WASTEWATER TREATMENT APPARATUS

Abstract

An apparatus for the treatment of wastewater having: a primary treatment module with at least one solids separation filter; a secondary treatment module with at least one microflotation unit and at least one oxidation treatment unit placed downstream of the at least one microflotation unit, the at least one oxidation treatment unit has an advanced oxidation process module for performing chemical processes, the advanced oxidation process module performing an ozone and hypochlorite treatment; a tertiary treatment module including at least one membrane filtration unit; the apparatus provided with sequentially flowing wastewater from the primary treatment module, through the secondary treatment module, and to the tertiary treatment module. A method for wastewater treatment in an apparatus having as sequentially treating wastewater through the primary treatment module, the secondary treatment module, and the tertiary treatment module.

Claims

1. An apparatus for the treatment of wastewater comprising the following elements: (i) a primary treatment module comprising at least one solids separation filter; (ii) a secondary treatment module comprising at least one microflotation unit and at least one oxidation treatment unit placed downstream of said at least one microflotation unit, wherein said at least one oxidation treatment unit comprises an advanced oxidation process module for performing chemical processes, said advanced oxidation process module performing an ozone and hypochlorite treatment; (iii) a tertiary treatment module including at least one membrane filtration unit; said apparatus being provided with means for sequentially flowing wastewater from element (i) to (iii).

2. The apparatus according to claim 1 wherein said advanced oxidation process module performs said ozone treatment and said hypochlorite treatment sequentially.

3. The apparatus according to any one of claim 1 or 2 wherein said at least one microflotation unit comprises one or more microflotation systems including a microbubble generator and a float tank containing wastewater, said microbubble generator being configured to inject a pressurized water/microbubble mixture into said float tank.

4. The apparatus according to any one of claims 1 to 3 wherein the at least one oxidation treatment unit further comprises at least one ozone treatment module, a hydrogen peroxide treatment module or an electrochlorination module, taken alone or in combination.

5. The apparatus according to any one of claims 1 to 4 wherein said advanced oxidation process module further performs any of the following chemical processes, taken alone or in combination: ozone and hydrogen peroxide treatment, or a Fenton process treatment.

6. The apparatus according to any one of claims 1 to 5 wherein the at least one membrane filtration unit comprises one or more ultrafiltration units.

7. The apparatus according to claim 6 wherein said tertiary treatment module further comprises at least one reverse osmosis filter or nanofiltration unit downstream of said one or more ultrafiltration units.

8. The apparatus according any one of claims 1 to 7 wherein said tertiary treatment module further comprises at least one UV disinfection unit downstream of said membrane filtration unit(s).

9. The apparatus according to any one of claims 1 to 8 further comprising a sludge treatment unit connected to said secondary treatment module by means for delivering sludge from said secondary treatment module into said sludge treatment unit.

10. The apparatus according to any one of the preceding claims further comprising at least one wastewater collecting unit connectable with a discharge of wastewater and situated upstream of said primary treatment module; means for flowing wastewater from said at least one wastewater collecting unit to said primary treatment module.

11. The apparatus according to any one of the preceding claims wherein the total suspended solids removed from wastewater downstream of said secondary treatment module is equal to or greater than 90%, calculated as secondary treatment module inlet versus secondary treatment module outlet.

12. The apparatus according to claim 11 wherein the total suspended solids removed from wastewater downstream of said tertiary treatment module is equal to or greater than 95% with respect to the total suspended solids content in the primary treatment module influent.

13. A method for wastewater treatment in an apparatus according to any one of claims 1 to 12 comprising sequentially treating wastewater through said primary treatment module, said secondary treatment module, and said tertiary treatment module.

14. The method according to claim 13 wherein the method is performed on a vessel and comprises the additional subsequent step of discharging overboard the treated wastewater downstream of said tertiary treatment module.

15. The method according to claim 13 comprising the additional subsequent step of recycling at least part of the treated wastewater downstream of said tertiary treatment module as technical water.

16. The method according to claim 13 comprising the additional subsequent step of recycling at least part of the treated wastewater downstream of said tertiary treatment module as potable water, where said tertiary treatment module comprises at least one reverse osmosis filter or nanofiltration unit downstream of said ultrafiltration unit.

17. The method according to claim 13 wherein wastewater is sequentially fed to and from each said primary, secondary and tertiary treatment module in a continuous fashion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The invention may be understood by reference to the preceding description taken in conjunction with the accompanying figures.

[0073] FIG. 1 schematically shows an apparatus for the treatment of wastewater, in accordance with a first embodiment of the present invention;

[0074] FIG. 2 schematically shows an apparatus for the treatment of wastewater, in accordance with a second embodiment of the present invention;

[0075] FIG. 3 schematically shows a preferred embodiment of the microflotation unit of the apparatus of FIG. 2;

[0076] FIG. 4 schematically shows a cross-sectional view of the float tank of FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS

[0077] The figures shall be understood to be schematic illustrations of the invention: the number of parts showcased therein and/or their relative dimensions and proportions are not depicted true to life, but arranged and sized only for clarity and convenience purposes.

[0078] In the following figures, identical reference numerals denote parts performing the same or substantially the same function.

[0079] FIG. 1 illustrates an apparatus for the treatment of wastewater comprising the following elements: a primary treatment module (100) that performs a primary solids separation, a secondary treatment module (200) that performs a further solids separation via microflotation and an oxidation treatment, and a tertiary treatment module (300) that performs a post-filtration treatment, also known as polishing. An optional wastewater collecting unit (400), connectable with a discharge of wastewater, is also shown. The optional unit (400) and the modules (100, 200, 300) are sequentially connected, respectively, by means (401, 101, 201). These may be conduits or piping suitable for sequentially flowing wastewater from one element to the next. The wastewater to be treated enters the apparatus via means (010) and is discharged after the tertiary treatment step via conduit (301).

[0080] FIG. 2 depicts an embodiment of the apparatus for the treatment of wastewater that may be advantageously used, for instance, on board of vessels. The wastewater collecting unit (400) consists of a grey water collecting unit (410) and a black water collecting unit (420) respectively connected with a discharge of grey water and a discharge of black water through means (011, 012).

[0081] Both collecting units (410, 420) are connected to the solids separation unit (110), containing one or more solids separation filters, of the primary treatment module (100). The solids separation unit (110) is connected to the microflotation unit (210), which in turn feeds the effluent to the oxidation treatment unit (220) of the secondary treatment module (200). The latter is connected to a membrane filtration unit (310) located upstream of a reverse osmosis filter (320), of the tertiary treatment module (300). After the tertiary treatment, the purified water may be discharged overboard via appropriate means (321) or reused as technical or potable water. The microflotation unit (210) may be further connected to an optional sludge treatment unit (230) to reduce the water content in the sludge, to facilitate its handling and disposal.

[0082] As shown schematically in FIG. 3, the microflotation unit 210 comprises a microbubble generator 211 and a float tank 212. The microbubble generator 211 is a pressurized water tank receiving water via line 213. Air is injected into the microbubble generator 211 via one or more lines 214 which terminate in suitable nozzles within the microbubble generator 211 in order to generate a mixture of pressurized water and microbubbles where the microbubbles have sizes predominantly in the range of 10-80 μm, preferably in the range of 30-70 μm. The pressurized water/microbubble mixture is transferred to float tank 212 via line 215. Float tank 212 receives wastewater from the primary treatment unit 100 via line 216 and discharges the treated wastewater to the oxidation treatment unit 220 via line 217. The skimmed microbubbles with attached solids are transferred to the sludige treatment unit 230 via line 218.

[0083] FIG. 4 shows a schematical cross-sectional view of float tank 212. As can be taken from FIG. 4, wastewater from the primary treatment unit enters the float tank via line 216 which is arranged above the entrance of the pressurized water/microbubble mixture which enters float tank 212 via line 215 from the microbubble generator 211 of FIG. 3. A vertically slanted baffle 219 arranged within float tank 212 ensures an intimate mixture of incoming wastewater with the injected microbubbles. Microbubbles with adhering solids are skimmed from the water surface in the upper region of the float tank 212 and discarded via line 218 to the sludge treatment unit 230 of FIG. 2. Treated wastewater is discarded via line 217 to the oxidation treatment unit 220 of FIG. 2.

[0084] In the context of the present application, with the term “module” or “element” it is not necessarily meant a physical enclosure containing one or more units performing specific tasks for treating wastewater. The terms may also refer to a physical space where a unit, or an assembly of units of same or different kind, is located, and perform the tasks described in connection to that “module” or “element”. The “module” or “element” may consist of the single unit or of a set of inter-connected units.

[0085] The following examples are included to demonstrate particular ways of reducing the invention to practice, whose practicability has been largely verified in the claimed range of values.

[0086] It should be appreciated by those of skill in the art that the equipment, compositions and techniques disclosed in the following represent equipment, compositions and techniques discovered by the inventor to function well in the practice of the invention; however, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the scope of the invention.

EXAMPLE

[0087] An apparatus for the treatment of wastewater was installed on a cruise ship for treating black and grey water in an amount of 1000 cubic meters per day.

[0088] The apparatus comprised a wastewater collecting unit receiving black water and grey water form a ships double bottom tanks and consisting of a black water container and grey water container. Each container was connected to the primary treatment module by feed pumps which fed the water to be treated to two solids separation filters of the screen press kind, with 250 microns mesh

[0089] The effluent from the solids separation presented a reduction of the amount of TSS of 50% and underwent the secondary treatment step. The effluent was fed to 4 microflotation units, each unit being able to treat 10 cubic meters per hour, and then to an oxidation treatment unit. The oxidation unit performed a multi injection of ozone and hypochlorite.

[0090] Form the oxidation unit, the effluent water was fed to the tertiary treatment: it was conveyed into an ultrafiltration unit comprising ceramic membranes and a nanofiltration unit.

[0091] The apparatus was operated for 4 months with a throughput flow rate of 40 cubic meters per hour.

[0092] No fouling of the ultrafiltration membrane was observed and the TSS removed from wastewater was measured to be>99% downstream of the secondary and the tertiary treatment module, and 99% downstream of the tertiary treatment module.

[0093] The treated wastewater was analysed and the performance in regards to the presence of common contaminants is reported in TABLE 1.

TABLE-US-00001 TABLE 1 Primary Secondary Tertiary treatment treatment treatment effluent effluent effluent [ppm] [ppm] [ppm] Influent [% reduction [% reduction [% reduction [ppm] vs influent] vs influent] vs influent] TSS 830 269 5 <5 67.5% >99% >99% COD 1124 487 69 37 (hom.) 56.6% 93.8% >96% BOD 636 364 17 5 42.7% 97.3% >99%

[0094] The previous description shall not be intended as limiting the invention, which may be used according to different embodiments without departing from the scopes thereof, and whose extent is solely defined by the appended claims.

[0095] Throughout the description and claims of the present application, the term “comprise” and variations thereof such as “comprising” and “comprises” are not intended to exclude the presence of other elements, components or additional process steps.

[0096] The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention before the priority date of each claim of this application.