DK177393B1

DK177393B1 - Method and apparatus for extracting or concentrating carbonaceous compounds from a fluid

Info

Publication number: DK177393B1
Application number: DKPA201170491A
Authority: DK
Inventors: Nicolaj Oerskov Olsen; Elaheh Roshani
Original assignee: Horsens Vand En As
Priority date: 2011-09-02
Filing date: 2011-09-02
Publication date: 2013-03-18
Also published as: EP2751039A1; WO2013029615A1

Abstract

This invention relates to a method for extracting or concentrating carbonaceous corn pounds from a fluid containing carbonaceous material during wastewater, sludge or biomass treatment using a wastewater plant, which method comprises steps of: -(i) collecting, mixing the fluid in a bio process tank -(ii) subjecting the fluid to clarification in a clarification tank thereby obtaining a dan fied fluid, which separates between a treated fluid and a sludge fluid -(iii) subjecting at least one of the clanified fluids and predominantly the sludge fluid to ultrasonic irradiation using an ultrasound system to form a disintegrated fluid -(iv) subjecting the disintegrated fluid to a separation process using a centrifuge to form a rejected fluid and centrifuged fluid -(v) subjecting the centrifuged fluid to digestion in a digester to form a carbon rich gas suitable for further industrial utilization in a gas refiner or in a gas engine.

Description

DK 177393 B1 i

Method and apparatus for extracting or concentrating carbonaceous compounds from a fluid.

Field of the Invention 5 The present invention relates to a method for extracting or concentrating carbonaceous compounds from a fluid containing carbonaceous material during wastewater, sludge or biomass treatment using a wastewater plant. The invention further relates to an apparatus for extracting or concentrating carbonaceous compounds from a fluid containing carbonaceous material.

10 Background of the Invention

Treatment of wastewater or sludge is an important part of preserving nature and conserves natural resources in an industrial society being defined in an urban or rural area.

15 Moreover existing wastewater plants established to treat or process wastewater and waste material to circulate or re-circulate water into the natural water cycle exist.

A disclosure of a treatment of wastewater or sludge is known from patent application W001/16037, which discloses a method and a system for treating sludge in a waste-water plant and comprising the steps of concentrating the sludge, selecting a desired 20 homogenizing pressure, disrupting a least a portion of the celluar matter in concentrated sludge at the desired homogenizing pressure, digesting the disrupted sludge to produce methane gas.

Although the system and method of treating sludge is a starting point to extract carbo-25 naceous compounds, the system and method are amongst other things, inferior due to the use of high pressure since this high pressure will disrupt the cell walls of bacteria in the sludge and thus result in a less effective extraction of carbonaceous compounds.

Cell disruptions occur at high pressures such as 100 to 200 bars, approximately, where the cell wall disruptions are caused by the extracellular pressure.

30 DK 177393 B1 2

Even the use of a Super Micro-Gap homogenizing valve to reduce pressure will still result in cell wall cavitation.

A further drawback of the high pressure used in the system and method mentioned 5 above, is that it consumes more energy and therefore has a poor energy balance.

Object of the Invention

It is an object of the present invention to improve the absorptive capacity of nutrients such as ammonium (NH4+) from the fluid or matter being treated.

10 Another object of the present invention is to provide means and methods for more efficient and effective extraction of carbonaceous compounds from a fluid in a waste-water or sludge treatment process or plant.

Description of the Invention

At least one object is met according to this invention by a method for extracting or 15 concentrating carbonaceous compounds from a fluid containing carbonaceous material during wastewater, sludge or biomass treatment using a wastewater plant, which method comprises steps of: -(i) collecting, mixing the fluid in a bio process tank -(ii) subjecting the fluid to clarification in a clarification tank thereby obtaining a 20 clarified fluid, which separates between a treated fluid and a sludge fluid -(iii) subjecting at least one of the clarified fluids and predominantly the sludge fluid to ultrasonic irradiation using an ultrasound system to form a disintegrated fluid -(iv) subjecting the disintegrated fluid to a separation process using a centrifuge to form a rejected fluid and centrifuged fluid -(v) subjecting the centrifuged fluid to di-25 gestion in a digester to form a carbon rich gas suitable for further industrial utilization in a gas refiner or in a gas engine.

In one embodiment the digestion is anaerobic. In another embodiment the digestion is aerobic.

30 DK 177393 B1 3

According to an embodiment of the invention, the method is special in that it further includes a step of subjecting the fluid to clarification in a clarification tank containing aquatic bio plants or weeds such as Duckweed, Azollas or Algae.

5 Thereby increasing the overall efficiency of the method in that the aquatic bio plants to clean the wastewater by removing ammonium.

A further effect is that the aquatic bio plants accumulate carbon thereby reducing or eliminating the need to add pure carbon to the process.

10

The actual use of Duckweed has shown to be particular effective due to the fast reproduction time of Duckweed in the wastewater plant environment.

Several species of Duckweed can be used: Duckweed (Lemna minor), Greater Duck-15 weed Lemna polyrrhiza), Gibbous Duckweed or Fat Duckweed (Lemna gibba), or Star Duckweed (Lemna triscula).

According to an embodiment, the aquatic bio plants used are Azollas. Azollas increase the overall efficiency and it has been found that Azollas are beneficial.

20

Azollas bind Nitrogen thereby producing fertilizers. Azollas are rich on essential amino acids, proteins, vitamins, and minerals thereby providing valuable feed stock for animals. Azollas bind Carbon Dioxide thereby binding Carbon and enhancing carbonaceous content. Azollas can be used to produce biogas due to its carbonaceous 25 content and bio diesel due to the plants high oil content.

Several species of Azollas can be used: Caroliniana, Filiculoides, Mexicana, Mecro-phylla, or Pinnata.

30 The aquatic pants including Duckweed and Azollas are particularly suited as the have high growth or reproduction rates in the wastewater environment. Thereby aquatic plants increase the absorption of nutrition from the wastewater. A further increased effect is that they bind carbon for bio fuel and/or biogas production. A further in DK 177393 B1 4 creased effect is that they bind carbon and introduce carbon to the process tanks thereby reducing or eliminating the need for feeding external carbon to the process tanks.

5 It has further shown that aquatic plants such as Duckweed and Azollas are suited for decomposition or disintegration by use of ultrasound. Thereby further enhancing the wastewater plant's biomass entering the wastewater process.

According to an embodiment of the invention, the method is special in that it further 10 includes a step of feeding back fluid to the bio process tank, which feedback preferably is the rejected fluid from the centrifuge.

Thereby the fluid, and here predominantly the rejected fluid from the centrifuge, with nutrition will re-enter the wastewater process in the bio process tank thereby utilizing 15 the process tanks.

According to an embodiment of the invention, the method is special in that it further includes a step of feeding fluid back to the ultrasound system, which feedback preferably is at least part of the centrifuged fluid from the centrifuge.

20

Thereby the fluid, and here predominantly the rejected fluid from the centrifuge, with nutrition and bio mass and in particular aquatic plant remains will re-enter the decomposition process caused by the ultrasonic system.

25 According to an embodiment of the invention, the method is special in that it further includes a step of performing a Chemical Oxygen Demand (COD) measurement, a COD-measurement, on a fluid using a COD-meter in at least one process tank and preferably of the rejected fluid from or in the centrifuge.

30 Thereby obtaining a measurement or indication of the amount of organic compounds in the fluid and preferably the rejected fluid from the centrifuge, which rejected fluid is fed back into an earlier stage of the wastewater plant process.

DK 177393 B1 5 A person skilled in the art will find different places to perform the measurement and the COD-meter is understood to be a unit configured for performing the COD- measurement more or less automatically although a manual, intermitted or periodic COD-measurement is within the scope of the invention.

5

Likewise the person skilled in the art will chose a particular COD-measurement method. A starting point could be the ISO 6060, which describes a standard method for measuring chemical oxygen on demand.

10 The person skilled in the art will most likely seek to get a measure expressed in milligrams per liter (mg/L) although the person skilled in the art will know that a relative measure of a value that will imply or from which the absolute COD-measure can be derived will suffice for the purpose of using the COD-measure or indicator to control the feedback process.

15

The person skilled in the art will according to the invention use a COD-measure to regulate the amount of fluid to be fed back. In a particular embodiment the regulator is a gate or a valve simply opening for the feedback of fluid to occur when the COD-measure or indicator passes a threshold.

20

In an embodiment the regulator has access to a look-up table with values that for the particular plant have been found to be optimal.

In an embodiment the regulator is implemented on a computer and the control algo-25 rithm used to control valves and the amount of fluid to be fed back relies on calculations and optimisations of free variables identified in the feedback loop.

According to an embodiment of the invention, the method is special in that it further includes the steps of performing a effect or power measurement of the power con-30 sumption of at least one process tank using at least one power meter and preferably in the ultrasound system; - performing an estimate of the residual energy in the fluid and preferably the rejected fluid based on the COD-measurement; DK 177393 B1 6 - performing and projection of the energy needed to reprocess the fluid in the feedback and preferably the rejected fluid - performing a comparison of the projected energy needed to reprocess the fluid in the feedback and preferably the rejected fluid with the estimated residual energy in the 5 fluid and preferably the rejected fluid based on the COD-measurement to provide an feedback or no feedback decision indicator, which indicator determines if the fluid is to be fed back for reprocessing thereby automating the method.

Thereby the regulator can be optimized with respect to energy consumption. Thereby 10 the regulator can be optimized with respect to obtaining as much energy from in the biomass such as biogas as compared to the energy needed to concentrate or extract the biomass or biogas.

Having these measures, a person skilled in the art will find it natural to begin to ex-15 periment with standard optimisation or control systems.

According to an embodiment of the invention, the method is special in that it further includes at least one of the steps of: - parting or chopping the fluid and in particular the 20 - buffering and/or stirring the fluid by stirring means.

Thereby the matter or materials embedded in the fluid will be parted resulting in a larger surface area. Furthermore the chopper willing will allow for material to be added from an external source at this point in the process.

25

The buffering and/or stirring of the fluid will mix the fluid thereby enhancing the biological process.

According to an embodiment of the invention, the method is special in that it further 30 includes a step of: - delivering the products or residue products to a receiving tank, and from the receiving tank feeding the products or residue products to the wastewater plant and preferably: DK 177393 B1 7 - feeding the agricultural products or residue products to the chopper for chopping the agricultural products or residue products, or - feeding the food products or residue products to the buffer tank to be blended or stirred with stirring means.

5

Thereby the previously disclosed process plant can be directly used to process agricultural products or residue products and thereby converting or extracting from these carbonaceous compounds in the form of a carbon rich gas suitable for further industrial utilization in a gas refiner or in a gas engine.

10

Or thereby extract carbonaceous compounds from food products or residue products added to the process.

The buffer further allows for a controlled feed of material into the system.

15 A person skilled in the art will during operation and depending on the size of the plant, time constants and so, find at least a suitable feeding point and chopping size. Some times copping or parting of food products will be needed and the chopper is easily modified, altered or changed to facilitate food or agricultural products to enter 20 at a suitable sizes and speed

At least one object is met according to this invention by a method for producing usable energy such as electricity or heat from a carbon rich gas is special in that it includes a step of burning the gas in a in a gas engine, converting the gas in a fuel cell, 25 or any other type of engine or chemical devices configured for converting chemically bound energy to energy in the form of electricity or mechanical energy.

At least one object is met according to this invention by a fluid, such as a wastewater or sludge, treatment plant comprising a series of process tanks interconnected by con-30 duits, which process tanks are: - a bio process tank for collecting, mixing and pre processing a fluid - a secondary clarifier for clarifying the fluid into a treated fluid and a sludge fluid, and a conduct arranged to transfer the sludge fluid to DK 177393 B1 8 - an ultrasound system for disintegrating the sludge fluid into a disintegrated fluid - a centrifuge for centrifuging the disintegrated fluid into a rejected fluid and a centrifuged fluid - a digester for digesting the centrifuged fluid and by degassing the centrifuged fluid 5 forming a carbon rich gas and optionally: a chopper inserted after the second clarifier for chopping a fluid fed to the chopper, which chopper optionally has means for receiving agricultural products or residue products directly or from a first receiving tank; and/or 10 - a buffer tank with stirring means inserted before the ultrasound system for buffering and/or stirring the fluid and optionally has means for receiving food products directly or from a second receiving tank; - a first feedback conduit connecting the centrifuge back to the bio process tank and allowing a rejected fluid to be fed back to the bio process tank based on signals from a 15 feedback controller with inputs from a COD-meter measuring the COD from the centrifuged fluid and optionally from a power-meter measuring the power consumed by at least the ultrasonic system.

Thereby an apparatus is provided to extract or concentrate carbonaceous compounds 20 from a fluid containing carbonaceous material during wastewater, sludge or biomass treatment. In particular the apparatus is to make a carbon rich gas suitable for further industrial utilization in a gas refiner or in a gas engine.

Description of the Drawing 25 This invention will be described and exemplified in relation to the drawings, where:

Figure 1 shows a schematic flow chart of a wastewater plant for extracting or concentrating carbonaceous compounds from a fluid, 30 figure 2 shows a schematic flow chart of a wastewater plant for extracting or concentrating carbonaceous compounds from a fluid with feedback conduits for recirculation of fluids based on power consumption and COD-measurements, DK 177393 B1 9 figure 3 shows a schematic flow chart of a wastewater plant for extracting or concentrating carbonaceous compounds from wastewater added agricultural or food products, 5 figure 4 shows the removal of Ammonia using A Duckweed and B Azolla, and figure 5 shows the growth or doubling time for Duckweed.

Detailed Description of the Invention

Embodiments of the present invention are described in the following in terms of tech-10 nical features as described below.

No Term I Wastewater plant ~~2 Fluid 3 Bio process tank OR Primary clarifier 4 Secondary clarifier 5 Ultrasound system 6 Centrifuge 7 Digester 8 Converter 9 Conduit or Pipe 10 Treated fluid or treated water II Sludge fluid 12 Disintegrated fluid 13 Rejected fluid / Treated water 14 Centrifuged fluid / sludge 15 Carbon rich gas OR biogas 16 Gas refiner 17 Gasengine 20 First Feedback conduit or pipe 21 COD-meter 22 Power-meter 23 Second Feedback conduit 24 Buffer tank 25 Stirring means 26 Chopper 27 First Forward conduit 28 Second forward conduit 30 First Receiving Tank 31 Second Receiving Tank 32 Agricultural products or residue products 33 Food products or residue products 5 DK 177393 B1 10

Figure 1 shows a schematic flow chart of a wastewater plant 1, which wastewater plant lisa plant suitable for treatment of a fluid 2 that primarily but not exclusively is wastewater.

The shown schematic is a wastewater plant 1 consisting of a series of elements comprising a bio process tank 3, or a primary clarifier, a secondary clarifier 4, an ultrasound system 5, a centrifuge 6 and digester 7.

10 The shown wastewater plant furthermore has a converter 8 for handling the gas.

Each of the main elements is connected in series via a conduit 9 between each element. Each conduit 9 is made to according to the nature of the fluid, being a sludge, a gas or combinations thereof. The conduit 9 is a pipe, a channel or any other means for 15 guiding the fluid between two points. A person skilled in the art will find it easy to select the proper material, size, and/or connectors to interconnect different process tanks as needed according to the invention.

In the second clarifier 4 the fluid 2 is parted in a treated fluid 10 and a sludge fluid 11.

20 The treated fluid 10 is generally thinner than the sludge fluid 11. Due to differences in densities of essentially water and other matters in the fluid 2 gravitation will tend to part or to separate the fluid 2 into a treated fluid 10 and a sludge fluid 11. In some cases the separation is very distinct like when oil and water separates and in other cases the separation is not so clear and the separation it more graduate.

25

The sludge fluid 11, or predominantly the sludge fluid 11, is conducted to the ultrasound system 12 via a conduit 9.

The ultrasound system 5 disintegrates matters in the sludge fluid 11 by ultrasonic 30 cavitation to a disintegrated fluid 12. The matter being aggregated matter of fibres, organic matter, cellulose etc, depending on the waste product being processed.

The disintegrated fluid 12 is in this embodiment conducted to the centrifuge 6 that separates the disintegrated fluid into a rejected fluid 13 and a centrifuged fluid 14.

DK 177393 B1 11

The centrifuged fluid 14 is conducted to the digester 7 via a conduit 9. In the digester 7 the centrifuged fluid degasses and a carbon rich gas 15 is released.

5 The carbon rich gas 15 is in this embodiment furthermore shown to be conducted to a converter 8 that has a gas refiner 16 and a gas engine 17 for producing electricity from the refined gas.

Figure 2 shows in a similar vein to figure 1 a schematic flow chart of a wastewater 10 plant 1.

The wastewater plant 1 is a plant suitable for treatment of a fluid 2. The shown schematic has like the plant in figure 1 a series of elements comprising a bio process tank 3, or a primary clarifier, a secondary clarifier 4, an ultrasound system 5, a centrifuge 15 6, digester 7, and a converter 8 that has a gas refiner 16 and a gas engine 17 for pro ducing electricity from the refined gas.

The wastewater plant 1 further has first feedback conduit 20 configured for feeding back preferably the rejected fluid 13 from the centrifuge 6 to the bio process tank 2.

20 In the first feedback conduit 20 there is a Chemical Oxygen Demand (COD) meter 21 configured to perform measurement of Chemical Oxygen Demand (COD).

In the shown embodiment there is a power-meter 22 measuring the power consumption of the ultrasound system 22.

25

According to a further embodiment there is a second feedback conduit 23 configured for feeding back the centrifuged fluid 14 from the centrifuge 6 back to a buffer tank 24 that has stirring means 25 and further is connected to the ultrasound system 5 via a conduit 9.

30

According to a further embodiment there is a chopper 26 inserted between the secondary clarifier 4 and the buffer tank 24, or the ultrasound system 5.

DK 177393 B1 12

In one variant of the shown embodiment a first feed forward conduit 27 that bypasses the chopper 26 and the buffer tank 24 and connects the secondary clarifier 4 to the ultrasound system 5. In some aspects the first feed forward conduit 27 is like a conduit 9 from figure 1. In other aspects the first feed forward conduit 27 allows for some 5 sludge fluid 11 and treated fluid 10 to be fed forward directly via the feed forward conduit 27 allows for some to be further processed on the chopper 26 and the buffer tank 24.

In another variant of the shown embodiment a second forward conduit 28 connects the 10 centrifuge 7 with the digester 7. In some aspects the second feed forward conduit 28 is much like the conduit 9 from figure 1.

In other aspects the second feed forward conduit 28 allows for part of the centrifuged fluid 14 to be fed directly to the digester 7 and other part of the centrifuged fluid 14 to 15 be fed back via the second feedback conduit 23.

Figure 3 shows in a similar vein to figure 1 and 2 a schematic flow chart of a waste-water plant 1.

20 The wastewater plant 1 is a plant suitable for treatment of a fluid 2. The shown schematic has like the plant in figure 1 a series of elements comprising a bio process tank 3, or a primary clarifier, a secondary clarifier 4, an ultrasound system 5, a centrifuge 6, digester 7, and a converter 8 that has a gas refiner 16 and a gas engine 17 for producing electricity from the refined gas.

25

In an embodiment building on to the wastewater plant 1 shown in figure 2, the shown embodiment further has a first receiving tank 30 configured for receiving agricultural products or residual products 32, which first receiving tank 30 has a conduit 9 that connects to the chopper 26 or a conduit 9 connected to the chopper 26.

30

In an embodiment, illustrated in figure 3, there is second receiving tank 31 configured or receiving food products or residue products 33, which second receiving tank 32 has a conduit 9 that connects to the buffer tank 24 or thereto a leading conduit 9.

DK 177393 B1 13

In variants of the embodiments shown in figure 2 and figure 3 there is a direct conduit 9 from the ultrasound system 5 to the digester 7. In between the ultrasound system 5 and the digester 7, there can be a mixer or a macerator.

5

Thereby this embodiment is suited for effective production of biogas or carbon on the basis of the presence of aquatic plants such as Azolla or Duckweed and received agricultural products or residual products 32 or food products or residual products 33.

10 Examples:

The invention as disclosed has been tested on a small scale. Amongst a series of tests and experiments used the following are representative.

Procedure to remove NH/ from (secondary) clarifier using a NH4+-kit (ex. Hack-15 Lange type LCK 305) as commonly used on wastewater plants is as follows: - fill aquatic plant (Duckweed) in 1 1 bottle with fluid from the (secondary) clarifier tank whilst stirring; - gently remove foil from tube 20 - add 0.5 ml test - immediately close tube - shake - read after 15 min at 600 nm 25 A procedure to decompose aquatic plants, Duckweed and Azolla, using ultrasound is as follows: - 30 g Azolla/Duckweed is measured - these are dissolved in 200 ml water in a blender/mixer for 3 - 6 min to form 30 a fluid - 2 g taken under stirring for a COD-measurement - let the fluid settle for about 15 min - 2 g taken for a COD-measurement DK 177393 B1 14 - perform ultrasound treatment on fluid for 30 - 60 min - let the fluid settle for about 15 min - 2 g taken for a COD-measurement 5 The COD-measurement is conducted using a standard Hack-Lange Kit (ex. Type LCK 514), which is commonly used on wastewater plants.

The COD-method used relies on an indirect determination of the total organic material and a few inorganic materials. Oxidizable substances react with sulphuric acid - po-10 tassium dichromate solution using silver sulphate as a catalyst. Chloride is masked by mercury sulphate and the green coloration (600 nm) from Cr+3 is measured.

The results were as follows: 15 Figure 4 shows the NH4+ -removal from the (secondary) clarifier is seen in figure 4.A for Duckweed and for Azolla in figure 4.B. Both figures show the level of ammonium [mg/1] versus time [days].

In the case of Duckweed, a fluid with ammonium-ions were taken from the secondary 20 clarifier tank and Duckweed was added under stirring in a 11 bottle and exposed only to natural laboratory light. In the case of Azolla, concentrated ammonium ions were used.

It is seen that the process reduces the amount of ammonium.

25

Likewise experiments have been performed to show the removal of Phosphor. In that case P-kit was used.

Figure 5 shows an example of the growth rate of Duckweed. The graph shows an in-30 crease in leaves of Duckweed (found by counting) over time. The graph shows that Duckweed has a doubling time at about 2.2 days. Azolla was found to have a doubling time at about 2.0 days. Hence aquatic weed, such as Duckweed and Azolla grow fast DK 177393 B1 15 and thereby efficiently capture and concentrates carbon and introduces carbon into the process.

The positive effect of using ultrasound is exemplified in the following tables. The 5 COD-analysis has been done as described before.

Duckweed:

Amount Volume Dry matter COD COD

[g] [ml] Dm [mg/1] [g/kg Dm] [%]

Total COD 30 200 6 6040 1208

Dissolved be- 3500 700 fore ultrasound

Dissolved after 4961 992 ultrasound

Azolla:

Amount Volume Dry matter COD COD

[g] [ml] Dm [mg/1] [g/kg Dm] [%]

Total COD 30 200 9 7850 2355

Dissolved be- 3255 977 fore ultrasound

Dissolved after 4657 1400 ultrasound 10

In both cases it is seen that the use of ultrasound has a large impact of the organic matter dissolved. For Duckweed there is an increase from 700 g/Kg Dm without ultrasound to 992 g/Kg Dm using ultrasound. For Azolla there is an increase from 977 g/kg Dm without ultrasound to 1400 g/kg Ts using ultrasound.

15 16 5 DK 177393 B1

The production of biogas from aquatic plants in the case of no feedback is estimated in the tables given below. Both tables show the estimated amount of methane gas in kg from the amount of Duckweed and Azolla respectively.

From Duckweed to Biogas

Amount of Total Amount of COD in di- Estimated Estimated Duckweed Amount of Methyl , , . COD gester biogas biogas m3 doubling time ane production UC 66 m [g/kg [Kg Ts] [Kg] [d] per year digester Ts] [m3] tank [kg] 4400 1208 1208* (4400*0706)/1000=319 0,25*319=80 80/0,65=123 2 (365/2)*123=22462

From Azolla to Biogas

Amount Total Amount of COD in di- Estimated Estimated Azolla- Amount of Meth- ,, COD gester biogas biogas m3 doubling ane production per ot Azolla [g/kg [KgTs] |Kg| time year indi- Ts] [d] [m3] gester tank [kg] 4400 2355 2355*(4400*0,09)/1000=933 0,25*933=233,25 233,25/0,65=359 2 (365/2)*359=65517,5 10 The production of carbon from aquatic plants is estimated in the tables given below.

Both tables show the estimated amount of carbon in kg from the amount of Duckweed and Azolla respectively. The carbon produced in the secondary clarifier is fed back to the bioprocess tank.

15 Carbon from Duckweed to be fed back to bioprocess tank

Amount of Duck- COD Duckweed Estimated production .. , after Amount Dm in digester doubling time of Carbon weed m secondary ^ [Kg] |days] [Year] clarifier sound [kg] [g/kg] 4400 992 (4400*0,06)=264 2 (365/2)*264=48180

Claims

A method of recovering or concentrating carbonaceous compounds in a fluid (2) containing carbonaceous material by wastewater treatment using a wastewater system (1), comprising the steps of: - (i) collecting and mixing the fluid (2) in a biological process tank (3), - (ii) subject the fluid (2) to clearance in a clearance tank (4), thereby providing a clear fluid which is separated into a treated fluid (10) and a sludge-containing fluid (11) (iii) subjecting at least one of the clarified fluids (10, 11) and mainly the sludge-containing fluid (11) to ultrasonic irradiation using an ultrasonic system (5) to form a degraded fluid (12), (iv) subjecting the degraded fluid (12) to a separation process using a centrifuge (6) to form a discarded fluid (13) and centrifuged fluid (14), - (v) subjecting the centrifuged fluid (14) to fermentation in a fermentation device (7) for forming a carbonaceous gas (15) which is suitable for further industrial use in a gas refiner (16) or in a gas engine (17).

Process for the extraction or concentration of carbonaceous compounds according to claim 1, characterized in that it further comprises the step of: - (iia) subjecting the fluid (2) to a clearing tank (4) containing aquatic plants such as duckweed, Azollas or algae.

A method for recovering or concentrating carbonaceous compounds according to claim 1 or 2, characterized in that it further comprises the step of: 25. returning fluid to the biological process tank (3), the return being preferably the discarded fluid (13) from the centrifuge (6).

A method for recovering or concentrating carbonaceous compounds according to any one of claims 1 or 3, characterized in that it further comprises the step 30 of: - returning fluid to the ultrasonic system (5), which feedback preferably comprises at least part of it. centrifuged fluid (14) from the centrifuge (6). DK 177393 B1 18

A process for recovering or concentrating carbonaceous compounds according to any one of claims 1 or 4, characterized in that it further comprises the step of: - performing a Chemical Oxygen Demand (COD) measurement, a COD-5 measurement on a fluid using a COD meter (22) in at least one process tank (3, 4 5. 6, 7) and preferably of the discarded fluid (13) from or in the centrifuge (6).

Process for the extraction or concentration of carbonaceous compounds according to any one of claims 1 to 5, characterized in that it further comprises the steps of: 10. performing an effect or power measurement of the power consumption of at least one process tank (3, 4, 5, 6, 7) using at least one power meter (22) and preferably in the ultrasonic system (5), - make an estimate of the residual energy in the fluid and preferably the discarded fluid (13) on the basis of the COD measurement, 15. perform a calculation of that energy , which is required to retreat the fluid in the return and preferably the discarded fluid (13), - perform a comparison of the calculated energy required to re-treat the fluid in the return and preferably the discarded fluid (13) with the estimated residual energy of the fluid, preferably the discarded fluid on the basis of the COD measurement, to provide a feedback or non-feedback decision indicator, which indicator determines whether the fluid must be returned for re-treatment so that the process is automated.

A method for recovering or concentrating carbonaceous compounds 25 according to any one of claims 1 to 6, characterized in that it further comprises at least one of the steps: - part or comminuting the fluid and in particular - placing the fluid in a buffer tank and / or stirring the fluid with stirring means (25).

Process for the extraction or concentration of carbonaceous compounds from agricultural (32) or food (33) products or residues (32, 33) according to any one of claims 1 to 7, characterized in that it further comprises a step of: DK 177393 B1 19 - transport the products or residues (32, 33) to a receiving tank (30, 31) and from the receiving tank (30, 31) transport the products or residual products (32, 33) to the wastewater plant (1) and preferably: - supply the agricultural products or residues (32) for the comminuting device (26) 5 for comminuting the agricultural products or residues (32), or - adding the food products or residues (33) to the buffer tank (24) for mixing or stirring with stirring means (25).

A process for producing usable energy such as electricity or heat from a carbonaceous gas (15) according to any one of claims 1 to 8, characterized in that it further comprises the step of: - burning the gas in a gas engine (17), converting the gas in a fuel cell or any other type of engine or chemical device adapted to convert chemically bonded energy into energy in the form of electricity or mechanical energy. 15

A fluid treatment plant (2), such as wastewater or sludge treatment plant, comprising a series of process tanks interconnected with conduits (9), which process tanks are: - a biological process tank (2) for collecting, mixing and pretreating a fluid (2) 20. a secondary clearing device (4) for clearing the fluid (2) into a treated fluid (10) and a sludge fluid (11), and a conduit (9) arranged to transfer the sludge fluid (11) to an ultrasonic system ( 5) for breaking down the sludge fluid (11) into a degraded fluid (12), - a centrifuge (6) for centrifuging the degraded fluid (12) into a discarded fluid (13) and a centrifuged fluid (14). 25