HRP980049A2 - Technological process for processing a silt originating from all kinds of communal and industrial waist water filters - Google Patents

Description

The field to which the invention relates

This invention relates to the technological process of processing sludge from all types of purifiers (mechanical, chemical-mechanical, mechanical-biological, etc.), which, under the conditions of technological transformation, carries out its physico-chemical conversion, immobilization and neutralization, as one form inertization of the material, which gives it completely new physical and chemical properties and characteristics.

According to this invention, the invention belongs to the technological process and equipment for the processing of materials, whereby its original state is changed, which can be further exploited, and according to the MKP it is classified as: B01J, B05B, C08B.

Technical problem

Purifier sludge is problematic from an ecological point of view, and a material harmful to human health. Its existence in nature or in the conditions of a person's living or working environment is unpleasant, but also a serious threat to the general ecological habitat.

Regardless of its chemical composition, the sludge from the treatment plant is disposed of in different forms (wet, semi-dry or dry), and in some cases it is simply left on open ground surfaces as discarded material.

Disposing of sludge from industrial wastewater treatment to a municipal or sanitary landfill, burning, mixing with other materials or handling without supervision is strictly prohibited in many countries, and disposal methods are prescribed by special rules, regulations and laws.

The particular reason for this is the existence of many chemical, and for nature and environment, harmful contents in such sludges, such as halogens, nitrogen, sulfur and hydrocarbon compounds, heavy metals, etc.

State of the art

As far as the author of this invention is aware, the ecological solution for sludge from purifiers exists only as a dehydration process, i.e. only partial inertization of sludge, mostly from municipal wastewater treatment systems, and where the final product remains the same material, so it is a process only due to the reduction of the volume of sludge and physical drying, which is then easier to transport, but which is still harmful to the environment and human health, and is not suitable for further industrial exploitation.

Presentation of the essence of the invention

The primary goal of the invention is the physico-chemical conversion of sludge into a new technical material, which is no longer harmful to human health. The secondary goal of the invention is that, after the sludge inertization process, the new material thus obtained can be used industrially due to its new physico-chemical and mechanical properties.

A further goal of the invention is that sludge begins to be viewed as a useful raw material, and no longer as a material that is unusable or dangerous to human health.

There are several types of sludge, which depends on the type of purifier used and the technology of subsequent use.

Sludges are mostly wet and dense materials, like a doughy mass. brown to black color, which has a different chemical composition.

The relative density of sludge is ≈1.8 - 2.3 g/cm3, which depends on the technology of its use and drying, the type and method of filtering, and the content of heavy metals in the mixture.

Such physico-chemical properties of sludge on the one hand indicate the reasons for its danger to human health, and on the other hand, based on this invention, the technological possibility of its use for the purpose of inertization and stabilization up to the stage of its conversion into an ecologically appropriate state and form, and the possibility of further industrial exploitation.

The technological procedure for the use of purifier sludge, according to this invention, is carried out with a pre-technological treatment of mixing in closed devices and ev. necessary shredders, which are equipped with containers for dosing other waste types of organic/inorganic materials and fillers, and containers with attached spraying devices, with which these are introduced into the sludge mixture in a ratio of 1: (0.1-0.3).

The same mixture is then conveyed by closed screw conveyors to the reactor unit, where calcium-based reactants such as: calcium hydroxide Ca(OH)2, calcium oxide (CaO), calcium carbonate (CaCO3), and/or calcium sulfate (CaSO4) are added ) in different ratios, which will ultimately depend on the type and chemical composition of the processed sludge.

If the sludge is more pure (lower content of halogens, hydrocarbons, amino-sulfur and nitro compounds, etc.), then the ratio of these additives is mostly 1 : (0.1-0.2). If the sludge is significantly polluted, and has a higher content of halogen, sulfur, hydrocarbon and nitro compounds, then these relative ratios shift towards 1 : (0.2-0.4).

The content of water in the sludge should not be higher than 50%, and if it is more than that, then the content of calcium hydroxide Ca(OH)2 in the structure of calcium supplements must be increased by 1.1 times as many percentages as the percentage of water is more of 50% in sludge.

Some sludges have >65% water, which would mean that the content of calcium-based additives would have to be increased by 1.1 (65-50) = +16.5%, therefore, in total, the same should be present in the structure of the additives ≈ 26.5 - 49.5%.

Tanks for reception and mechanical pre-treatment of sludge are closed systems, so that the unpleasant smell cannot spread into the surrounding area, and mixing with other additions to the process supports the operation of the plant.

In the reactor space, an exothermic reaction takes place, which develops a temperature at the level of ≈ 400 K, when the conditions of vacuum gas encapsulation with the appearance of microexplosions are also realized, which finally aims at solidifying the entire cartridge. External sources of thermal energy are not required.

The only products of the process that leave the plant are: solidified and water vapor.

Due to the possible occurrence of mercaptans (sulfites and sulfides), as well as other sulfo-, halogeno-, amino- and similar gas contents, which appear due to their content in the sludge, certain filter systems for retention, absorption or condensation are attached to the treatment plants of such gas contents, and their return with separated particles back to the same process.

Vacuum-gas encapsulation and solidification of certain types of waste material has already been described earlier in the applications of the same author, namely: P940323N; P940324A; P940325A; P931506A, P970530A and P970177A.

A detailed description of at least one way of realizing the invention

Treatment sludges are found in various places, mostly mixed with many other types of waste or disposed materials, and in different shapes and forms. In accumulations that have been exposed to atmospheric influences for a longer time, many types of sludge have an increased moisture content.

They are usually present in a more serious quantity of communal or sanitary landfills.

For the processing procedure according to this invention, it is best to immediately transport the sludge directly into the premixer for preparation, and then continuously dose it into the solidification reactor.

This kind of sludge is conveniently transferred into the associated steel tank of the processing plant (pumps, screw conveyors), which has a combined cover. After the sludge waste has filled the space in the tank, the second tank of the plant is also filled, which contains other additives needed in this process as additives for more successful use: many powdered materials from the pharmaceutical industry and drug production, powders from electrofilters and other ashes, slag and slag incinerators, various dust from industry, residues from the rubber, leather and footwear industry, shavings from the metal processing industry, emulsions, dried and polymerized various organic residues, salts and oils, etc.).

Silos with dispensers and screw conveyors are used for adding calcium-based reactants.

According to the type of sludge and the type of organic/inorganic supplements-additives, the amount and type of calcium supplements is determined.

In its pretreatment, the sludge goes through the phase of preparing the mixture for processing, which is done by screw conveyors, where the mixture is formed, which is then introduced into the reactor space, and into which, on the other hand, a calcium-based additive enters.

Calcium hydroxide Ca(OH)2 will be added to the mixture first, followed by calcium oxide (CaO) and, if necessary, other calcium compounds.

It is best when the facility's capabilities are such that the composition of the mixture in the processing process and the speed of its addition to the process can always be selected.

It is also advantageous to have a reactor with a variable number of revolutions in order to determine as accurately as possible and thus be able to choose the speed of the chemical reaction in the solidification process.

When an exothermic reaction occurs, it is necessary to control the temperature of the process and set its limit to a maximum of 400 K, because high temperatures do not favor encapsulation conditions, but more numerous microexplosions, which will turn the solidified into too small particles and increase the volume of steam release. The duration of the reaction will depend on the time of achieving the TTT-equilibrium state in the reactor (temperature, time, transformation).

Vacuum gas encapsulation, which represents the goal of the technology according to this invention, will be enabled only when such a balance is achieved, i.e. when the equilibrium conditions for processing the mixture have been set according to the amount, speed and type of additions to the process, and then also according to the amount and speed and processing conditions in the reactor.

Organic/inorganic additives usually require more attention, because if various toxic materials are present, then it is important to have their chemical analysis. Although such analyzes are different, in some cases they are done using the sample method, so they are not entirely accurate, nevertheless the most important data from such analyzes for this technological processing procedure would be:

- acidity or alkalinity (pH)

- water content, in % or through data on loss on annealing at 873 K

- halogen and sulfur contents, in mg/kg

- contents of heavy metals, in mg/kg

- phenol contents, in mg/kg

- caloric value, in MJ/kg

There are usually no major technical problems with municipal sludge, but you should be careful about the presence of foreign elements such as: metal pieces, larger pieces of plastic, rubber, wood, steel ropes, etc. They need to be removed and separated into a systematic primary selection of materials before processing in the reactor.

If the pH is approximately neutral (pH 5 - 9), the processing processes are optimal and the equilibrium reaction will occur relatively quickly (sometimes in just 15 seconds), and if this pH is low (e.g. acid tars), the reactions are more violent, to elevated temperatures, greater evaporation and intensified microexplosions in the vacuum and gaseous space of the reactor. Then the balance of the state is achieved by a combination of additives in the pre-treatment and regulation and regulation of the speed of the technological processing procedure.

In order to explain the functioning of the process according to this invention, examples and rules of a well-managed technology of treatment of sludge mixture from industrial waste water purifiers will be given here, and for the cases that most often appear in practice.

Refinery sludges from the petrochemical industry can have, for example, the following characteristics:

pH 3 - 4

65% water, 2% halogen,

8% of total sulfur, 5% of heavy metals,

10% of content incl. hydrocarbons, 10% other

During mixing, attention is paid to the density of the mixture, and the most favorable is the one that has the appearance of mud and soil. Calcium-based supplements are added to this mixture continuously throughout the dosing section in the following relative proportions:

I. in pretreatment: Ca(OH)2 22 - 44%

average 33%

II. during processing: CaO 10 - 20%

average 15%

In the total cartridge (per 1000 liters), these additives have a share of = 150 - 330 liters, and with the application of the rule of the sum of additives [Ca(OH)2+CaO] according to the additive factor of 1.1 times the increased percentage of the difference of 50% of water in mud.

Based on these relationships, the total amount of material that participates in the process must have the following ratio to the volume mass of 100%:

- sludge ≈ 60%

- org./inorg. supplement ≈ 10%

- Ca(OH)2 ≈ 20%

- CaO ≈ 10%

Such a mixture will achieve an exothermic reaction in a time of about 0.7 minutes, and then a vacuum gas encapsulation will occur in a time longer than 1.5 - 2.1 minutes. The process temperature will be around 375 K, and the solidified will be a fine-grained, gray, dry powdery material. Evaporation of water vapor will be uncharacteristic and relatively small in scope and duration. The smell that will eventually appear in the room will be due to the possible presence of phenol and halogen in the sludge, but without any reason for special interventions, because the concentration will in any case be below the permissible limit.

The solidified will have less water, so it will be lighter than it, on which it will float and will not mix with it. After intensive and long-term mixing with water, any sulfates (gypsum) that may be present will dissolve, which will remain as sediment, and the water between the floating solidified and the sediment will be extremely clear.

There will be no visible traces of the input material in the solidified. It will have a completely homogeneous and unique composition throughout the cross-section. After it cools down, it is possible to briquette it to 1/3 of the initial volume, thus reducing its total volume, which is about 10 - 15% larger than the processed material insert.

From 700 liters of processed material and 300 liters of calcium-based additives, about 1100-1500 liters of solidified + water vapor will be obtained, and after pressing it will have a final volume of about 400 liters.

As the specific gravity of the input materials is generally higher than 1 g/cm3, and of the solidified below 1 g/cm3, such pressed solidified will have a density of about 3 g/cm3.

This kind of solidified does not release oil, does not release input components, does not have a chemical composition in the eluate analysis that would have illegal contents. The solidified material has a very high waterproof coefficient Kv ≈ 2-5⋅10-9 m/s and is therefore usable for waterproofing in civil engineering.

If the input material had a higher content of total hydrocarbons, and therefore an increased caloric value, for example 15 MJ/kg, then the solidified will keep it at the level of 55 - 65% and have Hd ≈ 8-10 MJ/kg. It will be usable as a technological addition in many industrial processes (cement plants, lime plants, brick factories, glass plants) or as an addition to asphalt and aerated concrete.

The incoming sludge lost all of its initial properties and remained firmly encapsulated in a calcium shell, as did the other contents of the overall mixture.

Over the course of several hundred years (according to the analysis of the American institute in Atlanta in 1987 and the tests of the RGN Mining and Geological Institute in the Republic of Croatia), this solidified will petrify after 100 - 150 years (P940324A; P940325A; P931506A, P970498A).

It is possible to pre-determine solidifieds according to quality and properties already in the processing process itself, and according to the target purpose of further exploitation.

If the solidified would be used for the purpose of waterproofing in civil engineering, then the proportion of calcium-based additives can be increased in the processing process by 10 - 30%.

If the solidified is to be prepared for use for the purpose of building protective barriers against dangerous, toxic, toxic and radioactive materials, as a special protective powder (P970177A), then hydrocarbons with higher contents of heavy metals (Pb) can be dosed into the mixture or even added separately as shavings (Fe, Cr, Mn, Zn), and maintain the sludge content at the same level. Additives based on calcium should not exceed 15 vol% of the total amount of the cartridge.

Solidifieds that would be used in the process of creating technological clinker in the production of bricks or in the production of building materials and cement plants, and that would serve as additives in the production of plates, blocks, profiles and similar products for construction, increased sludge additions favor the quality of such solidifieds, and at the same time it is also possible to increase the contents of some other inert, but also polluted types of waste materials (oily soil, sands-deoxidizers, fat ash, cleaning powders, waste salts, etc.).

Solidifieds that will be used as additives to asphalt should have similar properties to those used for waterproofing, with the fact that it can be shipped while still hot, since it maintains a temperature of 370 K even after >24 hours of standing.

Solidifieds can come out of the processing process at lower temperatures than Tsol ≈ 370 K, if the process is conducted with lower contents of calcium oxide (CaO), and with higher contents of other calcium-based additives. Then the processing capacity decreases, because the reaction speed is significantly slowed down.

The process, which would have <10% additions of calcium oxide, and if the sludge had an increased content of total hydrocarbons, then the temperature of the solidified exit from the reactor would be below 340 K, with the fact that it would finally rise in the aggregate to 370 K and remain so for at least 24 hours.

The processing process is carried out calmly and the aim is to obtain the so-called "still wet" solidified, i.e. one that has started the solidification process, but has not finished it. The end of solidification then takes place in a cluster in a time not longer than 10 minutes. Such management of the process would ensure a low-temperature solidification regime and the smallest evaporation stage.

Method of application of the invention

The invention is applied using a processing plant, which has different processing capacities and which will depend on the available quantities of purifier sludge. The most favorable form of application of processing technology, including pre-treatment supplements, is industrial waste, which did not have the possibility of re-refining or other means of utilization, and due to significant pollution, they may not be burned, disposed of in landfills, nor are other procedures and methods of treatment provided for them.

Sludges are pre-treated and kneaded using an appropriate procedure, and after large pieces of foreign substances such as metals, plastic, glass, wood and the like have been removed from its contents. If it is about smaller pieces of waste (granulation 2 - 5 mm), they will not interfere with the processing process, and if their content is at the level of 5 - 10% of the total amount of processed material.

Glass and related waste (ceramics, crystals, silicates) do not hinder the processing process, but even improve it.

Plastic waste based on polyester resins, natural resins, polystyrene, propylene, rubber and similar materials do not interfere with the processing process even with larger contents on the cartridge.

Rubber, chips, paper, styrofoam, fabric, leather and similar contents will not interfere with the processing process if their parts are finely chopped.

Steel pieces, pieces of iron, pieces of non-ferrous metals, steel ropes and similar pieces and profiles must be removed, because they could damage the plant, and in case they pass through the opening for dosing the mixture, they will pass through the processing process and find themselves in solidified in unchanged form, from where they are easily separated by sieving.

Sand, stones, gravel and soil will be completely turned into powder - solidified.

Special sludges and oily wastes, refinery, petrochemical and other hydrocarbon-based wastes must be in a liquid state or in a flowing state such as resins, pastes, paraffin oils, fuel oil, tar and the like, so they enter the process freely.

In the event that hydrocarbons are present in the oil as solids, powder, ash, soil or a similar solid fraction, only the moisture content is checked, so if it is lower than 20%, a liquid fraction with about 10% excess moisture should be added to it, so that their volume ratio is stoichiometrically subordinate to the volume % Cao in exothermic conditions.

In the event that the sludge has a content of total hydrocarbons higher than 35%, then organic/inorganic additives and inert materials are added to the processing cartridge.

The proportion of water in the hydrocarbon phase will depend on the total moisture of the entire cartridge, so that the mixture would have a total of about 25 - 30% after pretreatment.

Very high water contents are not favorable for the treatment process, and if the sludge has more than 70% of it in other additions to the process, there should be no water at all:

many sludges, especially refinery and petrochemical ones, oil heaters, oil sludge, clay sediments and filtered briquettes, sludges and emulsions contain ≈ 50% water, and the processing process is carried out by adding a certain amount of inert additives to the mixture, up to the limit of 30 - 50 %.

By checking the quality of the obtained solidified, finally, the most favorable ratios of adding these two types of materials to the processing cartridge are determined.

The processing of sludge mixtures, which have an elevated water content, and those, which must be carried out in an excess of added calcium oxides, results in solidifieds, which are used as excellent waterproofing materials.

In this way and on these possible relationships, the processing of sludge has no technical-technological limitations, but it is necessary to determine what kind of solidified will be obtained from the processing process as a necessary result of such quality of the cartridge.

the processing process is carried out quietly, without noise, smoke, fire, unpleasant smells, explosions, emissions or other undesirable effects on the environment.

Filter systems of such plants are equipped with appropriate devices for multiple purification of gas contents and collection of particles (P970177A), also for their condensation, and return of condensate and particles back to the process.

Solidifieds can be collected in bags, containers or silos as powder, and then transported to the destination using a box truck or tank truck.

solidified powder is dry, often very fine, loose and loose, so it needs to be additionally protected by covering during transport.

The best way to manipulate and transport solidified is by briquetting it into smaller solid pieces, blocks and other forms using a press.

With press pressures of the order of 50 - 200 bar, it is possible to press this solidified to 1/3 to 1/4 of the initial volume, making it easier to transfer and transport.

If the solidified will be used as a technical protective material against the influence of dangerous, poisonous, toxic and radioactive materials, then it remains in powder form.

In order to facilitate the application of solidified powder, it is packed in so-called jumbo bags with a volume of 1000 liters, which ensures its transport and manipulation in the best possible way.

At the exit from the process, the solidified is usually warm and has a temperature of 370 K, so its pressing or packaging, due to technical reasons, is best postponed for some time, when the temperature will be more suitable for work and manipulation.

The cooling rate of the solidified is very low due to the retained thermal properties and relatively high calorific value. The same amounts to about 25 - 40°/day.

This property is optimal when using solidifieds for the purpose of mixing with asphalt, also when used in cement plants or brick factories.

When using solidified powder, for example in the production of technical protective barriers (P970177A), it must be located in silos from which it is forced or free-falling into models or molds, so that it does not spread in the work area.

The best results of processing the sludge mixture are obtained at plants with a processing capacity of 3 to 15 m3/h, where it is still possible to adjust technical parameters in order to regulate physico-chemical processes.

With higher processing capacities, it is necessary to attach a double line for vacuum gas encapsulation, because excessive degassing is also possible.

then the plants must have partial expansions of the vertical section at the encapsulation sites, and a longer horizontal line for the sites where the solidification itself takes place, as well as specially designed circumferential pushers, cleaners and mixers on the reactor shaft.

With such plant designs, it is possible to increase the processing capacity up to 50 m3/h.

Claims (9)

1. Technological procedure for the processing of sludge of all types of waste water purifiers from municipal and industrial sources, in which its content, regardless of type, type and form, is subjected to treatment, preparation for processing, larger pieces of waste are removed and the moisture content is determined, indicated by the fact that liquid and/or solid types of other waste materials are added to the sludge in ratios from 1:0.1 to 1:0.4 in order to obtain a mixture, which corresponds to the implementation of vacuum gas encapsulation in a processing plant using calcium-based additives. 2. Technological process according to claim 1, indicated by the fact that calcium hydroxide and calcium oxide are added to the prepared sludge mixture in a ratio that is 1.1 times higher than the difference in moisture content in the mixture above 40% water, and other calcium-based additives complete up to the total required amount of calcium-based supplements. 3. Technological process according to claims 1-2, characterized by the fact that the processing of the sludge mixture with calcium-based additives is carried out under the conditions of vacuum gas encapsulation and solidification of the entire processed cartridge, where the only outputs from the processing process are dry, hydrophobic powder solidified and aqueous steam, while the gaseous contents are filtered, and its condensates and particles are returned to the same treatment process. 4. Technological procedure according to claims 1-3, characterized by the fact that the treatment is performed at a temperature of up to 400 K in a closed system of physico-chemical processes, and that heat is obtained by exothermy of reactants, without external energy supply. 5. Technological procedure according to requirements 1-4, characterized by the fact that the solidification process will be carried out regardless of the type of sludge, type of additives and water content, and by means of predetermining their mutual relationship and the speed of the process, in which case a lower or higher processing temperature, more or less degassing, lighter or heavier, coarser or finer solidified. 6. Technological procedure according to requirements 1-5, characterized by the fact that the solidifieds obtained differ from each other in terms of physico-chemical and mechanical properties, and can be used as waterproofing materials, technological and technical materials for the purpose of building protective barriers against dangerous, poisonous, toxic and radioactive materials, and also as additives in the technological processes of cement plants, lime plants and the production of building materials. 7. Technological procedure according to requirements 1-6, characterized by the fact that the quality of the solidified can be influenced by the choice of the type of sludge and additives to the process, the content of total moisture, the speed of conducting the degassing process and determining the processing capacity of the mixture. 8. Technological process according to claims 1-7, characterized by the fact that the obtained solidified powder has a temperature of about 370 K and that its cooling rate is 25 - 40°/day, that it is compressible from 1/3 to Ľ of its original volume, and which can be pressed into briquettes, slabs and blocks, and that it is pumpable, transportable and environmentally friendly and stable material, which will petrify after 100-150 years. 9. Technological procedure according to claims 1-8, characterized by the fact that the process of processing the sludge mixture with calcium-based additives takes place without noise, smoke, fire, explosions, radiation, odors or other undesirable effects on the environment.