DE10139829A1 - Additive to stabilize biomass - Google Patents

Abstract

The invention relates to additives comprising factors which influence the metabolism of aerobic and/or anaerobic micro-organisms, said factors being immobilised on an organic carrier material and/or enveloped by the same. The inventive additive can be used in the biological purification of waste water and in compost preparation, enabling the respective treatment installation to be stabilised.

Description

The present invention relates to an additive for Stabilization, especially of the biomass in the biological Waste treatment. The additive is suitable for stabilization biological sewage systems and for composting. It takes place also used in biological soil and air cleaning.

Open biological processes, which are usually biological waste treatment can be used and partially open Processes are generally very difficult controllable and difficult to optimize in their overall performance. The The reason for the biological instability lies in the open or partially open character of these process plants. The through the Entry of organic and inorganic substances in the Population of microorganisms caused fluctuations significantly affect process performance. This one Fluctuations both over longer periods, for example conditionally by the change of season, but also by hourly Changes in environmental conditions can occur Dynamics of such systems are very large.

In Germany and Austria alone, process volumes of more than 10,000,000 m ³ are estimated for the area of biological wastewater treatment. Due to this large scope, improvements in process performance are of great economic and ecological importance. For an efficient and sustainable increase in the performance of biological processes, it is an aim of the invention to stabilize and optimize the process itself and not to control the external process conditions and influencing factors by much greater effort. Stabilization is understood here to mean keeping various process parameters constant while largely excluding external influences.

To achieve the goal of biological stabilization and It's closer to dynamic control of anaerobically operating processes necessary the internal processes and interaction of the better understand the microorganisms involved. It is known, that many microorganisms have developed a strategy to Counteract fluctuations in the populated environment. she surround themselves with a matrix of polysaccharides and Proteins. Due to the three-dimensional structure of this long-chain The so-called biofilm is created as a scaffold for molecules microbial growth. This scaffold holds the biofilm together and at the same time serves as protection for the microorganisms from chemical and physical changes. Furthermore can through extracellular enzymes that are bound in the matrix, the metabolism of the microorganisms partly outside the Cell take place.

• - Unter spezifischem Substratmangel aufwachsende Mikroorganismen sind durch extrazelluläre Spaltung von hochmolekularen Stoffen in der Lage, den Stoffwechsel aufrecht zu erhalten. Durch die räumliche Nähe der Enzyme zur Zellmembran wird die Diffusion der niedermolekularen Spaltprodukte in die Zelle ermöglicht.
• - Bakterien, die in Symbiose mit anderen Arten wachsen, wie die Nitrifikanten Nitrosomonas sl und Nitrobacter sl verwenden die extrazelluläre Matrix, um in räumlicher Nähe zu bleiben.
• - Auch die Ausbildung von Substratketten wird durch die räumliche Fixierung ermöglicht. So dient das Stoffwechselprodukt einer Art als Substrat für eine andere Art von Mikroorganismen.
• - Toxische Substanzen können in der extrazellulären Matrix gebunden werden und damit nicht ins Zellinnere vordringen und die Mikroorganismen schädigen.

This property of the formation of biofilms is the basis for the formation of activated sludge flakes in wastewater treatment plants using the (aerobic) activated sludge process. According to current knowledge, the biofilm in the form of the mud flake serves several purposes:

• - Microorganisms growing up with a specific lack of substrate are able to maintain the metabolism by extracellular cleavage of high-molecular substances. The proximity of the enzymes to the cell membrane enables the diffusion of the low-molecular cleavage products into the cell.
• - Bacteria that grow in symbiosis with other species, such as the nitrificants Nitrosomonas sl and Nitrobacter sl, use the extracellular matrix to stay in close proximity.
• - The formation of substrate chains is also made possible by the spatial fixation. The metabolic product of one type serves as a substrate for another type of microorganism.
• - Toxic substances can be bound in the extracellular matrix and thus do not penetrate into the cell interior and damage the microorganisms.

So since the biofilm is essential in processes biological waste disposal, this applies To support biofilm and thus the formation of necessary micro-habitats to maintain optimal To increase the conditions of the microorganisms that settle on it. Optimal methods for this have not yet been developed.

The goal is therefore a higher tolerance to fluctuations in the Ambient conditions in the entire process system. The Mining capacity needs to be increased.

The present invention therefore relates to an additive comprising an inorganic and / or organic Carrier material and factors immobilized on and / or encased by it, which the metabolism of aerobic and / or anaerobic Affect microorganisms.

In the context of the present invention, the Term "factors" all substances vegetable or otherwise of biological origin, which are able to Metabolism and / or the viability of microorganisms are involved in a biodegradation process, in one To influence direction that the process is happening stabilized.

An additive according to the invention provides a controlled one Release of the immobilized or enveloped in it Factors over time for sure. The carrier material offers mechanical protection for a biofilm formed on it. Especially the training of the biofilm is supported and thereby the Formation of micro-habitats to maintain optimal Conditions of the microorganisms settling on it increased. This leads to a higher tolerance towards Fluctuations in environmental conditions in an open or partially open biological process plant. In combination with a targeted Availability of factors that affect the overall system Stabilize performance, the mining capacity can be more specific Substrates are significantly and sustainably improved.

Preferred embodiments of the additive according to the invention result from subclaims 2 to 10.

Thereafter, it is advantageous in terms of environmental compatibility to select the carrier material from natural and / or synthetic organic polymers. The carrier material must in any case be toxicologically safe (LD ₅₀ ) and free of contaminants. A suitability for implementation with the factors according to the invention which influence the metabolism of microorganisms is a prerequisite.

According to the invention, the carrier material in particular Cellulose [poly-β- (1,4) -D-glucose], derivatized and / or regenerated cellulose used.

The cellulose derivative used is, in particular, cellulose xanthate into consideration. Starting materials for the carrier material can in suitably raw materials or waste products of Be paper industry, which include cellulose and its derivatives.

It is also possible to use modified starch, which consists of different types of grain, but also from corn and tomatoes can be won. Also come as a carrier material inorganic substances, such as gypsum, cement, zeolite and / or bentonite, in Question.

• - Nährstoffe allgemeiner Art (Substrat) zur Aufrechterhaltung des Stoffwechsels der Mikroorganismen bei fehlendem Eintrag in das System;
• - Wachstumsfaktoren und Spurenelemente, die nicht als Substrat dienen und nicht im Substrateintrag enthalten sind, jedoch für die Lebensfähigkeit der Mikroorganismen notwendig sind;
• - Organische Polymere biologischen Ursprungs zur Induktion des Biofilmwachstums. Durch die Forcierung sessiler Mikroorganismen im Biofilm werden durch die Substratkonkurrenz nicht-sessile Mikroorganismen zurückgedrängt. Der Austrag von Mikroorganismen aus der Prozessanlage, beispielsweise im Nachklärbecken, wird dadurch deutlich verringert;
• - Aus Pflanzen isolierte Proteine als spezifisches Substrat. Spezifische Substrate können angezeigt sein, um Symbiosen und dadurch alternative Substratreduktionswege zu forcieren;
• - Enzyme für eine extrazelluläre Substratumsetzung, um leichter abbaubare Metabolite zu erhalten oder toxische Substanzen in nicht-toxische Spaltprodukte umzusetzen;
• - Selektiv wirkende Biozide und Fungizide biologischen Ursprungs, die eine gezielte Populationskontrolle oder Mikroflora ermöglichen. Durch diese Strategie können Mikroorganismen, die aufgrund ihrer Eigenschaften im System nicht erwünscht sind, zurückgedrängt werden. Molekularbiologische und biotechnologische Verfahren können zur Herstellung solcher spezifischen Substanzen im industriellen Maßstab eingesetzt werden.
  Beispielhaft zu erwähnen sind jene Mikroorganismen, die durch ihre Wuchsform oder durch Gasbildung die Belebtschlammflocke voluminös und leicht machen (Zoogloea sl, Sphaerotilus sl). Durch die Notwendigkeit, am Prozessende die organische Masse vom gereinigten Abwasser konstruktionsbedingt durch möglichst rasche Sedimentation zu trennen, sind langsam oder überhaupt nicht sedimentierende Schlammflocken nachteilig. Es käme zu einem erhöhten Austrag organischer Masse aus der Anlage, was zu vermeiden ist.

There are numerous factors that can influence the metabolism of microorganisms. In the context of the present invention, this means:

• - General nutrients (substrate) to maintain the metabolism of the microorganisms in the absence of entry into the system;
• - growth factors and trace elements that do not serve as a substrate and are not included in the substrate entry, but are necessary for the viability of the microorganisms;
• - Organic polymers of biological origin to induce biofilm growth. By forcing sessile microorganisms in the biofilm, non-sessile microorganisms are pushed back by the substrate competition. The discharge of microorganisms from the process plant, for example in the secondary clarifier, is thereby significantly reduced;
• - Proteins isolated from plants as a specific substrate. Specific substrates may be indicated to force symbioses and thereby alternative substrate reduction pathways;
• - Enzymes for an extracellular substrate conversion in order to obtain more easily degradable metabolites or to convert toxic substances into non-toxic fission products;
• - Selective biocides and fungicides of biological origin that allow targeted population control or microflora. This strategy can suppress microorganisms that are not wanted due to their properties in the system. Molecular biological and biotechnological processes can be used to produce such specific substances on an industrial scale.
  Examples include those microorganisms that make the activated sludge voluminous and light due to their growth form or gas formation (Zoogloea sl, Sphaerotilus sl). The need to separate the organic mass from the cleaned wastewater at the end of the process due to the design by means of the fastest possible sedimentation means that slow or non-sedimenting sludge flakes are disadvantageous. There would be an increased discharge of organic matter from the plant, which should be avoided.

By using vegetable starting substances for Isolation of each factor results in advantages biological and economic aspects. For one, they are Starting substances in procurement are inexpensive, on the other hand they are ecologically completely harmless. Both are suitable vegetable waste products from the food and Feed production, as well as cultivated plants or parts from that. By suitable and known to the expert Extraction processes can enrich the factors.

• - Inhaltsstoffe für ein gezieltes Wachstum von Mikroorganismen
• - Niedriger organischer Stoffgehalt
• - Verfügbarkeit
• - Niedrige Aufbereitungs- und Herstellungskosten.

The selection of the plant material from which the factors can be obtained will therefore be based on the following criteria:

• - Ingredients for a targeted growth of microorganisms
• - Low organic matter content
• - Availability
• - Low processing and manufacturing costs.

The additive from the factors mentioned and the carrier material can be in a wide range in its composition can be varied so that the optimal combination in terms of Sales rate, but also with regard to the manufacturing process and the stability can be easily determined.

So the ratio of carrier material / factors can be broad Vary the range from 0.01 to 99. Ideal ratios of Carrier material / factors range from 1 to 10 and preferably from 0.1 to 0.3.

On the one hand, this relationship can be Process conditions to be found on the other hand by the Determine factor size and the type of factors used.

The final composition, including the carrier and factor (s), can be in particle, granule or fiber form. she can usually in stabilizers, precipitation aids and other for the operation of a specific process plant contain suitable additives.

The additive according to the invention is preferably found in the biological wastewater treatment and composting Application. Other areas of application are biological soil and air purification.

By immobilizing the factors or wrapping them a controlled, preferably delayed delivery of the factors to the treatment medium reached over time (see the following Tables 5 and 6). The use of the invention Material is therefore batch-wise or also continuous, depending on Use case, possible.

The following are detailed details of the properties the additives of the invention, their preparation, their Application and effectiveness described.

1. Backing material

Although other carrier materials are possible, the Experiments described below used cellulose. Cellulose [poly-β- (1,4) -D-glucose] is numerous because of its and strong intermolecular and ultramolecular Hydrogen bonds and crystallinity as such are not water soluble.

Cellulose is used in the context of the present invention either as a matrix or as a shell for the nutrients, Growth factors, proteins, minerals, etc., together as factors designated. The combination of carrier and factors depends of their required relationship to each other and the desired release rate.

The cellulose is usually activated under alkaline conditions to form alkali cellulose and reacted with CS ₂ to form cellulose xanthate. The cellulose xanthate is soluble in dilute sodium hydroxide solution and leads to so-called regenerated cellulose with acid, whereby CS _{2 is released} again and can be removed from the manufacturing process under suitable and environmentally friendly conditions. The factors can be introduced in the alkaline range by adding them to the cellulose xanthate and in the acidic range directly in the refiner when regenerating the cellulose. Depending on that, one will achieve immobilization or an encasing of the factors.

When wrapping the factors, the achieved or too Achieving shell density is an essential property for the Diffusion of the factors through the membrane. With a relationship Cellulose: factor of 1:10 and a factor size of 50 µm should the sheath should be between 10 and 20 µm thick for optimal sustained release of the factors in the aqueous environment or guarantee a process plant.

2. Raw material sources for the extraction of the factors

The selection of the one used to obtain the factors Vegetable or biological material initially depends on the active ingredient content (all factors) of the vegetable Material, but also for economic reasons Relative to its price.

A list of potential raw material sources is shown in Table 1: Table 1

Tables 2 and 3 below are common Summary of properties of certain nutrients. You are D. Belitz, W. Grosch, Textbook of Food Chemistry, Springer Taken from publisher.

Table 2 shows usable fractions of different types of cereals. Table 2 Fractions of Different Grains (Average)

The nutrient content or the content of biologically available factors is shown in Table 3: Table 3 Chemical composition of the cereal types (mean values)% - (wt.)

The factors were either isolated individually or in form their, for example, aqueous suspension or slurry of Raw material with the carrier material, preferably on Cellulose base, processed.

The advantageous ratio of carrier material to factors is shown in Table 4 below: Table 4

The products MK1 to MK5 mean those obtained from corn germ Additives and products 51 to 54 obtained from soy Additives. The table also shows the percentage of bioavailable Factors throughout the product with 25% dry matter too remove.

3. Investigation of the effect of the additives according to the invention

50 ml of activated sludge from biology and 50 ml of waste water sample to be tested are each mixed with 200 mg of the compositions MK1 to MK5 or S1 to S4 according to the invention and aerated in a water bath at the temperature of the aeration stage of a sewage treatment plant. The extinction, the NH4 ⁺ and PO4 ^- content and the sludge volume are determined after various times on a filtered sample. The results are summarized in comparison to a zero sample in Tables 5, 6, 7 and 8 and shown graphically in Fig. 2 to 5. When adding an additive according to the invention, there is generally a marked reduction in the sludge volume, the extinction and the NH4 ⁺ content.

4. Laboratory experiments

The batch tests are carried out in glass, tempering and sterilizable reactors.

The experiments with continuous reaction are in a laboratory wastewater treatment plant. The system corresponds to the Requirements of DIN / DEV 38 412 and OECD 303 A (Couplet Units Test).

Also a mobile facility for the treatment of 200-600 l of wastewater built per day.

• - Ammonium und Phosphat
• - CSB
• - O₂-Gehalt
• - Trockensubstanz
• - Schlammindex
• - Metallgehalt.

The following parameters are determined:

• - ammonium and phosphate
• - COD
• - O ₂ content
• - dry matter
• - sludge index
• - metal content.

Influence of the additive on the nitrification rate

Nitrification is the microbial oxidation of ammonium (NH4 ⁺ ) via nitrite (NO2 ^- ) to nitrate (NO3 ^- ). The nitrificants are sensitive microorganisms, so that the nitrification rate is strongly influenced by various chemical compounds in addition to the physical parameters mentioned above.

protocol

• - Add 1.5 l to the weighed-in sludge in beakers Inflow wastewater.
• - Immediately after mixing water and sludge 50 ml of the homogeneous mixture are taken from each batch Mixed and fine, previously soaked paper filter.
• - The beakers with the mud-water mixtures 50 ppm of the product MK1 added and by means of a Aquarium pump intensively ventilated with aeration stone. The The content of the oxygen entered is exemplary checked. It lies in the tests carried out between 5.9 and 8.6 mg / l
• - After 10, 20, 30, 40, 50 and 60 minutes everyone will Batch taken 50 ml of the mixture and immediately over fine Filtered paper filter.
• - The ammonium content of the filtrate is determined.

The results are shown in Table 9: Table 9

Laboratory and operational test in a paper mill

By using additives according to the invention, the sludge index (I _SV ) is to be reduced and a COD reduction is to be achieved. The plant biology should be stabilized and the system performance improved.

A total of three tests are carried out: tests in the laboratory, on the mobile pilot plant and on the operating plant self.

laboratory test

In the laboratory test (Table 10) it has been shown that the addition of additives MK1 to MK5 according to the invention generally improves bacterial respiration and the turbidity of the process. Table 10 Results of the laboratory test

MK1 to MK5: product variants with increasing nutrient and mineral content.

Bacterial breathing is generally significantly improved, the haze is reduced.

Pilot plant trial

The results of the pilot plant test (mobile test plant from Bioconsult) are shown in Table 11: Table 11 results of the pilot plant test

It can be seen that with the addition of the invention Composition of the sludge index compared to the zero sample has improved. The microscopic picture shows that the Flake structure of the sludge also due to the strong Improved reduction of filamentous organisms.

field test

The changes in the sludge index (I _SV ) and chemical oxygen demand (COD values) in the process are shown graphically in Fig. 1.

The sludge index was in the period of operational testing and reduced the haze. It was in this period Dosing quantity at approx. 0.25% to 0.35% of the dry substance in the Aeration tank. The dosage itself took the form of a aqueous suspension of the additives in the return sludge.

conclusion

The results from all three tests show a positive effect on the system performance. The sludge index was reduced in the pilot plant and operational test from 300 ml / g to 100 ml / g. At the end of the dosing, the stable phase was ended and the sludge index deteriorated again ( Fig. 1).

The turbidity in the process was also in the laboratory and Operational testing improved. The cloudiness improves without waiting sustainable.

The microscopic evaluation of the sludge samples shows one significant reduction in filamentous organisms. The Products according to the invention become in the course of the sludge age completely overgrown and are due to the inherent fluorescence in the Detectable mud.

Results of the operational test for Compost quality improvement

The aim of the experiment is to improve the quality of the compost to reach.

The use of MK1 as a multifunctional additive for the Stabilization of biological systems is based on the Combination of a carrier substance of modified cellulose and Nutrients of plant origin. On the backing material also growth factors and trace elements that are not considered Serve substrate and are not included in the substrate entry, however necessary for the viability of the microorganisms are bound.

MK1 (approx. 5 kg / day) was dosed into the excess sludge. It became a higher turbidity of the filtrate water Belt press and another sedimentation characteristic of the sludge observed.

laboratory tests

• 1. Komposteinsatz ohne MK1 (Kontrolle)
• 2. Komposteinsatz mit MK1

Two compost samples were examined to compare the quality of the compost:

• 1. Compost insert without MK1 (control)
• 2. Compost insert with MK1

Compost particle distribution

1.2 kg of the samples were sieved through different sieve sizes ( Fig. 2).

Organic substances in the filtrate water

50 g of compost (<3 mm) were mixed with 100 ml and 5 to 10 min stirred at 300 rpm. The samples were then 5 min Centrifuged to 6000 rpm in the laboratory centrifuge. Of the Different UV spectra (spectrophotometer JASCO V-530) and the metal content (Merck test kit) measured.

charge measurements

Müteck PCD 02 was used for the charge measurements.
Sample - without additive - 11 µeqv / g
Sample - with additive - 15 µeq / g.

germination test

10 corn and bean seeds were covered in a Petri dish with a 1: 1 compost: soil mixture and the germination process was observed. The results are shown in Table 12. Only earth was used as a control. The samples were germinated on the laboratory table and under laboratory temperature (20 ° C). Table 12

Conclusions

The effect of using products according to the invention became clear through the various biological tests assessed. Germination and growth process of the examined Plants are better in compost treated with the invention. Due to the particle size distribution, in particular one 25% reduction in compost volume found.

Claims (15)

1. Additive comprising an inorganic and / or organic Carrier material and immobilized thereon and / or thereof enveloped factors affecting the metabolism and the Viability of aerobic and / or anaerobic microorganisms that attack biodegradation reactions are involved. 2. Additive according to claim 1, characterized in that the Carrier material made of natural and / or synthetic organic polymers is selected. 3. Additive according to claim 1 or 2, characterized in that that the carrier material is cellulose [poly-β- (1,4) -D-glucose], is regenerated and / or derivatized cellulose. 4. Additive according to one of claims 1 to 3, characterized characterized in that the carrier material is cellulose xanthate is. 5. Additive according to one of claims 1 to 4, characterized characterized in that the inorganic carrier material made of gypsum, Cement, zeolite and / or bentonite is selected. 6. Additive according to one of claims 1 to 5, characterized characterized that the metabolism and viability biological factors influencing the microorganisms Are of origin. 7. Additive according to claim 6, characterized in that the the metabolism and viability of the Factors influencing microorganisms nutrient and / or Growth factors, minerals, proteins, enzymes, biocides and / or Are fungicides. 8. Additives according to claim 6 or 7, characterized in that that the ratio of carrier material / factors is between 0.01 up to 99 is included. 9. Additive according to claim 8, characterized in that the Ratio of carrier material / factors between 1 to 10, is preferably contained between 0.1 to 0.3. 10. Additive according to one of claims 1 to 9, in particle, Granular or fiber form. 11. Additive according to any one of claims 1 to 10, the further Stabilizers, fillers and other suitable Additives, such as sedimentation aids. 12. Use of an additive according to one of claims 1 to 11 in biological wastewater treatment. 13. Use of an additive according to one of claims 1 to 11 during composting. 14. Use of an additive according to one of claims 1 to 11 in biological air purification. 15. Use of an additive according to one of claims 1 to 11 biological soil cleaning.