DE202018000073U1 - Monitoring system for tanks, manure basins, slurry tanks, manure channels and ground basins for the storage of manure, liquid manure and silage seepage and for containers of biogas plants - Google Patents

Abstract

Monitoring system for above ground, earthed and underground containers, manure basins, slurry tanks, manure channels and basins for storage of manure, manure and silage and juices as well as containers of biogas plants, which are filled with generally water pollutants such as fermentation substrates and digestate or water pollutants characterized in that Installation of electrical measuring probes (electrodes), which are placed around and under the containers distributed in the ground, if necessary in combination with an inner electrode, which is immersed in the liquid in the container, a geoelectric monitoring for leakage detection can be performed.

Description

I. Short description

The invention relates to a monitoring and automated monitoring of containers, slurry basins, slurry tanks and manure channels and basins for storage of liquid manure, manure, and silage Seed to JGS facilities and containers of biogas plants that are filled with generally water pollutants such as fermentation substrates and digestate or water pollutants ,

"Basin ponds are ponds built into the ground or built by dams, which consist of soil in the floor and slope area and are lined with geomembranes opposite the ground." (Definition from the TRwS 792, DWA, 2015 ). "Manure basements, slurry tanks and manure channels in the sense of this TRwS are storage and collection facilities under stables. If necessary, they can also project beyond the footprint of a stable plant "(definition from the TRwS 792, DWA, 2015 ).

"Biogas plants" are: 1. plants for the production of biogas, in particular storage tanks, fermenters, condensate tanks and aftergarters, 2. facilities for storing fermentation residues or fermentation substrates, if they are in a close spatial and functional relationship with plants according to number 1, and 3. Filling plants belonging to the installations referred to in points 1 and 2 "(cf. AwSV, 2017 )

In the following, all types of containers, ground basins, slurry basins, manure tanks, manure channels of JGS plants and biogas plants, which are generally water-polluting substances or substances hazardous to water according to the definitions of regulations for facilities for handling water pollutants ( AwSV, 2017 ) are filled or operated, referred to as JGS storage facilities / biogas tank.

The invention covers above-ground JGS storage facilities / biogas tanks where only the floor slab is on the ground, JGS storage facilities / biogas tanks and underground JGS storage facilities / biogas tanks.

For automated leak detection of the JGS storage facilities / biogas tanks geoelectric measuring probes are used and geoelectric measurements are carried out.

"Single-walled JGS storage facilities for liquid, generally water-polluting substances with a total volume of more than 25 cubic meters must be equipped with a leak detection system" (cf. AwSV, 2017, Appendix 7, No. 3.1 ). For older existing installations where retrofitting of a leakage monitoring system is not possible or which would only be possible with a disproportionate effort, level measurements must be carried out (according to TRwS 792, DWA, 2015 ). If these are operationally or technically not feasible, visual inspections of critical points and / or groundwater measuring points can be established, depending on the individual case (according to TRwS 792, DWA, 2015 ).

These visual inspections should be carried out regularly, with examination points of 10 m or 30 m, depending on the size of the container, as per the instructions TRwS 792, DWA, 2015 ). This results in particular the difficulty of detecting possible leaks between the outcrops and in the bottom plate, or even the joints of the concrete slabs. In addition, due to the time intervals of the tests, potential leaks may not be detected until months after the first crack has occurred. At the groundwater measuring points, the checks of pH value, electrical conductivity, temperature, oxygen and other parameters should also be carried out once a year (according to TRwS 792, DWA, 2015 ), whereby a time delay between leakage and leakage detection would also be disregarded. In addition, the measurement of the general groundwater parameters in the inflow and outflow area does not allow any conclusions about the position of the potential leakages.

The above-mentioned difficulties of the previous testing options could be remedied by an automated monitoring system with individually controllable measurements, which also permitted range checks for different sections of the systems.

As a utility model, an automated monitoring system for JGS storage facilities / biogas tanks is to be protected by means of geoelectric measurements. For this, electrical measuring probes (electrodes) are distributed around and under the JGS storage facilities / biogas tanks, placed in the ground, so that then geoelectric monitoring can be carried out. By combining with an internal electrode immersed in the liquid in the container, the measurement can be supplemented if necessary.

The principle of geoelectric measurements is that a current is induced between two "current electrodes" and the potential difference between two other "potential electrodes" is measured. From the ratio of voltage or potential difference to the induced current, one obtains the specific electrical resistance (reciprocal of the electrical conductivity) of the soil volume, between which the potential difference was measured. The method is z. Eg at " KNÖDEL et al. 2005 "Described.

The specific electrical resistance of a soil is determined by various influencing parameters, including porosity, water content, chemical composition (such as salinity or cation exchange capacity), temperature, grain size distribution, orientation and shape (based on " FRIEDMANN 2005 "). Water content, chemical composition / salinity of the pore fluid and temperature, are the strongest influencing factors. If one knows the soil composition, or if one carries out a reference measurement, one can observe the change of a selected soil parameter over a period of time, if the other influencing parameters remain constant. Since the general soil parameters, such as storage or soil type (particle size distribution), do not significantly change in the subsurface under undisturbed conditions over a longer period of time, it can be assumed that potential changes in the electrical resistivity of a soil volume due to changes in water content or salinity, or due to the chemical composition.

Dry soil has a relatively high resistance (see Table 1). On the other hand, there are the lower electrical resistance values of different types of water or aqueous solutions, which are determined by their chemical composition with the dissolved constituents. The increase in the electrical conductivity, or the reduction of the electrical resistance of a soil, is accordingly determined mainly by its water saturation, or the chemical composition of the pore fluid. For comparison, values of water-saturated soils are given in Table 1.

The electrical resistance values for liquid manure, however, again stand out from the values for saturated soils due to the salt concentration. In the case of geoelectrical monitoring, a sudden leakage of the stored substances through a small leakage of a JGS storage facility or biogas tank (on a tank wall or the floor slab) would abruptly sharply reduce the electrical resistance value compared to the previously recorded values for the given floor volume and thus also to one Close leakage.

For the geoelectrical monitoring of the JGS storage facilities / biogas tanks, electrode chains are installed around and under the test object, whereby one current (I) is fed in via two of the installed electrodes (usually called electrodes A and B) and the apparent, between two other electrodes specific electrical resistance value for the volume (U) by measuring the voltage difference (usually referred to as electrodes M and N) can be determined (see. ). The calculation of the specific electrical resistances takes place via corresponding evaluation formulas (analogously KNÖDEL et al. 2005 ). In order to enable a high-resolution monitoring system with location of the leakage, the number, the electrodes to be installed, the distance between the electrodes and the number of electrode chains, depending on the size and shape of the container adapted. The arrangement of the various electrodes, the electrode distances and the specific measurement configurations make it possible to assess the location of a potential leak. In addition, during the measurement, a central electrode immersed in the JGS liquid / generally water-endangering or water-endangering liquid can be integrated into the measuring arrangement of the electrode chains.

Multicore cables are used for the electrode chains, with the respective cores being connected to electrodes at the appropriate depth. As electrodes, stainless steel rings are fastened to the outside of the pipe at regular intervals and connected to the respective wires of the cable through a hole in the pipe. The cables can be mounted in holes protected by plastic pipes.

The measurement is carried out by a computer / measuring device, by which the different electrodes can be controlled individually as current electrodes, or as potential electrodes for the specific resistance measurement of the corresponding floor volume. Depending on the distance between the electrodes, it is thus possible to make precise statements about the position of a possible leak.

II. Detailed presentation

A. Introduction

The storage and subsequent reuse of liquid manure, liquid manure, silage seepage and similar materials used in agriculture and in biogas plants make a significant contribution to soil improvement, air pollution control and climate protection.

However, a high uncontrolled entry of these accumulating substances poses a danger to the waters, especially to the groundwater. All the more important is a suitable construction and the regular maintenance of the equipment to ensure the tightness against material leakage.

Until the entry into force of the AwSV on April 1, 2017, construction, operation and maintenance were governed exclusively by the respective country ordinances. In order to do justice to the groundwater protection in the context of the water household law (§62 WHG), the German association for water management, waste water and waste e. V. (DWA) the rules for the construction and use of JGS plants as TRwS 792, (DWA, 2015) and for biogas plants as TRwS 793-1, (DWA, 2017) nationwide concretized. These regulations also define requirements for maintenance and inspection, including with regard to possible leaks. Thereafter, new plants, z. B. to integrate specific leakage monitoring systems (according to TRwS 792, DWA, 2015 ), which allow a quick and reliable detection of leaks in case of leakage. These systems consist of a sealing layer (leak detection foil) with overlying drainage layer and a drainage pipe (according to the requirements of TRwS 792, DWA, 2015). In addition, several expert reviews are planned before commissioning and then at regular intervals; z. B. Ordnungsprüfungen, technical tests and leak tests (according to TRwS 792, DWA, 2015).

The leak test prior to commissioning of JGS systems exists (loud TRwS 792, DWA, 2015 ) from two partial exams. A visual inspection and water level test as well as a test at full capacity under operation after one year. For biogas plants there is a duty to inspect before commissioning and a recurrent inspection obligation ( AwSV, 2017 ).

Problems with leaks are particularly the older existing facilities, as they are exposed for many years of the aggressiveness of concrete attacking organic acids and other components of liquid manure, liquid manure silagesickers and other generally water polluting and water polluting substances and a leakage monitoring system is usually missing. In addition, cracks may form in the concrete over time. Other problems include missing waterstops, joint tapes made of unsuitable materials that tend to corrosion, openings of the formwork anchors, spalling or the like.

For older existing systems, in which a retrofitting of a leakage monitoring system is not possible, or would be carried out only with a disproportionate effort, level measurements should be performed. If these are not operationally or technically feasible, visual inspections of critical points and / or groundwater measuring points can be established, depending on the individual case (according to TRwS 792, DWA. 2015 ).

These visual inspections should be carried out regularly, with examination points of 10 m or 30 m, depending on the size of the container, as per the instructions TRwS 792, DWA, 2015 ). This results in particular the difficulty of detecting possible leaks in the area between the outcrops, but especially in the bottom plate or joints of the concrete slabs. In addition, potential leaks may not be detected until months after the first crack has occurred. At the groundwater measuring points, the pH, electrical conductivity, temperature, oxygen and other parameters should also be checked once a year, which would also disregard a time delay between leakage and leakage detection.

A monitoring system, which could automatically check the containers at defined time intervals, would significantly reduce the cost of visual inspection by an expert (including emptying the containers, costs for experts, etc.) and ensure a higher level of safety or earliest possible leak detection.

Eg idea

As an alternative monitoring method geoelectric methods could be used. Geoelectrics is already regarded as a proven method for many environmental, geotechnical and engineering-geological questions (analogously to " KNÖDEL et al. 2005 "). The measuring principle consists of inducing a current between two (current) electrodes (A and B) and measuring the potential difference between two further (potential) electrodes (M and N) (cf. ). From the ratio of voltage or potential difference to induced current, one finally obtains the apparent electrical resistivity of the soil volume, between which the potential difference was measured. The calculation of the specific electrical resistances (the reciprocal of the electrical conductivity) takes place via corresponding evaluation formulas (analogously KNÖDEL et al. 2005 ).

The specific electrical resistance of a soil depends on various parameters, including porosity, water content, chemical composition (such as salinity or cation exchange capacity), temperature, grain size distribution, orientation and shape (see Friedman 2005 ). Water content, temperature and chemical composition / salinity are the strongest influencing factors.

Table 1 shows examples of the resistivity values of some soil materials and water types. The large differences in the resistance values between the dry and the saturated state show very strongly the influence of the water content, while the difference between the resistance values of the water types describes the strong influence of the salinity, or the chemical composition.

The chemical composition of the soil plays an important role in agriculture, accordingly geoelectric methods have already been widely used for the evaluation of agricultural land (see " CORVIN and LESCH, 2005 ").

If one knows the soil composition, or if one carries out a reference measurement, one can observe the change of a selected soil parameter over a period of time, if the other influencing parameters remain constant. Since the general soil parameters, such as storage or soil type (grain distribution); in the subsurface in undisturbed conditions over a long period does not change significantly, it can be assumed that potential changes in the electrical resistivity of a soil volume by changes in water content; or salinity; or due to the chemical composition. Accordingly, geoelectrics has already been used successfully for monitoring the propagation of groundwater or the propagation of (salt) tracers in the subsurface.

The resistance values z. Due to their composition, for example, liquid manure, manure, silage seepage, fermentation substrates and fermentation residues would have to correspond to the resistance values of brines (see Table 1) and stand out from the typical values for soil types. The geoelectrics thus offers high potential for checking the tightness of JGS systems, and also for the construction of an automated monitoring system. A sudden escape of the stored, highly saline liquid at a small leakage of a plant (on a container wall or the bottom plate) would abruptly decrease the electrical resistance value compared to the previously recorded values for the given soil volume and thus also suggest a leakage.

The idea is to install electrode chains around the vessel instead of the possible typical groundwater measuring points (one upstream, one downstream) with the annual measurements and to set up automated geoelectric monitoring (cf. ). Multicore cables can be used for the electrode chains, with electrodes of appropriate depth being used as the current or potential electrode on the respective cores. To reinforce, and to produce a uniform connection to the ground, the stripped portions of the wires can be reinforced in the respective heights with small wire nets and wound around the outer diameter of the pipe, or also be coupled to the outside, around the pipe mounted stainless steel rings. Various construction methods are tested with application of the utility model. The estimation of the location of a leak enables the arrangement of the various electrodes as well as the specific electrode configurations.

C. Carrying out the measurement

The measurement is carried out by geoelectric measuring devices or computer-controlled geoelectric measuring devices, through which the various electrodes as current electrodes and also individually the Potential electrodes for specific resistance measurement of the corresponding soil volume can be controlled. Depending on the distance between the potential electrodes, it is thus possible to make precise statements about the position of a possible leak.

As measuring apparatuses come various devices, such. B. RESECS II (geoserve) or GeoTom (Geolog2000) in question. For example, RESECS II allows the connection of several 100 measuring points (electrode connections) with one / multi-channel advice / multi-channel application. Depending on the size of the system and the number of electrodes used, a wide variety of ground units / units in the underground can be checked for changes in the specific resistance value, which allows accurate leak detection.

The purpose of the present paper is therefore to protect an automatic monitoring system for monitoring JGS storage facilities / biogas tanks using geoelectrics as a utility model.

D. Benefits of the surveillance system

• - No visual inspection necessary.
• - Continuous monitoring.
• - Automated testing according to individual ideas and intervals, also possible via remote control.
• - Verification of the method with conductivity probe possible because electrical resistance corresponds to the reciprocal of the electrical conductivity.
• - Different integral measurements possible (contrary to punctual measurements with a conductivity probe in the groundwater measuring point). This allows location of the leakage possible.
• - Possibility for spatial surveillance
• - By different measuring arrangements, a determination of the position of the leakage is possible.

III. References

• REGULATION ON PLANTS FOR THE CONTACT OF HYDROGEN-HAZARDOUS SUBSTANCES (AWSV) of 18 April 2017 (BGBI I p. 905 )
• CORWIN, D.L. and S.M. LESCH, 2005. Apparent soil electrical conductivity measurements in agriculture. In: Computers and Electronics in Agriculture. 46, p. 11-43
• GERMAN ASSOCIATION FOR WATER INDUSTRY, WASTEWATER AND WASTE E.V. (DWA), 2015. Worksheet DWA-A 792: Technical Rule of Substances Hazardous to Water (TRwS) JGS Installations (Draft). Bad Honnef: Siebengebirgsdruck. ISBN 978-3-88721-222-3
• GERMAN ASSOCIATION FOR WATER MANAGEMENT, WASTE WATER AND WASTE E.V. (DWA), 2017. Worksheet DWA-A 793-1: Technical rule for substances hazardous to waters (TRwS) Biogas plants - Part 1: Construction and operation with fermented substrates of agricultural origin (draft). Bad Honnef: Siebengebirgsdruck. ISBN 978-3-88721-516-3
• EGHBALL, B., 2002. Soil Properties as Influenced by Phosphorus and Nitrogen-Based Manure and Compost Applications. In: Agronomy Journal, 94, pp. 128-135
• FRIEDMAN, S.P., 2005. Soil properties. In: Computers and Electronics in Agriculture, 46, p. 45-70
• KNÖDEL, K., H. KRUMMEL and G. Lange, 2005. Handbook for the investigation of the underground of landfills and contaminated sites. Volume 3: Geophysics. 2nd Edition. Berlin-Heidelberg: Springer Verlag. ISBN 978-3-540-26606-8
• RUFETE, B., M.D. PEREZ-MURCIA, A. PEREZ-ESPINOSA, A.MORAL, J. MORENO-CASELLES and C. PAREDES, 2006. Total and faecal coliform bacteria persistence in a pig slurry amended soil. In: Livestock Science, 102, pp. 211-215

IV. Tables

Table 1: Examples of specific electrical resistance values of various soil materials and aqueous substances. material Electrical resistance [Qm] Electrical conductivity [S / m] source Gravel (dry) > 10,000 (dry) 0.001 Knödel et al., 2005 Gravel (water saturated) > 50 0.02 Sand (dry) > 10,000 (dry) 0.001 Sand (water-saturated) > 50 0.02 silt 20-50 0.02-0.05 boulder clay 30-70 0.014 to 0.033 loess 30-100 0.01 to 0.033 Clay (earth moist) 3-30 0.033 to 0.333 Clay (dry) > 1000 <0.001 Peat, humus, silt 15-25 0.04 to 0.066 Limestone (cleft, moist) 100 0.01 Limestone (compact) 100000 0.00001 Magmatite, Metamorphite (weathered, moist) 150 0,007 Magmatite, Metamorphite (compact) > 1,000,000 <0.000001 Distilled water > 1,000 <0.0001 Natural waters 10-300 0.003 to 0.1 Seawater (35 ‰) 0.25 4 brines <0.1 > 10 pig manure 0.514 1,946 Rufete et al., 2006 pig manure 1.852 to 2.63 0.38 to 0.54 Eghball, 2002

V. Embodiment

An embodiment of the invention of the monitoring system and automated monitoring system will be described with reference to to explained. Show it:

A. Fig. 1

In the area a current (I) is fed in and between the electrodes ( 4 ) the potential difference (U) is measured. According to Ohm's law, the ratio U to I gives resistance R. Due to the various parameters influencing the soil, such as chemical composition, water content, soil type, etc., the specific electrical resistance of the soil volume is measured here, and the potential difference between them was recorded. (see also Knödel et al., 2005; , Page 129)

B. Fig. 2

Example of possible arrangements of the electrode chains around a JGS storage facility / biogas tank in plan view.

C. Fig. 3

Example of possible arrangements of the electrode chains around a JGS storage facility / biogas tank in the side view.

D. Fig. 4

Example of possible arrangements of electrode chains around a ground basin in plan view.

E. Fig. 5

Example of possible arrangements of the electrode chains around a ground basin in the side view.

LIST OF REFERENCE NUMBERS

1

Current source (I)

2

Measuring device for potential difference (U)

3

Electrode A for feeding a low-frequency alternating or direct current into the underground

4

Electrode B for feeding a low-frequency alternating or direct current into the underground

5

Measuring electrode M

6

Measuring electrode N

7

earth's surface

8th

streamline

9

Container interior (filled during the measurement)

10

Measuring electrodes chain

11

central electrode

12

Connecting cable of a measuring electrode chain

13

Single electrode of a measuring electrode chain

14

Connecting cable central electrode

15

container wall

16

geomembrane

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• TRwS 792, DWA, 2015 [0002]
• TRwS 792, DWA, 2015 [0002]
• AwSV, 2017 [0003]
• AwSV, 2017 [0004]
• AwSV, 2017, Appendix 7, No. 3.1 [0007]
• TRwS 792, DWA, 2015 [0007]
• TRwS 792, DWA, 2015 [0007]
• TRwS 792, DWA, 2015 [0008]
• TRwS 792, DWA, 2015 [0008]
• KNÖDEL et al. 2005 [0011]
• FRIEDMANN 2005 [0012]
• KNÖDEL et al. 2005 [0015]
• TRwS 793-1, (DWA, 2017) [0020]
• TRwS 792, DWA, 2015 [0020]
• TRwS 792, DWA, 2015 [0021]
• AwSV, 2017 [0021]
• TRwS 792, DWA. 2015 [0023]
• TRwS 792, DWA, 2015 [0024]
• KNÖDEL et al. 2005 [0026]
• KNÖDEL et al. 2005 [0026]
• Friedman 2005 [0027]
• CORVIN and LESCH, 2005 [0029]
• Knödel et al., 2005 [0037]
• Rufete et al., 2006 [0037]
• Eghball, 2002 [0037]

Claims (2)

Monitoring system for above ground, earthed and underground containers, manure basins, slurry tanks, manure channels and basins for storage of liquid manure, manure and silage and juices as well as containers of biogas plants that are filled with generally water pollutants such as fermentation substrates and digestate or water pollutants characterized in that Installation of electrical measuring probes (electrodes), which are placed around and under the containers distributed in the ground, if necessary in combination with an inner electrode, which is immersed in the liquid in the container, a geoelectric monitoring for leakage detection can be performed. Automated monitoring system for monitoring above-ground, earth total annealed and underground container, manure pit, slurry trays, slurry channels and ground basin for the storage of liquid manure and silage and for containers of biogas plants which are filled with a generally water-polluting substances such as fermentation substrates and fermentation residues or water-polluting substances characterized in that the measurement is carried out by a computer / measuring device, by means of which the various electrodes can be controlled individually as current electrodes or as potential electrodes for the specific resistance measurement of the corresponding floor volume. Depending on the distance between the electrodes, it is thus possible to make precise statements about the position of a possible leak.

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