DE4209052A1 - Microbial degreasing without separate waste water treatment - using microorganisms for grease and oil removal and decomposition - Google Patents

Abstract

In a plant and process for microbial degreasing of surfaces, an existing degreasing bath (1) with an overflow weir is flange coupled to a tank (2) which has a conical bottom region and which contains a mechanical separator (4) for microorganisms, the output of the separator being returned to the degreasing bath. The tank (2) is pref. also provided with a membrane aerator or similar aerator (5) to provide circulation and mixing. The separator pref. consists of one or more porous filter elements (4) for quantitative retention of microorganisms and permeating exo-enzymes or bio-surfactants (low mol. wt. molecules). The tank is pref. fed with hydrocarbon decomposing microorganisms and nutrient soln. The degreasing bath (1) is pref. dosed with conventional builders, surfactacts or corrosion inhibitors. USE/ADVANTAGE - The plant and process are useful for removing oil, grease and other organic contaminants from metals, circuit boards, plastics and ceramics, e.g. prior to coating or other surface treatment. Degreasing and waste water treatment are combined, so that pollution control measures can be reduced, and chemical consumption is reduc

Description

The invention relates to a system and a method for microbial cleaning of surfaces from oils, fats or other organic pollution from the cult vation of microorganisms directly on / in a con conventional degreasing / deoiling bath.

The cleaning of technical surfaces from rust, Zun the and oxide layers, of lubricants from forming work, from corrosion protection oils, waxes and with metal abrasion and lapping paste pigments Hand sweat and fingerprints is in the area of the anla gene, machine and apparatus construction an indispensable model treatment step before further processing in the frame of coatings and surface treatments. Freak Metals, sheet metal, printed circuit boards, art are used fabrics but also ceramics.

In the metal and plastic processing industry two methods of cleaning have been introduced: Cleaning (mostly chlorinated and fluo due to fire risk hydrocarbons) and aqueous cleaning. The State of the art in this area is understandable Sage by Erich Lutter; Degreasing - basics, Theory and Practice, 2nd edition, Eugen Leuze Verlag, Saul gau described. Due to the potential threat to the Employees and the environment through chlorinated and fluorinated  connections, implemented by environmental legislation, immediately finds a relocation of the cleaning pro process on aqueous systems instead. The product of this Process is a mixture of detergents and abge dissolved oils, respectively fats and the other above named components that depend on the workpiece surface were solved. In contrast to solvent cleaning, at which the cleaning agent can be distilled off and the detached substances are in a concentrated form, alkaline are formed during aqueous cleaning steps or acidic wastewater that is only partly processed measures can be recycled and therefore one today pose a significant disposal problem.

A distinction is made between alkaline cleaners with pH <8, new tral cleaner with pH between 7.5 and 10 and acidic phos phat cleaner with pH between 3.5 and 5.5. Alkaline rice less make up the majority of the cleaning agents; they exist essentially from builders (framework) and surfactants (upper surface active substance). The tensides cause the detachment solution of fats and oils and have an emulsifying effect on them, so that they remain in solution; the scaffolding under support the degreasing and are decisive for the feast body distance from the surface. Ent hold corrosion inhibitors in addition to surfactants. Sour Phos phat cleaners play mainly in spray cleaning processes a role that is of secondary importance here tung is. Since cleaning baths "consume" (P. Kunz and G. Frietsch: Microbicidal substances in biological clarity Investments. Springer-Verlag-Heidelberg, 1986) the Her manufacturers of detergents meanwhile Offer systems from chemicals and membrane systems, which is a recovery of the cleaning bath used enable, or they offer directly biodegradable Detergent. The used cleaning and Rinsing solutions must be a biological after use be subjected to wastewater treatment.  

For all cleaning processes used in practice is therefore the problem of the disposal of the abge dissolved fats and oils and the used cleaning agents to put microorganisms in the foreground.

The invention has for its object a method and a system for degreasing / de-oiling surfaces propose the environmental impact or the measures to reduce emissions by already in Use the cleaning process. The task continues, Chemi save or completely replace kalien because with your Development, manufacture, formulation, distribution and environmental pollution.

These objects are achieved in that to the conventional degreasing / deoiling bath Tub or the like is flanged in the mi the path to the degreasing / de-oiling Chen active ingredient components are produced in that the greases removed in the degreasing / deoiling bath and Oils are introduced. The fats and oils are nutrients for the bacterial mixed population in the tub. Autoka increases analytically through increased nutrients the enzyme pool is responsible for the splitting of fat and the breakdown of the Fatty acid esters and glycerol or aliphatic and aromatic hydrocarbons. This enzyme pool unless it is extracellular, by a integrated agitator ball mill or comparable one directions (such as high pressure homogenization or ultrasound treatment) released for cell disruption. The up closed cell pulp is returned to the reactor pan leads, so that on the one hand an internal circulation of essential substances are created, whereby the fat and oil com component and cell building blocks permanently to carbon dioxide be set so that almost no sludge is produced becomes. The released active ingredient components for detachment the fats and oils from the surfaces and their front are separated via a selective filter system lubrication / deoiling bath supplied. That closes the circulation.  

The skilled worker is familiar (Schlegel, H .; Allgemeine Mikro biologie, Thieme-Verlag, various editions) that Mikroor hydrocarbons from natural sources Recognize (vegetable and mineral oils) as nutrients and can grow on it. Still is known that this also affects the effective amount of enzyme increased autocatalytically. In addition, it is known that Mineral oil and hydrocarbon degrading microorganisms in are able to synthesize biosurfactants, whereby the Cleaning process is directly promoted.

The microbiologist has many fat / oil-splitting microphones organisms to choose from, such as the Pseudomo bacterial strain nas spec. ATCC 21808 (see also H. Erdmann et al .; Ausge chose examples of the application of lipases in the or ganic preparative chemistry. Yearbook biotechnology volume 3, Hanser-Verlag- Munich 1990, pp. 353-370), the Tem temperature optimum around 50 ° C and pH optimum around 10 and the extracellularly an active and stable lipase in releases the surrounding medium.

A great deal has been reported recently about the degradation of aliphatic and aromatic hydrocarbon compounds, especially in connection with soil remediation (F. Lingens: Microbial degradation of aromatic compounds. Jahrbuch Biotechnologie Band 2 , Hanser-Verlag 1988, p. 297 -318 and R. Müller-Hurtig, F. Wagner: Microbial degradation of aliphatic hydrocarbons from an environmental perspective. Jahrbuch Biotechnologie Band 3, Hanser-Verlag 1990, pp. 337-350).

An overview of the range of microbial produ The contribution by H. Uhlig et al. (Use of enzyme preparations in technology. Yearbook Biotechnology Volume 1, Hanser Verlag 1987, pp. 303-340). It can therefore be assumed as certain that vegetable and mineral oils or fats from microorganisms can be mined and recycled.  

Wastewater treatment technology is also known (Jäger et al .: gwf-Wasser / Abwasser 130 (1989) 7, 328-333) that both in aerobic as well as anaerobic treatment basin in Mischkul structures and with the use of bacterial preparations carbon Hydrogens of natural origin and also synthetic Hydrocarbons microbially to carbon dioxide and water be implemented.

The method according to the invention is now based on a Propose plant technology that is already in the making place fats and oils essentially to carbon dioxide and Implement water and the chemicals previously required to remove the fats and oils from the surfaces sub stitches. About such a system technology for implementation low-emission processes in production never been reported or published anywhere.

To this element of a low-emission manufacturing process rens for technical use to develop a robust plant technology, the high bio enables mass concentrations or the concentration Microbially produced active ingredients in the order of magnitude of chemical concentrations previously used. He According to the invention, a filtration system with mi Croporous structures used by which the degreasing Oil removal / deoiling bath with all active ingredient components can penetrate, but not higher molecular weight compounds and especially the biomass. According to the invention Filtration system with a maximum pore diameter of 0.2 mm at short intervals with compressed air from the inside blown out to remove accumulated biomass bust. The filtration system takes over one Part of the ventilation of the flanged to the degreasing Tub system.

In the case of anaerobic degradation, the filter system is included produced biogas backwashed or separately outside attached to the tub.  

According to the method presented always select the microorganisms that are responsible for varying fat and oil use on the preserved Surfaces can grow. This runs according to the invention Process also largely except for the supply of acid self-sufficient fabric; d. H. the excess biomass is over ground or broken up a cell disruption plant and in the bioreactor system from the micro selected there organism community partly incorporated, partly Mineralized to carbon dioxide and water. This will except for a few states (running in the system, operating interruptions etc.) no dosing of additives necessary. Overall, this process produces wise no sludge, apart from possibly Business interruptions. According to the Anla genetic engineering continues on the existing degreasing / Oil removal technology turned off by temperature and pH-Be rich in previous degreasing / deoiling technology can be kept so that at the beginning of the process the chemicals previously used are still used can. This avoids business interruptions.

At the start of the process, microorganisms from one Stammsammlung (for example the German Stammsammlung for microorganisms in Braunschweig) or from egg activated sludge from a - preferably refinery - Ab water purification system or a somewhat stale bathroom be isolated and grown.

Assign the previously used chemicals an antimicro biological effect - it is relatively easy to determine ask if a removed and with a few drops Activated sludge inoculated sample even after six to eight Weeks show no microbial colonization -, al alternative detergent components are used. According to the invention, only biolo come as additives gisch inert components because they are microbial not be recycled and therefore constantly with the water can be circulated.  

The reactor according to the invention in the tub flanged to the degreasing / deoiling bath has a volume of the same order of magnitude as the connected bath - that is, between 2 and 4 m ³ . The pan is divided by baffles to reach a directional flow. According to the invention, a flow reversal is aimed by ventilating on the one hand via the ventilation device and on the other hand via the backwashing device. The trough is either beveled in the middle or on the side and can be zoned, if necessary, by installing floor panels in such a way that sedimentation, concentration and stacking of the excess biomass (over 30 g bio-dry matter / l) can occur in the lower area. From there, biomass is withdrawn to the cell disruption system from time to time, preferably during the business break or during breaks or breaks.

The advantages of the method according to the invention are already stated in the task: One so far necessary wastewater treatment is in the produc immediately integrated, which creates the advantage that the degrading microorganisms function as Rei take over all or part of the detergent components, if the cleaning requirements allow it. Will Striving for higher cleaning requirements can fig are worked so that the described plant and Process concept also used sensibly that can. This can save chemicals and the Disposal of residues from the cleaning process ver be simplified.

In the following the invention in connection with the Drawings using exemplary embodiments tert:

Fig. 1 shows schematically a degreasing / de-oiling bath, which has a funnel below. In addition, a ventilation device ( 5 ) and a filtration system ( 4 ) are attached, the filtration system also being coupled to the compressed air supply (see FIG. 2).

The drain of the filter system ( 4 ), which can be placed under vacuum ( 6 ), enters the bath ( 1 ). It contains the effective components for detaching the fats and oils from the surface. The drain from the funnel of the tub ( 2 ) is fed to a cell disruption system ( 3 ). The cell pulp is returned to the tub ( 2 ).

Fig. 2 shows the plant technology in plan view: The filter system ( 4 ) encloses the area of the ventilation outside and is provided with such filter surfaces that a sufficient circuit between the bath's ( 1 ) and tub ( 2 ) via the separating device ( 3 ) in connection with the vacuum pump ( 6 ) for sufficient bathroom renewal.

Fig. 3 shows an embodiment of the system technology according to the invention in the form of a flow chart: a bath ( 1 ) converted into a bioreactor system into which water and chemicals (a) are introduced. With the cleaned workpieces, part of the cleaning bath leaves the system ( 1 ), which is concentrated in the sink ( 2 ). An unrestrained portion of the cleaning and rinsing bath leaves the system (c). The rinsing bath content, predominantly microorganisms, (d) is concentrated again via a phase separation ( 3 ) and leads back into the cleaning bath (e); the depleted rinsing water is used again for rinsing (m). The degradation aids (f) and oxygen (g) are added to the bioreactor / cleaning bath system. The content of the system is additionally circulated via (i) in order to homogenize the bath. A partial stream is temporarily removed (h).

Fig. 4 shows a further embodiment of the system technology according to the invention in flow diagram form, in which the bioreactor ( 1 ) is shown in the bypass to the cleaning bath ( 4 ); the cleaning bath is continuously passed through the bioreactor (k).

Fig. 5 shows a further embodiment of the plant technology according to the invention in flow diagram form, in which the biomass formed in the bioreactor is retained in a phase separation plant ( 5 ) and only the extracellular enzymes are added to the cleaning bath (i).

The control of the An shown in the figures Layer technology is essentially the simplest Execution via simple and robust sensors (level, Oxygen content), via controllable three-way valves and clocked via timers.

To illustrate the order of magnitude, fol The following magnitudes are given by way of example: the biomas Concentration in the tub should be in the area around or above 30 g of organic dry matter per liter are the oxygen drove an oxygen concentration of not less than 2 mg / l enable. The enzyme concentration is so high centered that 1 liter of oil or fat per liter per hour can be implemented. The addition of ozone or per- Compounds exposed to UV light or light their wavelength to stimulate degradation are also possible.

Claims (14)

1. Plant and method for microbial degreasing / deoiling of surfaces, characterized in that an existing funnel-shaped / tapered tub is flanged to an existing degreasing / deoiling bath in conjunction with an overflow threshold, the tub is a mechanical separator contains device for microorganisms and the drain of the separator is returned to the degreasing bath. 2. Plant according to claim 1, characterized in that the tub content via membrane aerator or similar bare aerators as well as the mechanical separator device in the course of backwashing with oxygen is supplied and thereby circulated and mixed. 3. Plant according to claims 1 and 2, characterized records that the separator from one or several porous filter elements for quantitative Retention of microorganisms and permeating Exoenzymes or biosurfactants (molecules with low Molecular weight). 4. Plant according to claims 1 to 3, characterized records that alternate ventilation via the Membrane aerator or via the backwash process.   5. Plant according to claims 1 to 3, characterized records that the filter elements in a separate Chamber can be pressurized. 6. Plant according to claim 1, characterized in that the concentrated in the conical area, biological formed sludge by means of an agitator ball mill or a comparable cell-opening machine disintegrated and connected to the Ent lubrication bath flanged tub supplied again becomes. 7. The method according to claim 1, characterized in that the tub with hydrocarbon-degrading microorga nisms, that of a separate production, one strain collection or from a next to the respective Reini fermentation arranged originate, indicated is vaccinated. 8. The method according to claim 1, characterized in that also conventional in the degreasing / deoiling bath Builders, surfactants or corrosion inhibitors in addition be used in doses. 9. Plant and method according to claims 1 and 7, because characterized in that the cultivated in the tub microorganisms nutrient solutions for supplementary support Changes in hydrocarbon degradation are metered. 10. Plants and methods according to claims 1, 7 and 9 characterized in that the tub has a heater jacket or comparable temperature control devices Temperatures around 35 ° C (mesophilic conditions) or around 55 ° C (thermophilic conditions) is set. 11. Plant and method according to claims 1, 3 and 5 to 10, characterized in that the tub under Oxygenation can be operated.   12. Plant and method according to claims 1 to 11, there characterized by that for degreasing and De-oiling usable microbial products immediately be produced in the degreasing / deoiling bath and the surfaces directly in the presence of the Mi microorganisms are cleaned. 13. Plant and method according to claims 1 to 12, there characterized in that in addition to metallic and Plastic surfaces also contaminated or otherwise natural upper loaded with oils and fats surfaces can be freed from oils and fats. 14. Plant for performing the method according to one of the preceding claims, characterized in that in addition to a conventional treatment bath Degreasing / de-oiling a container with aeration direction and mechanical restraint for Biomass in transit for enzymes and surfactants as well if necessary, a plant for cell disruption and the Operation required control, security and Has control elements.