WO2018020243A1

WO2018020243A1 - Water treatment plant and related process

Info

Publication number: WO2018020243A1
Application number: PCT/GB2017/052179
Authority: WO
Inventors: Vitantonio DE NIGRIS; Federico RAVAZZI
Original assignee: Atlas Waste Technologies Limited
Priority date: 2016-07-29
Filing date: 2017-07-26
Publication date: 2018-02-01
Also published as: SMP201600255B; AU2017303847A1; EP3490942A1

Abstract

A wastewater treatment plant and related process involves the use of a storage tank (1) from which the reflux is charged to a heating tank (2) by means of a pump (3) and entered here in a cooling tank (4). From the cooling tank (4) the waste water passes through a plurality of columns (5) containing ion exchange resins, then passing through a control station (6) and then discharged into the sewage network, If the values of the verification parameters are acceptable.

Description

WATER TREATMENT PLANT AND RELATED PROCESS Field of the Invention The present invention relates to a water/sewage treatment plant and related process. The plant is particularly suitable for purifying water from industrial processes in which there is a high content of surfactants, biological fluids, heavy metals, liquid and disinfectant solvents, and other organic substances. Background to the Invention

Social, productive and recreational activities require and use large quantities of water which need to be purified before being returned to the environment. In fact, the amount of pollutants present in the waste water is usually far higher than the final recipients (soil, sea, rivers or lakes) are able to dispose of thanks to their self-depurative capacity. The purification treatments consist of a sequence of processes during which material is removed from the wastewater as concentrates in the form of sludge, so that the final effluent is compatible with the self-desiccating capacity of the recipient to which it is destined. These processes, which are very diversifiable according to the origin of waste water, are two types: chemical-physical processes, most commonly used in the treatment of water from industrial plants, and processes of biological nature, mostly used in the treatment waters of urban origin. Particularly referring to wastewater treatment processes from industrial plants, chemical-physical treatment and compost from a chemical process to render insoluble organic and inorganic pollutants in suspension and solution in water, followed by a physical process to separate the insoluble part from the final liquid effluent. In known applications, chemical reagents that favour the aggregation of pollutants are added to the waste water during precipitation during a few hours of sedimentation and then removed as sludge. Alternatively, or in succession, sedimentation phase, filtration processes are also used, among which the most common are "activated carbon" and "ion exchange resins".

In the first case, the discharges are transited into filters filled with organic vegetable carbon, about 2 to about 5 millimetres in diameter, externally powdered and with a high surface to volume ratio. The carbon retains many organic substances, which cannot be eliminated otherwise, by purifying the discharges. When its effectiveness decreases it is "regenerated" by washing with overheated steam at another pressure during which the pollutants are extracted and concentrated to be subsequently treated by special plants.

l In the second case, discharges are channelled into columns filled with non-soluble resins capable of exchanging ions with polluting substances in the wastewater. The resins are in the form of spherical granules of diameter less than a few millimetres. When the effectiveness decreases, it is possible to re-use them several times by means of washings that remove the sediment pollutants left by the waste water.

The main limitations of known systems are that the sedimentation phase requires a very long lasting life of the whole treatment cycle, often exceeding five hours, and which results in such high costs that it can only be justified if large quantities of reflux water. In particular, therefore, the disposal of waste from small industrial plants has not found a satisfactory solution to date, from the point of view of the cycle time and from the point of view of the costs it entails. In addition, in such facilities, the handling of chemical reagents that may be harmful to the health of operators is required.

The object of the present invention is therefore to overcome the drawbacks and limitations mentioned above.

Statements of Invention

The invention, as it is characterized by the claims, achieves the purpose by means of a thermal station, in which the wastewater is subjected to a heating which favours its purification.

The main advantage obtained by the present invention is essentially that the duration of the treatment cycle is drastically reduced to about one hour.

Another advantage of the invention is that the plant is particularly suitable to meet the needs for disposal of small quantities of waste water, even in the order of 100 to 500 litres. A further advantage is that the present invention provides a high cost product at very low cost.

Finally, the invention avoids manipulation of chemical reagents to benefit the health of the operators.

According to an aspect of the invention there is provided a waste water treatment plant, comprising a storage tank (1) for the water to be treated and a plurality of columns (5) containing ion-exchange resins, characterised in that it comprises a thermal station (10), interposed between the storage tank (1) and the columns (5), in which the water is subjected to temperature variations designed to reduce the organic pollutants present in it.

In a preferred embodiment of the invention said plant is characterised in that the thermal station (10) comprises a heating tank (2), transfer means (11) for transferring separate quantities of waste water from the storage tank (1) to the heating tank (2), heating means (12) located inside the heating tank (2), designed to heat the waste water to more than 50°C, a filtering device (13) for the heated waste water, designed to retain the suspended solids, a cooling tank (4), in which the temperature is brought back below 40°C.

In a preferred embodiment of the invention said plant is characterised in that the heating tank (2) comprises a discharge duct (21) for discharging to the outside vapours produced in the heating tank (2). In a preferred embodiment of the invention said plant is characterised in that the transfer means (11) comprise a pump (3) associated with a level sensor (31), which are designed to introduce predetermined quantities of waste water into the heating tank (2).

In a preferred embodiment of the invention said plant is characterised in that the heating means (12) comprise electric immersion heating elements (12'), designed to heat the waste water up to approximately 100°C.

In a preferred embodiment of the invention said plant is characterised in that the filtering device (13) comprises a nylon monofilament filter with a mesh porosity of approximately 5 μηι.

In a preferred embodiment of the invention said plant is characterised in that the thermal station (10) comprises an air heat exchanger (41) connectable to the cooling tank (4), in such a way as to create a waste water recirculating circuit for lowering its temperature to approximately 35°C.

In a preferred embodiment of the invention said plant is characterised in that the cooling tank (4) comprises an infeed duct (42), designed to introduce running water for promoting cooling of the waste water. In a preferred embodiment of the invention said plant is characterised in that the columns (5) containing ion-exchange resins comprise at least one first column (51), containing an organic resin, one second column (52), containing an activated carbon resin, one third column (53), containing a cation resin, one fourth column (54), containing an anion resin, arranged in such a way that the waste water passes through them in sequence so as to maximise the efficiency of the action of the resins. In a preferred embodiment of the invention said plant is characterised in that it comprises downstream of the columns (5), a check station (6), in which checks are carried out to verify whether or not the waste water can be discharged into the sewers.

In a preferred embodiment of the invention said plant is characterised in that the check station (6) comprises a collecting tank (61), equipped with a plurality of sensors (62, 63, 64), which are designed to detect the pH, conductivity and turbidity values of the waste water.

In a preferred embodiment of the invention said plant is characterised in that it comprises a recirculating duct (65), designed to return the waste water upstream of the columns (5), if it cannot be discharged into the sewers.

In an alternative preferred embodiment of the invention said plant optionally comprises a UV lamp (66) and /or UV lamp (67) adapted for the treatment of water with UV light. Preferably, said UV lamp emits light at a wavelength of 254 nm.

In a preferred embodiment of the invention said UV lamp (66) is adapted to treat waste water obtained from the control station (6) and discharged into the sewers. In a preferred embodiment of the invention said UV lamp (67) is adapted to treat water in the storage tank (1).

In a preferred embodiment of the invention said plant (20) comprises a control station (68) to control at least one parameter selected from the group consisting of: fluid flow parameters, level controls, alarm reception, pH analyzer, conductivity and turbidity.

In a preferred embodiment of the invention said control station (68) is controlled remotely.

According to an aspect of the invention there is provided a method for treatment of waste comprising the following steps:

- automatically loading a separate quantity of waste water from a storage tank (1) into a heating tank (2); - heating the waste water in the heating tank (2) up to temperatures of between 80 and 120 °C for a time of between 20 and 40 minutes, so as to degrade thermolabile substances and eliminate volatile substances;

- filtering the waste water arriving from the heating tank (2) through a nylon monofilament bag filter with a mesh porosity of between 3 and 7 μηι;

- cooling the filtered waste water in a cooling tank (4), where it is mixed with a quantity of running water that is between 40 and 60% of the quantity of waste water, until it reaches a temperature of between 30 and 40 °C;

- passing the cooled waste water through a sequence of columns (5) containing ion- exchange resins;

- passing the waste water arriving from the columns (5) through a check station (6), in which checks verify whether or not the waste water can be discharged into the sewers.

In a preferred method of the invention the method is characterised in that the cooling step comprises the passing of waste water through a recirculating circuit comprising the cooling tank (4) and an air heat exchanger (41), in such a way as to reduce the cooling times.

In a preferred method of the invention the method is characterised in that the cooled waste water is passed through the columns (5) according to an ordered sequence in which the waste water passes through a first column (51), containing an organic resin, then through a second column (52), containing an activated carbon resin, then through a third column (53), containing a cation resin, then through a fourth column (54), containing an anion resin, in such a way as to maximise the efficiency of the action of the resins. In a preferred method of the invention the storage tank (1) optionally comprises a UV lamp (67).

In a preferred method of the invention the waste water discharged into the sewers is optionally treated with light at a wavelength of 254 nm.

In a preferred method of the invention the waste water is not heated in the heating tank.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps. "Consisting essentially" means having the essential integers but including integers which do not materially affect the function of the essential integers.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Further advantages and features of the invention will be more apparent in the following detailed description, made with reference to the accompanying drawings, which represent a non-limiting example of execution, in which:

Figure 1 : illustrates the invention according to a perspective view of the assembly; Figure 2 - illustrates the invention in perspective view, with some parts removed to better illustrate its alterations;

Figure 3 - illustrates the invention according to a functional schematic view. A wastewater treatment plant comprises a storage tank (1) of the water to be treated and a plurality of columns (5) containing ion exchange resins, and a thermal station (10) interposed between the storage tank (1) And the columns (5), where the waters undergo temperature changes, thus reducing the organic pollutants present therein.

As can be seen in Figure 1 , the whole plant (20) has a compact footprint so that it can be housed in a container (30) of a cabin size, the maximum size of which is not more than a few meters.

As illustrated in Figures 2 and 3, the thermal station (10) comprises a heating tank (2), a transfer volume (1 1) of discrete waste water from the storage tank (1) to the heating tank (2). Means (12) located within the heating tank (2), suitable for heating waste water above 50 Celsius, a filtering device (13) of heated waste water, capable of retaining suspended solids, a Coolant tank (4), where the temperature is lower than 40 Celsius. The heating tank (2) is hermetically sealed but does not work under pressure: for this reason, it comprises a discharge duct (21) for the vapours produced inside it, which are conveyed into an activated carbon filter. The transfer means (11) comprise a pump (3) associated with a level sensor (31) so as to enter pre-determined amount of wastewater in the heating tank (2). The heating means (12) comprise immersion electric resistors (12), suitable for heating waste water up to about 100 Celsius. The filtering device (13) comprises a nylon-mesh nylon fabric filter with mesh size of about 5 μηι.

The thermal station (10) also includes, preferably, an air heat exchanger (41) connected to the cooling tank (4), so as to create a waste water recirculation circuit to lower the temperature to about 35 Celsius.

The cooling tank (4) comprises an inlet duct (42), suitable for introducing current water to facilitate the cooling of the waste water. If the amount of waste water treated at each cycle is about 50 litres, and it is advisable to add about 25 litres of running water: this allows for a rapid decrease of temperature and promotes a prolonged life of the resins, since dilution increases the efficiency of the Ion exchange.

A volt that, following recirculation between the cooling tank (4) and the heat exchanger (41), the temperature is reduced to below 35 Celsius, the waste water is started up to the columns (5) containing resins Ion exchange, where purification takes place, because the resins retain most of the pollutants present in the wastewater. The columns (5) comprise at least one first Column (51) in which there is an organic resin, a second Column (52) which contains activated carbon resin, a third Colum (53) in which there is a cationic resin, a fourth Column (54), in which there is a anionic resin, so that the waste water passes through them in sequence to maximize the efficiency of the resins themselves.

Downstream of the columns (5), there is a control station (6), where it is checked whether waste water can be drained into the sewers. The control station (6) comprises a collecting tank (61), provided with a plurality of sensors (62, 63, 64), suitable for detecting the values of PH, conduction and turbidity of waste water. From the control station (6), a recirculation duct (65) is put in order to bring the wastewater upstream of the columns (5) if they cannot be discharged into the sewers. A process for the treatment of waste water is carried out according to a sequence of phases in which at first it is automatically loaded from a storage tank (1) of a discrete amount of wastewater in a heating tank (2) followed by Heating the waste water into the heating tank (2) to temperatures between 80 and 120 ° C for a time ranging from 20 to 40 minutes, so as to degrade thermolable substances and eliminate volatile substances.

Filtering of waste water from the heating tank (2) is then carried out through a monofilament nylon filter bag with 3 to 7 μιη porous meshes: at this stage, all the solids already suspended originally in the waste water are eliminated Those that are created during the heating phase for the degradation phenomena; Follows the cooling of the filtered waste water into a cooling tank (4), where they are mixed with a quantity of running water between 40 and 60% of the amount of waste water up to a temperature of between 30 and 40 ° C. The cooling phase involves the passage of the waste water into a recirculation circuit including the cooling tank (4) and an air heat exchanger (41), so as to maintain the cooling times.

Proper purification occurs thanks to the passage of cooled waste water into a sequence of columns (5) containing ion exchange resins; Such a passage is carried out according to an oregano sequence in which the waste water passes into a first column (51), in which there is an organic resin, then in a second column (52), in which an activated carbon resin is found, A third column (53) containing a cationic resin, then a fourth column (54) containing an anionic resin, to maximize resin action efficiency. As a organic resin, it is preferable to use a resin of macroporous polystyrene resin with divinylbenzene with particles of between 400 and 1200 μηι in size, in which the quaternary ammonium groups interact with the wastewater absorbing most of the organic compounds. As active carbon, it is preferred to employ a granular active carbon with a mesh of between 8 and 30 μηι, obtained by physical activation with heat and steam of selected mineral raw materials: it has a good mechanical strength, great porosity, excellent absorbent capacity in numerous cases Organic pollutants such as surfactants, phenols, tannins and chlorine derivatives. The cationic resin is preferably made up of a divinylbenzene crosslinked polystyrene gel resin with particles of between 425 and 1200 μηι in size: the sulfonated groups interact with the waste water that yields hydrogen cations, thereby reducing the ammonium cation content of heavy metals discharged into the wastewater. As an anionic resin, a resin of macroporous polystyrene cross-linked with divinylbenzene is preferred, with a granulometry of between 300 and 1200 μηι. Quaternary ammonium groups Interact with wastewater that yields oxidic ions, reducing the anion content in wastewater. Finally, the wastewater from the colonies (5) passes to a control station (6), where it is checked whether the waste water can be drained into the sewers or must be returned to pass through the columns (5). In a preferred embodiment of the invention said whole plant (20) comprises optionally a UV lamp (66) for the treatment of waste water obtained from the control station (6) and to be discharged into the sewers.

In a further or alternative preferred embodiment said whole plant (20) comprises optionally a UV lamp (67) for the treatment of water in the storage tank (1).

In a preferred embodiment said UV lamps emit light at a wavelength of 254 nm.

The plant with UV lamps (66) and (67) are shown in figure 4. UV lamp (67) can be used alone or in combination with the thermal station (10) or in particular with the heating tank (2) depict in figure 4. UV treated water flows from the storage tank (1) to the heating tank (2) into the cooling tank(4) and then further onto the columns (5); however the water may optionally not heated after UV treatment.ln a preferred embodiment of the invention said whole plant (20) is managed remotely to set up and control at least one parameter selected from the group consisting of fluid flow parameters, level controls, alarm reception, pH analyzer, conductivity and turbidity. In a further preferred embodiment of the invention said remote control comprises also monitoring said at least parameter and treated quantity.

The attached charts also show, from a quantitative point of view, the effectiveness of the implant (20) and the process described above.

They show the results of the analysis carried out on 22 samples of wastewater in relation to some significant parameters measured before and after treatment.

Graph A refers to the measurement of C.O.D. (Chemical oxygen demand), which is the most important parameter for determining whether a liquid reflux can be re-entered into the environment: the upper acceptable limit is estimated at 500 milligrams per litre. The table associated with graph A shows, according to the order of the samples examined, the COD values, at the beginning and end of the treatment, and the percentage of abatement, in addition to the acceptable limit.

Graph B covers the amount of non-ionic surfactants present in the waste water before and after treatment. Graph C covers conductivity, while D and E graphs refer respectively to dissolved solids and suspended solids in wastewater. The tables associated with these graphs represent.

Examples

For some application (example drinking water) the phase of boiling and cooling liquid it is not necessary. Before treatment with resin, 2 UV lamps are installed, for the sterilization of fluid. One is positioned between source for loading and loading tank, in this way there is a pretreatment before flow in the resins, the second lamp is positioned after columns and before the final tank , to ensure a decrease of eventually bacteria charge before use of fluid. UV Lamps have the function of eliminating various types of microorganisms by the action of ultraviolet germicidal radiation (UV-C 254 nm). This system is capable of performing effective disinfection of the water to be treated without the addition of chemicals (eg chlorine disinfectants, etc.)

The use of UV rays allows a disinfection process that does not alter the odor, flavor and pH of the treated water. Ultraviolet light are indicated in particular for:

• Disinfection of well water, tank water, disinfection of source water that has microbial contamination such as viruses, bacteria (eg escherichia coli, conforms, etc.) and other microorganisms of various types, molds and spores, etc .

• after water treatment, such as downstream of activated carbon filtration systems, reverse osmosis units, etc.

• Water disinfection reverse osmosis plants

• Water disinfection for aqueduct waters

Remote control software

Software was developed that allows the remote control of the equipment. All instrumental features can be managed remotely. The specific functions are: set up of all fluid flow parameters, level controls, alarm reception, pH analyser, conductivity and turbidity onli Daily sending of cycles performed with all the parameters analysed and treated quantity.

Claims

1. A waste water treatment plant, comprising a storage tank (1) for the water to be treated and a plurality of columns (5) containing ion-exchange resins, characterised in that it comprises a thermal station (10), interposed between the storage tank (1) and the columns (5), in which the water is subjected to temperature variations designed to reduce the organic pollutants present in it.

2. The plant according to claim 1 , characterised in that the thermal station (10) comprises a heating tank (2), transfer means (11) for transferring separate quantities of waste water from the storage tank (1) to the heating tank (2), heating means (12) located inside the heating tank (2), designed to heat the waste water to more than 50°C, a filtering device (13) for the heated waste water, designed to retain the suspended solids, a cooling tank (4), in which the temperature is brought back below 40°C.

3. The plant according to claim 2, characterised in that the heating tank (2) comprises a discharge duct (21) for discharging to the outside vapours produced in the heating tank (2).

4. The plant according to claim 2, characterised in that the transfer means (11) comprise a pump (3) associated with a level sensor (31), which are designed to introduce predetermined quantities of waste water into the heating tank (2).

5. The plant according to claim 2, characterised in that the heating means (12) comprise electric immersion heating elements (12'), designed to heat the waste water up to approximately 100°C.

6. The plant according to claim 2, characterised in that the filtering device (13) comprises a nylon monofilament filter with a mesh porosity of approximately 5 μηι.

7. The plant according to claim 2, characterised in that the thermal station (10) comprises an air heat exchanger (41) connectable to the cooling tank (4), in such a way as to create a waste water recirculating circuit for lowering its temperature to approximately 35°C.

8. The plant according to claim 2, characterised in that the cooling tank (4) comprises an infeed duct (42), designed to introduce running water for promoting cooling of the waste water.

9. The plant according to claim 1 or 2, characterised in that the columns (5) containing ion-exchange resins comprise at least one first column (51), containing an organic resin, one second columns (52), containing an activated carbon resin, one third column (53), containing a cation resin, one fourth columns (54), containing an anion resin, arranged in such a way that the waste water passes through them in sequence so as to maximise the efficiency of the action of the resins.

10. The plant according to claim 1 or 2, characterised in that it comprises it comprises, downstream of the columns (5), a check station (6), in which checks are carried out to verify whether or not the waste water can be discharged into the sewers.

11. The plant according to claim 10, characterised in that the check station (6) comprises a collecting tank (61), equipped with a plurality of sensors (62, 63, 64), which are designed to detect the pH, conductivity and turbidity values of the waste water.

12. The plant according to claim 10, characterised in that it comprises a recirculating duct (65), designed to return the waste water upstream of the columns (5), if it cannot be discharged into the sewers.

13. The plant according to claim 1 wherein said plant comprises optionally UV lamp (66) and /or UV lamp (67) for the treatment of water with UV light.

14. The plant according to claim 13 wherein said UV lamp emits light at a wavelength of 254 nm.

15. The plant according to claim 14 wherein said UV lamp (66) is designed to treat waste water obtained from the control station (6) and discharged into the sewers.

16. The plant according to claim 14 wherein said UV lamp (67) is designed to treat water in the storage tank (1).

17. The plant according to claims 1-16 wherein said plant (20) comprises a control station (68) to control at least one parameter selected from the group consisting of fluid flow parameters, level controls, alarm reception, pH analyzer, conductivity and turbidity.

18. The plant according to claim 17 wherein said control station (68) is controlled remotely.

19. A waste water treatment method, characterised in that it comprises the following steps: i) automatically loading a separate quantity of waste water from a storage tank (1) into a heating tank (2);

ii) heating the waste water in the heating tank (2) up to temperatures of between 80 and 120 °C for a time of between 20 and 40 minutes, so as to degrade thermolabile substances and eliminate volatile substances;

iii) filtering the waste water arriving from the heating tank (2) through a nylon monofilament bag filter with a mesh porosity of between 3 and 7 μηι;

iv) cooling the filtered waste water in a cooling tank (4), where it is mixed with a quantity of running water that is between 40 and 60% of the quantity of waste water, until it reaches a temperature of between 30 and 40 °C;

v) passing the cooled waste water through a sequence of columns (5) containing ion-exchange resins;

vi) passing the waste water arriving from the columns (5) through a check station (6), in which checks verify whether or not the waste water can be discharged into the sewers.

20. The method according to claim 19, characterised in that the cooling step comprises passing the waste water through a recirculating circuit comprising the cooling tank (4) and an air heat exchanger (41), in such a way as to reduce the cooling times.

21. The method according to claim 19 or 20, characterised in that the cooled waste water is passed through the columns (5) according to an ordered sequence in which the waste water passes through a first column (51), containing an organic resin, then through a second column (52), containing an activated carbon resin, then through a third column (53), containing a cation resin, then through a fourth column (54), containing an anion resin, in such a way as to maximise the efficiency of the action of the resins.

The method according to claim 18 wherein the storage tank (1) optionally comprises UV lamp (67).

The method according to claims 22 wherein the waste water discharged into the sewers is treated by UV irradiation.

24. The method according to any one of claims 18 to 23 wherein the waste water is not heated in the heating tank but alternatively said water is treated by UV irradiation.