RU2378234C1 - Method for conversion of biodegradable hygienically unstable substrate into hygienically stable product - Google Patents

Abstract

FIELD: biotechnologies.

SUBSTANCE: invention is related to method for biological treatment of wastes, mainly wastes, which may pollute environment, wastes that emit odor, and hygienically unfit wastes. Mass produced from biodegradable, hygienically unstable, for instance potentially unsanitary substrate, is placed into cavity, which is separated from ambient atmosphere, and is processed by means of aerobic fermentation, including stage, at which the whole volume of mass is exposed to temperature of 70-80°C for 30-60 minutes. Mass temperature is mainly controlled during fermentation by amount of air supplied from outside and by intensity of mass turning.

EFFECT: conversion of biological wastes into raw material, which is hygienically stable, ie acceptable product suitable for additional processing without need in any special hygienical means, such as composting or conversion into fuel.

2 cl, 5 ex

Description

Field of Invention

The invention relates to a method for the biological processing of waste, mainly waste that is capable of polluting the environment, waste emitting odors, and hygienically unsuitable waste, and this solves the problem of ensuring hygiene for the subsequent handling of such waste. Subsequently, a hygienically stable substrate can be processed without the risk of environmental pollution, such as composting or processing into fuel.

Description of the Related Art

It is known that waste of biological origin is stored in landfills. The disadvantage of landfills is the growing demand for space for them, while the rules for the operation of landfills are tightened. It is also known that waste of biological origin is composted without additional verification. The disadvantage of composting without prior verification is that the recycled material becomes hygienically impeccable only after a few months. The inconvenience of storage, as well as composting, is that biological waste in landfills and composting sites is usually an increased danger, primarily polluting groundwater, emitting an odor, or because of their conditional pathogenicity they are a potential source of infection. It is also known that biological waste can be burnt, while a large volume of water in the burnt material is undesirable because the heat output decreases with increasing volume of water. When a large volume of water is contained, the fuel becomes non-flammable. Further, it is known that biological waste can be aerobically fermented. Czech Patent CZ286614 relates to a method for processing a mixture of waste from a treatment plant and solid biological waste, for example wood chips, sawdust or separated biological waste. This mixture, from which the mass is produced, is subjected to 2-4-day aerobic fermentation, after which it is dried to a dry mass of 70 - 90% and subsequently it is granulated or converted into briquettes. In this way, fuel is obtained. The disadvantage of this method is that the processing of the entire volume of the landfill into a hygienic product is not ensured, since this method is not carried out in a closed environment isolated from the environment, thus, heat is lost. This is manifested by a low temperature near the surface of the mass, where the fermentation method does not proceed efficiently enough, and thus the total processing time becomes longer. The next drawback is the spread of pathogenic organisms along with evaporating water, aerosols and solid elements during manipulation with the mass. Another disadvantage is the energy requirement for the process, since there is a need for a heat source to dry the substrate.

Description of the invention

The mentioned disadvantages are eliminated by the method of converting a biodegradable hygienically unstable substrate into a hygienically stable product according to this invention, in which the main thing is to place the mass in a cavity separated from the surrounding atmosphere, after which it is subjected to aerobic fermentation. Aerobic fermentation includes the stage at which the entire mass is exposed to a temperature of 70-80 ° C for 30-60 minutes at a time. Another alternative is to control the temperature of the mass during fermentation with the volume of air delivered from outside and the intensity of the mass turning over.

An advantage of the method according to this invention is the change of biological waste into a raw material that is not biologically active, does not pollute the environment and is not a source of interfering odor. Another advantage is the short processing time. The ease of implementation of the method should not be inadequately large, even at high productivity. An advantage is also low energy consumption for the implementation of the method, there is no need for an external heat source.

Examples of carrying out the invention

Example 1

A mass containing aerobic microorganisms, consisting of a mixture of straw of grain crops, chips and garbage from an urban sewage enterprise in a volume ratio of 1: 1: 1, was placed in a closed thermally insulated fermentation reactor, which is equipped with an air supply and exhaust gas discharge device.

The maximum size of inseparable elements in the mass is 50 mm. The temperature of the mass is raised by the method of aerobic fermentation so that the temperature in the fermentation reactor reaches 40-50 ° C after 8 hours. In this phase, steam was released from the reactor. Fermentation as such took place during the overturning of the mass and regulation of the amount of air delivered from outside in this temperature range for 36 hours. The intensity of the fermentation was controlled by the volume of air delivered from outside based on a temperature measurement and determination of CO ₂ in the gases emitted. After that, the amount of air delivered from outside was reduced so that the temperature gradually increased for 24 hours, until it reached the range of 70-80 ° C. The mass was stored at this temperature range for 35 minutes. The next phase is intensive ventilation, which was completed before reaching a maximum humidity value of 10%.

Example 2

The difference between example 2 and 1 is that the mass consists of 40% of the garbage from the textile industry and 60% of rape straw.

Example 3

The difference between example 3 and 1 is that the mass consists of 35% of the waste from the production of paper and pulp, 15% of wood chips and sawdust, 20% of green chips and 30% of rape straw.

Example 4

The difference between Example 4 and 1 is that the mass consists of 15% of the waste from starch production, 25% of rape straw, 25% of wood shavings and sawdust, 25% of green chips and 10% of pine bark.

Example 5

The difference between example 5 and 1 is that the mass consists of 50% of the garbage from the city sewer, 25% of atypical paper waste and 25% of rape straw.

For the mass, kitchen waste, sorrel energy straw, crushed municipal waste, food industry waste or plastic substrate can be used.

All% mentioned are related to volumes.

Claims (2)

1. A method of converting a biodegradable hygienically unstable substrate into a hygienic stable product, where the mass of the specified substrate is placed in a cavity separated from the surrounding atmosphere, and then the mass is treated with aerobic fermentation, which is due to externally delivered air, where aerobic fermentation involves the stage at which the mass is subjected the action of a temperature of 70-80 ° C, characterized in that the stage in which the mass is exposed to a temperature of 70-80 ° C, proceeds over the entire volume of the mass at the same time for 30-60 minutes, and in the process the mass is turned over during aerobic fermentation. 2. The method according to claim 1, characterized in that the temperature of the mass is regulated during fermentation by the amount of delivered air from the outside and the intensity of the mass turning over.