prepared from sewage sludge (options); Table 3 is presented, which shows the sanitary-bacteriological and sanitary-parasitological indicators of composts prepared according to option 1 and option 2.

The claimed method of preparing compost from sewage sludge (option 1) includes the following operations:

1) preparation of the paved area;

2) laying a layer of sawdust, the moisture content of which is 30-40%, on the prepared site;

3) spraying a layer of sawdust with a working solution of the EM-1 Baikal preparation at a consumption rate of 5 liters per 1 ton with a concentration of 0.0001% in the working solution;

4) laying on a layer of sawdust a layer of sewage sludge with a moisture content of 79-81% with a component ratio of 3: 1;

Operations 2-4 are repeated until a compostable heap of the required size is formed.

7) mixing layered sewage sludge with sawdust;

8) the formation of a collar from the resulting mixture having in the cross section the shape of an isosceles triangle;

9) measuring the temperature of the mixture heating at various points of the shoulder; when the composted mixture reaches a temperature of 50-60 ° C, the mixture is incubated for 20 days, during this time the biological disinfection of the mixture occurs;

10) repeated interruption of the shoulder during 2 months with an interval of 15-20 days;

11) compost exposure for 14-15 days.

The method for preparing compost from sewage sludge according to option 2 includes the same operations as the method for preparing compost from sewage sludge according to option 1, except for operation 3, where bird droppings with a humidity of 55-58% are added to the sawdust layer. The rate of introduction of bird droppings into the composted mixture is 5% of its weight.

Examples of specific performance of the method of preparation of compost from sewage sludge (options).

Example 1

Compost from sewage sludge according to the claimed method was prepared at the Department of Agrochemistry, Soil Science and Agroecology of the Tver State Agricultural Agricultural Academy in the summer of 2012 on a hard-coated site, the dimensions of which depend on the planned mass of compost. To obtain 1600 tons of compost, a 100 × 100 m site was set up with a slope of 0.5-1 ° to one edge relative to the soil surface and bordered by a ditch for rainfall runoff.

The composting process is carried out continuously as follows.

Sawdust of any tree species with a moisture content of 30-40% is delivered to the site by a mobile conveyor and laid in the form of a tape with a width of 3.5-4 m and a thickness of 1-1.2 m with subsequent processing by spraying with a backpack sprayer with a working solution of EM-1 "Baikal" at a rate of 5 liters per 1 ton with a concentration of 0.0001% in the working fluid.

A working solution of the EM-1 Baikal preparation is prepared as follows: 10-14 days before laying the compost, 40 ml of the EM-1 Baikal preparation is diluted in 4 l of non-chlorinated water with the addition of molasses 40 g. On the day of compost laying, the pre-obtained concentrate of the preparation EM-1 Baikal is diluted with non-chlorinated water in a ratio of 1: 100. After processing the sawdust layer with the working solution of the EM-1 Baikal preparation by mobile transport, sewage sludge is brought from the storage sites with a shelf life of less than 3 years with a moisture content of 79-81% and they are laid along the entire length of the sawdust layer. The mass of sewage sludge is 1/3 of the mass of sawdust. A continuous loader (PND-250), or a continuous snow blower, or using other available equipment of a similar purpose, mix the initial components of the compost. Next, a collar with a volume of 560 m ³ having a cross section in the form of an isosceles triangle with a base of 4 m and a height of 3 m is formed using the bulldozer from the resulting mixture.

To establish the degree of compost readiness after 10 days, the temperature of the mixture is heated at various points of the pile, for which several transverse triangular sections are conventionally distinguished along the length of the pile and the temperature of the mixture is measured at various cross-section heights, and at each measuring height, the temperature is determined at different depths from shoulder slope surface. When the temperature at all points of the collar reaches 50-60 ° C, the composting process proceeds normally with the biological disinfection of the mixture. Samples are taken characterizing the sanitary condition of the compost. The burt is kept for 20 days from the moment the composted mixture reaches a temperature of 50-60 ° C, after which the burr is crushed twice-thrice (within 2 months with an interval of 15-20 days), followed by exposure to 14-15 days for ripening. Ready compost is transported to places of use.

Ready compost (option 1) meets the requirements of GOST, is a fertilizer with the necessary agrochemical characteristics, which confirms its chemical composition (table 1). The content of heavy metals in compost prepared from sewage sludge (options) does not exceed the permissible standards and is presented in table 2. The bacteriological analysis performed in the testing laboratory of the Center for Hygiene and Epidemiology of the Tver Region confirms the sanitary and environmental safety of the compost obtained (table 3).

Example 2. Similar to example 1 of a specific method for preparing compost from sewage sludge, the only difference being that bird bioactivity with a moisture content of 55-58% in the amount of 5% of the composted mass, which is applied to each layer of sawdust with a feed dispenser of the KTP brand, is used as bioactivator. -6.

Ready compost obtained by the claimed method (option 2) meets the requirements of GOST, is a fertilizer with the necessary agrochemical characteristics, which confirms its chemical composition (table 1). The content of heavy metals in compost prepared from sewage sludge (options) does not exceed the permissible standards and is presented in table 2. The bacteriological analysis performed in the testing laboratory of the Center for Hygiene and Epidemiology of the Tver Region confirms the sanitary and environmental safety of the compost (options) (table) 3).

Analyzing the chemical composition of composts (options 1 and 2) obtained by the claimed method, as well as the data in tables 2 and 3, we conclude that indeed one of the most rational ways of disposing of sewage sludge is to include them in various organic composts.

The claimed method of preparing compost from sewage sludge (options) is industrially feasible, quite simple and cheap. Along with solving the problem of disposal of sewage sludge, it became possible to obtain inexpensive, environmentally friendly organic fertilizers of sufficiently high quality, expanding the range of organic fertilizers.

Table 1 The chemical composition of compost prepared from sewage sludge (options) Indicators Units Compost Composition Control (SAL) OSV: sawdust OSV: sawdust + EM “Baikal” OSV: sawdust + litter 2 months 5 months 2 months 5 months 2 months 5 months 2 months 5 months Humidity % 66,4 65.1 62.1 63,4 63,4 64,2 63.6 65.0 Ash content % 37.6 38,4 14.9 16.8 17,2 18,4 18.4 20,2 Acidity pH 7.8 8.2 5.9 6.2 6.0 6.3 6.2 6.4 C-organic. substance % 31,2 30.8 42.5 41.6 41,4 40.8 40.8 39.9 N total % 3.95 4.05 1.27 1.32 1.36 1.38 1.40 1.46 P ₂ O ₅ total % 3.33 3.40 0.82 0.91 0.90 0.94 0.94 0.98 K ₂ About total % 0.37 0.39 0.09 0.11 0.12 0.13 0.14 0.16 Moving iron mg / 100 g 36.3 39,4 3,1 3.3 4.2 4.8 5.3 5.7

Claims (4)

1. A method of preparing compost from sewage sludge, comprising mixing fresh sewage sludge with a shelf life of less than 3 years with an organic component, which is used in sawdust of any tree species, with the addition of a bioactivator and subsequent aerobic composting of the resulting mixture, characterized in that before mixing the components produce layered sawdust with a moisture content of 30-40% and sewage sludge, the humidity of which is 79-81%, in a ratio of 3: 1, while the sawdust is bioactivated by spraying working solution of the preparation EM-1 Baikal at a consumption rate of 5 l per 1 ton with a concentration of 0.0001% in the working fluid, in addition, aerobic composting of the resulting mixture is carried out in collars, and when the temperature of the composted mixture reaches 50-60 ° C, the mixture is kept for 20 days, after which the shoulder is repeatedly interrupted for 2 months with an interval of 15-20 days, followed by compost exposure for 14-15 days. 2. A method of preparing compost from sewage sludge, comprising mixing fresh sewage sludge with a shelf life of less than 3 years with an organic component, which is used for sawdust of any tree species, with the addition of a bioactivator and subsequent aerobic composting of the resulting mixture, characterized in that before mixing the components produce layered sawdust with a moisture content of 30-40% and sewage sludge, the humidity of which is 79-81%, in a ratio of 3: 1, while bird bio-activator is used as bioactivator t with a moisture content of 55-58% in an amount of 5% of the compostable mass, which is applied to each layer of sawdust, in addition, aerobic composting of the resulting mixture is carried out in collars, while when the compostable mixture reaches a temperature of 50-60 ° C, the mixture is kept for 20 days, after which is repeatedly carried out by breaking the collar within 2 months with an interval of 15-20 days, followed by compost exposure for 14-15 days. 3. The method according to claim 1 or 2, characterized in that the bird droppings with a moisture content of 55-58% are applied to the sawdust layer with a feed dispenser of the KTP-6 brand. 4. The method according to claim 1 or 2, characterized in that the aerobic composting of the mixture is carried out in collars having a cross-section in the form of an isosceles triangle with a base of 4 m and a height of 3 m