DE19653426A1 - Process for the degradation of pollutants - Google Patents

Description

The invention relates to a method for degrading pollutants fen from waste water, process solutions and drinking water under Ver use of persulfate.

The spectrum of anthropogenic pollutants in aqueous solutions is broad. There are a number of ver drive dealing with the treatment of aqueous solutions deal. Organohalogen compounds, organic carbon and COD concentrations from indu urban and municipal waste water or chemical, pharmaceutical ceutical or galvanic process solutions can be removed. Another goal is the oxidation of environmental toxins like CN⁻, Heavy metal cyanide complexes, NH₄⁺ and H₂S. Furthermore, the Desodorization and decolorization of waste water are aimed for.

The so-called TOC (total organic carbon = total carbon content) as a sum parameter for organic substances in the solutions mentioned should not be too high. The limits for the TOCs are worded in such a way that they prevent che mixed physical parameters e.g. B. the affected natural Chen surface waters change so much that their ecosy stem is seriously changed. For example, a high proportion of oxidizable substances lowering the Water existing oxygen concentration and thus the Ab die from aerobic organisms. (COD value)

In technology, harmful oxidants are harmful degradation mainly used hydrogen peroxide and ozone; under suitable conditions, it is also more reactive inert oxygen possible. In some cases, even today not yet on chlorine-based agents (hypochlorite, chlorordi oxide, chlorite) can be dispensed with - despite the associated  problems, d. H. Development of toxic organochlorine ver bonds.

There are also procedures that operate under high pressures (220.6 bar) and temperatures (374 ° C) with supercritical water Remove pollutant. This wet oxidation needs an ex tremendous effort in terms of material, energy and also the cost.

One of the strongest known oxidizing agents is per oxodisulfate with a standard redox potential of E _o = 2.06 V. Due to this high oxidation potential, peroxodisulfate can completely oxidize almost any organic substance to carbon dioxide and water (as well as phosphate, nitrate, etc.). In its reactivity, peroxodisulfate has some special features compared to other oxidizing agents: in contrast to hydrogen peroxide and ozone, peroxodisulfate is particularly inert and stable in the solid state for a long time. Reactions often only take place by activating them with catalysts or after increasing the reaction temperature.

So far, peroxodisulfate is used in addition to technical applications in the electroplating and printed circuit board industry and as a radical star ter for polymerizations also in analytics for determination of the DOC (dissolved organic carbon = dissolved organic Koh lenstoff) or TOC used and as a reagent in various those syntheses.

Compared to those used in wastewater treatment for a long time substances such as ozone, which are expensive and expensive to manufacture complicated to handle due to its toxicity, and Hydrogen peroxide, which u. U. in alkaline heavy metal hal explosive decay can, only a little resistance in the to be treated Solutions and an often not sufficiently large Oxidationswir kung (redox potential + 1.77 V), is working with  Peroxodisulfates comparatively unproblematic; they are easy to handle and in solid condition for a long time bil. Peroxodisulfates can therefore also be used otherwise destroy oxidants that are difficult to decompose. The at Reactions with peroxodisulfate resulting sulfates are un toxic.

Another problem is that in the aqueous solution mentioned solutions in addition to the TOC present organic halogen compound (AOX adsorbable organic halogen). The AOX-Ab construction takes place parallel to or after the TOC reduction, which means that sometimes an unacceptably high peroxo Use of disulfate is required to remove the toxic substances to dismantle on a sufficient scale.

A particularly great disadvantage is that in the presence of Chlorides in the aqueous solutions to be treated at Ver Use of peroxodisulfate as an oxidizing agent chlorine organic compounds are formed. At higher requ The concentration of peroxodisulfates can exceed this in addition, in the presence of chlorides, even chlorine emissions come.

DE 44 30 391 has already been used successfully Process for the degradation of pollutants in process solutions, Ab water and drinking water known as peroxodisulfates Oxidizer works. With this procedure the aqueous solutions with a mixture of peroxodisulfates Alkalis, in an equimolar ratio of 1: 0.5 to 1: 2, preferably 1: 1 added. If necessary, assets gates or catalysts added and / or by means of UV light, Microwave or ultrasound activated. The reaction temperature tur is between 20 and 120 ° C, particularly preferably at 80 ° C. It is in an alkaline medium, i.e. H. while maintaining pH well above 7 by adding correc appropriate amount of bases at the beginning of the process, ge is working. After approx. 180 min. can a total implementation of the TOC  to be expected. The long treatment time requires great Containers and equipment made from a very resistant material, such as Hastelloy alloys, tantalum, Teflon or the like. must exist because the reaction is very aggressive ven milieu takes place. Especially in the presence of Halogens have corrosion problems with inferior ones Materials.

When the peroxodisulfate reacts with one to oxidize sulfuric acid is basically formed in the substance. This Acid formation is a major disadvantage of oxidation of pollutants with peroxodisulfates in waste water, process sol solutions and drinking water, as this causes the pH in the sau shifted their area. So that could be the need a subsequent neutralization stage in which the initial or the desired pH value is set again becomes. The above publication solves this problem by that the aqueous solutions already at the beginning of the loading treatment with a larger amount of lye, which can absorb the formation of sulfuric acid.

Based on this state of the art, it is the task of present invention a method for the degradation of pollutant in waste water, process solutions and drinking water, the persulfate used as an oxidizing agent and by the the required treatment times are drastically reduced at the same time creating the opportunity with much smaller and therefore cheaper equipment get along and also a continuous process to arrive.

This problem is solved in that pollutant degradation with persulfate at at least 130 ° C, preferably 130 to 140 ° C and a pressure greater than 1 bar is carried out, wherein the basic reaction is the decomposition of persulfate into OH and SO₄ radical is.  

The pH range to be set may vary depending on the solution to the problem lie between 0 and 14 and thus covers the entire pH-Be rich, unlike previous systems based on the Ar process in a certain, usually alkaline pH range were assigned.

The temperature is not so high that it is too hot equipment would be necessary, as is the case with some Process is necessary, which ar at temperatures above 300 ° C work.

In itself, in chemical reactions it is naturally to be expected that the reaction times ver with increasing temperatures shorten. In the present case, however, it must be taken into account that the persulfates decompose very easily at higher temperatures are legal substances. At higher temperatures, the Decomposition rate usually with peroxidic Connections faster than the reaction rate of the reactions to be catalyzed in each case. Therefore the Re action of the radicals with one another with increasing temperature more likely.

The decomposition of 0.01 mol / l potassium peroxodisulfate in 0.1 mol NaOH with increasing temperature is in the table below summarized:

Table 1

The only thing that could have been expected was a deterioration in yields can be tet because the self-decomposition of the persulfate would have happened quickly that it was no longer with them eliminating pollutants could have reacted.

It is therefore an essential knowledge of the present Invention that actually degrades at temperatures between 130 and 140 ° C and a significant increase in overpressure could be replaced. Like the examples below is not only the total carbon content almost completely reduced, but also the AOX values, d. H. the values of the adsorbable, organically bound Halogens can be reduced to almost 0. Except according to the present invention, others can be used Impurities in aqueous solutions are broken down, so e.g. B. dyes and cyanides. Decomplexing is also toxic sher substances is possible.

By the present invention according to claim 1 Ab water, process liquids and drinking water cleaned, ent colors and deodorises with a compared to the conventional oxidizing agents ozone, hydrogen peroxide or also easy to handle oxidizing agents, namely the persulfate, which is also a particularly high oxide tion potential and thus a particularly high effectiveness in which has oxidation.

The present invention also enables the method driving continuously. For this, a Conti reactor type proposed, in which the incoming, un  treated and cold wastewater through the leaking, behan delte and therefore warm wastewater preheated in countercurrent is so that the energy costs are minimized. It should a dwell time of approx. 100 seconds at 130 ° C is guaranteed be the reactor size in proportion to the treated Ab to keep water as low as possible. By exothermic reaction NEN, such as B. the oxidation of hydrocarbons to Koh The system gets an additional amount of dioxide and water Heat input, which in turn has a positive effect on energy costs affects. Steam, waste heat z. B. is called Gases, organic heat transfer media and resistance heating in question.

Internals can be provided in the reaction space guarantee a better heat transfer to the reactor wall and at the same time an undesirable vertical cross-mixing ver prevent. These internals should be designed so that they Allow any gas to escape upwards can. Since the internals have good heat transfer as possible should have, they can be straight pipes, coils or plates, but also a simple one Filling with ceramic Raschig rings is possible.

In order to build up an overpressure in the reactor, the Ab an overflow valve installed depending on the water outlet desired reactor pressure to a certain discharge pressure can be put. The formation of gases would cause the Reactor are gradually emptied and the residence time would shorten. In this case, the upper part of the Reactor head a point level detector to be mounted. Detec If this gas phase, this switches the gas overflow til downstream shut-off valve and that to the waste water outlet overflow valve downstream shut-off valve the same early on. Via the second overflow valve in the gas line Gas now escapes until the point level detector again detects a liquid phase. In this state the gas closes shut-off valve and opens the waste water outlet shut-off valve. There  a pressure drop in the reactor against the escape of the gas ben, the opening of the gas shut-off valve should be closed additionally to a preset minimum reactor pressure be limited.

However, the method according to the invention is not limited to use limited in the device described above, son who can z. B. also with a classic tubular reactor in the Con procedure or in a normal pressure vessel in batches be driven.

Peroxodisulfates are suitable as active oxidation components, Peroxomonosulfate and mixtures of Peroxodisulfaten or Peroxomonosulfates with percarbonates and perborates.

In a preferred embodiment, a mixture of one Peroxodisulfate used with hydrogen peroxide, preferably as in a molar ratio of 0.1 to 2.0 moles of water peroxide per mole of peroxodisulfate. The addition of water peroxide leads to a further acceleration of the ver driving and opens up a possibility to use the Per to reduce the amount of sulfate since the hydrogen peroxide and its decay has an activating effect on the oxidation process like to exercise the peroxodisulfate.

The hydrogen peroxide is preferably in the form of sodium carbonate peroxohydrate introduced.

The addition of other known active oxidation components to the persulfate system is also conceivable.

In a further preferred embodiment of the method According to the present invention, 2-3 moles of persulfate used per mole of C or CH₂ to be broken down. This follows from the following formula:

(CH₂) _n + 3n S₂O₈ ^2- + 2n H₂O =

n CO₂ + 6n SO₄ ^2- + 6n H⁺

This prevents the targeted use of persulfate possible above the pollutant to be broken down.

According to the present method, long residence times avoided in the reactor, so that the time required for Treatment of the aqueous solutions drastically reduced. On this way you can also use smaller containers than that usual are used, which in turn leads to a reduction material costs because the reactions in one very aggressive milieu and the necessary containers and equipment made of very resistant materials lien must exist. The invention thus both a time saver as well as a significant reduction in Costs achieved while maintaining a high oxidation level performance is guaranteed.

The preferred residence times according to the present invention in a preferred embodiment are between 30 and 500 sec. in a very preferred embodiment between 80 and 300 sec. and with the particularly preferred Embodiment at about 100 sec.

The preferred residence times ensure an almost 100% Degradation of the impurities in the aqueous Solutions.

The method according to the present invention can be used with any Pressure that is greater than 1 bar, d. H. also the process can be operated at very low pressures the. Usually the pressure is chosen so that the temperature used to boil the liquid under is pressed.  

Because of the short dwell times in the reactor and one of them resulting favorable controlled system it is with the inventor process according to the invention possible at the wastewater outlet behind the Pressure stage to install a pH measurement depending on the desired end-of-run pH value, add an alkali solution for the controls incoming wastewater. Sometimes it is makes sense, since the pH value of the wastewater is caused by the Sulfuric acid decomposing persulfate quickly in the sometimes unwanted acidic area.

As the rate of decomposition of the persulfate decrease at the pH value increases and therefore there is even less dwell time times in the reactor, it also makes sense the pH in the reactor to a slightly alkaline level hold. This can be achieved by e.g. B. several Alkaline additions can be installed in the reaction area. This keeps the pH in a narrow pH window.

The added alkalis are the hydroxides, carbonates and / or Hydrogen carbonates of sodium or potassium are conceivable.

Since sulfate z. B. because of concrete corrosion in the discharge ordinance for the discharge of waste water is a problem represents ion, but would also be conceivable as milk of lime Add lye. Lime milk would be an instant precipitation of the the resulting sulfate.

To further accelerate the degradation reactions chen, sees a special embodiment of the method according to the invention the addition of catalysts.

Additives or fixed bed fillings can be used as catalysts of coal or graphite powder or granules in question come or also additives or fixed bed fillings from Adsor over-resin.  

In a particularly preferred embodiment Transition metals used as a catalyst.

Fixing the catalysts is particularly preferred Activated carbon.

The degradation reactions can also be accelerated by simultaneous irradiation with UV, microwave or ultrasound be achieved.

Another object of the invention is a device for carrying out the method according to one of claims 1 to 22, including a facility for mining Verunreini in aqueous solutions using persulfate, with a first container part for receiving the aqueous solution, wel cher has an inlet and an outlet and a Reak tion space forms, with a heating device for heating the aqueous solution is provided, with further heat transfer means are provided that heat transfer between the Allow heater and the aqueous solution, and wherein at least one pressure generating means is provided.

The attached drawing shows:

Fig. 1 shows the degradation of various pollutants depending on the residence time in the reaction space.

Fig. 2 shows an embodiment of a reactor for carrying out the method of the invention.

Fig. 3 and 4 each show yet another embodiment of a reactor for carrying out the method of the invention.

Fig. 5 shows the color scheme of a Lewafix color waste water. The numbers of the individual curves correspond to the test numbers of Example 3.

In Fig. 2, a reactor type 10 for the Conti process is shown schematically. The untreated wastewater 12 is pumped into a heat exchanger 16 using a feed pump 14 and is conveyed in the direction of the reactor interior. During this dwell time, the wastewater 12 absorbs the heat from the hot wastewater 18 that has already been treated, which cools down at the same time. The preheated waste water 12 runs into the reactor 20 and heats up there to the desired temperature. This circuit guarantees a very low energy requirement for the process, so that even larger amounts of wastewater can be managed without a greater energy requirement (example 4). By installing in the reactor 20 there is a better heat transfer to the reactor wall and at the same time an undesirable vertical cross-mixing is prevented ver. The internals should be designed in such a way that any gas that may be formed can escape freely upwards. Since the internals should have as good a heat transfer as possible, they can be designed as straight pipes, coils, plates, but also simple fillings with ceramic Raschig rings bring a positive effect. In order to build up an overpressure in the reactor, an overflow valve is installed before the waste water outlet, which can be adjusted to a specific discharge pressure depending on the desired reactor pressure. The formation of gases CO₂ / N₂ / O₂ would gradually empty the reactor and the dwell time would be reduced. In this case, a level detector is installed in the upper part of the reactor head. If this detects a gas phase, the shut-off valve downstream of the gas overflow valve and the shut-off valve downstream of the waste water overflow valve switch on simultaneously. Via the second overflow valve in the gas line, gas now escapes until the level detector detects a liquid phase again. In this state, the gas shut-off valve closes and the waste water outlet shut-off valve opens. Since there may be a pressure drop in the reactor when the gas escapes and thus gas expansion occurs at the same time, the opening of the gas shut-off valve is additionally limited to a preset minimum reactor pressure. This oscillating circuit enables trouble-free operation even in very low pressure ranges (e.g. 1-6 bar). Which has a cost-effective effect on the components for the process. Through an optimized preheating exchange, the energy costs can be further minimized. Values of <10 KWh / m³ wastewater can be achieved when using plate heat exchangers in example 4.

The reactor arrangement shown in FIG. 3 realizes a reactor with long and thin tubes, gas being generated rising into the gas collector and discharged either at intervals or via level detectors via the valves. The pressure regulator closes the valves when the system pressure drops below a limit.

In this figure there is only the schematic reactor and not the entire device with preheater, etc. shown. The main advantage of this embodiment is that it is long Tubular or tubular goods without high pressure levels (which may ent standing gases have to be pushed back in volume to ensure an even Conti operation) can be used as a reactor. The amount of gas collectors depends on the reactor.

In the device shown in Fig. 4, very thin-walled reactor tubes z. B. from PFA; PTFE etc. can be used. When the pressure in the "pressurized water" and in the reactor tube is kept the same. The reactor outer tube can be made of very cheap materials. Only the preheater and the line from the preheater to the reactor are made of corrosion-resistant (expensive) materials. This schematic representation can of course vary in form and type of heating. You can also use a different pressurized heat transfer medium instead of "pressurized water".

In the following the invention is explained in detail by means of examples and FIG. 1.

Examples of use example 1

In this example, the degradation rates for TOC, AOX and Dyes compared with each other at constant persulfate use and depending on the residence time in the reactor.

In a laboratory tube reactor that turns into a spiral bent 6 m long tube with an inner diameter of 4 mm were different with a piston diaphragm pump synthetically produced pollutant solutions.

The heated internal volume of the reactor was 75 ml Rohrwendel was in an oil bath thermostat that opened 135 ° C was heated. After the oil bath, the contents of the Pipe with water cooling to room temperature chilled. In order to maintain a constant pressure in the Preserving the reactor was a presettable overflow valve installed at the end of the pipe.

The pressure of the reactor was kept between 8-9 bar.

Solution concentrations

Solution A:
500 mg / l phenol (TOC 383 mg / l) in aqueous solution and 23.8 g / l sodium persulfate made alkaline with NaOH
Solution B:
500 mg / l tetrachlorophthalic anhydride in aqueous solution and 23.8 g / l sodium persulfate made alkaline with NaOH
Solution C:
50 mg / l dye Solanthrene Green Microperle MIX 7154 in aqueous solution and 2.4 g / l sodium persulfate made alkaline with NaOH

The solutions were set up and with three different ver funded by the reactor for a while.

30 sec dwell time (delivery rate 9 l / h)

Solution A:
TOC reduction to 158 mg / l = 58.7 6 degradation
Solution B:
167 mg / l proven as inorganic chloride = 67.1% degradation
Solution C:
VIS measurement of the coloring = 78% degradation

80 sec. Dwell time (delivery rate 3.38 l / h)

Solution A:
TOC reduction to 14 mg / l = 96.3% degradation
Solution B:
239 mg / l detected as inorganic chloride = 96.1% degradation
Solution C:
VIS measurement of coloration = 97.8% degradation

150 sec. Dwell time (delivery rate 1.8 l / h)

Solution A:
TOC reduction to 5 mg / l = 98.7% degradation
Solution B:
245 mg / l proven as inorganic chloride = 98.5% degradation
Solution C:
VIS measurement of coloration = 99.5% degradation

From the values shown it follows that after the invent According to the method according to the invention, the TOC values are already almost at 0 have fallen, d. H. an almost 100% reduction in damage substances took place. The same applies to the dismantling of AOX; the 98.5% degradation at 150 sec. dwell time of the tetra Chlorophthalic anhydride means an AOX value of less than 0.3 mg / l. Also has an almost 100% degradation of color fabrics, especially the Solanthrene Green Microperle MIX 7154, took place. This dye belongs to the Kate theory vat dyes, which with the already known Ver drive like B. H₂O₂ / UV are very difficult to degrade.

The sales performance is summarized in the attached FIG. 1.

Example 2

In this example, the degradation rate of AOX and TOC in sau environment with constant use of persulfate and depending shown by the length of time in the reactor.

In a laboratory reactor consisting of one standing vertically the enameled DN 25 pipe section with heating jacket and one on flanged 5 cm long DN 15 headboard, was over a front heated pipe section with a chlorine piston diaphragm pump phenol-containing solution with persulfate mixed with various NEN flow rates promoted.

The pipe was filled with Raschig rings in the heated area. To preheat the solution was between the metering pump and Re  actuator part a piece of pipe in an oil bath thermostat with 110 ° C submerged. The internal volume of the reactor was 93 ml Inlets and outlets of the reactor had a tube inside knife of 4 mm. At the bottom of the solution was to cool a piece of pipe submerged in a water bath. At the end This piece of pipe had an overflow valve that was set to 6 bar was set. Ther was a temperature control installed in the lower third of the reactor. Around to be able to maintain a constant reactor level in a 5 cm long DN 15 flanged to the reactor head Pipe section two conductive level indicators and a needle valve til installed above the upper sensor. When reporting a Gas needle through the bottom sensor was careful of the needle valve opened until the upper sensor is just through liquid was wetted and then the needle valve ge again closed.

Test conditions:
Temperature in the reactor: 130-135 ° C
Flow rates: 20-75 ml / min
Pressure: 5-6 bar

Starting solution:
A solution containing 500 mg / l 2-chlorophenol was mixed with 23.8 g / l sodium persulfate.

These results show that, as in Example 1, despite the acidic environments of the leaking solution, TOC and AOX almost can be completely dismantled in a short time.  

Example 3

This example shows that not only syn aesthetic color solutions, but also industrial waste water can be decolorized quickly and easily. Furthermore, in this example, the positive effect of persulfate / H₂O₂-Mi shown as an active component.

In the laboratory reactor described in Example 2, a Waste water from a dye liquor with persulfate for reaction brought. The waste water contained approximately 0.5-1 g / l Lewafix dye and components typically used in liquor such as sodium sul fat, Netzer, etc.

Test conditions:
Temperature in the reactor: 130-134 ° C
Reactor flow rate: 42 ml / min (132 sec residence time in the reactor)
Reactor pressure: 4.6-5.7 bar
pH enema: 10.7

The table shows the analyzes of the hazards through the reactor solutions:

In order not only to rely on the apparent color assessments, the color measurements are confirmed by the VIS spectra in FIG. 5.

The numbers of the individual curves correspond to the above ver search numbers. The absorption spectra shown were with a spectrophotometer in the visible range of 350-750 nm recorded.

The strong decrease in color is already evident when using 3 g / l Na persulfate (curve 5). The use of 3.4 g / l H₂O₂ (curve 8) brings hardly any discoloration effects. Mixtures from Na persulfate and H₂O₂ bring up to a certain H₂O₂- Concentration positive effects (curves 6 and 7). When using The solution was completely decolorized from 24 g / l Na persulfate.

The experiments show that persulfate is a quick and we the color wastewater was discolored. By Use of persulfate / H₂O₂ mixtures could be up to one Molar ratio of about 1: 1 (3 g / l persulfate / 0.4 g / l H₂O₂) an increase in TOC degradation and color degradation the measured values are about 6 g / l Correspond to Na persulfate, higher H₂O₂ additions had none positive effect. The use of pure H₂O₂ solutions as active component even in higher doses resulted in only one low TOC and color reduction.

Example 4

Example 4 is used to compare the degradation of TOC and AOX at different persulfate concentrations and a ver dwell time of 80 sec.

Two bundle heat exchangers, each with 25 internal DN 15 pipes ren (inner volume of the reactor 4.4 l) were ver screws and set up vertically. The lower heat exchanger served as a preheater for the wastewater to be treated  (in the coat) and at the same time as a cooler for the treated Sewage (inner pipes). The upper heat exchanger was named Re Actuator used, with thermal oil as a heat transfer medium for the man tel heating served. A pipe was installed above the reactor screwed barrel with a volume of approx. 12 l. Halfway there The height of the tube was a 2-rod insulated with Teflon probe as a conductive point level sensor inside the vessel leads. There was a presettable safety device on the tube safety valve and, in parallel, an overflow valve with after switched solenoid valve attached. In addition, a Screwed pressure sensor in this tube vessel. At the bottom of the lower heat exchanger was an over after a reduction flow valve with downstream solenoid valve attached. The Waste water was only through the jacket with a membrane pump of the lower heat exchanger and then into the tube vessel pumped. It went through the reactor and reached the Ab cooling phase via the overflow valve located below in atmo spherical conditions. All parts were complete Rock wool isolated.

Test parameters:
Reactor pressure: 5-6 bar
Delivery volume: approx. 200 l / h
Reactor residence time: 80 sec.
Temperature inlet preheater: 23 ° C
Middle reactor temperature: ⌀ 140 ° C
Temperature after cooling down: 54 ° C

Wastewater from a physical / chemical treatment for oil splitting plants with one
TOC value: 2278 mg / l
AOX value: 0.9 mg / l
inorganic chloride: 0.2 g / l
at a pH of 11.2 was used as an aqueous solution.

After the system had warmed up, an Ener energy input of 37 KWh / m³ of wastewater can be operated.

The concentration of persulfate was gradually increased and controls the pollutant degradation.

The example shows the dependence of the reduction in TOC or AOX values, that is, the breakdown of pollutants from the amount of persulfate used.

The AOX value decreases linearly in the present case the amount of persulfate used. AOX and TOC values are at 24 g / l persulphate used with a residence time of only 80 seconds already dropped to very low values.

Example 5

Example 5 demonstrates the possibility of keeping the pH constant in the keep alkaline to weakly alkaline range and thereby further increasing the reaction rate.

In the apparatus from Example 2, the reactor part (upper bundle heat exchanger) through a heatable pipe section replaced and this filled with ceramic sash rings. In the end A pH measuring and control device became the outlet of the waste water installed with integrated PID controller. Through this pH-in four diaphragm metering pumps (lye delivery) controlled via the analog output signal of the PID controller. The first pump was connected after the main feed pump  sen, the second pump dosed into the reactor head (Rohrge barrel), the third pump metered approx. 30 cm below the right top edge of the actuator metered into the reactor and the fourth pump approx. 60 cm below the top edge of the reactor into the reactor. Of the Setpoint of the wastewater outlet was set to pH 7.5 and the metering pumps are set to the same delivery volume. The Pump power increased proportionally to the analog signal.

Test parameters:
Volume of the reactor: 8.4 l
Reactor pressure: 6-8 bar
Volume flow: 260 l / h
Reactor residence time: 116 sec.
End of reactor temperature: 136 ° C
Temperature after cooling down: 41 ° C
Concentration of the dosed
Sodium hydroxide solution concentration: 5 mol / l

The aqueous solution used was wastewater, namely depo niesickerwasser with
TOC value: 301 mg / l
AOX value: 4.7 mg / l
Nickel (complex bound): 3.4 mg / l
inorganic chloride: 8.7 g / l
at a pH of 9.3.

The persulfate concentration was gradually increased and the Controlled pollutant degradation.

Results

Due to the gradual neutralization resulting from the Persul fat-forming sulfuric acid with the four lye additions becomes a way of working in the weakly alkaline range reali siert. This will increase the reaction rate again speed reached without AOX regeneration taking place finds.

With the present method it is therefore possible to harm substances in waste water, process fluids and drinking water degraded by persulfate, the residence times of each aqueous solution in the reaction system are very low and the reaction is carried out in any desired pH range can be. The short dwell times can save time and the containers and equipment used can run smaller than usual, which in turn leads to leads to a considerable saving in material, since this very resistant due to the aggressive reaction environment high - must be expensive. With the Ver driving will not only reduce the TOC values, but it all pollutants, including the highly toxic, com completely dismantled.

Claims (54)

1. A process for the degradation of pollutants in wastewater, process solutions and drinking water using Persul fat, characterized in that the degradation is carried out at at least 130 ° C, preferably 130 to 140 ° C and a pressure greater than 1 bar. 2. The method according to claim 1, characterized, that a peroxodisulfate as the active oxidation component is used. 3. The method according to claim 1, characterized, that a peroxomonosulfate as the active oxidation component is used. 4. The method according to claim 1, characterized, that a mixture of as the active oxidation component Peroxodisulfate with hydrogen peroxide, preferably in a molar ratio of 0.1 to 2.0 moles of water peroxide per mole of peroxodisulfate, is used. 5. The method according to claim 4, characterized, that the hydrogen peroxide in the form of sodium carbonate peroxohydrate is introduced. 6. The method according to claim 1, characterized,  that a mixture of as the active oxidation component Peroxodisulfate or peroxomonosulfate with percarbonates and / or perborates is used. 7. Method according to one or more of the preceding Expectations, characterized, that 2 to 3 moles of persulfate per mole of C to be broken down or CH₂ can be used. 8. Method according to one or more of the preceding Expectations, characterized, that the concentration of persulfate be 20 to 30 g / l wearing. 9. The method according to one or more of the preceding Expectations, characterized, that the aqueous solution between 30 and 500 sec. in the Reak gate lingers. 10. Procedure according to one or more of the preceding the claims characterized, that the aqueous solution in the Reak between 80 and 300 sec gate lingers. 11. The method according to one or more of the preceding Expectations, characterized, that the aqueous solution remains in the reactor for 100 seconds. 12. The method according to one or more of the preceding Expectations, characterized,  that the reaction at a pressure of 5 to 6 bar expires. 13. The method according to one or more of the preceding Expectations, characterized, that one or more pH-dependent lye dosages stations for the incoming wastewater are provided. 14. The method according to claim 13, characterized, that the pH value by the alkali metering at pH 7 to 9 is held. 15. The method according to claim 13 or 14, characterized, that the hydroxides, carbonates and / or hydro gene carbonates of sodium or potassium used who the. 16. The method according to claim 13 or 14, characterized, that lime milk is used as lye. 17. The method according to one or more of the preceding Expectations, characterized, that additional catalysts are added. 18. The method according to claim 17, characterized, that as catalysts additives or fixed bed fillings of coal or graphite powder or granules used will. 19. The method according to claim 17, characterized,  that as catalysts additives or fixed bed fillings of adsorber resins can be used. 20. The method according to claim 17, characterized, that transition metals are used as a catalyst. 21. The method according to any one of claims 17 to 20, characterized, that the catalysts are fixed to activated carbon. 22. The method according to one or more of the preceding Expectations, characterized, that in addition, exposure to UV light, microwave or ultrasound is provided. 23. Device for performing the method according to a of claims 1 to 22, comprising a device for Degradation of impurities in aqueous solutions using Persulfate, with a first container part for reception the aqueous solution, which has an inlet and an Has outlet and forms a reaction space, wherein a heater for heating the aqueous solution is provided further heat transfer means are provided, which a heat transfer between the Heizvorrich and the aqueous solution, and wherein there is at least one pressure generating means is seen. 24. The device according to claim 23, characterized that the heating device comprises a resistance heater. 25. The device according to claim 23, characterized,  that the heating device heat carriers such as steam, waste heat, e.g. B. includes hot gases or organic heat transfer media. 26. Device according to one of the preceding claims, characterized, that a second container part for receiving the heat transfer Gers is provided, the first carrier part little least partially runs in the second carrier part. 27. Device according to one of the preceding claims, characterized, that the first container part out as a pressure container part forms is. 28. Device according to one of the preceding claims, characterized, that the second container part out as a pressure container part forms is. 29. Device according to one of the preceding claims, characterized, that the facility is a Conti reactor type. 30. Device according to one of the preceding claims, characterized, that heat exchange means for heat exchange between the incoming wastewater and outgoing wastewater are seen. 31. The device according to claim 30, characterized, that the heat exchange means as countercurrent exchange with tel are trained. 32. Device according to one of the preceding claims, characterized,  that heat transfer means are provided in the reaction space are. 33. Device according to one of the preceding claims 32, characterized, that the heat transfer means are provided with means that prevent vertical cross-mixing. 34. Device according to one of the preceding claims 32 and 33, characterized, that the heat transfer medium gases in the reak Let the room escape upwards. 35. Device according to one of the preceding claims, characterized, that the heat transfer medium as straight pipes, pipe snakes or plates are formed. 36. Device according to one of the preceding claims, characterized, the heat transfer medium with a simple bed ceramic Raschig rings. 37. Device according to one of the preceding claims, characterized, that the heat exchange means the heat transfer means are. 38. Device according to one of the preceding claims, characterized, that before the outlet at least one adjustable over flow valve means is provided as a printer agent works. 39. Device according to one of the preceding claims, characterized,  that at least an adjustable gas spill valve means is provided, which derive gases from the allowed upper part of the container part. 40. Device according to one of the preceding claims, characterized, that at least one level detector in the upper part of the container part is provided. 41. Device according to claim 40, characterized, that the at least one level detector at least actuated a valve means. 42. Device according to one of claims 38 to 41, characterized, that the point level detector the overflow valve means and / or the gas overflow valve means depending a detected gas phase and / or a detected Controls liquid phase in the container part. 43. Device according to one of the preceding claims, characterized, that at least one on the container part Persulfate metering device is provided. 44. Device according to one of the preceding claims, characterized, that at least one on the container part Alkali metering device is provided. 45. Device according to one of the preceding claims, characterized, that the at least one alkali metering device depending on at least one measured pH value tet.   46. Device according to one of the preceding claims, characterized, that insulation means z. B. provided from rock wool are that isolate at least parts of the device. 47. Device according to one of the preceding claims, characterized, that the container part in the contact area with the aqueous Solution is provided with protective agents. 48. Device according to one of the preceding claims, characterized, that the container part and the equipment from acid-resistant material. 49. Device according to one of the preceding claims, characterized, that the protective agents are made of Teflon. 50. Device according to one of the preceding claims, characterized, that the second container part with pressure generating means are provided. 51. Device according to one of the preceding claims, characterized, that a pump device for conveying the aqueous Solutions is provided. 52. Device according to one of the preceding claims, characterized, that condensate drainage means are provided. 53. Device according to one of the preceding claims, characterized,  that gas collectors are provided on the container part communicate with the gas spill valve means. 54. Device according to one of the preceding claims, characterized, that the container part is made of PFA or PTFE etc.