DE4205787C1 - Water purification - uses micro biological degradation to decompose hydrocarbon(s) and surfactants present - Google Patents

Abstract

To decompose hydrocarbons and surfactants present in water, the water is emulsified in a mechanical emulsifier and then passed to at least two decomposition stages. Each these stages has a reactor with aerobically degrading microorganism. The mixture is separated and then, by flotation, gives a sedimentation with a low water content and a liq. The two phases, with a low water content, are returned separately or together ot the reactor. The separated liquid is passed through at least one further degrading stage with anaerobic decomposing micro organisms, before passing into further decomposition stages or the water pipeline. USE/ADVANTAGE - For cleaning water which has been soiled, e.g. in firefighting practice where fuel burning on a water surface has been extinguished with foams to give a toxic combination which can pass into public water supplies, or for cleaning water used in vehicle washing assemblies, or waste water which has penetrated used oils and cleaners. The system purifies soiled water to give a clear water free of residue, through micro biological degradiation.

Description

The invention relates to a process for the degradation of water contained hydrocarbons and surfactants, wherein at least two levels of degradation are provided, each degradation stage has a reactor with aerobic microorganisms, whose leaving mixed phase separated in a separator becomes a low-water and high-water phase, wherein the low-water phase is recycled to the reactor and the water-rich phase in the following stage of decomposition or in the sewerage network is routed.

Such a method is known from DE-OS 35 18 623.

In different areas fall with hydrocarbons and Surfactants contaminated problem wastewater. For example gets fuel on a fire fighting exercises Water template burned. The big fire thus generated is with surfactant-containing foam extinguishing agents. That turns into inevitably an intimate mixture or an emulsion Fuel residues, original water, fats, proteins and surfactants, which is not in a municipal because of the high toxicity Wastewater treatment plant may be initiated. This special wastewater can currently only through expensive combustion or chemical be disposed of with a high proportion of waste.

Furthermore, there is a need for disposal of, for example in car washes or at collection points for waste oils and cleaners accruing special wastewater.

The invention is therefore based on the object, the beginning to supplement described method such that with hydrocarbons and surfactants contaminated problem effluents by microbial Substance degradation can be almost completely and almost residue-free clarified.  

This object is achieved by the features specified in claim 1 solved a method.

In addition to the method mentioned above is as a pretreatment a mechanical emulsification provided to the in the Usually more or less strongly emulsified wastewater in one to transfer as fine and stable emulsion, thereby the subsequent biodegradation is supported.

Furthermore, in addition to the known method, the water-poor phase separated according to their floating and non-buoyant Separate shares from the mixed phase. This measure also makes the water-poor flotation phase returned to the reactor, so that the efficiency of the Substance degradation is increased in the reactor.

In addition, the invention provides that in at least a mining stage a residual mining device with anaerobically degrading Microorganisms is provided. This achieves, that anaerobic microorganisms in the reactor because of there existing amount of oxygen were not metabolizable, here without oxygen which is still in the water-rich phase Fragments of broken up in the reactor hydrocarbons processed. As a result, the expiring Water from the last mining device under observation of legally prescribed discharger limit values directly in the sewage network are fed.  

Advantageous embodiments of the invention are in the subclaims 2-4 listed.

An embodiment of the invention will be described below explained in more detail by drawings. Show it

Fig. 1 shows a device for the preparation of multiphase effluents in a block diagram,

Fig. 2 shows the device of FIG. 1 in concretized form,

Fig. 3 is a sketched emulsifier,

Fig. 4 shows a sketched reactor,

Fig. 5 is a scrap separator,

Fig. 6 is a sketched residual removal device.

In Fig. 1, a device for the degradation of hydrocarbons and surfactants contained in water is shown in a greatly simplified form. This device is used for the multi-functional treatment of multiphase problematic wastewater, which, for example, as mentioned above, incurred in fire-fighting exercises of the fire department or in vehicle washing systems.

The more or less strongly emulsified problem wastewater is first in the emulsifier E1 mechanically in a fine, possible stable emulsion transferred to the subsequent microbial Support pulping.  

At the emulsifier E1 close two consecutive To dismantling levels. Each of the two stages of degradation indicates first a reactor mixed with anaerobic microorganisms B1 or B2 on. Subsequently, the from the reactor B1 or B2 leaving mixing phase in a separator T91, T92 or T93, T94 in a water-poor flotation phase, a low-water Sedimentation phase and in a water-rich phase separated. To maintain the metabolic performance of microorganisms the two low-water phases are separated or back together in the reactor B1 or B2. The water rich Phase, on the other hand, is transferred to a remanufacturing device R11, R12 or R13, R14 passed, where anaerobic microorganisms complementary to the aerobic microorganisms in the reactor B1 or B2 cause a further reduction. By training two one behind the other connected degradation stages, it is possible to Milieubedingungen in particular the two reactors B1 or B2 and in the two residual mining devices R11, R12 or R13, R14 individually adjust that a specific Target group of chemical compounds preferably degraded becomes.

In addition to FIG. 1, FIG. 2 shows details and details of the device in question. In this drawing, first, the previously mentioned devices are again, namely the emulsifier E1, further from the first stage of the reactor B1, the separator with T91 and T92 and the residual decomposition device with R11 and R12 and finally from the second stage of the reactor B2, the Separator with T93 and T94 and the remover with R13 and R14.

Closer to the individual process steps, so passes initially volume controlled raw water from a not with represented, the problem waste water receiving reservoir in the emulsifier E1.  

The emulsified E1 from the emulsifier, finely emulsified raw water is via the dosage E8 in the reactor B1 the first stage initiated, wherein the total hydrocarbons degraded become.

From the reactor B1, a mixed phase is continuously withdrawn and passed into a two-stage separator.

In preliminary stage T91, a separation of the mixed phase into a water-lean, light biomass-containing flotation phase, a water-lean, heavy biomass-containing sedimentation phase and a water-rich phase. As in the still obtained from the precursor T91 low-water phase a larger proportion of heavy biomass is located to further deposition of this share a Nachstufe T92 provided. While the separated flotation phase of the precursor T91 is passed via the return G101 to the reactor B1, Initiate the sedimentation phase from the precursor T91 and the post-stage T92 via the feedback G102 in the reactor B1 back.

The separated water-rich phase, however, continues into the also two-stage residual removal device with a precursor R11 and a post-stage R12 out. Through the training two levels it is possible, one of the two levels also To operate aerobically, so the degradation performance in some problematic wastewater to increase. About the expiration G12 one receives the preclarified product water from the first stage, which via the inlet G14 into the second stage of degradation can.

This second stage of degradation has the same structure as the first one Abbaustufe, with a reactor B2, a two-stage separator with a precursor T93 and a post-stage T94 and a two-stage residual excavator with the steps R13 and R14, the recycles G103 and G104 to the reactor B2 and the process G17 of the second stage of degradation.  

However, both stages of degradation differ procedurally from each other. Thus, reactor B1 is the first stage of degradation on a small and the reactor of the second stage of degradation adjusted to a high oxygen content. By causes this difference in the milieu of the reactors B1 and B2 that the microorganisms contained in reactor B1 are mainly Hydrocarbons and those contained in the reactor B2 Microorganisms mainly degrade surfactants.

To achieve high efficiency in pulping in the reactors too achieve, in addition to the aforementioned oxygenation also other, the milieu of microorganisms determining Parameters kept as constant as possible to constant Re-adaptations of the organisms in changing conditions to avoid.

Thus, in reactor B1 of the first stage of decomposition, the COD (Chemical Oxygen Demand) content regulated. When falling short a lower limit will be out of the nutrient container G41 nitrates or phosphates via the dosage G51 the Reactor B1 supplied. If an upper limit is exceeded is obtained for example from the first stage of degradation, preclarified product water via branch stream G13 in passed the emulsifier E1, so that the reactor via the Dosage E8 diluted and thus raw water with low COD content is supplied.

In reactor B2 of the second stage, the regulation of the COD content simplified. When falling below a lower Limit values are nutrients from the container G42 on the Dosing G52 fed to the reactor B2. Since the reactor B2 in Normal operation preclarified product water of the first stage of decomposition obtained with low COD content, this is the case no inadmissible exceedances with regard to the COD value, so that measures to reduce the COD value spare in this reactor.  

Furthermore, in the reactor B1, the biomass index, that is the ratio of biomass to liquid monitored. Should an upper biomass index limit in reactor B1 are exceeded, so you pass the over the index limit Belebtschlammenge beyond the branch G15 to Oxidation in the reactor B2.

Should the discharger limits of the second stage Exceeding product water are exceeded, so the device can, without raw water is supplied on Circuit switched until the discharger limits fall below again.

For this purpose, on the one hand can be switched to total circuit, wherein the product water obtained from the first stage of degradation is directed to the second stage of degradation and where the from the second stage of degradation received product water in the first stage of degradation is returned.

On the other hand, each stage can be switched to single circuit with the product water obtained from each stage of degradation is led back to the respective reactor.

A circulatory operation of the device is about it In addition, after a shutdown, the device again to operate until the discharger limit values have fallen below become.

Referring to individual characteristics of the method and the device, so are the reactors with following, to be regulated Key data operated:

Reactor of the first stage of decomposition pH | 6,5-7,5 temperature 35 ° C oxygen content about 2 mg / l Chem. Oxygen demand 5000-8000 mg O₂ / l Nitrate depending on the KW content about 150-350 mg / l phosphate content 15-30 mg / l Hydrocarbon content 1000-2500 mg / l Throughput depending on the fabric supply 190-250 l / day organisms inhibition less than 30% sludge index 1: 3 to 1: 4

Reactor of the second stage of decomposition 20-30 ° C | Temperature oxygen content 6.5-7.5 mg / l Hydrocarbon content less than 15 mg / l sludge index Max. 1: 7 to 1:10

Furthermore, the obtained from the second stage, the Introduction to the sewer network certain product water following values, whereby the legally required Einleitwerte in parentheses.

pH value 7,0-8,5 (6,5-10,0) Hydrocarbon content 3-15 (20) mg / l nitrite content 3 (20) mg / l sulphate content 20-60 (600) mg / l

With regard to the residual sludge, an amount of 90 l per year accumulates at a throughput of 90 m³ of problematic wastewater. This small residual sludge amount is due primarily to the aforementioned sludge index and COD control which prevents the formation of excess biomass to be disposed of. Individual devices of the device shown in Fig. 2, Figs. 3-6.

Thus, the emulsifier E1 is sketched in Fig. 3, in which a high-speed mixing turbine E3 causes the mechanical emulsification of the raw water. The turbine E3 is driven by an electric motor E2. To assist the emulsification and to enrich the raw water with oxygen, air is blown from below into the emulsifier E1 via the ventilation line E10. From the line E12, the exhaust air is removed and passed through a filter to the outside.

While the raw water through the feed E6 in the emulsifier E1 passes, the discharge of the emulsified raw water takes place in the downstream reactor B1 via the dosage E8. Associated emulsions can be sampled via the branch E9 are taken. The level in the emulsifier E1 becomes automatic regulated. For this purpose, individual fill level sensors used, which have a float with reed contacts. With these sensors, the following, drawn limit values detected:

E41: Overfill, causes alarm and shutdown, in addition, an emergency overflow E5 is provided,
E42: normal full, switch off supply,
E43: normally empty, switch on supply,
E44: Dry running, causes alarm, switch off.

In addition, the fill level can be read via display E11 become.

Regarding the regulation of individual parameters, so are The output E14 samples taken for continuous CBS measurement. If an upper limit is exceeded, for example precleared via the inlet E7, from the first Removal product water added for dilution  become. About the dosage E13, for example, substances be added to adjust the acidity.

In Fig. 4 the reactor B1 is drawn. Via the feed B7, the emulsified raw water enters the reactor B1. Approximately in the middle of the container, the drain B12 is arranged, from where the mixed phase is passed to the separator with the stages T91 and T92. Via the return B111, the separated, water-poor flotation and sedimentation phase returns to the reactor B1. The air supply contains on the one hand a switchable valve B13, which is followed by an air flow meter B14, a check valve B15 and a shut-off B16. The associated ventilation nozzles B17 are arranged on the container bottom. The exhaust air can escape via the filter B10 at the top of the tank.

For mixing of the reactor contents is at the bottom the conically shaped container bottom continuously liquid taken and by means of the pump B21 up to a located above the liquid level nozzle assembly B6 promoted. This nozzle arrangement B6 leads to a a turbulence of the upper fluid layers, for Others will also get some oxygen through the resulting air turbulence achieved. Still supplied the pump B21 also a nozzle head B5 with liquid, which generates turbulent flows in the center of the tank. In the circulation circuit is a immersion jacket heater B41 for adjustment involved in the temperature. Furthermore, a sensor arrangement B3, which switches the temperature, the oxygen content, the pH, the activity the bacteria indicating CO₂ content and the nitrate content to capture. In the case of nutrient deficiency, the introduction B8 Nitrates or phosphates added. For revision of the reactor its contents can be drained via draining B18.  In this case, the container inner walls by means of a sprinkler device B9 be cleaned.

FIG. 5 shows the preliminary stage T91 of a separating device. (This device is also described in the still unpublished, DE-P 41 02 966.)

The precursor T91 has a vertically stretched volume, which is closed at the top and bottom by a mud collecting room T221 for the flotation phase and a sludge collection room T222 for the sedimentation phase. the mud collecting rooms T221 and T222 are shaped so that they are ascending or sinking mud flakes to the respective processes Focus on T25 and T26, from where the two low-water phases are conducted back to the reactor B1. The Initiation of the mixing phase coming from the reactor B1 takes place via the inlet T18.

Formed between the two sludge collection rooms T221 and T222 as a separating layer between the separated sludge phases a zone of clarified water, which is only small Has sludge shares. About the sampling line T19, whose Inlet opening with a sediment deflector arranged above T20 is protected, the pre-clarified water to similarly constructed post-stage T92 passed the separator.

The T91 precursor may be used as needed to eliminate blockages in addition to aerators T241 and T242 or Be equipped liquid spraying.

In Fig. 6, the precursor R11 of the first residual excavation device is outlined.

This precursor R11 is enclosed by a container and is divided into a lower Klarzone R52, in one over it arranged fixed bed R6 and in an upper Klarzone R51.  In the lower Klarzone R52, which from the inner, conical shaped bottom wall of the housing and through the bottom a support R3 is surrounded, opens an inlet R7, the which initiates the water-rich phase obtained from the secondary stage T92.

Above the support screen R3 is followed by the fixed bed R6, which is bounded at the top by a Abdecksieb R4 and which filled with so-called colonization bodies. When Colonization bodies are porous, large surface forming Granules of, for example, activated carbon, granulated lava or collapsed metallurgical coke.

The upper Klarzone R51 is surrounded by the Abdecksieb R4 and a removable, conically shaped hood R2. About the process R8 is the liquid in the post-stage R12 the Restabbaustufe directed.

With the help of the fan R9, it is possible during a system revision or malfunctions in the fixed bed To rid of colonization bodies of mud particles.

It is also possible with the help of the fan R9, the precursor R11 also to operate aerobically depending on the type of problem waste water. Gases can be discharged via the lockable vent R131 become.

Sedimented sludge particles can pass through the sediment R15 passed, for example, for oxidation in the reactor B2 become. A complete emptying is over the Line R121 possible.

The openings R101, R102, R103 and R104 are for removal of samples to control pulping.  

In a modification of the illustrated embodiment, it is possible that only in one stage degradation a residual removal device is provided. However, this will increase the ability to to clarify various problem waste waters, limited.

Furthermore, for further clarification additional degradation stages be provided. Within a mining stage, individual Devices can also be operated in parallel to either to obtain redundancy or parallel devices each to operate with individual parameters. So parallel reactors could each have a specific Milieu, wherein a reactor, for example used only for processing the separated flotation phase becomes.

To prevent heavy metals or toxic substances in the second stage of degradation can be reached, following the first stage of degradation in addition to the reverse osmosis principle provide working intermediate.

LIST OF REFERENCE NUMBERS
- to Fig. 2 concerning the entire facility:

G12 Drain of the product water obtained from the first stage of decomposition
G13 branch current
G14 Inlet of the product water obtained from the first stage of decomposition into the second stage of decomposition
G15 diversion of biomass from first stage of degradation
G17 Sequence of product water obtained from the second stage of degradation
G41 nutrient container
G42 nutrient container
G51 dosage for nutrients
G52 dosage for nutrients
G101 recycling for biomass
G102 recycling for biomass
G103 recycling for biomass
G104 recycling for biomass

to FIGS. 1, 2 and 3 relating to emulsifiers:

E1 emulsifier
E2 drive motor
E3 high-speed compound turbine
E5 emergency overflow
E6 feed for raw water
E7 enema
E8 dosage
E9 diversion
E10 ventilation line
E11 level indicator
E12 exhaust duct
E13 dosage
E14 Sampling output for continuous CBS measurement
E41 filling level position "overfilling"
E42 filling level position "normal full"
E43 filling level position "normally empty"
E44 filling level position "dry run"

to Figs. 1, 2 and 4 concerning reactor:

B1 reactor
B2 reactor
B3 sensor arrangement
B5 nozzle head
B6 nozzle arrangement
B7 inlet
B8 Introduction to nutrients
B9 Supply line to the sprinkler device
B10 exhaust air filter
B12 drain to the separator
B13 valve
B14 air flow meter
B15 check valve
B16 shut-off device
B17 air vents
B18 emptying
B21 pump
B41 dip jacket heating
B111 recycling for biomass

to FIGS. 1, 2 and 5 concerning separating device:

T18 inlet pipe
T19 sampling line
T20 sediment deflector
T25 process for buoyant sludge content (flotation phase)
T26 process for non-buoyant sludge content (sedimentation phase)
T91 precursor of the separator of the first stage of degradation
T92 post-stage of the separation device of the first stage
T93 precursor of the separator of the second stage of degradation
T94 post stage of the separation device of the second stage
T221 Sludge collection room for flotation phase
T222 Sludge collection room for sedimentation phase
T241 aerator
T242 aerator

to FIGS. 1, 2 and 6 relating to residual mining device:

R2 hood
R3 carrier screen for colonization body
R4 terminating screen
R6 fixed bed
R7 enema
R8 drain
R9 fan
R11 preliminary stage of the residual mining device of the first stage of degradation
R12 post-stage of the residual degradation device of the first stage of degradation
R13 precursor of the residual decomposition device of the second stage of decomposition
R14 post stage of the residual degradation device of the second stage of degradation
R15 sediment discharge
R51 upper clear zone
R52 lower clear zone
R101 Sampling ports
R102 Sampling ports
R103 Sampling ports
R104 Sampling ports
R121 drain line
R131 Venting

Claims (4)

1. A method for the degradation of hydrocarbons contained in water and surfactants in which, after a mechanical Emulsification in an emulsifier (E1) at least two levels of degradation are provided, each degradation stage a reactor (B1, B2) with aerobically degrading microorganisms has, whose exiting mixed phase in one Separator (T91 and T92, T93 and T94) separated gets into a low-water flotation phase, a low-water Sedimentation phase and a water-rich phase, the two low-water phases being separated or together be recycled to the reactor and wherein the water-rich phase before the introduction to the following Discharge level or in the sewerage network in at least a mining stage in a residual mining device (R11 and R12, R13 and R14) with anaerobically degrading Is guided by microorganisms. 2. The method according to claim 1, characterized that the reactor (B1) of the first stage of degradation to a low and the reactor (B2) of the second stage is set to a high oxygen content.   3. The method according to claim 1 or 2, characterized that in the reactor (B1) of the first stage of decomposition of the COD is regulated, whereby falls below one lower limit nutrients are added and at Exceeding an upper limit pre-clarified Product water is added to the preceding emulsifier (E1) becomes. 4. The method according to any one of claims 1-3, characterized that when exceeding a biomass index limit activated sludge in the reactor (B1) of the first stage of decomposition for oxidation in at least one of the following Reactor (B2) is passed, the degradation stages on Single or total circuit can be switched.