EP2651832A1

EP2651832A1 - Method for treating bodies of water

Info

Publication number: EP2651832A1
Application number: EP11801735.9A
Authority: EP
Inventors: Wolfgang König; Wolfgang Rabe; Günter Scholz
Original assignee: Rheinkalk GmbH
Current assignee: Rheinkalk GmbH
Priority date: 2010-12-17
Filing date: 2011-12-19
Publication date: 2013-10-23
Also published as: CA2821853A1; CN103354804A; WO2012080514A1; EA024888B1; US20130292344A1; BR112013015226A2; DE202011110411U1; EA201300718A1; US9290395B2

Abstract

The invention relates to a method for stabilizing and/or raising the pH of bodies of water and/or neutralizing bodies of water. According to the invention, a feed material containing an unburned lime product is used to stabilize and/or raise the pH of bodies of water and/or to neutralize bodies of water, wherein the unburned lime product has a grain size having a fraction < approximately 10 μm of ≥ 50%. With the aid of the proposed method, the pH of bodies of water can be stabilized and/or raised and/or bodies of water can be neutralized in an effective and ecologically harmless manner and at low cost.

Description

Process for the treatment of waters

The invention relates to a method for the treatment of

Waters, in particular for pH stabilization, pH increase and / or neutralization of waters, wherein a feedstock is introduced into a body of water to be treated. Furthermore, the invention relates to the use of an unburned lime product for the treatment of waters. Finally, the invention comprises an aqueous suspension containing the starting material and a vessel for introducing the feed into a body of water to be treated.

Acid precipitation, possibly in combination with other anthropogenic factors, has led to a gradual reduction in the pH of waters in recent decades. This so-called water acidification, which mainly occurs in low-base catchment areas, has an environmentally damaging effect. In strongly acidified waters, the pH values are regularly between 3.5 and 4.5. This acidity has a negative effect on the biocenoses of the affected waters, as acid-sensitive species

be displaced. Another negative effect of

Acid pollution is the increased release of toxic

Heavy metals (eg aluminum, lead, manganese, nickel, zinc) from upcoming rocks or soils. One of the most striking effects of aquatic acidification is the extinction of fish in heavily acidified waters. Also in the environment of mining and opencast mining, acidification of groundwater and surface water can increasingly occur. There is a problem of ore and coal mining

for example, in the formation of acid mine water. These can arise when due to the mining activity

Oxygen enters anoxic rock areas and there to an oxidation of iron disulfide minerals, such as

For example, pyrite or arksit leads. The oxidation of iron disulfide to iron (III) and sulfate goes with the

Release of protons. As a result, an open-pit mine with acidic, sulphate-containing water fills to form acid mining mines.

The mining and in particular the use of the

Open-pit mining technology results in cavities in the utilized landscape that fill with groundwater and surface water. In many cases, the rising groundwater and the associated geological and chemical conditions in the newly created overburden form a lake landscape characterized by very acidic waters. Another problem is the persistent supply of acidity into such waters with the inflowing groundwater. The pH drop to values of <6 associated with a possible increase in

Heavy metal contents, especially of iron and aluminum, often leads to a significant impairment or dying of formed or registered in the mining or opencast mining biocenosis. Different methods for treating acidic waters are known from the prior art, with so-called inlake methods in particular being carried out in practice. The known processes have in common that an alkaline substance for neutralization or pH increase is introduced into the water to be treated. DE 10 2006 001 920 A1 describes a two-stage

A method for improving the water quality of acidic waters, wherein in a first treatment stage, at a low pH, a calcium or calcium / magnesium-containing feed and in a second stage, at a higher pH, sodium hydroxide is used. On the one hand, this process is high overall

Product usage costs required. In addition, high efficiencies are achieved in this way in the high pH range, but there is a risk that the pH value rises to> 9, even at low overdose due to the high reactivity of caustic soda, which can lead to a significant impairment of the biocenosis ,

From DE 203 01 323 Ul is the use of burned

Dolomite with a total content of CaO / MgO of> 80% known as feedstock for the treatment of acid mine and mining waters, the feedstock having a grain size of <200 m with a share of> 90% and a bulk density of> 0.8 t / m ³ . This should be for

Neutralization of acid mine and mining waters are used and be particularly advantageous in waters with high sulfate contents, since unfavorable petrolization due to plaster bonding should be avoided. Due to the very reactive feedstock, there is also the problem here that in weakly acidic waters pH rises to> 9 and thus ecological problems are to be expected even with a slight overdose. DE 102007043751 A1 describes a process in which the pH increase is carried out in acidic waters in at least two stages such that the concentration of each neutralizing agent suspensions used in

Depending on the pH value is set. On the one hand, in the higher pH range of> 4.5, the concentration of the feedstock suspension should be kept lower than in the low pH range of <4.5. In addition, in the higher pH range burned reactive products such as quicklime or hydrated lime and in the lower pH range unburned inert products, such as limestone powder are used. In this way, an attempt is made to achieve a controlled pH increase in the pH range of> 4 with protection of the biocenosis. The disadvantage of this method, however, is that due to the efficiency when using unburned lime products in pH ranges of> 4 large product quantities are to bring with high entry costs. In addition, a high time requirement is required, the short-term reaction times required

can guarantee. This can be attributed to the fact that the rate of dissolution of unbaked lime products, such as limestone meal, against acidic reactants with increasing pH, for example at a pH of> 4, decreases sharply. When used in the prior art

Graining, the predominant, coarser fraction in the feedstocks reacts only partially at this pH value and sinks to the subsurface unused. From DE 20 2008 008 390 Ul is a starting material for the

Treatment and aftercare of acidic surface waters known to consist of a mixture of fired and / or cleared burned lime products and unburned

Lime products. A disadvantage of the described

The starting material is that its production involves a high level of logistics and equipment. In addition, due to the low efficiency when using unburned lime products in pH ranges of> 4 large quantities of products must be introduced with high input costs.

The methods known from the prior art have in common that they are burned by the use of reactive

Lime products, CaO or CaO x gO, hydrated lime, dolomite hydrate and milk of lime due to the high sulfate content, which reach up to> 2,000 mg / 1 in mining waters affected, gypsum formation and gegriesung, and thus low efficiencies to an inactivation of these feedstocks comes , This is probably on it

attributed to the fact that the calcined lime particles are covered by a plaster layer. On the one hand, the gypsum layer can cause the particles to become coarser, sink faster and accumulate at the bottom of the water, where they undesirably increase the pH. A disadvantage of the gravel is further that less reaction surface is available for neutralization of the water. As a result, this may result in the resulting

Iron hydroxide sludge the proportion of the neutralizing agent is contained in an appropriate excess. Another

Dissolution and reaction development is hindered and the product use made ineffective. This problem is usually counteracted by neutral or

Low sulfate water for mashing or preparation of a dilute suspension with increased effort and under

Acceptance of increased costs is supplied. A further disadvantage of the above-described processes known from the prior art is that in weakly acidic waters when using these reactive products even at low overdoses, pH increases to> 9 and thus ecological problems can occur. The same applies to the chemical products caustic soda and soda, which are also relatively expensive.

When using cheaper, but less reactive unburned lime products, such as commercial calcium carbonate, which is marketed as limestone flour with D-50 values of> 12] i, it comes in the pH range of> 6 due to the low solubility and the low Reactivity to low process efficiencies with high sedimentation levels of unreacted feed. Therefore, such unburned lime products are considered, if at all, only at lower pH and more reactive for complete neutralization

burnt lime products used.

Furthermore, common to the known from the prior art method that neutralization of the water, even if it is achieved by the constant influx of acid-forming groundwater is not of long duration. The influx of acidity, especially in the form of reaction products of pyrite weathering (Fe ²⁺ , Fe ³⁺ , S04 ^{2 ~} ) usually leads to a renewed pH drop to values of <6 and a

possible increase of heavy metal contents, in particular of iron and aluminum, which can lead to an impairment or dying of the biocenosis formed or registered in the Bergbausee. To counteract this and to maintain neutral conditions, it is therefore necessary to regularly carry out further, cyclically recurring aftercare treatments in addition to a start neutralization.

Starting from the above-described prior art, an object of the invention was to provide a cost-effective method with which it is possible in a simple and economically effective manner to treat acidic waters and also over a longer

Period to ensure the continuation of treatment success.

This object is achieved by the method specified in claim 1, which recited in claim 15

Use, the mentioned in claim 16 aqueous suspension and the water vehicle mentioned in claim 17.

Advantageous embodiments of the invention are specified in the dependent claims and are explained below as the general inventive concept in detail.

In the inventive method for the treatment of

Waters, a feedstock is introduced into a body of water to be treated in accordance with the above-mentioned prior art. According to the invention, a feedstock is used which contains an unfired lime product, in particular a fine-grained unbaked lime product, wherein the unfired lime product has a grain size with a fraction <about 10 m of 50%. Surprisingly, it has been shown that the fine grain of the unburned lime product in the feedstock results in unfired, less expensive lime products, despite their lower reactivity for the treatment of waters

can be used and that the treatment success also sets itself over a longer period. Without

To be bound by scientific theory, this surprising effect appears to be explained by the fact that the fine particles of the unburned lime product in the feedstock according to the invention do not reach the bottom of the product

Water, but float in the form of a cloud of particles in the water and act there as a buffer substance to a further drop in the pH by flowing acidic groundwater counteract.

Due to the lower reactivity of the unburned lime product, the risk of increase in strongly alkaline pH ranges due to overdosage associated with more reactive lime products is avoided. In addition, the reaction in the

Inventive material contained unfired

Lime product less quickly than the known from the prior art reactivate lime products, which also over a longer period sufficient

Buffer capacity can be maintained.

In appreciation of the process of the invention appears retrospectively the disadvantage of the known from the prior art use of commercially unfired

Lime products lie in the fact that, before it can ever come to a reaction with the less reactive feedstock, this sinks to the bottom of the water and can no longer be available for the reaction. That's how it is Use of commercially available CaC0 ₃ (eg limestone flour, D-50 value> 12 μηα) in the pH range of> 6 due to the low solubility and low reactivity to low

Process efficiencies with high sedimentation levels of unreacted feedstock.

In contrast, in the invention

Feedstock contained unfired lime product by its fine grain size floatable or Schwebefähig and a

Sedimentation to the bottom of the water to be treated is avoided. Surprisingly, the combination of a less reactive, unburned lime product with the fine grain according to the invention to excellent treatment results, which can be maintained especially over a longer period. That's why

for example, when using the method according to the invention for the neutralization of acidic waters to a pH stabilization, which lasts for months. In contrast to the known from the prior art method, the inventive method provides an ecologically safe, economical solution for the inlake treatment of acidic waters, with a sustainable adjustment of the pH to ^ 6 at a sufficiently high efficiency of

feedstock, even when acidity is supplied via groundwater or other sources, over periods of up to several months.

Furthermore, the unfavorable for the biocenosis pH fluctuations are avoided by the inventive use of unburned lime products, which in the intermittent introduction of hitherto conventional more reactive burned

Lime products were observed. For the purposes of the invention, waters are understood to mean all types of waters, in particular surface waters.

Groundwaters, flowing and / or stagnant waters. The inventive method is particularly suitable for the treatment of surface waters, in particular of natural lakes and / or mining or opencast mining lakes. Of particular practical relevance, the invention is particularly for the treatment of open acidic waters, in particular of

Opencast mines with a water volume of> 500,000 m ³ .

Such waters are often characterized by re-acidification by a prolonged supply of acidity with the inflowing groundwater or other acidic sources.

If fine graininess of the starting material or of the lime product is mentioned here, then in particular a grain size with at least a fraction <about 10 μm of 50%, an average particle size of less than about 40 μm and / or particle sizes of about 0.01 to about> 60 μπ \ meant.

A preferred embodiment of the invention provides that the starting material contains an unfired lime product which has a particle size of <about 10 pm of> 50%. Optimal results are obtained when the unfired lime product has a grain size with a proportion <about 4 μπι of ^ 50%, in particular a proportion <about 3 microns of ^ 50%. Experiments have shown that at

unburned lime products with coarser grain size does not come to the long-lasting neutralization according to the invention and a cyclic aftertreatment is necessary. This is probably due to the fact that feedstocks, in particular the unfired lime products contained therein with a coarser Grain are not hoverable and therefore fall to the bottom of the lake, which means that they are not for a longer period of time for a neutralization reaction

To be available.

If there is talk of grain, it is with the

Range specified in μπι the particle diameter. The indication of the grain size in "proportion smaller x m of ^ 50%" corresponds to the particle size distribution in the form of the D-50 value which is widespread in lime products. Under a D-50 value of 10 μι the skilled person understands that 50% or more of the particles have a particle diameter smaller than 10 μιη. There is a volumetric evaluation of the measurement results. Standard methods for determining the grain size of lime products are known to the person skilled in the art. The determination of the particle sizes, their distribution and the mean particle size has proven to be particularly practical

Laser diffraction, which is also called laser granulometry or laser diffraction proven (see ISO standard 13320-1). Unless indicated otherwise, the degrees of granulation and particle sizes given here are values determined by means of volumetric laser diffractometry. In this case, the particle size x (μπι) at the volume passage (D) of 50% is indicated as D-50 value. The commercially available

Laser diffractometers (eg Helos laser diffraction sensors of the company Sympatec) provide reliable and rapid measurements of both the particle sizes and their distribution in a sample over a measuring range of about 0.1 μm to about 8.75 mm. However, other measuring methods for determining the particle size are possible, for example by means of microscopy or the determination of the screen diameter. According to a further embodiment of the invention, the unfired lime product has a grain size with an average particle size of about 0.05 to about 40 μm, in particular an average particle size of about 0.05 to about 20 μm. In addition to the average particle size feature, the unburned lime product may also have the aforementioned particle size distributions (D-50 values). Accordingly, a particular embodiment of the invention provides that the starting material contains an unfired lime product having the aforementioned D-50 values and / or a grain size having an average particle size of about 0.05 to about 40 pm, in particular an average particle size of has about 0.05 to about 20 μπι. Experiments have shown that unfired lime products with coarser grain size do not suffer from the long-lasting neutralization according to the invention. In particular it may be contrary to the

According to the invention, fine-grained unbaked lime product to a re-acidification by inflow of acidic groundwater, which can not be buffered come. This is probably because feedstocks, in particular

unburned lime products, with a coarser grain size are not schwebefähig and therefore fall to the bottom of the lake and not for a longer period for a

Neutralization reaction are available. Unburned lime products with grain sizes with an average particle size of less than about 0.05 μπι are difficult to obtain and do not represent an economical alternative.

The teaching of the invention may according to another

Embodiment of the invention are also realized in that the starting material contains an unfired lime product, which has a grain size of about 0.01 to about 60 μι ^η , in particular from about 0.01 to about 40 μιτι has. Optimum results are obtained when the unfired lime product has a grain size of about 0.01 to about 20 μηα or a grain size selected from the group consisting of less than about 60 μπι, less than about 40 μκι, less than about 30 μηα and less than about 20 μηα , Unburned lime products with a coarser grain size do not show the inventive, long-lasting

Neutralizing effect. Finer unburned lime products with grain sizes below 0.01 μιη are difficult to produce and therefore do not represent an economical alternative. In addition, the contained in the feedstock according to the invention

unburned lime product also have one of the previously described particle size distributions (D-50 values) and / or one of the previously described mean particle sizes.

According to a further embodiment of the invention, a method for pH stabilization of weakly acidic

Surface waters provided, wherein the feedstock in a suspension with water in the treated

Water is introduced, characterized in that for pH stabilization of weakly acidic surface waters in the pH range of 5 to 7.5 as the feedstock an unbaked fine-grained lime product is used with a share of CaC0 ₃ of> 85%, the feedstock thereby a grain size from 0 to 40 μιη and by means of entry systems in a

Suspension concentration of 1 to 15 Ma.% Batchwise, each with 20 to 500 g / m ² on areas of each

20,000 to 100,000 m ^{2 is} applied. The teaching of the invention may according to another

Embodiment of the invention are also realized by the fact that the feedstock for pH stabilization of weak acidic surface waters in a suspension with water is introduced into the waters to be treated, characterized in that for the pH stabilization of weakly acidic surface waters in the pH range of 5.0 to 7.5, the feedstock of a fine microcrystalline

Sedimentary rock, which consists of> 85% photosensitized carbonic acid precipitated calcium carbonate and has a total age of 50 to 140 million years, is an unbaked fine-grained lime product and the

Feedstock has a grain size of 0.1 to 40 \ i and the proportion <4 pm while ^ 50%. In particular, the feedstock may have a grain size of 0.1 to 20 μιη while the proportion <3 μκι preferably ^ 50%. For the purposes of the invention, lime product is understood to mean all products obtained from carbonate rocks.

In particular, the term lime product used here should also include dolomitic limestone and dolomite.

Limestone based lime products have delivered optimal results in practical trials.

According to the invention, the starting material used is preferably an unbaked lime product. Preferably, the feed consists essentially of unbaked lime products. However, it is also possible that the starting material in addition to unbaked lime product and fractions of burned

Lime products and / or other additives.

As for the inventive method particularly suitable unburned lime product has an unfired

Lime product with a proportion of CaC0 ₃ of> 85 wt .-% proved. A natural substance which fulfills this requirement and is also present in the fine granularity provided according to the invention is, for example, fine chalk. Fine chalk is a fine one

Microcrystalline sedimentary rock, which consists of> about 85% by weight of precipitated by photosynthetic carbonic acid withdrawal calcium carbonate. Fine chalk usually has an approximate age of about 50 to about 140 million years. Since chalk is ready to use commercially available, it represents a particularly suitable for use in the method according to the invention fine-grained lime product.

It has been found that with a microcrystalline sedimentary rock such as fine chalk without elaborate grinding a very finely divided feedstock can be provided. Optimal results in this case provides a microcrystalline sedimentary rock such as fine chalk, which preferably has a mean grain size of about 0.01 to about 20 μιτι for use as feedstock or feedstock. The proportion <about 4 μιη is preferably ^ 50%.

As a particularly suitable inventive unburned lime product comes next to fine chalk and any other fine microcrystalline sedimentary rock, which precipitated to about> 85 wt .-% of photosynthetic carbonic acid withdrawal

Calcium carbonate is considered. The sedimentary rock preferably has an approximate age of about 50 to about 140 million years. Also mixtures of fine chalk and other sedimentary rocks are possible.

In addition to the treatment of waters in general, the process according to the invention can in particular Stabilization, the pH increase and / or the neutralization of waters serve. According to a preferred embodiment, the feed according to the invention is used for the pH stabilization of acidic waters. Sauer here means a pH of the body of less than about 7.5, in particular between about 2 and about 7.5.

The feedstock according to the invention is also suitable for pH stabilization of weakly acidic waters, that is

Waters in the pH range of about 5 to about 7.5. Herein is a surprising feature of the provided in the process according to the invention starting material to see because

unfired lime products have not been recommended as alkaline substances for inlake processes in this pH range so far (see DE 10 2007 043 751 AI).

According to a further embodiment of the method according to the invention, a strongly acidified body of water can first be subjected to a start neutralization in a first step or at least the pH can be raised to the weakly acidic pH range. This can be done both by incorporation of an unburned lime product with commercial grain size, such as limestone, as well as with others, the

Skilled in the art known feedstocks. In a second step, especially for pH stabilization and / or buffering, the body of water is treated with the starting material according to the invention, in particular one containing an unfired fine-grained lime product with a particle size of <about 10 μm of> 50%.

In use experiments, it has been found that the process of the invention is an ecologically safe, economical Solution for inlake treatment of weakly acidic waters. In particular, with the inventive

Method a sustained adjustment of the pH to ^ about 6 at a sufficiently high efficiency of

According to a preferred embodiment of the invention, the treatment with the fine-grained

unburned lime product or feed can also be used only for the installation of a buffer cloud in a body of water, which has previously been neutralized by other methods and / or already had a suitable pH of its own accord.

In principle, various methods are known to those skilled in the art, which are suitable to introduce the feed into the water to be treated. Practical experiments have shown that optimal results are achieved when the

Feedstock is introduced in a suspension with water in the water to be treated or applied to the water to be treated.

Accordingly, according to a further embodiment, the present invention provides an aqueous suspension containing at least one unburned lime product according to the invention, in particular one having a particle size of less than about 10 μm of 50%, for the treatment of waters. In practice, the suspension according to the invention can be mixed shortly before entry into the body of water to be treated. However, they are also ready to use, storable

Suspensions or premixes conceivable.

Suitable concentration ranges for the aqueous feedstock suspension used in the process according to the invention are, in particular, concentrations of about 0.1 to about 40% by weight. For many applications, a suspension concentration of about 1 to about 15% by weight is particularly practical. For economic and procedural reasons, it has proved to be advantageous if the starting material

batchwise introduced into the water to be treated or applied to the water to be treated. The optimum batch size for the particular water body, the prevailing conditions and the entry system used can be determined by means of on-site tests. In practice, the introduction of the feed has to be treated in the

Waters in batches of about 20 to about 500 g / m ² on areas ranging from about 20,000 to about 100,000 m ² proven.

If the introduction of the feedstock in the zu

Treating waters batchwise, the batch entry can be done for example by means of remediation vessels and / or by means of one or more piping distribution systems. This can the refurbishment ship and the

Pipe distribution system also work in an alternating operation for the feed intake. According to a further embodiment of the invention, for example, during the day the entry can be made by means of a refurbishment vessel and at night the entry can be made by means of a

Piping distribution system continued. One simultaneous introduction of the starting material by means of

Rehabilitation ship and pipeline distribution system is also possible. In practice, it has proven useful when the batch entry by means of remediation ship entry and / or by means of an alternating operation of a rehabilitation vessel and a pipeline distribution system. Sanierungsschiffe for the treatment of acidic waters with

Alkaline substances are known, for example, from WO 2009/037194 A2, whose disclosure content is hereby incorporated by reference. When talking about refurbishment vessel, it refers to all vessels that are capable of handling alkaline feedstocks

Water surface or in a body of water

to bring in.

In field trials, the introduction of the

Feedstock according to the invention by means of watercraft proved to be particularly advantageous.

Accordingly, the invention further provides a watercraft for introducing a feedstock according to the invention, in particular a green lime product with a

Grain with a share <about 10 μπι of> 50% in a water to be treated before, the vessel

Has at least one reservoir, which the

Contains feedstock. Optimal results are obtained when the vessel has the characteristics of the one described in WO

2009/037194 A2 described at least partially remediation ship. A further preferred embodiment of the invention provides for the introduction of the feedstock according to the invention by means of pipeline distribution systems.

Pipe distribution systems which are suitable for introducing alkaline feedstocks into the treatment of acidic waters are described, for example, in DE 102009049739 A1. The disclosure of this document is hereby expressly incorporated by reference.

Preferably, the piping distribution system operates in an alternating operation for the feedstock supply.

It has proved to be advantageous, the

Time intervals of the alternating operation of the

Adjust pipe distribution system with feed input depending on the wind direction and the wind speed. With such a procedure, a good distribution of the starting material can be ensured.

In practice, for example, optimal results can be achieved if the alternating operation of the

Pipe distribution system with feed entry is set from a wind speed of <about 1 m / s. At a lower wind speed that remains

Pipeline distribution system with feedstock entry out of service. In this case, the pipeline distribution system can continue to be operated and rinsed with seawater without adding material.

In terms of downtime and time intervals of alternate operation of the piping distribution system practical experiments have shown that the time intervals are preferably after a fixed operating time,

in particular after about one hour of operation, and / or with a wind speed dependent

Downtime in a time interval of

Z (time interval in h) = 3 x V (wind speed in km / h) / V ^{2 are} set. Here, the downtime for the use of material input of the pipe distribution system at high wind speeds in a direct dependence on the wind speed at high wind speeds are shorter than at low wind speeds.

The above to the dependence on wind speed and feed input said equally applies to the introduction of the feedstock by means of remediation ship. Thus, an advantageous embodiment of the invention provides that the restructuring vessel entry the parameters of

Feed input, such as amount,

Batch sizes, direction of travel, order area and

Insert mode, according to the wind strength and wind direction are set.

The entry of the input material can be done both by overwater and underwater distribution. By

Practical experiments have found that it is particularly gentle and beneficial for a still existing water biocenosis when in the free, deeper waters the

Feedstock distribution takes place via water, while at Shore area underwater distribution of the feedstock takes place.

The feedstock according to the invention also provides optimal results in areas of water that are difficult to access with a watercraft or pipe laying. It has been shown that the buffer cloud formed by the fine-grained feedstock in the water also in

Water bodies drifts that were not treated directly. This is probably due to the particularly fine

Particle size of the feedstock, or the contained therein unfired lime product, which thereby floats and

becomes floating and virtually self-distributing with the natural flow in the water. This effect can be exploited particularly advantageous if the

Inlet entry takes place at a natural confluence or at an influx into the water to be treated. This is due to flow-induced spread of

Feed cloud in the water an optimal distribution of the feed.

Practical experiments have further shown that with the method according to the invention, as well as the advantageous embodiments of the invention described above and in the dependent claims, a product or buffer cloud in the water in a layer thickness of up to about 10 m over longer

Periods can be established, the pH in this buffer cloud usually does not exceed about 7.5. The formation of the buffer cloud after introduction of the

Feedstock according to the invention can be used in suitable Local conditions are observed by aerial photographs over the treated waters.

The buffer cloud can be formed with the process according to the invention for periods of up to 3 months, without a complete reduction of feed to the riverbed. This is especially true in the case where the acidity input via groundwater or other sources is less than the alkalinity potential of the buffer cloud. The advantage of the formation of buffer clouds is that consuming short-term successive aftertreatments avoided and longer periods such as winter periods with

Ice cover the waters can be bridged easily.

With the application of the method according to the invention the disadvantages of a possible impairment of the biocenosis, unfavorable efficiencies, possible overdoses, high overall costs and in particular a rapid re-acidification are largely avoided. Finally, with the

proposed methods, the pH stabilization and in particular the aftercare by the use of unburned lime products are made overall cost. The principle of the invention will be explained in more detail below with reference to examples.

example 1

To be treating a mining lake with a volume of ³ million cubic meters, which in a period of 6 months as a result of Groundwater influence from an initial pH of 7 to a pH of 5.8 acidified. Until a pH value of 7 is reached again, a neutralization requirement of 0.3 mmol / l is determined.

For the treatment of the open-pit mine, the input material is a fine chalk containing 90% by weight of CaC0 ₃ .

used. The grain size of the starting material is determined using a laser diffraction sensor (Helos, Sympatec). The D-50 value of the starting material is between 2 and 4 μιη. The starting material has a grain size of <20 μητι. Of the

Total efficiency of the feedstock is determined in Technikumsversuchuch with 80%.

For the treatment of the sea comes about 650 t

Fine chalk. The feedstock is transported by silo truck

Lakes transported and brought here in batches of 6 t each in the reservoir of a distribution ship and from this as 4% feedstock suspension over a period of 20 min with 150 m ³ seawater on the surface of 1.500 m long and 40 m wide (60,000 m ² ) with an input amount of 100 g / m ² distributed. After each refill of the

Reservoir of a distribution ship, the order of the feedstock suspension takes place in another area of the sea surface. As a rule, the application of the feed suspension to the same takes place only once a day

Sea surface.

The total amount of feed is entered into the water in a period of about 2 weeks. After the implementation of the method, the pH is about 7.0 and the

Acid capacity in the form of K _s 4.3 value about 0.45 mmol / 1. With stabilization and improvement of the water quality in terms of both the pH and on the acid buffer by the

Treatment according to the invention can be achieved.

The spread of the feed suspension introduced by means of the remediation vessel below and above the water surface is followed by aerial photography. It is observed that according to the current and wind direction, the buffer cloud also drifts into areas of the lake, which with the

Renovation ship are difficult to access and therefore can not be treated directly.

By treating the acid potential until reaching a pH of 7 and additional installation of a buffer cloud with a total mass of unused

Fine chalk of approx. 220 t in the water body is only required after approx. 9 months if the acidity of the body of water remains the same.

Example 2 (comparative example)

An open pit residual sea had a weakly acidic pH. As raw material for the treatment of the lake, unfired limestone flour with a D50-value of> 12 μπ \ was used. The feed was introduced into the water by a watercraft. Much of the feed sank to the bottom of the lake without reacting. After

Treatment was in the immediate entry area

to observe short-term neutralization of the sea area. The inflow of acidic groundwater was followed by a short time treatment to re-acidify the lake, requiring re-treatment.

The invention has been described above with reference to exemplary embodiments. It is understood that the invention is not limited to those described

Embodiments is limited. Rather, arise for the skilled in the invention varied

Abwandlungs- and modification options and the

Scope of the invention is defined in particular by the following claims.

Claims

claims

1. A method for treating waters, wherein a

Feedstock is introduced into a body of water to be treated, characterized in that the starting material contains an unfired lime product, wherein the unfired lime product has a grain size with a share <about 10 μιη of ^ 50%.

2. The method according to claim 1, characterized in that the unfired lime product a grain with a

Share <about 4 μτα of ^ 50%, in particular a proportion <about 3 μπι of> 50%.

3. The method according to any one of claims 1 or 2, characterized

characterized in that the unfired lime product has a grain size with an average particle size of about 0.05 to about 40 μπι, in particular with a mean

Particle size of about 0.05 to about 20 pm.

4. The method according to any one of claims 1 to 3, characterized

characterized in that the unfired lime product is an unfired lime product with a CaC0 ₃ content of> about 85% by weight.

5. The method according to any one of claims 1 to 4, characterized

characterized in that the unfired lime product

Fine chalk is. ϊ. Method according to one of the claims 1 to 5, characterized in that the treatment of the water a pH stabilization, a pH increase and / or a

Neutralization means.

^] . A method according to claim 6, characterized in that the starting material for pH stabilization of weakly acidic waters in the pH range of about 5 to about 7.5 is used.

Method according to one of claims 1 to 7, characterized in that the starting material in a

Suspension is introduced with water into the water to be treated or applied to the water to be treated.

A method according to claim 8, characterized in that the feedstock by means of entry systems in a suspension concentration of about 1 to about 15 wt .-% on or applied.

Method according to one of claims 1 to 9, characterized in that the starting material batchwise, each with about 20 to about 500 g / m ^{2 is} applied to surface areas of about 20,000 to about 100,000 m ² .

Method according to one of claims 1 to 10, characterized in that the feedstock is introduced batchwise into the water and that the batch entry by means of remediation ship entry and / or by means of a pipeline distribution system or by means of an alternating operation of a rehabilitation vessel and a

Piping distribution system takes place.

12. The method according to claim 11, characterized in that the time intervals of the alternating operation of

Pipe distribution system with feed entry depending on the wind direction and the

Wind speed can be adjusted.

13. The method according to any one of claims 11 or 12, characterized in that the alternating operation of the

Pipe distribution system with feed entry from a wind speed of about 1 m / s

is set.

14. The method according to any one of claims 10 to 13, characterized in that the time intervals of

alternating operation of the

Pipe distribution system after a fixed operating time, in particular after a one-hour

Operating time, with a wind speed dependent downtime in a time interval of

Z (time interval in h) = 3 x V (wind speed in km / h) / V ^{2 are} set.

15. Use of an unburned lime product, which has a grain size with a share <about 10 m of ^ 50%, for the treatment of waters.

16. Aqueous suspension containing at least one unbaked lime product which has a grain size with a proportion of <about 10 μπι of ^ 50%, for the treatment of waters.

17. Watercraft for bringing in an unfired one

Lime product, which has a grain size with a fraction <about 10 pm of ^ 50%, as feedstock in a water to be treated, wherein the vessel has at least one reservoir containing the feedstock.