DE19505884A1 - Water treatment process and small-scale assembly removes phosphate ions - Google Patents

Abstract

In a process and assembly to remove phosphates and ammonium from water (1), ammonium magnesium phosphate (AMP; 4') is formed and removed in a cleaning stage (50) or sludge, contg. ammonium ions is removed, to produce water ( 11) that is generally free of ammonium. The pptd. AMP decomposes in all or part under the influence of liberated ammonia (6) or ammonium ions. The magnesium and phosphate (7, 12) portions are returned to the cleaning stage circuit. The novelty is that: (a) the water which is to be cleaned is first passed through a preliminary cleaning stage (40) in which phosphate ions are generally removed by the action of a suitable reagent (R2) incorporating a zeolite; (b) to facilitate the formation of AMP macrocrystals without the introduction of additional polymer flocculants, magnesium and/or iron ions are added to the water or the pre-cleaned water (13), before this enters the cleaning stage (50), which holds the two-valence metal ions formed in the AMP crystals. An assembly accelerates the crystallisation of the molecular AMP and separates the crystalline AMP from the water, in which the accumulated AMP is exposed to magnetic, electrical, electro-magnetic and/or mechanical fields and oscillating fields respectively.

Description

The invention relates to a method for cleaning with Phosphate ions and ammonium ion contaminated water the features of the preamble of claim 1. Furthermore particularly relates to the invention for this method suitable devices according to the features of the preambles of claims 4 and 6 and a method for cleaning water contaminated with ammonium ions according to the characteristics the preamble of claim 8.

In particular, the invention relates to methods of disposal imperfect, or not at all stabilized, municipal Faecal sludge in small communities or litter and split Settlements if there is no connection to the sewage system, however also for the temporary cleaning of leachate, liquid manure suspensions and other ammonium and phosphate containing Sewage

Chemical removal of ammonium ions and phosphate ions from wastewater through ammonium magnesium phosphate (AMP Precipitation is e.g. B. from the essay by Schulze-Rettmer and Blank in "Korrespondenz-Abwasser, 4/92, pp. 550-559" and known from DE-A1-37 32 896. In these publications the cleaning principle of AMP precipitation as a possible alterna tive to biological cleaning processes presented. The AMP hardly adsorbs any harmful substances during the precipitation process  Substances, neither organics nor heavy metals, and can be used as valuable commercial fertilizer can be further used.

The reaction

NH₄⁺ + Mg ²⁺ + PO₄ ^3- → MgNH₄PO₄

requires the presence or addition of these ions in the interference chiometric ratio N: Mg: P as 1: 1: 1. The one with the Adding associated high chemical costs as well as this associated transportation costs cause wastewater cleaning by AMP precipitation without recycling would be economical. That is why in the print cited above writings, the disclosure content of which by this reference in the present revelation is included the circle Running the magnesium and phosphate ions for the above reak proposed. The crystalline AMP is used for this higher temperatures

MgNH₄PO₄ · 6H₂O → MgHPO₄ + 6H₂O + NH₃

decomposes. This can be done both by dry heating as well by blowing water vapor into an AMP slurry after adding alkali.

The water to be cleaned with a pH of 6.8 to 7.8 is first in a first mixing stage by adding Phosphoric acid brought to a pH of 4 to 4.5. In In a second mixing stage, the pH is adjusted by adding Magnesium oxide, possibly with the addition of sodium hydroxide solution 9.5 increased. In a two-stage crystallization stage is at two different pH values and under different flow conditions AMP failed. The dwell time of the Water in the crystallization stage is over 60 minutes ten. With addition u. a. a solution with polymer flocculation the AMP is averaged in the second crystallization stage by forming macro crystals due to the polymer floc agents separated as a precipitate.  

Occurring residual concentrations of phosphate ions require the post-purification of the water while raising the pH by adding calcium hydroxide to 11 to 12. The Phos phations can then by means of iron chloride sulfate and additional polymeric flocculant removed from the water the. This neutralizes the water, however the operating costs are increased.

The overdosing of the precipitants or flocculants can by destabilizing the AMP or restabilizing others complexes to restore the ammonium and Lead phosphate ion content.

AMP and magnesium hydrogen phosphate (MHP) are also included this procedure according to the ent in the wastewater hold phosphate as an excess, which is not in Cycle can be performed. The removal of this over shot, as well as the withdrawn ammonium or phosphate com components and their transport is also relatively unprofitable very intensive.

Furthermore, in this known method is an on Line measurement of the ammonium ion and phosphate ion concentration to determine those dictated by stoichiometry Amounts of magnesium and phosphate ions added are very expensive lig.

In order for a method or a device of the beginning a kind as thorough as possible and economical water purification on a technical scale To achieve, a method for cleaning according to the invention of what is contaminated with phosphate ions and ammonium ions ser with the features of claim 1, a device with the features of claims 4 or 6 and a method for Generation of AMP featured with the features of claim 8 beat.  

In the method according to the invention, that which is to be cleaned Water before ammonium-magnesium-phosphate (AMP) precipitation a pre-cleaning stage in which the water is largely freed of phosphate ions; this will follow hereinafter referred to as the phosphate cleaning stage. The Phos phat cleaning level can also be a part of the in to remove the ammonium ions present in the water to be cleaned distant, a reagent mixture with ion exchange Properties, e.g. B. with a zeolite. The cleaning stage comprising the AMP precipitation - following referred to as the AMP precipitation stage - is water forwarded, which as a component of the AMP precipitation process contains essentially only ammonium ions. Due to the AMP Precipitation can be made from water free of ammonium and phosphate ions an AMP sludge from the AMP precipitation stage can be removed. Of the AMP sludge becomes a dewatering and drying facility tion fed. It is conceivable that the Ent watering device and the drying device in one Process step are summarized. By drying any water or crystal water that may still be present AMP withdrawn and the AMP - at least partially - under free put decomposed by ammonia. The remaining ingredients of the AMP (magnesium and phosphate components) are the Reini stage in the circuit again. Of course could instead of the drainage and drying facility all other methods which can be found in the prior art for the separation of ammonia or ammonium ions from the magne Sium and phosphate proportions are used if this An parts are in recirculable form after separation.

The method according to the invention not only makes it possible to an on-line measurement of the ammonium ions and phosphate ions Not to concentrate in the water to be cleaned, son it also allows for ammonium ion removal largely to dispense with the supply and discharge of chemicals ten.  

To education without the entry of polymer flocculants of AMP macro crystals is envisaged in the AMP crystals during the crystallization process Store metals, preferably manganese and / or iron. These metals can be found in the water surrounding the forming AMP are present as ions. Are particularly suitable Metals used as divalent metal compounds, e.g. B. FeO or MnO, the procedure.

In particular, this is in conjunction with during Crystallization process on the AMP or the metals acting, electrical, magnetic, electromagnetic and / or mechanical fields or vibration fields possible, the ferroelectric and ferrimagnetic Eigen of the AMP thus formed to control the microscopy fields on the crystallization nuclei to use the diamagnetic elements N, P and Mg completely as AMP too crystallize. Here z. B. electromagnetic and mechanical vibrations as well as occurring resonance effects the simultaneous piezoelectric polarization and Magnetostriction of the AMP under elastic volume and Changes in shape of the same.

Both individually and in combination is through the above mentioned process steps in an advantageous manner Residence time of the water in the cleaning reactor for bil reduced the AMP crystals and in particular one complete crystallization of the AMP is reached, so that on a downstream phosphate cleaning stage is dispensed with can be.

The crystals formed here have spontaneous, electri and magnetic polarization effects, macroscopic Dipole moments and a modified, magnetic permeabili open up. This eliminates the separation of these crystals promoted to the water.  

To take advantage of these effects explained below it provided the cleaning method according to the invention through the process step of adding divalent metal ions, especially of manganese or iron ions tern. On the one hand, this can be done by adding metal waste water containing ions or manganese and iron ions, which z. B. in drinking water treatment, too happen to the water to be cleaned. But it is also think bar, the ions at another suitable place - e.g. B. before Add AMP precipitation. These ions circulate in the magne sium and phosphate cycle with, and it will only eventuel le, procedural losses offset. Especially It is advantageous if the AMP has one after the precipitation Content of 3.5 to 5.1% of manganese oxide or iron oxide reached. The filling reaction can be advantageous in this way promote and it becomes a compact design of the process performing device allows.

To promote the crystallization of the molecular AMP and separation of the crystalline AMP from the water accelerate, a device is provided in which the formed AMP a combination of mechanical vibration and electromagnetic, time-varying fields is exposed. In addition to the state of the art cash opportunities such. B. the use of a stirrer and an electromagnet in connection with a vibra tional vibration device, as from WO 94/03252 be knows, there is the possibility of the water to be cleaned through a magnetic filter and / or a magnetic pump conduct.

The magnetic filter according to the invention consists of a bulk tion from iron balls through diamagnetic, with holes provided sheets is kept in shape and over iron sheets connected to at least one pole of an electromagnet is. It is particularly advantageous if the electromagnet  is designed as a multi-pole electromagnet, of which Poles out through iron sheets to both the electromagnet incoming as well as continuous field lines in the Magnetic filters are passed, the electromagnet generate alternating field and the magnetic filter through a Vibrator can be excited to vibrate. It is Z. B. conceivable that the iron balls of the magnetic filter hollow or with chrome-plated surface are formed. Of course can also ferromagnetic steel balls or other magne table materials or waste products, e.g. B. granules, the not corrode, be used. The typical size these particles should preferably be between 5 to 15 mm lie. The magnetic field strength preferably varies between 100 and 600 kA / m. Furthermore, it is advantageous if the magnetic filter has a suitably dimensioned hollow surrounds space through which the liquid to be filtered is directed.

The magnetic pump is made up of several levels each quadrupole-like on one of the water to be cleaned permanent magnets arranged through the flow tube, which a change in time generated by electromagnets and against the flow direction of the what to be cleaned sers or in the desired flow direction from what increasing magnetic field to be removed from AMP crystals is superimposed. To support the crystal formation of the AMP the electromagnets are activated by electrical pulses controls. The pumping action can be increased if the Pulses offset the electromagnet in time and space be fed. Of course they are different most spatial arrangements of the permanent magnets and Electromagnets conceivable.

Through the two devices - the magnetic pump and the magnetic filter - it becomes particularly possible in each a combined process or in a cleaning stage  both the effect promoting crystallization and precipitation electrical, magnetic, electromagnetic and / or me chanic vibration fields as well as the particles from rivers to use the liquid separating effect of these fields. Of the magnetic filter according to the invention and the magnetic pump according to the invention individually or in any combination with each other and with other separation devices driving or devices advantageous for the separation of magnetizable components made of fluids applied the.

The aforementioned and the claimed and in the Ausfü Example of the inventive method described steps and components to be used are subject to visually the process conditions or their size, space design, choice of materials and technical conception kei NEN special exceptions, so that the respective current application area known selection criteria limited application.

Further details, features and advantages of the item the invention result from the following description Exercise of the associated process flow diagrams and the drawing tion, in which - exemplary - preferred embodiment form a cleaning method according to the invention, in particular characteristics of a device according to the invention management of this cleaning process and special features using AMP. It goes without saying that the individual features, especially the individual ver driving steps individually and in any combination can advantageously be used with one another. It shows

FIG. 1 is a process flow diagram for an inventive cleaning process;

Fig. 2 is a process flow diagram for a further OF INVENTION dung according cleaning process;

Figure 3 is a process flow diagram for providing manganese and eisenionenhaltigem Mangnesiumphosphat.

Fig. 4 is a process flow diagram for a further OF INVENTION dung according cleaning process;

Figure 5 is a process flow diagram for a further OF INVENTION dung invention purification method, particularly for severely polluted waste water.

Fig. 6 is a Klärreaktor as a device for the AMP-FAEL averaging stage Reinigungsverfah the invention ren of Figure 2 to 5.

FIG. 7 shows a section through the clarification reactor according to FIG. 6 along the line AA according to FIG. 6;

Fig. 8 is an enlarged detail of the section shown in Figure 7 Darge section through the clarification reactor. and

Fig. 9 schematically shows the magnetic field strength in the Klärreak tor according to Fig. 6.

According to the example shown in Fig. 1 process flow diagram for an inventive cleaning process to clean the water 1 with the addition of Manganionen- and iron ions water containing 2 a phosphate cleaning stage 40 is aufgege from which through the formation and removal of a phos phathaltigen sludge 14 pre-cleaned water 13 removed ben . By adding a reagent R2 which contains a suitable zeolite, part of the ammonium ions contained in the water 1 to be purified is likewise precipitated and removed with the phosphate-containing sludge 14 . This leads to a qualitative improvement of this phosphate-containing sludge 14 , if this z. B. to be sold as fertilizer, and to an advantageous reduction in the ammonium ion content of the pre-cleaned water 13th

This pre-cleaned water 13 is a AMP-precipitation stage while adding a Magnesuimionen- and Phos phationen-containing solution 12, hereinafter referred to as manganese and iron ion-containing magnesium phosphate solution 12 denotes abandoned fiftieth Using the AMP precipitation reaction, ammonium and phosphate ion-free water 11 is removed from the AMP precipitation stage 50 and, after an aftertreatment (not shown in this figure), is removed from the process as purified water 9 . Because of the above-mentioned reduction in the ammonium ion content of the pre-cleaned water 13 before entering the AMP precipitation stage 50 , this can work more economically.

The AMP formed in the AMP precipitation stage 50 is taken from this as the AMP sludge 4 ', which will give up a decomposition device 31 '. In the decomposition device 31 'ammonia 6 is split off from the AMP with an increase in temperature. The magnesium and phosphate fractions 7 formed , hereinafter referred to as magnesium phosphate 7 , are fed back to the AMP precipitation stage 50 in the circuit by releasing ammonium ion-free water 11 as magnesium phosphate solution 12 .

Due to the circulation of the magnesium and phosphatane parts of the AMP formed in the AMP precipitation stage 50 , the magnesium ions and phosphations are present in a stoichiometrically correct ratio for the AMP precipitation reaction taking place in the AMP precipitation stage 50 . The manganese and iron ions accumulate in the AMP sludge 4 'and are circulated with the magnesium and phosphate fractions. The addition of the manganese ion and iron ion-containing water 2 is carried out in such a way that in the AMP sludge 4 'between 3.5 to 5.1% manganese oxide or iron oxide accumulate.

The method of the type described above makes it possible Lich, on the use of on-line measurement and control technology for monitoring the ammonium ion and phosphate ion concentrations waive tration. For process control only pH Value and flow rate measured as process variables. Hereby can the investment costs for process control ver be kept equally low.

In the process flow diagram shown in FIG. 2, a cleaning process according to the invention is presented, which includes the process steps of the process shown in FIG. 1. According to the process flow diagram shown in Fig. 2, the water to be cleaned 1 with the addition of manganese ion and iron ion-containing water 2 is fed to a pre-cleaning stage 40 , this pre-cleaning stage 40 a reagent R2 of suitable zeolite 25 , calcite 26 and hydrated lime 27 is added . Depending on the load on the water 1 to be purified, the composition or the amount of the reagent R2 added is varied. Furthermore, a polymer solution 24 can be added to the pre-cleaning stage 40 .

Pre-cleaned water 13 and the phosphate-containing sludge 14 which can be removed from the process as fertilizer 16 are removed from the pre-cleaning stage 40 . Part of the phosphate-containing sludge 14 is fed back to the preparatory stage 40 in order to make better use of the added reagents R2. The pre-cleaned water 13 is given to a cleaning stage 50 with the simultaneous addition of the magnesium phosphate solution 12 . It is understood that - as described above - the magnesium phosphate solution 12 contains manganese and iron ions. Using the AMP precipitation reaction, water 11 free of ammonium and phosphate ions is removed from the cleaning stage 50 . The AMP formed in the cleaning stage 50 is removed as the manganese and iron ion-containing AMP sludge 4 'and the decomposition device 31 ' abandoned. The decomposition device 31 'a reagent R3 containing manganese and iron ions and magnesium phosphate is removed, which is fed to the purification stage 50 and which has the corresponding precipitation reaction in the purification stage 50 corresponding stoichiometric ratio. Of course, the decomposition device 31 'manganese and iron ion-containing magnesium phosphate 7 can be abandoned as required. As described above, the decomposition device 31 'ammonia 6 is removed.

The cleaning stage 50 can be given 1 acid 23 and polymer solution 24 depending on the load of the water to be cleaned. In order to adjust the pH value, the purified water 9 from a post-treatment stage 45 can be added to the cleaning stage. The after-treatment stage 45 serves for the after-cleaning or treatment of the ammonium-free and phosphate-free water 11 . Depending on the wastewater load, polymer solution 24 , hydrated lime 27 and / or aluminum chloride 28 can be added.

A device for performing the method shown in FIG. 2 can be supplemented by a few extensions in a device for providing manganese and iron-ion-containing magnesium phosphate 7 according to the process flow diagram shown in FIG. 3. The water to be cleaned 1 is first fed to the cleaning stage 50 , from this given as pre-cleaned water 13 'the pre-cleaning stage or phosphate cleaning stage 40 and then fed as ammonium and phosphate ion-free water 11 ' to the after-treatment stage 45 , from which it was removed as purified water 9 can be. The water 1 to be cleaned is added water 2 containing manganese and iron ions, which contains a reagent R1 composed of manganese, iron oxide 20 , magnesium hydrogen phosphate 21 and calcined and / or anhydrous soda or lye 22 . To adjust the pH or to add phosphates, the reagent R1 can also acid 23 , z. B. H₃PO₄, HCl or H₂SO₄ added. To control the precipitation process, however, it is also conceivable to feed the calcined and / or anhydrous soda or lye 22 and / or the acid 23 directly to the cleaning stage 50 . It is of course conceivable to add magnesium oxide 21 to the reagent R1 instead of the magnesium hydrogen phosphate 21 .

The provision of the manganese and iron ion-containing magnesium phosphate according to the process flow diagram in FIG. 3 is characterized in that the magnesium phosphate 7 containing manganese and iron ions or the gaseous and iron ion-containing AMP formed with the help of magnesium hydrogen phosphate or magnesium oxide 21 Sludge 4 is precipitated in the same cleaning stage 50 under the same physical conditions as the circulating manganese and iron ion-containing AMP sludge 4 '. Except for the differences shown above, the methods according to FIGS. 2 and 3 are identical. The magnesium phosphate 7 containing manganese and iron ions produced according to the method according to FIG. 3 can be stored in a silo and serve as a stock to compensate for any losses when carrying out the method according to FIG. 2.

Furthermore, in the method according to FIG. 2, manganese and iron ions as well as calcined and / or anhydrous soda can of course also be added to the circuit via the reagent R3. It is of course conceivable to dispense with the addition of manganese and iron ion-containing water 2 in the method according to FIG. 2 if the manganese and iron ions are added according to the method according to FIG. 3 and then carried along in the AMP cycle.

In the process flow diagrams shown in FIGS . 4 and 5, cleaning methods according to the invention are provided, which include the process steps of the methods shown in FIGS . 1 and 2. For the sake of clarity, various process areas are highlighted by brackets numbered with Roman reference numbers. The processes presented in FIGS. 4 and 5 include in the process area I raw products and economically usable products, in process area II an AMP production, in process area III a phosphate ion ammonium ion cleaning and in process area IV post-cleaning.

According to the process flow diagram shown in FIG. 4, the water 1 to be cleaned is subjected to UV radiation 42 with the addition of water containing manganese and iron ions 2 , the reagent R2 containing zeolite, calcite and hydrated lime as well as a polymer solution 24 being added beforehand via corresponding metering devices 0 R2 and 024 can be added. The phosphate ion removal begins already during the UV radiation 42 in order to be completed in a phosphate cleaning stage 40 by precipitation of a phosphate-containing sludge 14 at a pH of 9.7 to 10. The pH value in the phosphate cleaning stage 40 is set by the hydrated lime present in the reagent.

It proves to be particularly advantageous if the phosphate purification stage 40 comprises a clarification reactor with a pulsating electromagnetic field, as known from WO 94/03252. However, a Lakos separator or a solid bowl centrifuge, as is known from WO 93/19853, is also conceivable. However, a clarification reactor of the type described below can also be used advantageously and remove phosphate, in particular calcium phosphate, and ammonium (as explained in the description of the method according to FIG. 1) from the water 1 to be purified, in particular by its magnetic devices.

For process control, the water inflow 08 and the pH 01 of the inflowing water 1 to be cleaned are measured. Since the part in the phosphate ion removal in the Phos phatreinigungsstufe 40 phosphate-containing sludge 14 formed to the supplied and fed back to be cleaned water 1.2 is, this recirculated sludge, gemes sen passes through the measuring device 010, an also as a process variable in process control. The pH in the phosphate cleaning step 40 is measured by the pH measuring device 03 . The phosphate-containing sludge 14 is then fed to a dewatering device 41 . The constituents that are solid after this drainage are removed from the process as fertilizer 16 .

It is advantageous to design the dewatering device 41 as a membrane press, as is known from WO 92/17264. Depending on the load on the water to be cleaned 1 , the UV radiation 42 can be dispensed with or this can be replaced or supplemented by treatment of the water 1 to be cleaned with oxygen, ozone or hydrogen peroxide. The catalytic oxidation of water rich in Mn, Fe and Mg ions as well as MnO₂ is particularly advantageous when combined with the use of hydrogen peroxide and UV radiation.

The pre-cleaned water 13 leaving the phosphate purification stage 40 (the amount flowing off is measured by the measuring device 013 ) is fed to the AMP precipitation stage 50 for ammonium ion removal. Likewise, depending on the design of the dewatering device 41 , the filtrate or fugate 15 is fed to the AMP precipitation stage 50 .

The AMP precipitation stage 50 is formed by a device of the type described below. It comprises the process steps of homogenization 51 and precipitation 52 in detail.

In the process step of homogenization 51 , the components fed to the AMP precipitation stage 50 , namely the pre-cleaned water 13 , the manganese and iron-containing magnesium phosphate solution 12 and purified water 9 are mixed thoroughly and the mixture to a pH value between 8.5 and 9, 2 set. The residence time of the liquid in this process step is preferably 5 minutes.

In the process step of precipitation 52 , the ammonium ions are removed from the water by precipitation and removal of AMP and water 11 largely free of ammonium and phosphate ions is obtained. The ammonium and phosphate ion-free water 11 is fed to an aftertreatment stage 45 which, for. B. comprises a clarification reactor known from WO 94/03252, the inflowing amount being detected by the measuring device 011 . Corresponding to the residual load of the water 1 to be cleaned, the ammonium-free water 11 in the after-treatment stage 45 is also added polymer solution 24 . By adding aluminum chloride 28 , the pH value, measured by the pH value measuring device 06 , is adjusted to neutral values by means of the metering device 028 in the after-treatment stage 45 .

Forming a sludge 17 , the post-treatment stage 45 can be removed 18 purified water. The sludge 17 is fed to the dewatering device 41 .

The cleaned water 18 from the aftertreatment stage 45 is passed through an activated carbon filter 46 and then subjected to a UV treatment 47 . It can be removed from the process as purified water 9 , controlled by a measuring device 09 '. The activated carbon filter 46 can be arranged in the clarification reactor comprising the aftertreatment 45 . It goes without saying that, depending on the load on the water to be cleaned 1 or the cleaned water 18, other post-cleaning stages are provided or the activated carbon filter 46 and / or the UV treatment 47 can be dispensed with.

To adjust the pH of the AMP precipitation stage 50 , as mentioned above, parts of the purified water 9 can be fed to the AMP precipitation stage 50 , the recirculated water quantity is measured by the measuring device 014 . The pH value is monitored by the pH value measuring device 04 at the beginning of the precipitation 52 and regulated by adding calcined and / or anhydrous soda or lye 22 . By adding acid 23 , sodium carbonate or sodium hydroxide, the pH in the second reaction space 52 b of the precipitation 52 can be adjusted. This is controlled by the pH value measuring device 05 . Furthermore, polymer solution 24 can be added between first reaction chamber 52 a and second reaction chamber 52 b. The removed from the precipitation te manganese and iron ion-containing AMP sludge 4 'is fed to a dewatering device 31 and then the dewatered mixture for drying and ammonia production a drying device 32 . In the drying device 32 , the temperatures are below 160 ° C, ammonia 6 is removed from the AMP. The remaining manganese and iron ion-containing magnesium phosphate 7 or R3 can be stored or slurried via a mixing device 34 with ammonium and phosphate-free water 11 and calcined and / or anhydrous soda or lye 22 and fed to the AMP precipitation stage 50 . The stored manganese and iron-containing magnesium phosphate R3 is returned to the AMP cycle via a metering device 0 R3. It is of course conceivable to use the method shown in FIG. 4 according to FIG. 3 for the production of magnesium hydrogenphosphate. It is also possible to feed manganese or iron oxide or calcined soda into the process via the metering device 0 R3.

In a collecting container 33 , ammonia water 8 forms as a usable product due to the addition of purified water 9 and ammonia 6 .

Furthermore, the basic conditions in the phosphate purification stage 40 are advantageous, since the pH of the pre-cleaned water 13 only has to be changed slightly during the transition to the AMP precipitation stage 50 , and thus chemicals are saved.

The method of FIG. 5 corresponds substantially to the presented in Fig. 4 purification process.

According to the process flow diagram shown in FIG. 5, the water 1 to be cleaned is subjected to UV radiation with the addition of water 2 containing manganese and iron ions, calcium carbonate 26 , calcium hydroxide 27 , a polymer solution 24 and a previously being used as the precipitation and cleaning agent Suitable zeolite 5 can be added via appropriate metering devices 024 , 025 , 026 and 027 . By adding aluminum chloride 28 via a corresponding metering device 028 , the pH value in the phosphate cleaning stage 40 is adjusted. The reagents 24 , 25 , 26 , 27 and 28 can be adapted to the load on the water 1 to be cleaned or the desired composition of the fertilizer 16 . It is Z. B. conceivable to add 28 iron chloride or iron sulfate instead of aluminum chloride. The pH of the AMP precipitation stage 50 can be adjusted by supplying a mixture of purified water and post-cleaned water 18 . By adding calcined and / or anhydrous soda or lye 22 , sodium carbonate or sodium hydroxide, the pH in the second reaction space 52 b of the precipitation 52 is adjusted. Furthermore - not shown in FIG. 5 - polymer solution 24 can be added between the first reaction chamber 52 a and the second reaction chamber 52 b.

As an extension to the previously described methods, the drying device 32 has two stages in the method presented in FIG. 5. The first drying stage 32 a, which preferably works at temperatures below 50 ° C, provides dewatered AMP 4 '' for further use. In the second drying stage 32 b, ammonia 6 is removed from the AMP in a known manner.

If the system AMP sludge 4 'or 4 ''or magnesium phosphate 7 is removed, the corresponding amount of magnesium phosphate must be fed back into the system. This is done by the metering device 021 in the form of magnesium hydrogen phosphate 21 , which is added to a reactor for crystallization 30 . By adding a calcined and / or soda ash or caustic 22 through the metering device 022 is set in the crystallization reactor 30, monitored by the pH meter 02, a pH from 8.5 to 9.2. The addition of ammonium ion-containing water 10 or pre-cleaned water 13 from the phosphate purification stage 40 or ammonia water 8 causes the formation of AMP sludge 4 in the crystallization reactor 30 , which, depending on the requirements in the specific process management, together with naturally occurring AMP 4 ''', Called struvite, the drainage device 31 is supplied. The partially purified water 5 originating from the crystallization reactor 30 is added to the water to be cleaned together with the water obtained by the drainage device 31 .

If necessary, phosphate ions are added via the metering device 023 by means of phosphoric acid 23 to the collecting container 33 with the supply of water 19 and ammonia 6 . If necessary, sulfuric acid can also be added as acid.

By means of the metering device 012 , magnesium phosphate solution 12 containing manganese and iron ions can be fed back to the crystallization reactor 30 . As a result, magnesium ions and phosphate ions can be recycled, including the crystallization reactor 30 . The use of the crystallization reactor 30 parallel to the AMP precipitation stage 50 enables the addition of required chemicals, such as phosphoric acid 23 or magnesium hydrogen phosphate 21 , in a particularly simple manner in order to adapt the process to changed stoichiometric conditions. It is also conceivable to use these chemicals and e.g. B. also feed magnesium oxide in other suitable places in the process. In this way, this method can also be used to produce AMP or magnesium hydrogen phosphate. Through the parallel connection of the crystallization reactor 30 to the AMP precipitation stage 50 , a change in the process sequence for starting the cleaning device or for producing magnesium hydrogen phosphate or AMP, which in particular contains manganese and / or iron ions and / or, as explained further below, is electromagnetically vorbe, is not necessary.

The methods of the type described above make it possible to obtain purified water that is less than 10 mg / l ammonium ions and less than 1.5 mg / l phosphate ions contains, in addition the chemical oxygen demand (COD) below 100 mg / l and the biological oxygen demand in 5 days (BSBS) is below 10 mg / l.

In FIGS. 6, 7 and 8, a Klärreaktor is presented, which may form a component of a device for carrying out the methods described above. In particular, the AMP precipitation stage 50 is realized by this clarification reactor. However, it is conceivable to use this clarification reactor advantageously in the pre-cleaning stage 40 or in the post-treatment stage 45 .

The clarification reactor comprises a substantially cylindrical reaction chamber 52 a, which is rotationally symmetrical with respect to a vertical central axis and opens at the bottom into a cone standing on the top, eight tubular cleaning columns 65 forming the reaction chambers 52 b, which are distributed circumferentially around the reaction chamber at a radial distance 52 a are arranged, as well as an above the reaction space 52 a to ordered, annular basin 51 for carrying out the method step of homogenization. In the middle of this basin, a conditioning chamber 53 generating a pulsating stimulating current is arranged, which is operatively connected in a known manner (WO 94/03252) with a vibrator 73 , a stirring device 75 consisting of motor and stirrer and a ring-shaped magnet 54 , and likewise in a known manner via a funnel-shaped flocculation chamber 55 opens into a central tube 56 , which extends through the reaction space 52 a to the tapered region tapering downwards.

The mouth end of the central tube 56 is surrounded by sieve-like, diamagnetic surfaces 60 , which form an expansion chamber 57 . The diamagnetic surfaces 60 forming the expansion chamber 57 are surrounded on the outside by ver chromed iron balls 59 . These iron balls 59 form a magnetic filter, the shape of which is essentially determined by the shape of the clarifier and corresponds to a truncated cone on the top with rectangular iron ball columns 59 a rising vertically on the clarifier tank wall. The truncated cone standing on the top is bounded at the bottom by a horizontally arranged diamagnetic surface. Below this surface is a sludge collection chamber 58 , to which a sludge discharge opening 70 leading to a screw pump 71 is connected at the bottom. According to the shape of the magnetic fil ters, the expansion chamber 57 is formed as a truncated cone. At the top, the magnetic filter is limited by a horizontally arranged, upper, diamagnetic boundary surface 60 a. Starting from this upper, diamagnetic boundary surface 60 a, the iron ball columns 59 a rise with a rectangular cross-section on the clarifier tank wall.

The radial arrangement of these iron ball columns 59 a can be seen from FIGS. 7 and 8. Furthermore, a breakup of the upper, diamagnetic boundary surfaces 60a shown in supervision is shown in these figures, so that the iron balls 59 underneath can be seen. Furthermore, the befind a handy iron balls 59 visible in the iron ball columns 59th Strip-shaped, in the main extension direction of the cleaning columns 59 a between the wall of the reaction chamber 52 a and the iron balls 59 arranged iron sheets 61 extend from the upper edge of the iron ball columns 59 a to annularly around the sludge opening 70 arranged magnet 81 , so that the iron balls 59 magnetic filter are magnetically coupled to the magnets 81 .

Around the reaction space 52 a around an annular, provided with baffles 64 mixing channel 63 is arranged, at the lower end of which is formed into a tubular cleaning column 65, a connection opening. The tubular cleaning columns 65 are arranged vertically, with a radial distance around the reaction space 52 a and each form a reaction space 52 b. The lower region of each tubular cleaning column 65 is in each case connected by an obliquely running connecting pipe 79 to the sludge collecting chamber 58 or the sludge discharge opening 70 . In the lower region of the tubular cleaning colons 65 there is a gas distribution nozzle 68 , through which air 69 can be blown into the tubular cleaning colons 65 . In the upper region of the tubular cleaning columns 65 is an overflow opening through which the water can flow into an overflow channel 76 in order to be removed from the clarification reactor as water free of ammonium and phosphate ions 11 .

On the tube walls of each tubular cleaning column 65 , 4 permanent magnets 67 are arranged quadrupole-like in 4 horizontal planes. The vertical distribution is shown in FIG. 6, the horizontal distribution in FIGS. 7 and 8. Furthermore, 4 magnets are each arranged in quadrupole-like fashion on the tube walls of the connecting tubes 79 in two planes. The course of the field lines is sketched out in FIGS. 6, 7 and 8. Each of the permanent magnets 67 of each quadrupole-like magnet arrangement is surrounded by a coil to form an electromagnet 66 , whereby the field formed by this permanent magnet 67 can be amplified. Each tubular cleaning column 65 and associated manifold 79 , the electromagnets 66 are arranged offset from a horizontal plane to the underlying by a permanent magnet 67 counterclockwise, so that a screw-like magnetic field is formed when the electromagnet 66 is switched on. Furthermore, the electromagnets 66 are formed or operable in such a way that the strength of the field generated by them H₂ (see FIG. 9) increases from top to bottom. The supply of the electromagnets 66 with electrical current is indicated by the power line 78 . The magnets 81 are also designed as electromagnets and can be controlled via power lines.

In the lower area of the clarification reactor or in the area of the magnets 81 , a vibrator 74 is connected to the clarification reactor in a manner so that both the iron balls 59 of the magnetic filter and the tubular cleaning columns 65 and the collecting tubes 79 can be excited to mechanical vibrations. Spreading of the mechanical vibrations is controlled by rubber buffers 80 .

Due to changing current directions in the magnets 81 , the iron sheets 61 are alternately polarized as magnetic north and south poles. The magnetic polarity of the iron sheets 61 is exemplarily shown at a time in FIGS. 7 and 8. Due to the time-varying polarity of the iron sheets 61 , the iron balls 59 and the space surrounding them - in particular the expansion chamber 57 , but also the free space of the reaction space 52 a arranged above the magnetic filter - are subject to an alternating magnetic flux. The magnetic or magnetizable components of the fluid flowing through the reaction chamber 52 a accumulate on the iron balls 59 due to the magnetic field. At least at the times at which the temporally Variegated Liche, magnetic flux is low, the to the iron balls 59 attached components of the fluid through the mechanical vibrations of the vibrator 74 of the Eisenku rules detached 59 and due to gravity in the direction of the sludge collection chamber 58 or the Schlammentleerungsöff opening 70 accelerated.

By the device described above, the mechani electrical, magnetic properties of the AMP be used in a particularly suitable manner if this Device operated in the manner explained below becomes. This takes advantage of the fact that AMP under influence external, temporally changeable, magnetic fields and mechanical vibrations due to its electrostrictive and piezoelectric properties and the incorporation of Manganese or iron during its crystallization is otherwise predominantly, loses ferroelectric properties. The  intrinsic, elec trical and mechanical vibration fields of the AMP crystal le - the natural frequencies that can be used advantageously are in essentially between 10 and 2000 Hz - promote in advantage the crystallization of the AMP. The one through domains education-related, macroscopic loss of ferroelectri properties causes the magnetic behavior the properties of the AMP crystals formed in this way dominated these crystals. The magnetic properties th of these crystals are determined by the strength of the alternating magnetic field acting on them diamagnetic to paramagnetic behavior.

For this reason, the pre-cleaned water 13 containing the magnesium phosphate solution 12 , manganese and iron after the process step of homogenization 51 in the conditioning chamber 53 and the flocculation chamber 55 is exposed to mechanical and electromagnetic vibrations. The mechanical vibrations are generated by the conditioning chamber 53 connected to the vibrator 73 and cause an electromagnetic field generated by the formed AMP crystals due to the piezoelectric effect. Furthermore, a time-varying magnetic field acts on the AMP due to the magnet 54 and the stirring device 75 . The pH of the fluid during the procedural step of homogenization 51 , in the conditioning chamber 53 and the flocculation chamber 55 is monitored by the pH measuring device 04 and, as already described above, via the addition of purified water 9 or post-cleaned Water 18 set.

The fluid is accelerated by funnel-shaped baffles in the central tube 56 and moves downward helically due to the rotary movement of the stirring device 75 in order to be braked in the expansion chamber 57 . The flocculation or crystallization of the AMP is promoted by the acceleration and deceleration in a known manner.

The magnetic filter removes the already formed AMP crystals from the fluid flowing through the magnetic filter or the reaction chamber 52 a in the manner described above. At the same time, the magnetic alternating field originating from the magnetic filter and the mechanical vibrations of the vibrator 74 promote the crystallization or precipitation of AMP molecules still dissolved in the fluid in the manner described above.

The pre-cleaned suspension passes through an overflow 62 due to hydrostatic pressure through the mixing channel 63 into the tubular cleaning columns 65 , in which it passes through the magnetic field formed by the electromagnets 66 and permanent magnets 67 in ascending order. The pH of the suspension in the tubular cleaning columns 65 is measured by the pH measuring device 05 and by the addition of calcined and / or anhydrous soda or lye 22 to a value between 8.8 and 9.2, in particular between 9.0 and 9.2, set to prevent the pH value from falling back, particularly in the case of very heavily contaminated wastewater. Due to its hydrostatic pressure, the water is conducted via an overflow from the cleaning columns 65 into the overflow channel 76 and can be removed from it as water 11 free of ammonium and phosphate ions.

The electromagnets 66 are excited in succession, from top to bottom with a pulse at a frequency of preferably about 50 Hz, so that an area with a high magnetic field moves helically from top to bottom through a reaction chamber 52 b. In Fig. 9, the maximum value H formed by the magnets of the magnetic field is represented as the sum of the fabric by the permanent magnets 67 th magnetic field H2 and the magnetic field H1 is formed by the electrical magnets 66. The strength of the magnetic field is preferably between 600 kA / m and 1000 kA / m.

The magnetic pump formed in this way accelerates due to the magnetic field dependent dia- or para magnetic behavior on the one hand, the sinking of the AMP crystals in the suspension in the direction of gravity, on the other hand, the pulsating magnetic field with the through the body of the clarification reactor transmitted vibrations of the vibrator 74 in the manner mentioned above, the flocculation of any AMP molecules still contained in the suspension.

In the method described above, it may further be advantageous to subject the recirculated magnesium and phosphate fractions supplied to the AMP precipitation stage 50 to a magnetic pretreatment, such as premagnetization by passage through a magnetostatic field. It is conceivable, inter alia, to carry out the premagnetization in the pre-cleaning stage 40 .

If it is possible due to the low load on the water to be cleaned 1 to dispense with the magnetic pump in the precipitation of the AMP, it is of course possible to use the tubular cleaning columns 65 for the post-treatment step 45 and z. B. to be provided with activated carbon filters.

The disclosure content of publications cited above WO 92/17264, WO 94/03252 and WO 93/19853 is by their Erwäh included in the present disclosure.

Reference list

Process area
I raw and economically usable products
II AMP production
III Phosphate-ammonium cleaning
IV post-cleaning

Products
1 water to be cleaned
2 water containing manganese and iron ions
4 manganese and iron ion-containing AMP sludge made of MgHPO₄ or MgO
4 ′ manganese and iron ion-containing AMP sludge, circulated
4 ′ ′ AMP
4 ′ ′ ′ natural AMP, struvite
5 partially purified water
6 ammonia
7 Magnesium phosphate containing manganese and iron ions
8 ammonia water
9 purified water
10 water containing ammonium ions
11 Water free of ammonium and phosphate ions
11 ′ ammonium and phosphate ion-free water
12 magnesium phosphate solution containing manganese and iron ions
13 pre-cleaned water (containing nitrate)
13 ′ pre-cleaned water
14 phosphate-containing sludge (with ammonium contents)
15 filtrate / fugate
16 fertilizers
17 mud
18 purified water
19 Mixture of purified and purified water ( 8 , 18 )

Reagent
19 water
20 manganese, iron oxide
21 MgHPO₄, MgO
22 calcined and / or anhydrous soda or lye
23 acid (H₃PO₄, H₂SO₄, HCl)
24 polymer solution
25 zeolite
26 calcite, CaCO₃
27 hydrated lime, Ca (OH) ₂
28 ALCL₃
R1 mixture of manganese, iron oxide, magnesium hydrogen phosphate and calcined and / or anhydrous soda
R2 mixture of zeolite, calcite and hydrated lime
R3 Magnesium phosphate containing manganese and iron ions

Procedural steps
30 crystallization reactor
31 drainage device
31 ′ decomposition device
32 drying device
33 collecting container
34 mixing device
40 pre-cleaning stage, phosphate cleaning stage
41 drainage device
42 UV radiation
45 post-treatment level
46 activated carbon filter
47 UV treatment
50 cleaning level, AMP precipitation level
51 homogenization
52 precipitation

Measuring devices
01 pH value, inflow
02 pH value, crystallization reactor
03 pH value, phosphate cleaning level
04 pH value, reaction space 52 a
05 pH value, reaction space 52 b
06 pH value, post-treatment level
08 Amount of water inflow
09 Amount of the drained, purified water
09 ′ pH value, purified water
010 recirculated sludge
011 Amount of water free of ammonium and phosphate ions
013 Amount of water draining off, containing ammonium
014 recirculated purified or post-cleaned water quantity

Dosing devices
07 Magnesium phosphate
012 magnesium phosphate
021 magnesium hydrogen phosphate
022 calcined and / or anhydrous soda or lye
023 acid (phosphoric acid, sulfuric acid, hydrochloric acid)
024 polymer solution
025 zeolite
026 calcite, calcium carbonate
027 calcium hydroxide
028 aluminum chloride
0 R2 reagent R2
0 R3 reagent R3

Sewage reactor
52 a reaction space
52 b reaction space
53 Conditioning chamber
54 magnet
55 flocculation chamber
56 central tube
57 expansion chamber
58 sludge collection chamber
59 iron ball
59 a iron ball columns
60 diamagnetic surface
60 a upper, diamagnetic boundary surface
61 sheet iron
62 overflow
63 mixing channel
64 baffles
65 tubular cleaning columns
66 electromagnets
67 permanent magnets
68 Gas distribution nozzle
69 air
70 sludge discharge opening
71 worm pump
73 vibrator
74 vibrator
75 stirring device
76 overflow channel
78 power line
79 connecting pipes
80 rubber buffers
81 magnets

Claims (11)

1. A method for cleaning water contaminated with phosphate ions and ammonium ions ( 1 ), in which
ammonium ions are removed from the water in a purification stage ( 50 ) by the formation and precipitation of ammonium magnesium phosphate (AMP) ( 4 ′) and removal of the AMP or a sludge containing the AMP and water ( 11 ) which has largely been freed from ammonium ions is obtained,
the precipitated AMP decomposes, at least partially, with the release of ammonia ( 6 ) or ammonium ions and
the magnesium and phosphate fractions ( 7 , 12 ) thus formed are fed to the cleaning stage in the circuit,
characterized
that the water to be cleaned in a pre-cleaning stage ( 40 ) upstream of the cleaning stage is largely freed of phos phations. 2. Cleaning method according to claim 1, characterized in that the water to be cleaned ( 1 ) or the pre-cleaned water ( 13 ) before or when it enters the cleaning stage ( 50 ) for storage or attachment to or in the cleaning stage ( 50 ) formed AMP crystals, divalent metal ions, preferably manganese and / or iron ions, are added. 3. Cleaning method according to claim 2, characterized in that the metal ions with the magnesium and phosphate portions ( 7 , 12 ) are supplied in the circuit of the cleaning stage. 4. Apparatus for cleaning water contaminated with phosphate ions and ammonium ions ( 1 ), consisting of a cleaning stage ( 50 ) and a decomposition stage ( 31 , 32 ) and a circuit ( 4 ', 7 , 12 ), in which
ammonium ions are removed from the water in the cleaning stage ( 50 ) by the formation and precipitation of ammonium magnesium phosphate (AMP) ( 4 ′) and removal of the AMP or a sludge containing the AMP and water ( 11 ) largely freed from ammonium ions is obtained,
the precipitated AMP decomposes, at least partially, with the release of ammonia ( 6 ) or ammonium ions and
the magnesium and phosphate fractions ( 7 , 12 ) thus formed are fed to the cleaning stage in the circuit, in particular for carrying out the method according to one of claims 1 to 3,
characterized,
that the cleaning stage ( 50 ) comprises a filter made of magnetized or magnetizable particles ( 59 ) for cleaning the water sers of impurities. 5. The device according to claim 4, characterized in that a vibrating device ( 74 ) with the magnetized or magnetizable particles ( 59 ) is so connected that they are set in oscillatory movements. 6. Device for cleaning water contaminated with phosphate ions and ammonium ions ( 1 ), consisting of a cleaning stage ( 50 ) and a decomposition stage ( 31 , 32 ) and a circuit ( 4 ', 7 , 12 ), in which
ammonium ions are removed from the water in the cleaning stage ( 50 ) by the formation and precipitation of ammonium magnesium phosphate (AMP) ( 4 ′) and removal of the AMP or a sludge containing the AMP, and water ( 11 ) largely freed from ammonium ions is obtained,
the precipitated AMP decomposes, at least partially, with the release of ammonia ( 6 ) or ammonium ions and
the magnesium and phosphate fractions ( 7 , 12 ) thus formed are fed to the cleaning stage in the circuit,
in particular for performing the method according to one of claims 1 to 3,
characterized,
that the cleaning stage ( 50 ) has a pump made up of magnets arranged in several planes ( 67 ), in which the planes electromagnets ( 66 ) with time-changeable magnetic fields, preferably with magnetic fields of varying strength, are assigned. 7. The device according to claim 6, characterized in that the cleaning stage ( 50 ) comprises a reaction chamber ( 52 b) with a reaction chamber wall and the pump each level an integer number of magnets arranged on the reaction chamber wall ( 67 ) with alternating center of the reaction chamber Showing north and south Poland and per level at least one electromagnet ( 66 ) is assigned a magnet ( 67 ) derge stalt that the field of the electromagnet ( 66 ) can be superimposed on the field of the magnet ( 67 ) reinforcing. 8. A method for purifying water contaminated with at least ammonium ions ( 1 , 13 ), in which with the addition of phosphate and magnesium ions ( 12 , 21 , 23 , R1, R3) by formation and precipitation of AMP ( 4 ') and removal of the AMP or a sludge containing the AMP, ammonium ions are removed from the water and water largely freed from ammonium ions ( 11 ) is obtained, characterized in that metals, preferably manganese, are added to or deposited in or on the AMP crystals formed and / or iron. 9. Cleaning method according to claim 8, characterized ge indicates that these metals act as ions in which the AMP surrounding water.   10. Cleaning method according to claim 9, characterized ge indicates that the metals in the form of divalent metal compounds, preferably MnO and / or FeO, the process be added. 11. Cleaning method according to one of claims 8 to 10, characterized in that the AMP and the metals during formation and / or precipitation magnetic, elec trical, electromagnetic and / or mechanical fields or exposed to vibration fields.