Compact sewage treatment plant and method for treating sewage

Abstract

The present invention relates to a compact sewage treatment plant comprising at least one solids retention tank (101), comprising: at least one grating (102) and at least one cover (103); at least one aerobic reactor tank (200), comprising activated sludge technology or MBBR technology; at least one air blower (202); at least one air diffuser (203); at least one gas outlet pipe (204) and at least one cover (103); at least one settling tank with a conical bottom (300), which comprises: at least one air lift (301); at least one deflector baffle (302); at least one channel (303) and at least one cover (103); at least two fluid pipes (404); wherein at least one fluid pipe (404) connects the effluent inlet and outlet; at least one fluid pipe for air injection (401); at least one fluid pipe (402); at least one fluid pipe (403); and at least one machine room (500). The present invention further relates to a method for treating sewage.

Description

[0001] Compact wastewater treatment plant and wastewater treatment method

[0002] Technical Field

[0003]

[0001] The present invention pertains to the field of wastewater, sewage or sludge and mud treatment, processes for rendering harmful chemical agents innocuous or less harmful, in which chemical transformations are carried out on substances, separation of solids from liquid effluents, sedimentation tanks or filtration devices and special arrangements in floating vessels for wastewater or sewage treatment.

[0004] Introduction

[0005]

[0002] The present invention relates to a compact wastewater treatment plant for residential, commercial, and industrial plants, which can be installed underground or above ground and has the main stages of (i) solids retention, (ii) aeration with microbubble incorporation, and (iii) sedimentation.

[0006] Fundamentals

[0007]

[0003] As is common knowledge for a technician in the field, Compact Wastewater Treatment Plants (CWTPs) are designed to occupy small spaces and offer efficient wastewater treatment solutions in urban or industrial areas with space limitations. There are several types of compact plants, each designed to meet different needs and specific conditions, such as compact wastewater treatment plants, anaerobic systems, such as septic tanks, biodigesters, etc.

[0008]

[0004] There are also aerobic systems, increasingly used as an alternative to conventional septic tanks and septic tanks, represented by various types and configurations of wastewater treatment plants, especially operating through the aerobic (aerobic) sludge activation process in plants of varying sizes, and technologies such as MBBR, Activated Sludge, etc. can be applied.

[0009]

[0005] The state of the art reveals a trend towards the development of wastewater treatment plants with aerobic reactors based on the sludge activation or "animation" principle, first patented by the German engineer Karl Imhoff in 1924, whose surname is, in some countries, synonymous with or a descriptive reference for activated sludge water treatment plants.

[0010]

[0006] Wastewater treatment plant tanks can be manufactured from a variety of materials, depending on specific needs, budget, type of treatment, and environmental conditions. Some of the most common materials include reinforced concrete, stainless steel, polypropylene (PP), among others, and may require the installation of additional elements upstream or downstream of the treatment plant, demand the use of pumps and filters or pumping systems, or not achieve satisfactory levels of productivity, etc.

[0011] State of the art

[0012]

[0007] Known state-of-the-art solutions for treatment plants of the nature discussed here can be verified in state-of-the-art documents such as the Spanish document ES 1074002, entitled "domestic wastewater treatment plant", which discloses a domestic wastewater treatment plant, comprising a tank with an influent inlet to be treated, a treatment circuit and a treated water outlet, characterized by the said tank comprising: a first settling compartment into which the wastewater from the inlet is discharged, and where the separation of suspended particles by sedimentation, and of fats and oils by flotation occurs, with microorganisms carrying out an anaerobic decomposition process without oxygen, producing gasification, hydrolysis and mineralization of said wastewater, with a first passage through a diversion passage to a compartment of the biological reactor,A compartment of the biological reactor equipped with aeration and external air injection means and supports for attaching biomass microorganisms that perform aerobic decomposition of organic compounds; this compartment being a biological reactor connected by a second double-diver duct to a clarifier compartment, having for its evacuation a water outlet of the overflow type from the treated water surface, and means to recirculate the sediments from its bottom to the settling compartment by means of a conduit.

[0013]

[0008] Document ES 1074002, despite presenting a domestic sewage treatment plant with an aerobic system, reveals a liquid clarification stage, unlike the stages presented in the present invention, which provide a highly efficient and high-quality sewage treatment process.

[0014]

[0009] Another patent document whose solution can be mentioned is the American document US 20110127214, entitled "Energy optimization in an anoxic, facultative aerobic plant using fine bubbles, without sludge production", which refers to a wastewater treatment system with intermittent aeration and low energy consumption, comprising: a pump tank or PLC-controlled tank for pumping, level and liquid flow control;The liquid is pumped to the aerobic treatment device or to the UASB device, whose aerobic treatment comprises an air diffusion unit or fine bubble diffusers operating intermittently and diagonally, with a high density of diffusers in the aerobic zone, where it would be optional for this region to be deeper than the other zones, an agitator, not only the agitator but also the blower, is controlled as a function of time by a PLC, the agitator then operating after the diffusers stop, and energy is also applied to prevent sludge sedimentation inside the aeration tank. Next, the water goes to a settling tank that separates the liquid from the sludge and directs the excess sludge to the UASB anaerobic sludge digester, by means of another solenoid valve;The UASB has a chamber for biogas accumulation, which can be burned, with the combustion system controlled by the PLC. This section also includes a settling unit that separates anaerobic sludge from the resulting liquid. The sludge-free liquid is separated by a sedimentation unit. This unit has a channel with scum screens at the top, ensuring the liquid is free of slag and sludge. The liquid is then transferred to a disinfection chamber designed to allow the disinfectant to reside. The disinfectant is supplied by a dosing pump and controlled by the PLC; optionally, a transducer can be used to control the disinfectant concentration.

[0015]

[0010] US patent 20110127214, despite presenting a domestic wastewater treatment plant with an aerobic system, does not disclose the solids retainer, unlike the steps presented in the present invention, which provide a highly efficient and high-quality wastewater treatment process.

[0016]

[0011] Thus, the state of the art does not offer robust, simple, and low-cost solutions for a compact wastewater treatment plant.

[0012] There is, therefore, room for a compact wastewater treatment plant that: a) can be produced in a standardizable and scalable process; b) guarantees a high-quality product with low production costs, low raw material consumption, and high robustness for the proposed application; c) allows for the modularization of tank production to meet a wide range of wastewater flow rates; d) allows the combination of three or more tanks of different volumes, enabling great flexibility in assembly and adapting to various needs, whether by daily volume or time of day; e) allows its tanks to be installed both buried and above ground; f) allows for the extension of the tank access nozzle to make the installation depth more flexible;g) allow for the removal of the aeration and air lift system for maintenance; h) maintain the high efficiency of the treatment system through aerobic treatment systems with technologies such as MBBR (Moving Bed Biofilm Reactor) or activated sludge, with a significant reduction in costs, enabling access to many more projects, making it possible for more disadvantaged communities to have access to highly efficient basic sanitation; i) guarantee speed of supply and ease of installation; and j) allow for modularization and future increases in treatment flow, simply by adding more equipment to the already installed system.

[0017] Objectives of the invention

[0018]

[0013] One of the objectives of the invention is to provide a compact wastewater treatment plant, according to the characteristics of claim 1 of the attached claims.

[0019]

[0014] Another objective of the invention is to provide a method for treating sewage, in accordance with the characteristics of claim 5 of the attached claims.

[0020]

[0015] Other features and details of the features are represented by the dependent claims.

[0021] Brief description of the figures

[0022]

[0016] For a better understanding and visualization of the object of the present invention, it will now be described with reference to the attached figures, representing the technical effect obtained through an exemplary embodiment that is not limiting the scope of the present invention, in which, schematically:

[0023] Figure 1: presents a perspective view of a compact, buried wastewater treatment plant using aerobic activated sludge treatment technology, according to the present invention;

[0024] Figure 2: shows a front view of the compact underground wastewater treatment plant, using aerobic activated sludge treatment technology, from Figure 1;

[0025] Figure 3: shows a front cross-sectional view of the compact underground wastewater treatment plant, using aerobic activated sludge treatment technology, from Figure 1;

[0026] Figure 4: shows a top view of a compact wastewater treatment plant with exposed installation, according to the present invention, using aerobic treatment technology with MBBR; and

[0027] Figure 5: presents a cutaway perspective view of the compact wastewater treatment plant with exposed installation, using aerobic treatment technology with MBBR;

[0028] Figure 6: presents a perspective view of the biomedia that are inserted inside the aerobic reactor tank when the MBBR type technology is used.

[0029] Detailed description of the figures

[0030]

[0017] A compact wastewater treatment plant (100), comprising:

[0031] - at least one solids retention tank (101), comprising: at least one grate (102) and at least one lid (103);

[0032] - at least one aerobic reactor tank (200), comprising: activated sludge technology or MBBR technology, at least one air blower (202), at least one air diffuser (203), at least one gas outlet pipe (204) and at least one cover (103);

[0033] - at least one conical bottom settling tank (300), comprising: at least one air lift (301), at least one baffle (302), at least one chute (303) and at least one lid (103); and

[0034] - at least two hydraulic pipes (404), wherein at least one hydraulic pipe (404) connects the effluent inlet and outlet; - at least one hydraulic pipe for air injection (401) into the air diffusers (203);

[0035] - at least one hydraulic pipe (402) that injects air into the air lift (301);

[0036] - at least one hydraulic pipe (403) that directs the sludge; and

[0037] - at least one engine room (500).

[0038]

[0018] The solids retention tank (101) is responsible for initially receiving the sewage in the compact sewage treatment plant (100). It is used to retain or filter solid particles and separate the fluid flow, such as coarser inorganic solids, and residual oils and greases. Heavier materials, such as sand, are deposited inside the solids retention tank (101), at its bottom. Preferably, the solids retention tank (101) is manufactured in HDPE (high-density polyethylene) by the rotomolding process, and can have a capacity between 750L and 10,000L.

[0039]

[0019] The screening (102) can be, but is not limited to, a solids-retaining basket-type screening (102). The screening (102) uses perforations on the order of 23 mm in diameter to retain solid particles from the sanitary effluent, and can be installed inside the solids-retaining tank (101) or even before as a preceding tank to the solids-retaining tank (101), by means of metal screening in masonry boxes. The solids-retaining basket-type screening (102) has the function of filtering larger solids, such as cloths and plastics, that may clog the passage of sanitary effluent through the piping during the process.

[0040]

[0020] The cover (103) may be, but is not limited to, a screw-on inspection cover (103) with click seal. The cover (103) has the function of closing the tanks (101, 200, 300) and allows access during the installation and maintenance of the tanks (101, 200, 300).

[0041]

[0021] Additionally, the cover (103) allows the addition of extensions (104), wherein the extensions act as extensions to lengthen or extend covers (103). Extensions (104) may be necessary to accommodate tanks (101, 200, 300) at different depths or installation locations or, for example, to facilitate access and inspection of the tanks (101, 200, 300).

[0042]

[0022] The aerobic reactor tank (200) is manufactured in HDPE (high-density polyethylene) by the rotomolding process. The aerobic reactor tank (200) can have a capacity between 3,000L and 10,000L. This unit is equipped with a bottom air distribution system by means of ballasted air diffusers and hydraulic components. Inside the aerobic reactor tank (200), the decomposition of organic matter present in the sewage occurs through the action of aerobic microorganisms, i.e., bacteria that need oxygen to survive, generating byproducts such as carbon dioxide and water.

[0043]

[0023] In one of the operating modes of the aerobic reactor tank (200) activated siodine technology is used and comprises fine bubble air diffusers.

[0044]

[0024] In a second alternative embodiment of the present invention for the operation of the aerobic reactor tank (200), MBBR (Moving bed biofilm reactor) technology is used.

[0045]

[0025] In this process involving the use of MBBR technology, biomedia (201) are inserted, which aim to increase the surface area available for bacteria to settle. Thus, the greater the number of bacteria present in the system, the greater the treatment capacity, resulting in an increase in treatment capacity without the need to increase the size of the aerobic reactor tank (200).

[0026] The aerobic reactor tank (200) that receives the biomedia (201) also receives biomedia retention devices (205), which are configured as pipes with several perforations with diameters smaller than the biomedia (201). The relationship between the diameter of the perforations in the biomedia retention devices (205) and the diameter of the biomedia (201) prevents the biomedia (201) from passing through to the other stages of the process, as well as preventing them from causing blockages in the treatment system pipes.

[0046]

[0027] At least two biomedia retention devices (205) are installed in the aerobic reactor tank (200), wherein at least one of the biomedia retention devices (205) is installed in the inlet hydraulic pipe (404) and at least one of the biomedia retention devices (205) is installed in the outlet hydraulic pipe (404).

[0047]

[0028] In the context of the present invention, considering that the effluent flow flows from the solids retention tank (101) towards the conical bottom settling tank (300), the inlet hydraulic pipe (404) is the pipe that connects the solids retention tank (101) to the aerobic reactor tank (200), while the hydraulic pipe (404) that connects the aerobic reactor tank (200) to the conical bottom settling tank (300) is the outlet pipe.

[0048]

[0029] The air blower (202) is the device responsible for compressing ambient air and directing it to the aerobic reactor tank (200), thus providing the oxygen necessary for the growth and activity of aerobic microorganisms that decompose organic matter in the effluent, being sized according to the model and size of the compact wastewater treatment plant (100).

[0049]

[0030] The compressed air from the air blower (202) is released into the tank through the air diffuser (203) or aerators (not shown), creating air bubbles that help oxygenate the effluent. It is noteworthy that the air blower (202) injects sufficient air into the system to ensure that the microorganisms receive enough oxygen to grow and carry out the decomposition of organic matter.

[0050]

[0031] In this way, the amount of air supplied by the air blower (202) is carefully controlled to ensure ideal conditions for the biological activity of microorganisms present in the aerobic reactor tank (200), in accordance with the technical literature and current standards governing the preparation of hydraulic-sanitary projects for sanitary sewage treatment plants such as NBR 12.209, which indicates the applicable air mass according to the biological oxygen demand.

[0051]

[0032] The air diffuser (203) is a device used to introduce oxygen into the liquid medium, this device works by dispersing compressed air into small bubbles in the liquid, increasing the contact area between the air and the water, increasing the efficiency of oxygen transfer.

[0052]

[0033] The air diffusers (203) comprise ballast, or counterweights, which allow the air diffuser (203) to remain at the bottom of the tank, even after air injection. Preferably, the material used as ballast may be sand, gravel, cementitious mortar or any combination thereof.

[0053]

[0034] The use of ballast eliminates the need to fix the air diffusers (203) to the bottom of the tank, avoiding leak problems and facilitating the removal of the air diffuser assembly (203) for maintenance.

[0054]

[0035] The tubular air diffuser (203) with fine bubble ballast is used in activated iodine type technology systems, being designed to create fine air bubbles through porous tubes or special membranes with micro-perforations that help in the uniform dispersion of oxygen in the liquid medium.

[0036] Preferably, the air diffuser (203) comprises porous tubes or hoses made of materials such as silicone, rubber or porous polymers, into which air is introduced through these porous tubes or hoses, which have small orifices or pores along their length. These pores allow the air to be released in the form of fine bubbles into the liquid medium.

[0055]

[0037] Coarse bubble air diffusers (203), used in MBBR (moving bed biofilm reactor) type technology, are devices used in aeration systems to introduce large air bubbles into the liquid.

[0056]

[0038] It should be noted that the term "thick bubbles" refers to larger air bubbles, which have a larger surface area and provide efficient oxygen transfer.

[0057]

[0039] The coarse bubbles keep the biomedia in rotational and translational motion, generating the appropriate hydrodynamics for the development of the bacteria and the process. The appropriate hydrodynamics refers to avoiding dead zones to ensure an adequate flow of water and oxygen in all parts of the aerobic reactor tank (200), a uniform distribution of the effluent and control of the flow rate in the aerobic reactor tank (200).

[0058]

[0040] The coarse bubbles introduced by the air diffusers (203) are reduced to fine bubbles due to shear caused by the movement of the biomedia, increasing the efficiency of oxygen transfer. Preferably, the coarse bubble air diffusers (203) are made of materials such as polyethylene or PVC.

[0059]

[0041] It should be noted that the air diffusers (203) can be adapted to produce fine or coarse bubbles, depending on the application requirements of the invention.

[0060]

[0042] The gas outlet pipe (204) can be connected to the pipeline of the development where the wastewater treatment plant is being installed and prevents the formation of a gas pocket inside the tank, since the aerobic treatment system used in the present invention generates odorless gases.

[0061]

[0043] The conical bottom settling tank (300) is responsible for settling the organic matter from the system, reintroducing the organic matter into the aerobic reactor tank (200) and releasing the treated effluent from the system, being designed in such a way as to allow the solid particles present in the liquid being treated to settle to the bottom of the conical bottom settling tank (300), while the clarified water or water with less solids is removed from the top of the conical bottom settling tank (300).

[0062]

[0044] The conical bottom settling tank (300) has a conical bottom that has a conical or inverted conical shape, this design facilitates the separation of the sedimented solids from the liquid, directing them to the center of the bottom of the tank, where they can accumulate and be removed more easily.

[0063]

[0045] Preferably, the conical bottom settling tank (300) has a capacity between 750L and 3,000L and is manufactured in HDPE (high-density polyethylene) by the rotomolding process.

[0064]

[0046] The air lift (301) is a feeder pipe or similar structure that transports the accumulated sludge from the bottom of the conical bottom settling tank (300) to the aerobic reactor tank (200) using air pressure to create an upward or downward flow and is the system responsible for reintroducing the organic matter present at the bottom of the conical bottom settling tank (300) into the aerobic reactor tank (200) through vacuum created in the piping.

[0065]

[0047] Compressed air is injected by the air blower (202) into the bottom of a hydraulic pipe (402) when the air is released, and a mixture of air and liquid is formed. The rise of this mixture, which is lighter than the surrounding liquid, creates an upward motion, pushing the liquid upwards through the air lift (301).

[0066]

[0048] The Baffer Deflector (302) is a plastic part located in the conical bottom settling tank (300) responsible for ensuring the undisturbed fall of organic matter from the aerobic reactor tank (200).

[0067]

[0049] The trough (303) is a structure to help remove suspended solids, being responsible for preventing the entrainment of solids, avoiding the presence of sludge flocs in the treated effluent that leaves the system.

[0068]

[0050] The channel (303) may be, but is not limited to, a weir-type channel (303), designed with an incline or slope that prevents the entrainment of solids when directing water to an outlet pipe, channeling the water in a controlled manner to avoid damage caused by flooding and preventing the presence of sludge flakes in the treated effluent leaving the system. In short, a weir is a structure designed to manage the flow of water efficiently and in a controlled manner, thus avoiding possible problems of flooding or accumulation of water in the conical-bottomed settling tank (300).

[0069]

[0051] It should be noted that after the effluent exits the conical bottom settling tank (300) and the treated effluent passes through the channel (303), the treated water from the compact wastewater treatment plant (100) may be released to a sewage outlet or to a water reuse tank for use in toilets, irrigation, car washing, etc.

[0070]

[0052] Preferably, the channel (303) is made of metal or plastic and has a series of teeth or blades spaced along its length.

[0071]

[0053] Alternatively, a chlorination box may be added after the conical bottom settling tank (300), depending on the application.

[0072]

[0054] The hydraulic pipes (404) connect the effluent inlet and outlet using a PVC pipe, being responsible for making the network inlet and outlet connections and for the connection between the tanks (101, 200, 300).

[0073]

[0055] The hydraulic air injection pipe (401) connects the air blower (202) to the aerobic reactor tank (200), wherein, in the hydraulic air injection pipe (401), compressed air exits the air blower (202) and is sent to the aerobic reactor tank (200) to supply the oxygen necessary for the growth and activity of aerobic microorganisms that decompose the organic matter in the effluent.

[0074]

[0056] The hydraulic pipe (402) makes the connection between the air blower (202) and the conical bottom settling tank (300), wherein, in the hydraulic pipe (402), the compressed air exits the air blower (202) and is sent to the air lift (301) of the conical bottom settling tank (300) to facilitate the detachment of sludge particles from the bottom of the conical bottom settling tank (300).

[0075]

[0057] The hydraulic pipe (403) makes the connection between the conical bottom settling tank (300) and the aerobic reactor tank (200), wherein, in the hydraulic pipe (403), the sludge exits the conical bottom settling tank (300) and goes towards the aerobic reactor tank (200).

[0076]

[0058] The machine room (500) is a space designed to house equipment such as air compressors, pumps, motors, generators, transformers, valves, control panels and other devices needed to operate and control the compact wastewater treatment plant (100).

[0077]

[0059] The machine room (500) is constructed with specific structural and safety considerations to house this equipment, offering protection against weather, temperature control, adequate ventilation and easy access for maintenance and safe operation of the equipment.

[0060] Additionally, in an alternative embodiment of the present invention, it is possible to combine three or more tanks (101, 200, 300) of different volumes, allowing for flexibility and the possibility of modularization and future increases in treatment flow rate, simply by adding more equipment to the already installed system.

[0078]

[0061] The compact wastewater treatment plant (100) can be installed with the tanks (101, 200, 300) buried or above ground.

[0079] Method

[0080]

[0062] Wastewater treatment method, comprising the following steps: i. effluent entry into the solids retention tank (101); ii. retention of coarser inorganic solids and residual oils and fats from the effluents that will pass through screening (102); iii. retention of heavier material at the bottom of the solids retention tank (101); iv. effluent entry into the aerobic reactor tank (200); v. inclusion of air in the effluent with the formation of bubbles for the growth of bacteria for the digestion of organic matter, by the air blower (202) and the air diffuser (203); vi. effluent entry into the settling tank with conical bottom (300); vii. settling of the effluent / biological sludge by the baffle deflector (302) for a controlled downward flow of the effluent, separating the sludge at the bottom and the treated effluent at the top; viii. injection of the sludge remaining at the bottom of the conical bottom settling tank (300) into the aerobic reactor tank (200), via the air lift (301); and ix.effluent passing through the channel (303) to remove sludge flocs.

[0081] Conclusion

[0082]

[0063] It will be readily understood by those skilled in the art that modifications can be made to the present invention without departing from the concepts set forth in the description above. Such modifications should be considered as falling within the scope of the present invention. Consequently, the particular embodiments described in detail above are merely illustrative and exemplary and not limiting as to the scope of the present invention, to which the full extent of the appended claims and any equivalents thereof should be given.

Claims

CLAIMS 1. Compact wastewater treatment plant (100), characterized by comprising: - at least one solids retention tank (101), comprising: at least one grate (102) and at least one lid (103); - at least one aerobic reactor tank (200), comprising: activated sludge technology or MBBR technology, at least one air blower (202), at least one air diffuser (203), at least one gas outlet pipe (204) and at least one cover (103); - at least one conical bottom settling tank (300), comprising: at least one air lift (301), at least one baffle (302), at least one trough (303) and at least one lid (103); - at least two hydraulic pipes (404), wherein at least one hydraulic pipe (404) connects the effluent inlet and outlet; - at least one hydraulic pipe for air injection (401) into the air diffusers (203); - at least one hydraulic pipe (402) that injects air into the air lift (301); - at least one hydraulic pipe (403) that directs the sludge; and - at least one engine room (500).

2. Compact wastewater treatment plant (100), according to claim 1, characterized in that the aerobic tank (200) additionally comprises biomedia (201), together with MBBR technology.

3. Compact sewage treatment plant (100), according to claim 1, characterized in that the cover (103) comprises additionally at least one extension (104).

4. Compact sewage treatment plant (100), according to claim 1, characterized in that the compact sewage treatment plant (100) can be installed with the tanks (101, 200, 300) buried or exposed.

5. Wastewater treatment method, characterized by the fact that it comprises the following steps: i. effluent entry into the solids retention tank (101); ii. retention of coarser inorganic solids and residual oils and fats from the effluents that will pass through the screening (102); iii. retention of heavier material at the bottom of the solids retention tank (101); iv. effluent entry into the aerobic reactor tank (200); v. inclusion of air in the effluent with the formation of bubbles for the growth of bacteria for the digestion of organic matter, by the air blower (202) and the air diffuser (203); vi. effluent entry into the settling tank with conical bottom (300); vii. settling of the effluent / biological sludge by the baffle deflector (302) for a controlled downward flow of the effluent, separating the sludge at the bottom and the treated effluent at the top; viii.injection of the sludge remaining at the bottom of the conical bottom settling tank (300) into the aerobic reactor tank (200), via the air lift (301); and ix. passage of the effluent through the trough (303) for removal of flocs. of mud.

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