IT202100016640A1 - FILTER MODULE AND WASTE TREATMENT PLANT INCLUDING AT LEAST THE SAID FILTER MODULE - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

?FILTER MODULE AND WASTE TREATMENT PLANT INCLUDING AT LEAST THE SAID FILTER MODULE?

The present invention ? relating to a filter module and a wastewater treatment plant comprising at least said filter module.

Preferably, the present invention finds application in the sector of the treatment of wastewater from the digestate obtained in biogas or biomethane production plants.

Biogas or biomethane production plants are normally fueled with biomass. Among the biomasses used for the production of biogas or biomethane we find FORSU (Organic Fraction of Urban Solid Waste). The OFMSW? substantially the material obtained from the differentiated collection of organic waste and includes food residues or food preparations and similar fractions, such as for example food paper soiled with food residues.

OFMSW is normally accumulated in suitable structures called digesters (or fermenters) in which an anaerobic fermentation takes place which determines the generation of biogas.

The residue resulting from the fermentation process in the digester is normally referred to as digestate.

The digestate deriving from OFMSW? a semi-solid material that pu? be exploited as a fertilizing material.

However, before proceeding with the use of the digestate ? it is preferable to carry out some treatments aimed at obtaining a material suitable for composting or even for disposal.

These treatments produce contaminated water that cannot be used. be disposed of in the traditional way. There? leads to high disposal costs for digestate treatment plants.

? therefore an object of the present invention is to provide a filtering module capable of treating the digestate effectively, concentrating the polluting substances in a small volume and producing easily purified aqueous by-products so that they can be disposed of through traditional discharge systems.

In accordance with these purposes, the present invention ? relating to a filter module for a wastewater treatment plant comprising a casing and a main body housed in the casing; the main body extending along a longitudinal axis and being configured so as to define at least a first channel for the passage of the wastewater to be filtered in a first direction of advancement; the main body being made of a macroporous material such as to allow the passage, through it, of at least a fraction of the permeate of the waste and block the passage of a fraction of the concentrate of the waste.

? furthermore, a further object of the present invention is to provide a digestate treatment plant capable of solving the problems of the known art, significantly reducing the disposal costs of the treatment by-products.

In accordance with these purposes, the present invention ? relating to a plant as claimed in claim 11.

Further characteristics and advantages of the present invention will become clear from the following description of a non-limiting embodiment thereof, with reference to the figures of the accompanying drawings, in which:

? figure 1 ? a schematic representation, with parts cut away for clarity, of a digestate treatment plant according to the present invention;

? figure 2 ? a schematic perspective representation, with parts in section and parts removed for clarity, of a detail of the system of figure 1 comprising the filtering module according to the present invention;

? figure 3 ? a perspective schematic representation, with parts removed for clarity, of a detail of the filter module of figure 2;

? figure 4 ? a schematic representation, with parts in section and parts removed for clarity, of a detail of the system of figure 1 comprising the filtering module according to a variant of the present invention;

? figure 5 ? a schematic perspective representation, with parts removed for clarity, of a detail of the filter module of figure 4.

In figure 1 ? reference number 1 indicates a wastewater treatment plant.

In the non-limiting example described and illustrated here, the plant 1 ? configured to treat digestate, for example resulting from the fermentation process in the digester of a biogas plant (not shown).

The plant 1 ? then connected to a wastewater source 2.

Wastewater source 2 can? be a digester or a tank fed by a digester.

In the non-limiting example described and illustrated here, the waste water source 2 ? a tank fed by the digester, after a pre-treatment with a screw separator or centrifuge or vibrating screen.

Plant 1 comprises a main filtering station 4, a terminal refining station 5 (?final polishing?) and, preferably, auxiliary filtering stations 6 arranged between the main filtering station 4 and the terminal refining station 5.

In the non-limiting example described and illustrated here, there are two auxiliary filtering stations 6 and they are arranged in series with the main filtering station 4, as we will see in more detail. after you.

Preferably, between the main filtering station 4 and the subsequent auxiliary filtering station 6? provided a first tank 7a for collecting the permeate coming from the main filtering station 4 and between the auxiliary filtering stations 6? a second tank 7b is provided for collecting the permeate coming from the auxiliary filtering station 6 located immediately downstream of the main filtering station 4.

Preferably, downstream of the main filter station 4? a device 13a is provided for the controlled dosing of sulfuric acid (H2SO4). In particular, the sulfuric acid is released by regulating a metering pump 13b. The controlled dosing of sulfuric acid improves the filtration of the main filter station 4 and prevents limescale deposits in the subsequent filter stations. Furthermore, the controlled dosage of sulfuric acid allows the formation of ammonium sulphate, thus enriching the the concentrated harvest that pu? be used in compost.

With reference to Figure 1 and Figure 2, the main filtering station 4 comprises a filtering circuit 8 provided with at least one filtering module 9 provided with an inlet 10a and an outlet 10b, a delivery line 11, which connects the inlet 10a of the filter module 9 to the waste water source 2, at least one delivery pump 12, arranged along the delivery line 11, at least one permeate collection line 14 connected to at least one filter module 9, at least one concentrate collection line 15 connected to the output 10b of the filtering module 9, and a recirculation line 16 which connects, as we will see in more detail? forward, the output 10b of the filter module 9 to the delivery line 11.

In particular, the permeate sampling line 14 ? connected to an auxiliary output 17 of the filtering module.

With reference to figure 2, the filter module 9 (schematically represented) extends along a longitudinal axis A and comprises a casing 20 and a main body 21 housed in the casing 20.

The main body 21 ? configured so as to define at least a first channel 23 for the passage of the wastewater to be filtered in a first direction of advancement and ? made of a macroporous material such as to allow the passage, through it, of at least a fraction of the permeate of the waste and block the passage of a fraction of the concentrate of the waste.

Is the concentrate blocked by the filter module 9 ? mostly composed of suspended solids, colloidal fractions and organic substances.

Preferably, the first channel 23 ? placed parallel to the longitudinal axis A.

The casing 20 ? equipped with the auxiliary outlet 17 connected to the permeate sampling line 14.

In the non-limiting example described and illustrated here, the main body 21 is endowed with a plurality of first channels 23 arranged side by side and parallel to each other.

In other words, in the main body 21 ? obtained a plurality? of first channels 23.

Each first channel 23 ? provided with an input 24 and an output 25.

The filter module 9 ? preferably provided with a head chamber 27, which ? connected to the delivery line 11 and ? fed with the wastewater to be filtered and with a terminal chamber 28, which ? connected to the concentrate collection line 15.

In the example of figures 1 and 2, the head chamber 27 ? in fluidic communication with the input 24 of the first channels 23 and the terminal chamber 28 ? in fluidic communication with exit 25 of the first channels 23.

With reference to figure 3, each first channel 23 ? provided with an internal coating 30, which covers the internal surface of the first channel 23.

The inner lining 30 ? also macroporous and, preferably, comprises titanium oxide.

The porosity? of the internal coating 30 varies according to the needs between 0.01 micron and 0.1 micron.

The thickness of the inner lining 30 ranges from 13 to 21 microns.

The inner lining 30 ? preferably deposited by sintering on the inner surface of each channel 23.

Advantageously, the internal lining 30 gives a high resistance to the abrasive phenomena caused by the suspensions present in the wastewater at high speeds. ring roads.

The main body 21 macroporous ? preferably made of a stainless steel alloy.

The casing 20 ? also preferably made of stainless steel.

Preferably, each first channel 23 has an internal diameter of between 16mm and 22mm, preferably between 18mm and 20mm.

The head chamber 27 and the end chamber 28 are coupled to the casing 20 so as to avoid the use of gaskets.

In use, the passage of waste under pressure in each first channel 23 determines the passage of at least a fraction of permeate through the internal surface of the first channel 23 and the blockage of at least a fraction of concentrate inside the first channel 23. The fraction of concentrate is then conveyed towards the outlet 25 of each first channel 23 and collected by the concentrate collection line 15.

The fractions of permeate which have passed through the walls of the first channels 23 are conveyed into the permeate collection line 14.

Advantageously, the main filtering station 4 operates automatically with continuous discharge of the concentrated fraction and the permeate fraction.

In figures 5 and 6 ? illustrated is a second embodiment of a filter module 109 according to the present invention.

In figures 5 and 6 the same reference numerals will be maintained to indicate identical or similar parts to the embodiment illustrated in figure 2.

The filter module 109 of figure 4 comprises a main body 121 and a casing 120 which houses the main body 121.

Essentially, the filter module 109 differs from the filter module 9 of Figure 2 in that the main body 121 comprises at least one first channel 123 and at least one second channel 124. The first channel 123 is configured in such a way that the passage of the wastewater to be filtered takes place in a first feed direction D1, while the second channel 124 ? configured in such a way that the passage of the wastewater to be filtered takes place in a second direction of advance D2, preferably opposite to the direction of advance D1.

1. The second channel 124 ? in fluid connection with the first channel 123. In particular, the second channel 124 is configured so as to be fed with the wastewater coming out of at least one first channel 123.

The main body 121 ? made of a macroporous material such as to allow the passage, through it, of at least a fraction of the permeate of the waste and block the passage of a fraction of the concentrate of the waste.

Is the concentrate blocked by the 109 filter module? mostly composed of suspended solids, colloidal fractions and organic substances.

Preferably, the filter module 109 comprises a plurality of of first channels 123 and a plurality? of second channels 124.

Preferably the first channels 123 are arranged side by side and parallel to the longitudinal axis A and the second channels 124 are arranged side by side and parallel to the longitudinal axis A.

The casing 120 ? equipped with the auxiliary outlet 17 connected to the permeate sampling line 14.

Each first channel 123 ? provided with an input 126 and an output 127.

Each second channel 124 provided with an input 128 and an output 129.

In figure 4 ? represented, for simplicity? display, only one first channel 123 and only one second channel 124. Figure 5 shows the plurality of channels 123 and the plurality? of second channels 124.

The 109 filter module? preferably provided with a head chamber 130, which ? provided with a separator septum 131 so as to define an inlet section 133 of the head chamber 130 and an outlet section 134 of the head chamber 130.

The input section 133 and the output section 134 are not directly connected to each other.

The inlet section 133 of the head chamber 130 ? fluidically connected to the inputs 126 of the first channels 123 and the output section 134 of the head chamber 130 ? fluidly connected to the outputs 129 of the second channels 124.

The input section 133 ? connected to the delivery line 11 via input 10a and ? fed with the wastewater to be filtered and the outlet section 134 ? connected to the concentrated collection line 15 through the outlet 10b.

The 109 filter module? further provided with an end chamber 138, which ? in fluidic communication with the outputs 127 of the first channels 123 and the inputs 128 of the second channels 124.

In other words, the terminal chamber 138 puts the first channels 123 in serial communication with the second channels 124.

The first channels 123 and the second channels 124 are provided with an internal coating (not visible in figures 4 and 5), which covers the internal surface respectively of the first channels 123 and of the second channels 124.

The internal coating of the first channels 123 and of the second channels 124 ? similar to the one shown in figure 3 and ? also macroporous and, preferably, comprises titanium oxide.

The porosity? of the internal coating varies according to the needs between 0.01 micron and 0.1 micron.

The thickness of the internal lining varies from 13 to 21 microns.

The internal coating of the first channels 123 and of the second channels 124 ? preferably sintered on the inner surface of each channel 123 and 124.

Preferably, the first channels 123 and the second channels 124 have an internal diameter between 16mm and 22mm, preferably between 18mm and 20mm.

The head chamber 130 and the end chamber 138 are coupled to the casing 120 so as to avoid the use of gaskets.

In use, the waste under pressure coming from the delivery line 11 reaches the inlet section 133 of the head chamber 130, cross each first channel 123, flow into the terminal chamber 138 to then cross each of the second channels 124 and discharge into the outlet section 134 of the head chamber 130.

The passage of waste under pressure in the first channels 123 and in the second channels 124 determines the passage of at least a fraction of permeate through the internal surface of the first channels 123 and of the second channels 124 and the blockage of at least a fraction of concentrate inside the first channels 123 and second channels 124.

The fraction of concentrate leaving the outlet section 134 of the head chamber 130 is then withdrawn from the concentrate collection line 15.

The fractions of permeate which have passed through the walls of the first channels 123 and of the second channels 124 are conveyed into the permeate collection line 14.

Referring again to Figure 1, the concentrate fraction collected by the concentrate collection line 15 is accumulated in a dedicated tank 35.

The permeate fraction collected from the permeate withdrawal line 14 is conveyed to the first tank 7a and from here fed to the auxiliary filtering station 6. The auxiliary filtering station 6 fed by the first tank 7a comprises a pump 36a and at least one filter 37a.

The 37a filter? configured to block any concentrate present in the permeate leaving the main filtering station 4. In particular, the filter 37a blocks any low molecular weight organic and non-organic substances, including any ammonia present.

The concentrate blocked by the filter 37a is fed to the tank 35, while the permeate is fed to the second tank 7b

The second tank 7b feeds the last auxiliary filtering station 6, which is preferably substantially identical to the auxiliary filtering station fed by the tank 7a. In particular, the auxiliary filtering station fed by the tank 7b comprises a pump 36b and two filters 37b arranged in series and configured to block any organic and non-organic substances that may still be present. The concentrate blocked by the filters 37b is fed to the tank 35, while the permeate is fed to the final refining station 5.

The filters 37 can be polymeric membranes, for example, spiral.

The terminal refining station 5 comprises a system for controlling the ammonia concentration levels in the permeate and a chlorination system (not shown). If the ammonia value detected in the inlet permeate exceeds a threshold value, the permeate is conveyed to the chlorination system where oxidation takes place via hypochlorite and filtering (preferably with activated carbon) for the removal of residual chlorine. The terminal refining station 5 also comprises, at the input, a PH sensing system. On the basis of the measured PH, the final refining station 5 regulates a dosing pump for the dosing of sodium chloride 38 (NaCl) arranged upstream of the final refining station 5.

The permeate cos? treated, then, ? ready to be discharged into traditional drainage systems, reused for industrial uses or discharged into surface waters, being compliant with the rules currently in force.

Advantageously, thanks to the present invention, the by-products deriving from the digestate effluents can be disposed of in a simple and economic way.

The concentrate accumulated in tank 35 can be used as a fertilizer, while the permeate can? be discharged into traditional drainage systems, reused for industrial uses or discharged into surface waters in a controlled manner and without any environmental risk.

The plant 1 ? furthermore provided with a washing system 40, which ? configured to convey pressurized water upstream into the filter modules 9 or 109 of the main filter station 4. Preferably, the washing system 40 comprises a tank 41 in which accumulated the washing fluid, a pump 42 and a delivery line 43, which connects the tank 41 with the permeate withdrawal line 14.

The flushing fluid? preferably water.

Preferably, the washing system 40 is activated when the pressure difference detected between the inlet 10a of the filter module 9, 109 and the outlet 10b of the filter module 9, 109 is ? below a certain threshold value.

Advantageously, the plant according to the present invention does not produce sludge. The result is a competitive process in terms of management costs, aimed at respecting the environment and safe from a hygienic-sanitary point of view also for the people in charge of managing the system.

Furthermore, the filter module 9, 109 according to the present invention can subjected to extreme washing and processing conditions. For example can? withstand a pH range of 0-14 and temperatures up to 177?C.

Finally, the particular structure of the filter module 9, 109 guarantees high resistance to thermal or mechanical shocks during operation and guarantees the absence of product losses caused by leakage or degradation of the sealing gaskets, thanks to the construction which provides for the total absence of gaskets polymeric.

Finally, it is clear that modifications and variations can be made to the apparatus and method described herein without departing from the scope of the appended claims.

Claims (13)

1. Filter module (9; 109) for a wastewater treatment plant (1) comprising a casing (20; 120) and a main body (21; 121) housed in the casing (20; 120); the main body (21; 121) extending along a longitudinal axis (A) and being configured so as to define at least a first channel (23; 123) for the passage of the wastewater to be filtered in a first advance direction (D1); the main body (21; 121) being made of a macroporous material such as to allow the passage, through it, of at least a fraction of the permeate of the waste and block the passage of a fraction of the concentrate of the waste. The filter module according to claim 1, wherein the main body (121) is configured to define at least one second channel (124); the second channel (124) being configured so as to be fed with the wastewater leaving the at least one first channel (123). The filter module according to claim 2 comprising an end chamber (138), which is in fluid communication with an output (127) of the at least one first channel (123) and with an input (128) of the at least one second channel (124). 4. Filtering module according to claim 2 or 3, comprising a head chamber (130) provided with a separator septum (131) configured to define an inlet section (133) of the head chamber (130) fluidically connected to an inlet ( 126) of the at least one first channel (123) and an outlet section (134) of the head chamber (130) fluidically connected to an outlet (129) of the at least one second channel (124). The filter module according to any one of claims 2 to 4, wherein the at least one second channel (124) is? configured to allow the passage of wastewater in a second advance direction (D2), opposite to the first advance direction (D1). 6. Filter module according to any one of the preceding claims, wherein the at least one first channel (23; 123) is? arranged along a direction parallel to the longitudinal axis (A). The filter module according to any one of claims 2 to 6, wherein the at least one second channel (124) is? substantially parallel to the first channel (123). 8. Filter module according to any one of the preceding claims, wherein the at least one first channel (23; 123) is? provided with an internal lining (30), which covers the internal surface of the first channel (23; 123); the inner coating (30) comprising titanium oxide. 9. Filter module according to any one of the preceding claims, wherein the main body (21; 121) is? made of a stainless steel alloy. 10. Filter module according to any one of the preceding claims, wherein the at least one first channel (23; 123) has an internal diameter between 16mm and 22mm, preferably between 18mm and 20mm. 11. Wastewater treatment plant, preferably from digestate, comprising at least one main filtering station (4) connected to a wastewater source (2); wherein the main filtering station comprises a filtering circuit (8) equipped with: - at least one filter module (9; 109) of the type claimed in any one of the preceding claims and provided with an inlet (10a) and an outlet (10b); - at least one delivery line (11) which connects the inlet (10a) of the filtering module (9; 109) to the waste water source (2); - at least one delivery pump (12), arranged along the delivery line (11); - at least one permeate withdrawal line (14) connected to the at least one filter module (9; 109) and configured to withdraw the at least one fraction of permeate from the filter module (9; 109); And - at least one collection line (15), connected to the outlet (10b) of the filter module (9; 109) and configured to collect the at least one fraction of concentrate leaving the at least one filter module (9: 109). 12. Plant according to claim 11, wherein the filtering circuit (8) comprises a recirculation line (16) which connects the outlet (10b) of the filtering module (9; 109) to the delivery line (11). 13. Plant according to claim 11 or 12, comprising at least one auxiliary filtering station (6) fed at least with the permeate fraction taken from the permeate withdrawal line (14).