DE10244915A1 - Filtering process for separating polar organic compounds from effluent produced from biological clarifying plant comprises pre-filtering waste via micro-filter and adsorption-pressure filtering using deformable filter material - Google Patents

Abstract

Filtering process comprises pre-filtering waste via a micro-filter and adsorption-pressure filtering using a deformable filter material. Independent claims are also included for: (1) filter cartridge for the adsorption-pressure filtering stage; and (2) filtration unit consisting of the filter cartridge and a micro-filter which is connected to the cartridge via a line.

Description

The invention describes a filtration process for the separation of polar organic compounds in liquid or solid form from waste water biological treatment plants using a microfiltration in combination with a pressure filtration with a suitable filter material, as well as a filter cartridge to use the filtration process.

From the Federal Environment Agency's 2000 annual report for the elimination of active pharmaceutical ingredients from wastewater, that active pharmaceutical ingredients with municipal wastewater treatment the essential cleaning step "microbial metabolism" of the organic Pollutant load (biological wastewater treatment) partially unchanged or metabolized over standing. Water with a drug load thus enters the circulation via the receiving water of the surface water from which drinking water again in the densely populated countries is won.

Because part of the drug ingredients (e.g. antibiotics) physiological effects even in molecular quantities trigger capable, exists for Humans and animals pose an acute danger due to increasing immunization against them Active pharmaceutical ingredients. Practical procedures for separating such Biodegradable drug ingredients on a μg / l scale therefore wanted.

Membrane separation processes win in recently, Time is becoming increasingly important for the purification of water. Thereby with increasing separation effect in the sequence microfiltration (separations <0.2 μm) Ultrafiltration (separations 0.1-0.01 μm), nanofiltration (0.01-0.001 μm) and reverse osmosis (<0.001 μm) each increasing technical effort and thus higher costs and lower flow volumes to be expected in the membrane separation process.

In terms of molecular size, there are only membrane separation processes with separations in the range <0.001 μm, i.e. nanofiltration and reverse osmosis for the elimination of active pharmaceutical ingredients in each case with acceptance from technically opposite the microfiltration more complex and therefore disadvantageous processes suitable.

Examples of such partitions will be in the accompanying book for the 4th AACHEN CONFERENCE on urban water management and process engineering, 11-12 September 2001, membrane technology in water treatment and wastewater treatment (editors T. Melin and M. Dohmann) in the contribution A13 by S. Schiewer, M.Gallenkemper, T. Wintgens and T. Melin based on the separation of endocrine active nonylphenol (estrogenic activity). In contribution A 16 by A. Schäfer, Sydney will be opportunities and limits on the elimination of trace pollutants in wastewater treatment and water treatment with membranes, here with nanofiltration and reverse osmosis. Because in wastewater due to metabolizations and mining operations the molecular size of the organic Pollutants decrease, the separability is even with the nanofiltration and reverse osmosis less than surface water treatment. Microfiltration as in the following claimed teaching alone are not for separation of active pharmaceutical ingredients with molecular sizes of << 0.1 μm.

In the DE 199 62 791 A1 the control of a process combination of biological water purification and unspecified adsorption steps for the water treatment of chlorine-free drinking water and as a preliminary stage for the purest water production is described. In particular, the synchronization of backwashing of the adsorption steps with biology is protected. Cleaning effects on the ppb scale [μg / l] are achieved.

A method and a device for the continuous biological purification and reuse of wastewater containing surfactants are described in US Pat DE 198 34 945 A1 described. For this purpose, the impurities contained in the water are attached to the adeorbent. The adsorbent is then biologically cleaned. The degree of surfactant contamination is reduced in accordance with the residence time of the adsorbent suspension in the bioreactor.

A method and a device for the continuous biological purification and reuse of wastewater containing surfactants are described in US Pat DE 198 34 945 A1 described. For this purpose, the impurities contained in the water are attached to the adsorbent. The adsorbent is then biologically cleaned. The degree of surfactant contamination is reduced in accordance with the residence time of the adsorbent suspension in the bioreactor. Here, an organic load, namely a proportion of surfactant, is specifically obtained in the cleaning stage. A drug drug separation would not be possible in this way.

In the GB P 2 191 109 discloses a multilayer filter in which the individual filter layers consist of crosslinked polyether polyurethanes. This procedure should be similar to that in the US 4,303,533 , in which a two-layer filter made of elastic foam is described as a filter for waste water from paper mills, the filter can be used as widely as possible. In the latter document, the compression and decompression of the filter material is used to regenerate the filter. The filtration takes place discontinuously and is completed by pressing out the filter material for filter regeneration. Compared to the claimed teaching, the separation does not take place under pressure.

According to the DE 290 13 35 Mixtures of hydrophobic liquids in water can be separated by filtration over water-repellent polyurethane foam particles. The hydrophobic liquid is in the foam is retained at the water passage and can then be obtained by pressing out the compressible material. Compared to the claimed teaching, the separation is also not under pressure.

In the EP 0 608 441 B1 and the DE 197 38 067 A1 fiber materials are used for deep filtration in the upstream. The fiber material is used in the form of defined structures, in the caverns and cavities of which the suspension is fixed. The smaller surfaces of such filter media compared to foams limit the range of suitability for the separation of dissolved substances.

The DE 101 01 313 A1 describes a filtration method and a filtration device for separating solid, liquid and gaseous substances from a fluid. Here, the fluid is passed through at least one compressible filter, the filter effectiveness being able to be set as a function of the pressure applied to the filter. In a preferred embodiment, the compressible filter consists of polyurethane foam. In the examples named to explain the process, loads from laundry and dyeing waste water and metal complexes from water are separated in the ppm range (mg / l). Our own experiments described in Example 1 of the teaching claimed here show that the method for separating active pharmaceutical ingredients in the μg / l range is not suitable, since the ability to fix the polar organic pollutant load is exhausted after technically irrelevant short downtimes.

Common to the known methods, that so far there has been no suitable and practical method of separation of poorly degradable active pharmaceutical ingredients with a harmless Residual concentration from waste water gives. Especially for dissolved Active pharmaceutical ingredients do not have suitable filtration processes, which is a significant reduction in drug load in waste water, in particular from hospital wastewater, allow.

Based on this, it was task the present invention to provide a filtration process which effectively separates difficult-to-decompose polar enables organic compounds. It was also an object of the present invention for such Filtration particularly suitable devices are available too put.

This task is accomplished through the filtration process with the features of claim 1, the filter cartridge with the features of claim 11 and the filtration unit with the features of Claim 18 solved. The other dependent ones Expectations show advantageous developments. In claims 21 and 22 describes the use of the method according to the invention.

According to the invention is a filtration process for the separation of polar organic compounds in liquid or solid form, especially pharmaceutical residues, from waste water biological sewage treatment plants provided. Pharmaceutical residues are included in this registration both active pharmaceutical ingredients but also their cleavage and decomposition products to understand.

• a) einer Vorfiltration der Abwässer aus bilogischen Kläranlagen über einen Mikrofilter und
• b) einer sich anschließenden Adsorptions-Druckfiltration unter Verwendung eines verformbaren Filtermaterials.

The method according to the invention is based on the combination of two filtration steps, namely

• a) a pre-filtration of the wastewater from bilogical sewage plants via a microfilter and
• b) a subsequent adsorption pressure filtration using a deformable filter material.

Pressure filtration in the process of the invention means that Filter material is kept permanently under compression, whereby the filtration properties of the material properties of the filter material, on the amplitude of the compression applied to the filter material and depends on the length of time that the active ingredients remain on the filter.

In contrast, the method according to the invention offers reliable separation of dissolved drug residues with membrane separation processes relatively low molecular weights in the range between 300 and 400 daltons.

An immersion filter, for example in the form of an immersion membrane, is preferably used as the microfilter. The immersion filter is preferably integrated in an aeration tank of a biological sewage treatment plant, the wastewater being sucked through the immersion filter at a pressure of 0.1 to 0.6 bar, particularly preferably 0.3 to 0.4 bar. The permeability is about 60 l / m ² h - bar.

Prefiltration follows fixation of drug residues in the μm range by adsorption on a deformable filter material. The extent of the desired Adsorption is by pressurizing the filter adjustable.

Coming as a deformable filter material all deformable filter materials known from the prior art in question. Filter materials based on the based on the foams defined in DIN 7726. Such foams have according to DIN 53421 Compressive strengths in the range between 15 and 80 kPa. For example only Foam plastics can be used as filter materials, e.g. foamed Polyurethane or native foamed Polymer materials, e.g. B. sponges, called. However, it is also possible to use a carbonate adsorbent use.

For the separation of the polar organic compounds, this is the case with the adsorption pressure filtrate filter material used is preferably permanently compressed at a pressure between 0.1 and 10 kPa. The total residence time of the contaminated waste water in the pressure filter can be up to 500 min.

The one used in pressure filtration Filter material can preferably be cleaned in that the filter material without pressurization in the uncompromised state using a organic solvent, particularly preferably ethyl alcohol, is regenerated.

In an advantageous further training the process becomes the flow rate and thus the residence time of the wastewater in the adsorption pressure filtration by means of at least one pump and / or at least one valve controlled.

It is further preferred that the waste water the adsorption pressure filtration in the form of a cycle several times passes. This can improve the efficiency of the separation of the polar organic Connection can be improved.

According to the invention, a filter cartridge is also used for the Adsorption pressure filtration provided from a housing that a deformable filter material and a compression unit for compression of the filter material. The housing has at least one an inlet and outlet opening, those with quick release coupling elements for easy coupling are connected to supply and discharge systems.

The filter cartridge can be so simple Can be integrated into existing filtration systems. The quick release coupling elements thus enable simple Change and exchange of the entire filter cartridge.

The housing preferably consists of Filter cartridge made of a glass fiber reinforced plastic, which through the the compression unit can withstand the pressure generated.

The compression unit is there preferably from at least one stamp and at least two on opposite Perforated plates enclosing the filter material. The deformable filter material is thus between the pressure stable Perforated plates fixed under pressure using the compression unit. The wastewater settles when it passes the deformable filter material compared to the housing size one longer Stretch back. This ensures effective use of the filtration space.

In an advantageous further training is the pressure stamp with regard to an adjustable degree of compression controllable.

Regarding the filter materials used be on the previous list the foams referenced.

According to the invention, there is also a filtration unit from at least one previously described filter cartridge and at least provided a microfilter, the microfilter with the Filter cartridge over a line is connected and the filter cartridge to the microfilter is connected downstream. It is preferred that the microfilter is an immersion filter is. The filtration unit can preferably be located directly in the aeration tank a biological sewage treatment plant be integrated.

It is also advantageous if the filtration unit additionally integrated pumps and / or valves to control the flow rate through the filter cartridge and / or the microfilter.

The method according to the invention is used for the Purification of waste water of polar organic compounds, especially drug residues.

The object of the invention is based on the following figures and examples are explained in more detail without this the embodiments mentioned here to restrict.

1 shows a schematic representation of the process flow according to the invention for the separation of polar organic compounds from waste water from biological sewage treatment plants;

2 shows a sectional view of the filter cartridge according to the invention.

In 1 the process sequence according to the invention is schematically outlined. In the aeration tank of the biological sewage treatment plant 24 is the immersion filtration module 25 integrated. The waste water from this unit, which is pre-cleaned but still contains active pharmaceutical ingredients, is discharged via a pump 20 , The wastewater is controlled by a valve 26 the influx 23 the filter cartridge holder 21 fed. In the bracket 21 is the filter cartridge according to the invention 10 fixed, with the coupling elements 11 . 18 a tight connection between the filter cartridge 10 and the inflow and outflow 23 . 22 is guaranteed.

The filter cartridge according to the invention 10 is in 2 shown as a sectional drawing. Via the coupling element 11 the feeder becomes the filter cartridge 10 fixed in the holder (not shown) and connected to the inlet (not shown). Via an inner tube 12 is the wastewater via the feed coupling element 11 in a pressure room 14 below a pressure-stable perforated plate 15 passed, the lower perforated plate 15 rests on an abutment ring. Through openings 13 in the lower part of the inner tube 12 the wastewater enters the pressure chamber 14 , Due to the water pressure in the inner pipe via a further pump (not shown), the waste water is discharged through the filter material located in the interior of the filter cartridge 16 pressed and filtered. The required compression is applied to the filter material 16 by a pressure stamp 17 on the upper perforated plate 15 and thus on the filter material 16 homogeneously transmitted. The wastewater cleaned in this way passes through the coupling element 18 the discharge via the drain (not shown), with the coupling element 18 the filter cartridge 10 fixed in the holder (not shown).

Comparative Example 1

Pharmaceutically active separation through biology and immersion microfiltration

The wastewater with the drug load is a sewage treatment plant drain taken. This wastewater is exclusively biologically cleaned. The filtration integrated in the aeration tank. of the sewage treatment plant processes via a Immersion microfiltration does not result in significant drug separation from the sewage. For dichlofenac, Phenazone, carbamazepine, sota-lol, Erythromycin and trimethoprin. were unchanged or practically unchanged concentrations determined. Some other active pharmaceutical ingredients e.g. B. roxithromycin, Bisoprolol, Atenolol and Metoprolol were only around 10-20% off the Water depleted.

Comparative Example 2

Arzneiwirkstoffabtrennunq through biology and pressure filtration with a filter cartridge

Also direct pressure filtration of sewage treatment plant processes without Passage of immersion filtration over a filter cartridge biased at 3 kPa (0.5 l / h, 1 h) resulted unsatisfactory results insofar as the tool life is insufficient the filter under the claim of separating active substances in the μg range given is. About that In addition, the separation results that could only be achieved at short notice were included 30-85% also unsatisfactory.

example 1

Arzneiwirkstoffabtrennunq through biology, immersion microfiltration and pressure filtration with filter cartridge

First the pressure filtration with one suitable foamed Polyurethane as filter material after the immersion micro-filtration after biological purification, allowed for a period of 1 Hour a separation of the drug load from the wastewater between 44 and 100%. A pressure of 3 kPa was applied to the filter material applied and a flow rate of 0.5 l / h of wastewater through the filter material. The active ingredient separation described in detail in Table 1 was more than 8 days (service life of the filter cartridge) possible.

The analysis (concentration determinations of the active pharmaceutical ingredients) was carried out using a liquid chromatograph coupled triple quadrupole mass spectrometer API365 (LC-MS / M5) from Applied Biosystems. The wastewater referred to as the "sewage plant exit" is exclusive biologically cleaned. With "Filtrat" this becomes the process the pressure filtration after passage of the filter combination (biology / immersion microfiltration / pressure filter cartridge) withdrawn wastewater referred to. The cleaning effect is also indicated in the form of percentage separation from the water.

Table 1 shows one using a filter combination of a microfilter and a pressure filter cartridge wastewater treatment plant drain cleaned with hydrophilic PUR as filter material and the degree of cleaning in percent.

Table 1

Example 2

The following example was a comparison the suitability of different filter materials for the separation of active pharmaceutical ingredients with exclusive Pressure filtration carried out. The starting point was pure solutions of the active pharmaceutical ingredients in water.

The Filtration Procedure In a first series of experiments, the inflow of air with 3kPa loaded 10 cm high filter made of polyester urethane foam or from a carbonate adsorbent Hydrolit CA from Akdolit 0.5 l / h of the solution with a total load of 6600 μg / l of active pharmaceutical ingredients a period of 480 minutes. The analysis is carried out using the with a liquid chromatograph coupled triple quadrupole mass spectrometer AP1365 (LC-MS / MS) from Applied Biosystems. The results are summarized in Table 2, the amount of drug active substance presented 6600μg / l each shows, where the fixed amount of drug active ingredient is given in% is.

Table 2

With the hydrolite there is a only insignificantly less adsorptive fixation of the active pharmaceutical ingredients than with the polyester urethane.

In a further series of experiments Drug separations with a foamed polypropylene and polyurethane / foams compared.

The Adsorption Procedure was the influx of the filter cartridges charged with 3 kPa (10 cm filter height) 0.5 l / h of the solution of the active pharmaceutical ingredient at a defined concentration (10 μg / l each) via a Period of 60 minutes. The volume of metered in the circuit Water was 400 ml, that for volume of sample taken from the analysis sample 100 ml. The analysis was carried out again using LC-MS / MS. The results of the separation in% contains Table 3.

Table 3

The hydrophilic polyurethane foam separates active pharmaceutical ingredients much better than a hydrophobic one provided polyurethane foam and the polypropylene foam from aqueous solution.

Claims (22)

Filtration process for the separation of polar organic Connections in liquid or solid form, in particular pharmaceutical residues, from waste water biological sewage treatment plants by combination a) a pre-filtration of the waste water through a Microfilter and b) a subsequent adsorption pressure filtration under Use of a deformable filter material. Filtration method according to claim 1, characterized in that an immersion filter is used as the microfilter. Filtration process according to at least one of the preceding Expectations, characterized in that the immersion filter in an aeration tank a biological sewage treatment plant is integrated and the wastewater with a pressure of 0.1 to 0.6 bar, preferably 0.3 to 0.4 bar, is sucked through the immersion filter. Filtration process according to at least one of the preceding Expectations, characterized in that foam plastic as a deformable filter material, e.g. foamed Polyurethane can be used. Filtration method according to at least one of claims 1 to 4, characterized in that as a deformable filter material native foamed Polymer materials, e.g. sponges, be used. Filtration method according to at least one of claims 1 to 5, characterized in that as a deformable filter material a carbonate adsorbent is used. Filtration process according to at least one of the preceding Expectations, characterized in that in the adsorption pressure filtration compresses the filter material with a pressure between ... and 10 kPa becomes. Filtration process according to at least one of the preceding Expectations, characterized in that the filter material by means of an organic solvent is regenerated in the non-compressed state. Filtration process according to at least one of the preceding Expectations, characterized in that a flow rate in the adsorption pressure filtration means controlled at least one pump and / or at least one valve becomes. Filtration process according to at least one of the preceding Expectations, characterized in that the waste water is the adsorption pressure filtration goes through several times in one cycle. Filter cartridge for adsorption pressure filtration a deformable filter material and a compression unit to compress the filter material housing with at least one inlet and outlet opening, those with quick release coupling elements for easy coupling are connected to supply and discharge systems. Filter cartridge according to claim 11, characterized in that the housing from a glass fiber reinforced Plastic is made. Filter cartridge according to at least one of claims 11 or 12, characterized in that the compression unit from at least a pressure stamp and at least two on opposite sides of the filter material inclusive Perforated plates exist. Filter cartridge according to at least one of claims 11 to 13, characterized in that the pressure stamp with respect to a adjustable degree of compression is controllable. Filter cartridge according to at least one of claims 11 to 14, characterized in that the filter material from at least a foam plastic, e.g. foamed polyurethane. Filter cartridge according to at least one of claims 11 to 15, characterized in that the Filter material consists of at least one natively foamed foam plastic, for example a sponge. Filter cartridge according to at least one of claims 11 to 16, characterized in that the filter material from a carbonate Adsorbent exists. Filtration unit from at least one filter cartridge according to at least one of the claims 11 to 17 and at least one microfilter, the microfilter with the filter cartridge a line connected and the filter cartridge downstream of the microfilter is. Filtration unit according to claim 18, characterized in that the microfilter is an immersion filter. Filtration unit according to at least one of claims 18 or 19, characterized in that the filtration unit pumps and / or Valves to control the flow rate through the Has filter cartridge and / or the microfilter. Use of the method according to one of claims 1 to 10 for the purification of waste water of polar organic compounds. Use according to claim 21 for the purification of wastewater of drug residues.