Compact wastewater treatment and recovery system

Abstract

Modular and transportable wastewater treatment and recovery system adapted to combine the use of two technologies aimed at providing a compact modular system with high wastewater treatment potential; said system comprising a first MBBR reactor in which an oxidation, nitrification and denitrification phase of said wastewater is carried out, and a second MBR reactor adapted to carry out a refinement in an aerobic environment with biomass composed of activated sludge and bacteria produced by the MBBR reactor, completing the degradation of the organic and ammonia substance, as well as guaranteeing an ultrafiltration treatment which allows separating solids and bacteria from the purified water; in the first MBBR reactor the purification takes place through a biofilm which adheres to a plastic support, in the second MBR reactor the purification process is based on activated sludge with high concentrations of solids and bacterial load in suspension.

Description

[0001] COMPACT WASTEWATER TREATMENT AND RECOVERY SYSTEM

[0002] Description

[0003] Field of the art

[0004] The invention relates to an innovative wastewater treatment and recovery system by combining two MBBR and MBR reactors made in separate tanks or included within a single casing, making the entire system modular and easily transportable within urban or industrial areas which are difficult to access.

[0005] Prior art

[0006] Climate change is significantly affecting access to water resources, with greater environmental protection for its preservation being decisive, combined with the possibility of adequate recovery and reuse of wastewater. There are various areas of Latin America, Africa, India, but also some areas further south in Europe, where the availability of water resources is already limited.

[0007] The technologies proposed on the market for this purpose are excessively expensive for developing countries, but also Western countries, and must have more accessible costs for adequate diffusion.

[0008] Marketing plants with high potential and simultaneously at low costs seems to be an impossible concept today.

[0009] There is no current technology which, in terms of equivalent inhabitants served, allows producing wastewater with characteristics suitable for reuse and safe from a health and environmental point of view.

[0010] The extensive purification of wastewater and the reuse of purified water for irrigation purposes in fields and hydroponic crops would allow a rational use of water. Therefore, making purified wastewater available for reuse would allow for its preservation and would limit the use of natural water, which should be reserved as a priority for drinking use and the agri-food industry.

[0011] In the current state of the art, purification systems are used which involve the use of a Moving Bed Biofilm Reactor (MBBR), i.e., a plant for the biological purification treatment of wastewater. Moving bed biofilm reactors are part of the family of moving support biofilm systems, which are replacing traditional activated sludge processes in the biotreatment of polluted wastewater deriving from civil and industrial settlements.

[0012] The main applications of the purification and process system concern wastewater treatments, both civil and industrial. MBBR systems are particularly effective for the removal of nitrogen and phosphorus and organic carbon (COD and BOD).

[0013] MBBR technology allows creating biological treatment processes which can be aerobic, anoxic or anaerobic.

[0014] The treatment steps which can be achieved through the MBBR process are:

[0015] • removal of organic matter: biological treatment, roughing and refining;

[0016] • nitrification: oxidation of organic nitrogen compounds in the reduced state carried out by autotrophic bacteria;

[0017] • denitrification: removal of nitrogen compounds present in solution in the form of NO3' and NO2' (produced by previous nitrification) by denitrifying bacteria.

[0018] The MBBR technology developed is used in wastewater treatment plants in municipalities and civil settlements, in fish farms, but also finds application in industrial wastewater and in particular in the food industries, in paper mills and chemical plants.

[0019] MBBR technology is still not widespread in Italy, while applications are increasing especially in Northern Europe: it is also suitable for the adaptation of existing systems thanks above all to its characterizing simplicity of construction and management. Such technology can also be installed in existing basins, replacing activated sludge technology.

[0020] However, MBBR reactors have a number of disadvantages which affect their diffusion on the market: opportunity to carry out filtration and refinement at the end of the process to allow the reuse of purified wastewater; • energy consumption not optimized due to aeration systems with medium-large bubbles;

[0021] • limited process control.

[0022] A further system used in wastewater purification is that which uses the MBR (Membrane BioReactor) process, which is a biological water purification system consisting of the combination of the traditional activated sludge purification process and a membrane separation system (ultrafiltration), which replaces the normal secondary settler. By retaining the sludge through the membranes, such a system therefore has the advantage of reaching high concentrations of activated sludge in biological reactors (10-12 kgSS / m3), unsustainable for traditional systems. The use of membranes instead of the sedimentation tank also avoids any leakage of sludge into the purified effluents, which are very frequent in civil, urban and industrial wastewater treatment plants, often subject to various problems (variability of instantaneous flow rates with consequent increase in surface hydraulic load, presence of light sludge, bulking from filamentous bacteria, etc.).

[0023] However, the MBR reactor has a lower treatment capacity for the same volume, when compared with MBBR technology.

[0024] In recent years, no filed patent has managed to resolve the above-mentioned problems, as in the case of patent US2022204376 published on 06 / 30 / 2022, which describes a plurality of steps aimed at purifying water by reducing the concentration of selenium present within the water to be treated. Patent US2022204376 does not describe the use of any machinery or specific reactors which can be used for wastewater purification.

[0025] The object of the present patent application is therefore to provide a wastewater treatment and recovery system which can be easily transported and modulated based on the demand of the urban or industrial areas served, maintaining high purification standards.

[0026] Description of the invention

[0027] According to the present invention, a wastewater treatment and recovery system is created which effectively solves the above problems.

[0028] The treatment system object of the invention comprises the combination of two technologies which today, in the current state of the art, work independently of each other. The biological processes resulting from the combination of the two technologies give rise to a profoundly different biological process.

[0029] The technology which is based exclusively on the MBBR reactor allows high performance in terms of abatement, but cannot reduce solids and bacterial load in the purified water through classic sedimentation systems to make the reuse of purified water safe.

[0030] The technology which is based exclusively on the MBR biological reactor is instead characterized by high purification yields, but lower treatment capacity for the same volume, if compared with the MBBR technology, allowing the solids to be effectively separated through the ultrafiltration membranes, allowing the production waters with a very low residual pollutant load and zero bacterial load.

[0031] Therefore, the plant used in the treatment system in question is a hybrid obtained through the combination of the two technologies indicated above, resulting in significant advantages on the market. Firstly, the ease linked to the installation of the treatment systems which, included inside a rigid casing, can be modulated based on the required potential of the urban area to be served or the characteristics of the industrial wastewater to be treated.

[0032] Thanks to the modularity characterizing the present wastewater treatment system, the transport of the reactors used is advantageously simple, which can be easily loaded directly onto trucks for road transport or inside naval containers to reach more isolated sites and areas.

[0033] Once the modular system, comprising a first MBBR reactor and a second MBR reactor, has been installed in the location where it is necessary to treat the wastewater, it is fed by an equalization tank installed on the sewer system, necessary to collect the wastewater to be purified coming from urban or industrial areas, before being purified and treated using the system object of the invention.

[0034] At least a submersible electric pump, installed inside said equalization tank introduces the wastewater that has reached said equalization / lifting tank into the treatment system. By way of non-limiting example, said submersible electric pump is operated by an electrical system. Before the wastewater reaches the first MBBR reactor, a screening system filters and separates it from any solid substances which cannot take part in the purification inside the two MBBR and MBR reactors; said screening system is installed downstream of said equalization tank. Subsequently, the coarsely filtered wastewater enters the first section of the purification system represented by the MBBR reactor (Moving Bed Biofilm Reactor) in which the oxidation phase of said wastewater is carried out, further carrying out a nitrification process in aerobic conditions and denitrification, in anoxic conditions.

[0035] The MBBR treatment phases can be separated by creating distinct anoxic compartments for denitrification and aerobic compartments for oxidation and nitrification. As an alternative to separate sections, the oxidation and denitrification processes are carried out in the same reactor, creating aerobic and anoxic phases through the activation and deactivation of the aeration system. The alternating cycle process, in which the denitrification oxidation / nitrifi cation process is carried out in the same MBBR reactor is the object of the invention.

[0036] A second MBR reactor (Membrane Biological Reactor) is instead installed downstream of the first MBBR reactor: this section is characterized by high purification efficiency, further allowing to effectively separate the solids through ultrafiltration membranes, allowing to produce water with a very low load of residual pollutants and almost zero bacterial load.

[0037] Said reactors are connected by means of internal passages of the reactor or through connection pipes.

[0038] The first MBBR reactor and the second MBR reactor, in order to facilitate the transport and installation thereof, are contained within a rigid casing with different dimensions adapted to modulate the wastewater treatment and recovery system based on the potential requests, the needs of the area available for installation and to facilitate transportability. Said rigid casing, in a parallelepiped embodiment thereof, can be made of stainless steel, carbon steel, polypropylene or fiberglass structurally sized to adequately protect the two reactors even during transport, further simplifying the assembly thereof with further modules, in order to increase the wastewater treatment capacity.

[0039] The system requires a minimum of two blowers to supply air to the biological reactors. The two blowers ensure the air flow required by the wastewater purification processes inside the first MBBR reactor and inside the second MBR reactor.

[0040] In order to direct the air coming from said two blowers inside the first MBBR reactor and inside the second MBR reactor, two air lines consisting of special ducts are used.

[0041] A permeate extraction line consisting of a pump and a pressure control system inside and outside the MBR reactor ensures the flow of the treated and already purified liquid, after passing through the first MBBR reactor and the second MBR reactor.

[0042] The waste water treatment and recovery system further comprises a station for dosing chemical agents on the extraction line necessary to ensure the constant cleaning of the membranes which could become clogged when the permeate passes through.

[0043] Lastly, at least a sampling well is installed downstream of the wastewater treatment and recovery system object of the invention, adapted to make the treated water flow out constantly, preventing any possible obstruction of the outlet pipes of the treatment system object of the invention.

[0044] The advantages offered by the present invention are evident in the light of the description presented thus far and will be even clearer thanks to the attached figures and the detailed description.

[0045] Description of the figures

[0046] The invention will be described hereinafter in at least a preferred embodiment by way of nonlimiting example with the aid of the appended figure, in which:

[0047] - FIGURE 1 shows the generic diagram of the wastewater treatment and recovery system object of the invention. The schematic section shown allows explaining the path followed by the treated wastewater, up to the final purification of the water which ends in its collection inside a sampling well 21. Figure 1 therefore shows the components included within the innovative wastewater treatment system, which have a very precise installation order so as to be able to carry out wastewater purification while maintaining high quality standards. The wastewater coming from urban or industrial centers reaches an equalization tank 10 where a submersible pump 13 is installed which is adapted to lift said water up to a screening system 14 for an initial coarse filtering. The wastewater then reaches, by means of the use of a plurality of pipes 11, the first MBBR reactor 17 and the second MBR reactor 18, which can also be contained inside a rigid casing 22 which allows for an easy transport thereof. Two blowers 12 introduce air inside the two reactors 17 and 18, exploiting a special air line 15. A permeate line 19 is adapted to facilitate the exit of the treated liquid, making it pass through a treatment station 20 using chemical agents.

[0048] Detailed description of the invention

[0049] The present invention will now be illustrated by way of a purely non-limiting or binding example, resorting to the figure which illustrates some embodiments with respect to the present inventive concept.

[0050] With reference to FIG. 1, it illustrates the operating diagram of the treatment and recovery system of wastewater which is commonly produced by urban areas and industrial areas.

[0051] In order to make the wastewater usable again, it is necessary to use the treatment system obj ect of the invention, which, thanks to the combination of the MBBR reactor 17 with the MBR reactor 18, is adapted to purify any volume of wastewater, said treatment system being modular in order to adapt to the demands of the surrounding urban or industrial area.

[0052] The wastewater is then collected in an equalization tank 10 where, through a submersible pump 13, it is pushed to a screening system 14 adapted to perform a first filtering, eliminating the solid parts which are created by sedimentation, (by way of indicative but not exhaustive example).

[0053] By means of a plurality of pipes 11, said wastewater then reaches a rigid casing 22, which contains an MBBR reactor 17 and an MBR reactor 18 therein. Said reactors 17, 18 are adapted to purify the wastewater, sanitizing it and removing the bacteria which are most harmful to human health.

[0054] At least two blowers 12 are adapted to send a jet of air inside said reactors 17, 18, facilitating the purification process occurring therein.

[0055] The air conveyed by the two blowers 12 is conducted to said reactors 17, 18 by means of a dedicated air line 15.

[0056] The wastewater is lastly conveyed toward a sampling well 21 by means of a permeate line 19 which further comprises a vent valve 16. Said vent valve 16 can be further provided with an anti-odor filter to avoid polluting dispersions into the surrounding environment. A treatment station 20 using chemical agents is installed on said permeate line 19, for the purpose of chemically treating the wastewater which requires particular alterations.

[0057] Finally, it is clear that modifications, additions or variations that are obvious to a person skilled in the art can be made to the invention described so far, without thereby departing from the scope of protection provided by the attached claims.

Claims

Claims1. Wastewater treatment and recovery system, characterized by the fact of combining the use of two technologies aimed at providing a compact modular system with high wastewater treatment potential; said system comprising a first MBBR reactor (17) suitable for carrying out an oxidation, nitrification and denitrification phase of said wastewater, and a second MBR reactor (18) suitable for carrying out refinement in an aerobic environment with biomass composed of activated sludge and bacteria produced by the MBBR reactor (17), completing the degradation of the organic and ammonia substance as well as guaranteeing an ultrafiltration treatment which separates solids and bacteria from the purified water; in the first MBBR reactor (17) the purification takes place through a biofilm (adhesive biomass) which adheres to a plastic support, in the second MBR reactor (18) the purification process is based on mixed sludge composed of biomass generated by the MBBR process and activated sludge (suspended biomass) with high concentrations of solids and bacterial load in suspension; said wastewater treatment and recovery system comprising:- at least an equalization tank (10), where wastewater from urban or industrial areas is collected, before being purified and treated;- at least a submersible electric pump (13), installed inside said equalization tank (10), capable of introducing the wastewater that has reached said equalization tank (10) into the treatment system;- at least a wastewater screening system (14), installed downstream of said equalization tank (10), capable of filtering and separating said wastewater from any solid substances which cannot take part in the purification inside the two reactors MBBR (17) and MBR (18);- at least an MBBR (17) (Moving Bed Biofilm Reactor) suitable for carrying out the oxidation step of said wastewaters, further carrying out a nitrification and denitrification process, in aerobic and anoxic conditions;- at least an MBR reactor (18) (Membrane Biological Reactor), characterized by high purification efficiency, further allowing to effectively separate the solids through ultrafiltration membranes, allowing to produce water with a very low load of residual pollutants and almost zero bacterial load;- a plurality of pipes (11), able to connect said reactors (17, 18), favoring the flow of wastewater during the purification phases;- at least a rigid casing (22), capable of including inside the first MBBR reactor (17) and the second MBR reactor (18), in order to facilitate their transport and installation, modulating the treatment and recovery system of wastewater according to the needs of the area served;- at least two blowers (12), designed to facilitate the flow of air inside the first MBBR reactor (17) and inside the second MBR reactor (18), facilitating the purification processes of the treated wastewater;- at least two air lines (15), consisting of special ducts, able to direct the air coming from said two blowers (12) inside the first MBBR reactor (17) and inside the second MBR reactor (18);- at least a permeate line (19), designed to facilitate the flow of treated and already purified liquid, after passing through the first MBBR reactor (17) and the second MBR reactor (18);- at least a station (20) for dosing chemical agents, suitable for further purifying the treated water that crosses the permeate line (19);- at least a sampling well (21), installed downstream of the wastewater treatment and recovery system, capable of making the treated water flow out constantly, preventing any possible obstruction of the outlet pipes of the treatment system object of the invention.

2. Wastewater treatment and recovery system, according to the preceding claim 1, characterized in that said rigid casing (22) is made of stainless steel, iron, fiberglass or polypropylene, in order to protect the two reactors (17, 18) inside it even during transport, further simplifying its assembly with further modules, in order to increase the wastewater treatment capacity.

3. Wastewater treatment and recovery system, according to any one of the preceding claims, characterized in that said submersible electric pump (13), suitable for introducing the wastewater into the purification system, is operated by a hydraulic system4. Wastewater treatment and recovery system, according to any one of the preceding claims, characterized in that the entire treatment system is subject to a plurality of regulations which determine the degree of purification of the wastewater, at the discretion of the specialized personnel in charge.

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